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Fauzia KA, Effendi WI, Alfaray RI, Malaty HM, Yamaoka Y, Mifthussurur M. Molecular Mechanisms of Biofilm Formation in Helicobacter pylori. Antibiotics (Basel) 2024; 13:976. [PMID: 39452242 PMCID: PMC11504965 DOI: 10.3390/antibiotics13100976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2024] [Revised: 10/11/2024] [Accepted: 10/12/2024] [Indexed: 10/26/2024] Open
Abstract
BACKGROUND Biofilm formation in Helicobacter pylori (H. pylori) helps bacteria survive antibiotic exposure and supports bacterial colonization and persistence in the stomach. Most of the published articles have focused on one aspect of the biofilm. Therefore, we conducted the current study to better understand the mechanism of biofilm formation, how the biofilm contributes to antibiotic resistance, and how the biofilm modifies the medication delivery mechanism. METHODS We conducted a literature review analysis of the published articles on the Helicobacter pylori biofilm between 1998 and 2024 from the PubMed database to retrieve eligible articles. After applying the inclusion and exclusion criteria, two hundred and seventy-three articles were eligible for our study. RESULTS The results showed that biofilm formation starts as adhesion and progresses through micro-colonies, maturation, and dispersion in a planktonic form. Moreover, specific genes modulate each phase of biofilm formation. Few studies have shown that mechanisms, such as quorum sensing and diffusible signal factors, enhance coordination among bacteria when switching from biofilm to planktonic states. Different protein expressions were also observed between planktonic and biofilm strains, and the biofilm architecture was supported by exopolysaccharides, extracellular DNA, and outer membrane vesicles. CONCLUSIONS This infrastructure is responsible for the increased survival of bacteria, especially in harsh environments or in the presence of antibiotics. Therefore, understanding the biofilm formation for H. pylori is crucial. This study illustrates biofilm formation in H. pylori to help improve the treatment of H. pylori infection.
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Grants
- XXXX Universitas Airlangga
- DK62813 NIH HHS
- 26640114, 221S0002, 16H06279, 15H02657 and 16H05191, 18KK0266, 19H03473, 21H00346, 22H02871, and 23K24133 Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan
- XXXXX Japan Society for the Promotion of Science Institutional Program for Young Researcher Overseas Visits and the Strategic Funds for the Promotion of Science and Technology Agency (JST)
- xxxx Japanese Government (MEXT) scholarship
- xxxx Japan Agency for Medical Research and Development (AMED) [e-ASIA JRP]
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Affiliation(s)
- Kartika Afrida Fauzia
- Research Center for Preclinical and Clinical Medicine, National Research and Innovation Agency, Bogor 16915, Indonesia;
- Helicobacter pylori and Microbiota Study Group, Institute of Tropical Disease, Universitas Airlangga, Surabaya 60131, Indonesia
| | - Wiwin Is Effendi
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, Universitas Airlangga, Surabaya 60131, Indonesia
| | - Ricky Indra Alfaray
- Department of Environmental and Preventive Medicine—The Research Center for GLOBAL and LOCAL Infectious Disease (RCGLID), Faculty of Medicine, Oita University, Yufu 879-5593, Japan; (R.I.A.); (Y.Y.)
| | - Hoda M. Malaty
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA;
- Division of Gastroentero-Hepatology, Department of Internal Medicine, Faculty of Medicine—Dr. Soetomo Teaching Hospital, Univcersitas Airlangga, Surabaya 60286, Indonesia
| | - Yoshio Yamaoka
- Department of Environmental and Preventive Medicine—The Research Center for GLOBAL and LOCAL Infectious Disease (RCGLID), Faculty of Medicine, Oita University, Yufu 879-5593, Japan; (R.I.A.); (Y.Y.)
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA;
- Division of Gastroentero-Hepatology, Department of Internal Medicine, Faculty of Medicine—Dr. Soetomo Teaching Hospital, Univcersitas Airlangga, Surabaya 60286, Indonesia
| | - Muhammad Mifthussurur
- Helicobacter pylori and Microbiota Study Group, Institute of Tropical Disease, Universitas Airlangga, Surabaya 60131, Indonesia
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA;
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Leyton J, Fernández J, Acosta P, Quiroga A, Codony F. Reduction of Helicobacter pylori cells in rural water supply using slow sand filtration. ENVIRONMENTAL MONITORING AND ASSESSMENT 2024; 196:619. [PMID: 38878080 PMCID: PMC11180159 DOI: 10.1007/s10661-024-12764-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 05/25/2024] [Indexed: 06/19/2024]
Abstract
Helicobacter pylori is a microorganism that infects 60% of the population and is considered the main cause of atrophic gastritis, gastric and duodenal ulcers, and gastric cancer. Different emerging pathogens have been found in drinking water and their presence is considered to be an important public health problem. For this reason, it is necessary to carry out the validation of reliable technologies for this type of pathogens and evaluate their performance. This paper reports, for the first time, H. pylori reduction in a drinking water pilot plant of two slow sand filters (SSF). Inlet water was taken from a gravel filtration system of a rural water supply in Colombia and then inoculated with viable cells of H. pylori. By determining the Genomic Units (GU) through quantitative Polymerase Chain Reaction (qPCR), the concentration of GU/sample was measured. In the inlet water amplification for SSF1 and SSF2 were 5.13 × 102 ± 4.48 × 102 and 6.59 × 102 ± 7.32 × 102, respectively, while for the treated water they were 7.0 ± 5.6 and 2.05 × 101 ± 2.9 × 101 GU/sample for SSF1 and SSF2, respectively. The SSF pilot plant reached up to 3 log reduction units of H. pylori; therefore, since there is not an H. pylori contamination indicator and its periodic monitoring is financially complicated, the SSF could guarantee the drinking water quality necessity that exists in rural areas and small municipalities in developing countries, where infection rates and prevalence of this pathogen are high.
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Affiliation(s)
- Javier Leyton
- Department of Environmental and Sanitary Engineering, Faculty of Civil Engineering, Universidad del Cauca, Popayán, Colombia.
| | - Javier Fernández
- Department of Environmental and Sanitary Engineering, Faculty of Civil Engineering, Universidad del Cauca, Popayán, Colombia
| | - Patricia Acosta
- Department of Physiological Sciences, Faculty of Health Sciences, Universidad del Cauca, Popayán, Colombia
| | - Andrés Quiroga
- Department of Physiological Sciences, Faculty of Health Sciences, Universidad del Cauca, Popayán, Colombia
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3
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Moreno Y, Moreno-Mesonero L, Soler P, Zornoza A, Soriano A. Influence of drinking water biofilm microbiome on water quality: Insights from a real-scale distribution system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171086. [PMID: 38382601 DOI: 10.1016/j.scitotenv.2024.171086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 02/07/2024] [Accepted: 02/17/2024] [Indexed: 02/23/2024]
Abstract
Biofilms, constituting over 95 % of the biomass in drinking water distribution systems, form an ecosystem impacting both the aesthetic and microbiological quality of water. This study investigates the microbiome of biofilms within a real-scale drinking water distribution system in eastern Spain, utilizing amplicon-based metagenomics. Forty-one biofilm samples underwent processing and sequencing to analyze both bacterial and eukaryotic microbiomes, with an assessment of active biomass. Genus-level analysis revealed considerable heterogeneity, with Desulfovibrio, Ralstonia, Bradyrhizobium, Methylocystis, and Bacillus identified as predominant genera. Notably, bacteria associated with corrosion processes, including Desulfovibrio, Sulfuricella, Hyphomicrobium, and Methylobacterium, were prevalent. Potentially pathogenic bacteria such as Helicobacter, Pseudomonas, and Legionella were also detected. Among protozoa, Opisthokonta and Archaeplastida were the most abundant groups in biofilm samples, with potential pathogenic eukaryotes (Acanthamoeba, Naegleria, Blastocystis) identified. Interestingly, no direct correlation between microbiota composition and pipe materials was observed. The study suggests that the usual concentration of free chlorine in bulk water proved insufficient to prevent the presence of undesirable bacteria and protozoa in biofilms, which exhibited a high concentration of active biomass.
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Affiliation(s)
- Yolanda Moreno
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Camino de Vera s/n, 46022, Valencia, Spain.
| | - Laura Moreno-Mesonero
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Camino de Vera s/n, 46022, Valencia, Spain
| | - Patricia Soler
- Empresa Mixta Valenciana de Aguas, S.A. (EMIVASA), Av. del Regne de València, 28, 46005, Valencia, Spain
| | - Andrés Zornoza
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Camino de Vera s/n, 46022, Valencia, Spain; H2OCITIES, SL, Arte Mayor de la Seda, 15, 46950 Xirivella, Valencia, Spain
| | - Adela Soriano
- Empresa Mixta Valenciana de Aguas, S.A. (EMIVASA), Av. del Regne de València, 28, 46005, Valencia, Spain
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Farrokhi Y, Neshati Z, Saniee P, Makhdoumi A. The potential of Bacillus and Enterococcus probiotic strains to combat helicobacter pylori attachment to the biotic and abiotic surfaces. Int Microbiol 2023; 26:907-915. [PMID: 36943595 DOI: 10.1007/s10123-023-00347-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/04/2022] [Accepted: 03/16/2023] [Indexed: 03/23/2023]
Abstract
The prevention of biofilm formation plays a pivotal role in managing Helicobacter pylori inside the body and the environment. This study showed in vitro potentials of two recently isolated probiotic strains, Bacillus sp. 1630F and Enterococcus sp. 7C37, to form biofilm and combat H. pylori attachment to the abiotic and biotic surfaces. Lactobacillus casei and Bifidobacterium bifidum were used as the reference probiotics. The biofilm rates were the highest in the solid-liquid interface for Lactobacillus and Bifidobacterium and the air-liquid interface for Bacillus and Enterococcus. The highest tolerances to the environmental conditions were observed during the biofilm formations of Enterococcus and Bifidobacterium (pH), Enterococcus and Bacillus (bile), and Bifidobacterium and Lactobacillus (NaCl) on the polystyrene and glass substratum, respectively. Biofilms occurred more quickly by Bacillus and Enterococcus strains than reference strains on the polystyrene and glass substratum, respectively. Enterococcus (competition) and Bacillus (exclusion) achieved the most inhibition of H. pylori biofilm formations on the polystyrene and AGS cells, respectively. Expression of luxS was promoted by Bacillus (exclusion, 3.2 fold) and Enterococcus (competition, 2.0 fold). Expression of ropD was decreased when H. pylori biofilm was excluded by Bacillus (0.4 fold) and Enterococcus (0.2 fold) cells. This study demonstrated the ability of Bacillus and Enterococcus probiotic bacteria to form biofilm and combat H. pylori biofilm formation.
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Affiliation(s)
- Yeganeh Farrokhi
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Zeinab Neshati
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
- Novel Diagnostics and Therapeutics Research Group, Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Parastoo Saniee
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Science and Biotechnology, Shahid Beheshti University G. C, Tehran, Iran
| | - Ali Makhdoumi
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran.
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5
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Hassanbhai AM, Phoon MC, Chow VT, Ho B. The Association of Helicobacter pylori Biofilm with Enterovirus 71 Prolongs Viral Viability and Survival. Int J Mol Sci 2023; 24:14500. [PMID: 37833947 PMCID: PMC10572889 DOI: 10.3390/ijms241914500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 09/16/2023] [Accepted: 09/21/2023] [Indexed: 10/15/2023] Open
Abstract
The transition time during which a virus leaves its host and infects the next susceptible host is critical for virus survival. Enterovirus 71 (EV71) is stable in aqueous environments, but its molecular interactions with bacteria and their biofilms are not well-established. Helicobacter pylori is a highly successful gut bacterial pathogen, with its capacity to form biofilms being linked to its transmission. Given that both are gut-associated microbes, we hypothesized that biofilms formed by H. pylori may play a significant role in the survival of EV71 in the external environment. In this study, we examine the interactions of EV71 with the preformed biofilm of H. pylori to mimic its natural state in the environment. Immunofluorescence confocal microscopy and scanning electron microscopy revealed that EV71 particles persisted for up to 10 days when incubated with the H. pylori biofilm. Furthermore, the presence of the H. pylori biofilm significantly augmented viral viability, as verified through virus plaque assays. Interestingly, the viability of EV71 was dependent on the quantity of H. pylori biofilm formation. Thus, two H. pylori strains able to generate large amounts of biofilm could facilitate EV71 viability for up to 17 days, whereas two other H. pylori strains that produced moderate or low quantities of biofilm could not prolong virus viability. It is interesting that biofilm contains N-acetyl-glucosamine and glycosaminoglycan, and that EV71 has binding affinity to cell-surface heparan sulfate glycosaminoglycan, which acts as an EV71 attachment receptor. The synergistic ability of H. pylori biofilm to promote EV71 viability for extended periods implies that H. pylori biofilm may serve as an additional pathway of EV71 transmission.
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Affiliation(s)
- Ammar M. Hassanbhai
- Department of Microbiology & Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore; (A.M.H.); (M.C.P.); (B.H.)
| | - Meng Chee Phoon
- Department of Microbiology & Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore; (A.M.H.); (M.C.P.); (B.H.)
| | - Vincent T. Chow
- Department of Microbiology & Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore; (A.M.H.); (M.C.P.); (B.H.)
- Host and Pathogen Interactivity Laboratory, NUHS Infectious Diseases Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Bow Ho
- Department of Microbiology & Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore; (A.M.H.); (M.C.P.); (B.H.)
- Department of Food Science & Technology, Faculty of Science, National University of Singapore, Singapore 117542, Singapore
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6
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Castagnini LA, Gilger MA. Helicobacter pylori. PRINCIPLES AND PRACTICE OF PEDIATRIC INFECTIOUS DISEASES 2023:954-959.e5. [DOI: 10.1016/b978-0-323-75608-2.00174-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2025]
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Biofilm Formation as a Complex Result of Virulence and Adaptive Responses of Helicobacter pylori. Pathogens 2020; 9:pathogens9121062. [PMID: 33353223 PMCID: PMC7766044 DOI: 10.3390/pathogens9121062] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 12/11/2022] Open
Abstract
Helicobacter pylori is a bacterium that is capable of colonizing a host for many years, often for a lifetime. The survival in the gastric environment is enabled by the production of numerous virulence factors conditioning adhesion to the mucosa surface, acquisition of nutrients, and neutralization of the immune system activity. It is increasingly recognized, however, that the adaptive mechanisms of H. pylori in the stomach may also be linked to the ability of this pathogen to form biofilms. Initially, biofilms produced by H. pylori were strongly associated by scientists with water distribution systems and considered as a survival mechanism outside the host and a source of fecal-oral infections. In the course of the last 20 years, however, this trend has changed and now the most attention is focused on the biomedical aspect of this structure and its potential contribution to the therapeutic difficulties of H. pylori. Taking into account this fact, the aim of the current review is to discuss the phenomenon of H. pylori biofilm formation and present this mechanism as a resultant of the virulence and adaptive responses of H. pylori, including morphological transformation, membrane vesicles secretion, matrix production, efflux pump activity, and intermicrobial communication. These mechanisms will be considered in the context of transcriptomic and proteomic changes in H. pylori biofilms and their modulating effect on the development of this complex structure.
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8
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Oluwaseun Alegbeleye O, Sant’Ana AS. Understanding the public health burden of unconventional produce-associated enteropathogens. Curr Opin Food Sci 2020. [DOI: 10.1016/j.cofs.2020.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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9
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Helicobacter pylori Biofilm Formation and Its Potential Role in Pathogenesis. Microbiol Mol Biol Rev 2018; 82:82/2/e00001-18. [PMID: 29743338 DOI: 10.1128/mmbr.00001-18] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Despite decades of effort, Helicobacter pylori infections remain difficult to treat. Over half of the world's population is infected by H. pylori, which is a major cause of duodenal and gastric ulcers as well as gastric cancer. During chronic infection, H. pylori localizes within the gastric mucosal layer, including deep within invaginations called glands; thanks to its impressive ability to survive despite the harsh acidic environment, it can persist for the host's lifetime. This ability to survive and persist in the stomach is associated with urease production, chemotactic motility, and the ability to adapt to the fluctuating environment. Additionally, biofilm formation has recently been suggested to play a role in colonization. Biofilms are surface-associated communities of bacteria that are embedded in a hydrated matrix of extracellular polymeric substances. Biofilms pose a substantial health risk and are key contributors to many chronic and recurrent infections. This link between biofilm-associated bacteria and chronic infections likely results from an increased tolerance to conventional antibiotic treatments as well as immune system action. The role of this biofilm mode in antimicrobial treatment failure and H. pylori survival has yet to be determined. Furthermore, relatively little is known about the H. pylori biofilm structure or the genes associated with this mode of growth. In this review, therefore, we aim to highlight recent findings concerning H. pylori biofilms and the molecular mechanism of their formation. Additionally, we discuss the potential roles of biofilms in the failure of antibiotic treatment and in infection recurrence.
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10
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Zhong Q, Carratalà A, Shim H, Bachmann V, Jensen JD, Kohn T. Resistance of Echovirus 11 to ClO 2 Is Associated with Enhanced Host Receptor Use, Altered Entry Routes, and High Fitness. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:10746-10755. [PMID: 28837336 PMCID: PMC5607461 DOI: 10.1021/acs.est.7b03288] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/17/2017] [Accepted: 08/24/2017] [Indexed: 05/29/2023]
Abstract
Waterborne viruses can exhibit resistance to common water disinfectants, yet the mechanisms that allow them to tolerate disinfection are poorly understood. Here, we generated echovirus 11 (E11) with resistance to chlorine dioxide (ClO2) by experimental evolution, and we assessed the associated genotypic and phenotypic traits. ClO2 resistance emerged after E11 populations were repeatedly reduced (either by ClO2-exposure or by dilution) and then regrown in cell culture. The resistance was linked to an improved capacity of E11 to bind to its host cells, which was further attributed to two potential causes: first, the resistant E11 populations possessed mutations that caused amino acid substitutions from ClO2-labile to ClO2-stable residues in the viral proteins, which likely increased the chemical stability of the capsid toward ClO2. Second, resistant E11 mutants exhibited the capacity to utilize alternative cell receptors for host binding. Interestingly, the emergence of ClO2 resistance resulted in an enhanced replicative fitness compared to the less resistant starting population. Overall this study contributes to a better understanding of the mechanism underlying disinfection resistance in waterborne viruses, and processes that drive resistance development.
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Affiliation(s)
- Qingxia Zhong
- Laboratory
of Environmental Chemistry, School of Architecture, Civil and Environmental
Engineering, École Polytechnique
Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Anna Carratalà
- Laboratory
of Environmental Chemistry, School of Architecture, Civil and Environmental
Engineering, École Polytechnique
Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Hyunjin Shim
- Jensen Lab, School
of Life Sciences, EPFL, CH-1015 Lausanne, Switzerland
| | - Virginie Bachmann
- Laboratory
of Environmental Chemistry, School of Architecture, Civil and Environmental
Engineering, École Polytechnique
Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Jeffrey D. Jensen
- Jensen Lab, School
of Life Sciences, EPFL, CH-1015 Lausanne, Switzerland
| | - Tamar Kohn
- Laboratory
of Environmental Chemistry, School of Architecture, Civil and Environmental
Engineering, École Polytechnique
Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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Attaran B, Falsafi T. Identification of Factors Associated with Biofilm Formation Ability in the Clinical Isolates of Helicobacter pylori. IRANIAN JOURNAL OF BIOTECHNOLOGY 2017; 15:58-66. [PMID: 28959353 PMCID: PMC5582254 DOI: 10.15171/ijb.1368] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Background
A few reports confirm the ability of Helicobacter pylori to form biofilm. However, conclusive data do not exist concerning the factors that favor this ability.
Objectives
Evaluation of the factors associated with the biofilm formation ability of H. pylori including bacterial, physical and chemical, and environmental factors was the research’s aim.
Materials and Methods H. pylori isolates from gastric biopsy specimens of patients infected chronically were screened for biofilm formation ability. Association of bacterial properties such as motility, auto-aggregation, cell hydrophobicity, and extracellular polymeric substances (EPS) with in vitro biofilm formation ability of H. pylori was evaluated. The effects of environmental factors such as growth-medium, temperature, oxygen-tension, pH, β-cyclodextrin, gastric secreted mucins, and sub-inhibitory concentration of amoxicillin were also evaluated.
Results
Ability of clinical H. pylori isolates to form biofilm in was quantitatively compared. The coccoid shape H. pylori cells were observed by scanning electron microscopy, the images were illustrative of the attachment of cells to form microcolony. The levels of hydrophobicity, motility and auto aggregation of two isolates with highest and lowest biofilm formation ability were the same. However, the signifi cant role of mucins (P < 0.05) in elevating the biofilm formation was observed. Other factors influencing biofilm formation were: pH, atmosphere and sub-MIC of antibiotics.
Conclusion
Mucins have a signifi cant role in elevating the biofilm formation, also pH, atmosphere and sub-MIC of antibiotics influence biofilm formation.
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Affiliation(s)
- Bahareh Attaran
- Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Vanak, Tehran, Iran
| | - Tahereh Falsafi
- Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Vanak, Tehran, Iran
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Orta de Velásquez MT, Yáñez Noguez I, Casasola Rodríguez B, Román Román PI. Effects of ozone and chlorine disinfection on VBNC Helicobacter pylori by molecular techniques and FESEM images. ENVIRONMENTAL TECHNOLOGY 2017; 38:744-753. [PMID: 27432258 DOI: 10.1080/09593330.2016.1210680] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Helicobacter pylori is a pathogen bacteria associated with chronic gastritis, peptic ulceration, and gastric carcinoma. H. pylori has a spiral morphology, which under certain conditions of stress becomes a coccoid form. This type of morphology has been linked to a viable but non-culturable (VBNC) state, which is thought to allow its persistence in the environment. Membrane damage in VBNC H. pylori in water as a mechanism for inactivation using ozone (O3) and chlorine disinfection has not been reported in the literature. In this paper, disinfection assays with ozone and chlorine were conducted to evaluate their effects on VBNC H. pylori cells. The use of fluorescent dyes such as propidium monoazide (PMA) coupled with quantitative real-time polymerase chain reactions produced results necessary to assess the viability of the microorganism and demonstrate the effect of each disinfectant on the bacterial count. Applying ozone showed a 5-log bacterial reduction using a disinfectant concentration and exposure time (CT) of 4 mg min/L. Chlorine disinfection for the same 5-log reduction required a higher CT value. Field emission scanning electron microscope images of ozone-treated VBNC H. pylori also showed severe cell damage. The use of PMA revealed that chlorine produced physical damage in the membrane in addition to the known inhibiting effect on cell enzymatic processes. These findings are important for the detection and control of VBNC H. pylori cells in drinking water systems.
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Affiliation(s)
- María Teresa Orta de Velásquez
- a Coordinación de Ingeniería Ambiental , Instituto de Ingeniería, Universidad Nacional Autónoma de México , Distrito Federal , Mexico
| | - Isaura Yáñez Noguez
- a Coordinación de Ingeniería Ambiental , Instituto de Ingeniería, Universidad Nacional Autónoma de México , Distrito Federal , Mexico
| | - Beatriz Casasola Rodríguez
- a Coordinación de Ingeniería Ambiental , Instituto de Ingeniería, Universidad Nacional Autónoma de México , Distrito Federal , Mexico
| | - Priscila Ivette Román Román
- a Coordinación de Ingeniería Ambiental , Instituto de Ingeniería, Universidad Nacional Autónoma de México , Distrito Federal , Mexico
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13
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Environmental Review & Case Study: Evaluating the Significance of Certain Pharmaceuticals and Emerging Pathogens in Raw Water Supplies. ACTA ACUST UNITED AC 2017. [DOI: 10.1017/s1466046611000196] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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14
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Ng CG, Loke MF, Goh KL, Vadivelu J, Ho B. Biofilm formation enhances Helicobacter pylori survivability in vegetables. Food Microbiol 2016; 62:68-76. [PMID: 27889168 DOI: 10.1016/j.fm.2016.10.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 09/12/2016] [Accepted: 10/02/2016] [Indexed: 02/06/2023]
Abstract
To date, the exact route and mode of transmission of Helicobacter pylori remains elusive. The detection of H. pylori in food using molecular approaches has led us to postulate that the gastric pathogen may survive in the extragastric environment for an extended period. In this study, we show that H. pylori prolongs its survival by forming biofilm and micro-colonies on vegetables. The biofilm forming capability of H. pylori is both strain and vegetable dependent. H. pylori strains were classified into high and low biofilm formers based on their highest relative biofilm units (BU). High biofilm formers survived longer on vegetables compared to low biofilm formers. The bacteria survived better on cabbage compared to other vegetables tested. In addition, images captured on scanning electron and confocal laser scanning microscopes revealed that the bacteria were able to form biofilm and reside as micro-colonies on vegetable surfaces, strengthening the notion of possible survival of H. pylori on vegetables for an extended period of time. Taken together, the ability of H. pylori to form biofilm on vegetables (a common food source for human) potentially plays an important role in its survival, serving as a mode of transmission of H. pylori in the extragastric environment.
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Affiliation(s)
- Chow Goon Ng
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Mun Fai Loke
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore; Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Khean Lee Goh
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Bow Ho
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore; Singapore Precision Medicine Centre Pte Ltd, Singapore 608783, Singapore.
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15
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Guimarães NM, Azevedo NF, Vieira MJ, Figueiredo C. Water-induced modulation of Helicobacter pylori virulence properties. Mem Inst Oswaldo Cruz 2015; 109:414-9. [PMID: 25075780 PMCID: PMC4155841 DOI: 10.1590/0074-0276140024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 05/22/2014] [Indexed: 01/25/2023] Open
Abstract
While the influence of water in Helicobacter pylori culturability
and membrane integrity has been extensively studied, there are little data concerning
the effect of this environment on virulence properties. Therefore, we studied the
culturability of water-exposed H. pylori and determined whether
there was any relation with the bacterium’s ability to adhere, produce functional
components of pathogenicity and induce inflammation and alterations in apoptosis in
an experimental model of human gastric epithelial cells. H. pylori
partially retained the ability to adhere to epithelial cells even after
complete loss of culturability. However, the microorganism is no longer effective in
eliciting in vitro host cell inflammation and apoptosis, possibly due to the
non-functionality of the cag type IV secretion system. These H.
pylori-induced host cell responses, which are lost along with
culturability, are known to increase epithelial cell turnover and, consequently,
could have a deleterious effect on the initial H. pylori
colonisation process. The fact that adhesion is maintained by H.
pylori to the detriment of other factors involved in later infection
stages appears to point to a modulation of the physiology of the pathogen after water
exposure and might provide the microorganism with the necessary means to, at least
transiently, colonise the human stomach.
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Affiliation(s)
- Nuno M Guimarães
- Institute of Molecular Pathology and Immunology, Medical Faculty, University of Porto, Porto, Portugal
| | - Nuno F Azevedo
- Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Maria J Vieira
- Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Ceu Figueiredo
- Institute of Molecular Pathology and Immunology, Medical Faculty, University of Porto, Porto, Portugal
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16
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Mazaheri Assadi M, Chamanrokh P, Whitehouse CA, Huq A. Methods for Detecting the Environmental Coccoid Form of Helicobacter pylori. Front Public Health 2015; 3:147. [PMID: 26075197 PMCID: PMC4446911 DOI: 10.3389/fpubh.2015.00147] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 05/08/2015] [Indexed: 12/29/2022] Open
Abstract
Helicobacter pylori is recognized as the most common pathogen to cause gastritis, peptic and duodenal ulcers, and gastric cancer. The organisms are found in two forms: (1) spiral-shaped bacillus and (2) coccoid. H. pylori coccoid form, generally found in the environment, is the transformed form of the normal spiral-shaped bacillus after exposed to water or adverse environmental conditions such as exposure to sub-inhibitory concentrations of antimicrobial agents. The putative infectious capability and the viability of H. pylori under environmental conditions are controversial. This disagreement is partially due to the fact of lack in detecting the coccoid form of H. pylori in the environment. Accurate and effective detection methods of H. pylori will lead to rapid treatment and disinfection, and less human health damages and reduction in health care costs. In this review, we provide a brief introduction to H. pylori environmental coccoid forms, their transmission, and detection methods. We further discuss the use of these detection methods including their accuracy and efficiency.
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Affiliation(s)
- Mahnaz Mazaheri Assadi
- Environmental Biotechnology Group, Biotechnology Department, Iranian Research Organization for Science and Technology , Tehran , Iran
| | - Parastoo Chamanrokh
- Maryland Pathogen Research Institute, University of Maryland , College Park, MD , USA
| | | | - Anwar Huq
- Maryland Pathogen Research Institute, University of Maryland , College Park, MD , USA
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17
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Falkinham JO. Common features of opportunistic premise plumbing pathogens. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:4533-45. [PMID: 25918909 PMCID: PMC4454924 DOI: 10.3390/ijerph120504533] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 04/20/2015] [Accepted: 04/20/2015] [Indexed: 12/29/2022]
Abstract
Recently it has been estimated that the annual cost of diseases caused by the waterborne pathogens Legionella pneumonia, Mycobacterium avium, and Pseudomonas aeruginosa is $500 million. For the period 2001-2012, the estimated cost of hospital admissions for nontuberculous mycobacterial pulmonary disease, the majority caused by M. avium, was almost $1 billion. These three waterborne opportunistic pathogens are normal inhabitants of drinking water--not contaminants--that share a number of key characteristics that predispose them to survival, persistence, and growth in drinking water distribution systems and premise plumbing. Herein, I list and describe these shared characteristics that include: disinfectant-resistance, biofilm-formation, growth in amoebae, growth at low organic carbon concentrations (oligotrophic), and growth under conditions of stagnation. This review is intended to increase awareness of OPPPs, identify emerging OPPPs, and challenge the drinking water industry to develop novel approaches toward their control.
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Affiliation(s)
- Joseph O Falkinham
- Department of Biological Sciences, Virginia Tech., 1405 Perry Street, Blacksburg, VA 24061, USA.
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18
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Chamanrokh P, Shahhosseiny MH, Mazaheri Assadi M, Nejadsattari T, Esmaili D. Three Tests Used to Identify Non-Culturable Form of Helicobacter pylori in Water Samples. Jundishapur J Microbiol 2015; 8:e16811. [PMID: 26034541 PMCID: PMC4449853 DOI: 10.5812/jjm.8(4)2015.16811] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 06/12/2014] [Accepted: 09/13/2014] [Indexed: 02/06/2023] Open
Abstract
Background: Helicobacter pylori, causing the most common chronic bacterial infection, exist in two forms; bacilli and coccoid. The coccoid form is identified as viable but non-culturable bacteria. Objectives: The current study aimed to conduct culture, polymerase chain reaction (PCR), and loop-mediated isothermal amplification (LAMP) tests to identify coccoid forms of H. pylori. Materials and Methods: The PCR and LAMP tests were optimized using specific primers for glmM gene. The sensitivity and specificity of the tests were determined. The current experimental study was conducted on 10 different strains isolated from clinical cases (H1-H10). The isolates were added to tap water and incubated at three different temperatures for one and two months intervals. After pure-culturing of the bacteria, DNAs were extracted and PCR and LAMP were performed. Results: Ten copies of targeted DNA were required for PCR detection whereas only five copies gave a positive reaction by LAMP assay, with 100% specificity. Of the 10 isolates inoculated in water for one and two months at three different temperatures 4, 22, and 37°C, only three cases (5%) were found positive in the first month; 13 (21.6%) and 29 cases (48.3%) were also positive by PCR and LAMP tests in the first and second months. Conclusions: Results of the current study confirmed that molecular methods such as PCR and LAMP were much more sensitive, rapid, and specific than culturing to identify non-culturable coccoid forms of H. pylori in water.
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Affiliation(s)
- Parastoo Chamanrokh
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, IR Iran
- Corresponding author: Parastoo Chamanrokh, Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, IR Iran. Tel: +98-9372727679, E-mail:
| | - Mohammad Hassan Shahhosseiny
- Department of Microbiology, Shahre Qods Branch, Islamic Azad University, Shahre Qods, IR Iran
- Iranian Gene Fanavar Institute (IGF), Tehran, IR Iran
| | - Mahnaz Mazaheri Assadi
- Department of Biotechnology, Iranian Research Organization for Science and Technology, Tehran, IR Iran
| | - Taher Nejadsattari
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, IR Iran
| | - Davood Esmaili
- Department of Microbiology, Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, IR Iran
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19
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Mahapatra A, Padhi N, Mahapatra D, Bhatt M, Sahoo D, Jena S, Dash D, Chayani N. Study of biofilm in bacteria from water pipelines. J Clin Diagn Res 2015; 9:DC09-11. [PMID: 25954617 DOI: 10.7860/jcdr/2015/12415.5715] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 02/12/2015] [Indexed: 11/24/2022]
Abstract
CONTEXT A biofilm is a layer of microorganisms contained in a matrix (slime layer), which forms on surfaces in contact with water. Their presence in drinking water pipe networks can be responsible for a wide range of water quality and operational problems. AIM To identify the bacterial isolates, obtained from water pipelines of kitchens, to evaluate the water quality & to study the biofilm producing capacity of the bacterial isolates from various sources. SETTINGS AND DESIGN A prospective study using water samples from aqua guard & pipelines to kitchens of S.C.B Medical College hostels. MATERIALS AND METHODS Standard biochemical procedures for bacterial identification, multiple tube culture & MPN count to evaluate water quality & tissue culture plate (TCP) method for biofilm detection was followed. STATISTICAL ANALYSIS STATA software version 9.2 from STATA Corporation, College station road, 90 Houston, Texas was used for statistical analysis. RESULTS One hundred eighty seven isolates were obtained from 45 water samples cultured. The isolates were Acinetobacter spp. (44), Pseudomonas spp.(41), Klebsiella spp.(36) & others . Biofilm was detected in (37) 19.78 % of the isolates (95% CI 30.08% -43.92%) including Acinetobacter spp.-10, Klebsiella spp. - 9, Pseudomonas spp. - 9, & others, majority (34) of which were from kitchen pipelines. CONCLUSION Water from pipeline sources was unsatisfactory for consumption as the MPN counts were > 10. Most of the biofilm producers were gram negative bacilli & Pseudomonas & Acinetobacter spp. were strong (4+) biofilm producers.
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Affiliation(s)
- Ashoka Mahapatra
- Associate Professor, Department of Microbiology, AIIMS , Bhubaneswar S.C.B. Medical College, Cuttack, Odisha, India
| | - Nupur Padhi
- Undergraduate Student, S.C.B. Medical College , Cuttack, Odisha, India
| | - Dharitri Mahapatra
- Assistant Professor, Department of Microbiology, S.C.B. Medical College , Cuttack, Odisha, India
| | - Mamta Bhatt
- Senior Resident, Department of Microbiology, S.C.B. Medical College , Cuttack, Odisha, India
| | - Debasish Sahoo
- Senior Resident, Department of Microbiology, SUM Hospital , Bhubaneswar, Odisha, India
| | - Swetlina Jena
- Post Graduate Student Student, Department of Microbiology, S.C.B. Medical College , Cuttack, Odisha, India
| | - Debabrata Dash
- Post Graduate Student Student, Department of Microbiology, S.C.B. Medical College , Cuttack, Odisha, India
| | - Nirupama Chayani
- Professor and Head, Department of Microbiology, S.C.B. Medical College , Cuttack, Odisha, India
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20
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Vandervoort KG, Brelles-Mariño G. Plasma-mediated inactivation of Pseudomonas aeruginosa biofilms grown on borosilicate surfaces under continuous culture system. PLoS One 2014; 9:e108512. [PMID: 25302815 PMCID: PMC4193768 DOI: 10.1371/journal.pone.0108512] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Accepted: 08/31/2014] [Indexed: 11/18/2022] Open
Abstract
Biofilms are microbial communities attached to a surface and embedded in a matrix composed of exopolysaccharides and excreted nucleic acids. Bacterial biofilms are responsible for undesirable effects such as disease, prostheses colonization, biofouling, equipment damage, and pipe plugging. Biofilms are also more resilient than free-living cells to regular sterilization methods and therefore it is indispensable to develop better ways to control and remove them. The use of gas discharge plasmas is a good alternative since plasmas contain a mixture of reactive agents well-known for their decontamination potential against free microorganisms. We have previously reported that Pseudomonas aeruginosa biofilms were inactivated after a 1-min plasma exposure. We determined that the adhesiveness and the thickness of Pseudomonas biofilms grown on borosilicate were reduced. We also reported sequential morphological changes and loss of viability upon plasma treatment. However, the studies were carried out in batch cultures. The use of a continuous culture results in a more homogenous environment ensuring reproducible biofilm growth. The aim of this work was to study plasma-mediated inactivation of P. aeruginosa biofilms grown on borosilicate in a continuous culture system. In this paper we show that biofilms grown on glass under continuous culture can be inactivated by using gas discharge plasma. Both biofilm architecture and cell culturability are impacted by the plasma treatment. The inactivation kinetics is similar to previously described ones and cells go through sequential changes ranging from minimal modification without loss of viability at short plasma exposure times, to major structure and viability loss at longer exposure times. We report that changes in biofilm structure leading to the loss of culturability and viability are related to a decrease of the biofilm matrix adhesiveness. To our knowledge, there has been no attempt to evaluate the inactivation/sterilization of biofilms grown in a continuous system.
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Affiliation(s)
- Kurt G. Vandervoort
- Physics and Astronomy Department, California State Polytechnic University, Pomona, California, United States of America
| | - Graciela Brelles-Mariño
- Biological Sciences Department, California State Polytechnic University, Pomona, California, United States of America
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21
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Culotti A, Packman AI. Pseudomonas aeruginosa promotes Escherichia coli biofilm formation in nutrient-limited medium. PLoS One 2014; 9:e107186. [PMID: 25198725 PMCID: PMC4157881 DOI: 10.1371/journal.pone.0107186] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 08/14/2014] [Indexed: 11/19/2022] Open
Abstract
Biofilms have been implicated as an important reservoir for pathogens and commensal enteric bacteria such as Escherichia coli in natural and engineered water systems. However, the processes that regulate the survival of E. coli in aquatic biofilms have not been thoroughly studied. We examined the effects of hydrodynamic shear and nutrient concentrations on E. coli colonization of pre-established Pseudomonas aeruginosa biofilms, co-inoculation of E. coli and P. aeruginosa biofilms, and P. aeruginosa colonization of pre-established E. coli biofilms. In nutritionally-limited R2A medium, E. coli dominated biofilms when co-inoculated with P. aeruginosa, and successfully colonized and overgrew pre-established P. aeruginosa biofilms. In more enriched media, P. aeruginosa formed larger clusters, but E. coli still extensively overgrew and colonized the interior of P. aeruginosa clusters. In mono-culture, E. coli formed sparse and discontinuous biofilms. After P. aeruginosa was introduced to these biofilms, E. coli growth increased substantially, resulting in patterns of biofilm colonization similar to those observed under other sequences of organism introduction, i.e., E. coli overgrew P. aeruginosa and colonized the interior of P. aeruginosa clusters. These results demonstrate that E. coli not only persists in aquatic biofilms under depleted nutritional conditions, but interactions with P. aeruginosa can greatly increase E. coli growth in biofilms under these experimental conditions.
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Affiliation(s)
- Alessandro Culotti
- Department of Civil and Environmental Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois, United States of America
| | - Aaron I. Packman
- Department of Civil and Environmental Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois, United States of America
- * E-mail:
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22
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Ryan M, Hamilton K, Hamilton M, Haas CN. Evaluating the potential for a Helicobacter pylori drinking water guideline. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2014; 34:1651-1662. [PMID: 24660760 DOI: 10.1111/risa.12190] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Helicobacter pylori is a microaerophilic, gram-negative bacterium that is linked to adverse health effects including ulcers and gastrointestinal cancers. The goal of this analysis is to develop the necessary inputs for a quantitative microbial risk assessment (QMRA) needed to develop a potential guideline for drinking water at the point of ingestion (e.g., a maximum contaminant level, or MCL) that would be protective of human health to an acceptable level of risk while considering sources of uncertainty. Using infection and gastric cancer as two discrete endpoints, and calculating dose-response relationships from experimental data on humans and monkeys, we perform both a forward and reverse risk assessment to determine the risk from current reported surface water concentrations of H. pylori and an acceptable concentration of H. pylori at the point of ingestion. This approach represents a synthesis of available information on human exposure to H. pylori via drinking water. A lifetime risk of cancer model suggests that a MCL be set at <1 organism/L given a 5-log removal treatment because we cannot exclude the possibility that current levels of H. pylori in environmental source waters pose a potential public health risk. Research gaps include pathogen occurrence in source and finished water, treatment removal rates, and determination of H. pylori risks from other water sources such as groundwater and recreational water.
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Affiliation(s)
- Michael Ryan
- Department of Civil Architectural and Environmental Engineering, Drexel University, Philadelphia, PA, USA
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23
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Percival SL, Suleman L. Biofilms and Helicobacter pylori: Dissemination and persistence within the environment and host. World J Gastrointest Pathophysiol 2014; 5:122-132. [PMID: 25133015 PMCID: PMC4133512 DOI: 10.4291/wjgp.v5.i3.122] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 02/23/2014] [Accepted: 05/19/2014] [Indexed: 02/06/2023] Open
Abstract
The presence of viable Helicobacter pylori (H. pylori) in the environment is considered to contribute to the levels of H. pylori found in the human population, which also aids to increase its genetic variability and its environmental adaptability and persistence. H. pylori form biofilms both within the in vitro and in vivo environment. This represents an important attribute that assists the survival of this bacterium within environments that are both hostile and adverse to proliferation. It is the aim of this paper to review the ability of H. pylori to form biofilms in vivo and in vitro and to address the inherent mechanisms considered to significantly enhance its persistence within the host and in external environments. Furthermore, the dissemination of H. pylori in the external environment and within the human body and its impact upon infection control will be discussed.
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24
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Cellini L. Helicobacter pylori: A chameleon-like approach to life. World J Gastroenterol 2014; 20:5575-5582. [PMID: 24914317 PMCID: PMC4024766 DOI: 10.3748/wjg.v20.i19.5575] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 12/10/2013] [Accepted: 01/20/2014] [Indexed: 02/06/2023] Open
Abstract
Helicobacter pylori (H. pylori) is widely adaptable for colonization in human stomachs in more than half of the world’s population. The microorganism is characterized by an unusual capability of arranging itself in both genotypic and phenotypic ways. Stressing conditions, including antimicrobial agents in sub-inhibitory concentrations, facilitate entering the viable but nonculturable state in which bacterial cells acquire the coccoid form. This morphotype represents an important strategy for bacterial survival in unsuitable conditions and also allows escape from the immune system. H. pylori is capable of forming biofilm outside and inside the host. For the bacterial population, the sessile growth mode represents an ideal environment for gene rearrangement, as it allows the acquiring of important tools aimed to improve bacterial “fitness” and species preservation. Biofilm formation in H. pylori in the human host also leads to recalcitrance to antibiotic treatment, thus hampering eradication. These lifestyle changes of H. pylori allow for a “safe haven” for its survival and persistence according to different ecological niches, and strongly emphasize the need for careful H. pylori surveillance to improve management of the infection.
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25
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Atapoor S, Safarpoor Dehkordi F, Rahimi E. Detection of Helicobacter pylori in Various Types of Vegetables and Salads. Jundishapur J Microbiol 2014; 7:e10013. [PMID: 25147709 PMCID: PMC4138632 DOI: 10.5812/jjm.10013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 04/25/2013] [Accepted: 06/01/2013] [Indexed: 12/26/2022] Open
Abstract
Background: There is a possibility for the presence of Helicobacter pylori in vegetables due to their close contact with polluted water, soil and feces. Objectives: This study was carried out to detect the presence of H. pylori in vegetables and salads in Iran. Materials and Methods: In total, 460 vegetable and salad samples were collected and transferred immediately to the laboratory. All samples were cultured and tested for the presence of H. pylori using the Polymerase Chain Reaction technique. Results: The results showed that 44 of 460 samples (9.56%) were positive for H. pylori using the culture method. The Polymerase Chain Reaction technique showed that 50 of 460 samples (10.86%) were positive for H. pylori. Un-washed leek, traditional salad, un-washed basil and un-washed lettuce were the most commonly contaminated samples. The presence of the bacteria in various vegetables was statistically significant (P < 0.05). Conclusions: Vegetables are a new source of H. pylori and accurate washing of vegetables improves such contaminations.
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Affiliation(s)
- Shahrzad Atapoor
- Faculty of Agriculture and Natural Sciences, Shahrekord Branch, Islamic Azad University, Shahrekord, IR Iran
| | | | - Ebrahim Rahimi
- Department of Food Hygiene and Public Health, College of Veterinary Medicine, Shahrekord Branch, Islamic Azad University, Shahrekord, IR Iran
- Corresponding author: Ebrahim Rahimi, Department of Food Hygiene and Public Health, College of Veterinary Medicine, Shahrekord Branch, Islamic Azad University, Shahrekord, IR Iran. Tel: +98-9133278377, Fax: +98-3813361060, E-mail:
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26
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Helicobacter pylori. MICROBIOLOGY OF WATERBORNE DISEASES 2014. [DOI: 10.1016/b978-0-12-415846-7.00007-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2025]
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27
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Bahrami AR, Rahimi E, Ghasemian Safaei H. Detection of Helicobacter pylori in city water, dental units' water, and bottled mineral water in Isfahan, Iran. ScientificWorldJournal 2013; 2013:280510. [PMID: 23606812 PMCID: PMC3628665 DOI: 10.1155/2013/280510] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Accepted: 02/03/2013] [Indexed: 12/17/2022] Open
Abstract
Helicobacter pylori infection in human is one of the most common infections worldwide. However, the origin and transmission of this bacterium has not been clearly explained. One of the suggested theories is transmission via water. This study was conducted to determine the prevalence rate of H. pylori in tap water, dental units' water, and bottled mineral water in Iran. In the present study, totally 200 water samples were collected in Isfahan province and tested for H. pylori by cultural method and polymerase chain reaction (PCR) by the detection of the ureC (glmM) gene. Using cultural method totally 5 cultures were positive. Two out of 50 tap water samples (4%), 2 out of 35 dental units' water (5.8%) samples, and 1 out of 40 (2.5%) from water cooler in public places were found to be contaminated with H. pylori. H. pylori ureC gene was detected in 14 (7%) of water samples including 5 tap water (10%), 4 dental units' water (11.4%), 1 refrigerated water with filtration, and 4 (10%) water cooler in public places samples. This may be due to the coccoid form of bacteria which is detected by PCR method.
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Affiliation(s)
- Ahmad Reza Bahrami
- Faculty of Veterinary Medicine, Islamic Azad University, Shahrekord Branch, Shahrekord, Iran
| | - Ebrahim Rahimi
- Department of Food Hygiene, Faculty of Veterinary Medicine, Islamic Azad University, Shahrekord Branch, Shahrekord, Iran
| | - Hajieh Ghasemian Safaei
- Department of Microbiology, Faculty of Medical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
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28
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Zeng DN, Fan ZY, Chi L, Wang X, Qu WD, Quan ZX. Analysis of the bacterial communities associated with different drinking water treatment processes. World J Microbiol Biotechnol 2013; 29:1573-84. [PMID: 23515963 DOI: 10.1007/s11274-013-1321-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 03/12/2013] [Indexed: 10/27/2022]
Abstract
A drinking water plant was surveyed to determine the bacterial composition of different drinking water treatment processes (DWTP). Water samples were collected from different processing steps in the plant (i.e., coagulation, sedimentation, sand filtration, and chloramine disinfection) and from distantly piped water. The samples were pyrosequensed using sample-specific oligonucleotide barcodes. The taxonomic composition of the microbial communities of different DWTP and piped water was dominated by the phylum Proteobacteria. Additionally, a large proportion of the sequences were assigned to the phyla Actinobacteria and Bacteroidetes. The piped water exhibited increasing taxonomic diversity, including human pathogens such as the Mycobacterium, which revealed a threat to the safety of drinking water. Surprisingly, we also found that a sister group of SAR11 (LD12) persisted throughout the DWTP, which was always detected in freshwater aquatic systems. Moreover, Polynucleobacter, Rhodoferax, and a group of Actinobacteria, hgcI clade, were relatively consistent throughout the processes. It is concluded that smaller-size microorganisms tended to survive against the present treatment procedure. More improvement should be made to ensure the long-distance transmission drinking water.
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Affiliation(s)
- Dan-Ning Zeng
- Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China
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Ngwenya N, Ncube EJ, Parsons J. Recent advances in drinking water disinfection: successes and challenges. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2013; 222:111-70. [PMID: 22990947 DOI: 10.1007/978-1-4614-4717-7_4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Drinking water is the most important single source of human exposure to gastroenteric diseases, mainly as a result of the ingestion of microbial contaminated water. Waterborne microbial agents that pose a health risk to humans include enteropathogenic bacteria, viruses, and protozoa. Therefore, properly assessing whether these hazardous agents enter drinking water supplies, and if they do, whether they are disinfected adequately, are undoubtedly aspects critical to protecting public health. As new pathogens emerge, monitoring for relevant indicator microorganisms (e.g., process microbial indicators, fecal indicators, and index and model organisms) is crucial to ensuring drinking water safety. Another crucially important step to maintaining public health is implementing Water Safety Plans (WSPs), as is recommended by the current WHO Guidelines for Drinking Water Quality. Good WSPs include creating health-based targets that aim to reduce microbial risks and adverse health effects to which a population is exposed through drinking water. The use of disinfectants to inactivate microbial pathogens in drinking water has played a central role in reducing the incidence of waterborne diseases and is considered to be among the most successful interventions for preserving and promoting public health. Chlorine-based disinfectants are the most commonly used disinfectants and are cheap and easy to use. Free chlorine is an effective disinfectant for bacteria and viruses; however, it is not always effective against C. parvum and G. lamblia. Another limitation of using chlorination is that it produces disinfection by-products (DBPs), which pose potential health risks of their own. Currently, most drinking water regulations aggressively address DBP problems in public water distribution systems. The DBPs of most concern include the trihalomethanes (THMs), the haloacetic acids (HAAs), bromate, and chlorite. However, in the latest edition of the WHO Guidelines for Drinking Water Quality, it is recommended that water disinfection should never be compromised by attempting to control DBPs. The reason for this is that the risks of human illness and death from pathogens in drinking water are much greater than the risks from exposure to disinfectants and disinfection by-products. Nevertheless, if DBP levels exceed regulatory limits, strategies should focus on eliminating organic impurities that foster their formation, without compromising disinfection. As alternatives to chlorine, disinfectants such as chloramines, ozone, chlorine dioxide, and UV disinfection are gaining popularity. Chlorine and each of these disinfectants have individual advantage and disadvantage in terms of cost, efficacy-stability, ease of application, and nature of disinfectant by-products (DBPs). Based on efficiency, ozone is the most efficient disinfectant for inactivating bacteria, viruses, and protozoa. In contrast, chloramines are the least efficient and are not recommended for use as primary disinfectants. Chloramines are favored for secondary water disinfection, because they react more slowly than chlorine and are more persistent in distribution systems. In addition, chloramines produce lower DBP levels than does chlorine, although microbial activity in the distribution system may produce nitrate from monochloramine, when it is used as a residual disinfectant, Achieving the required levels of water quality, particularly microbial inactivation levels, while minimizing DBP formation requires the application of proper risk and disinfection management protocols. In addition, the failure of conventional treatment processes to eliminate critical waterborne pathogens in drinking water demand that improved and/or new disinfection technologies be developed. Recent research has disclosed that nanotechnology may offer solutions in this area, through the use of nanosorbents, nanocatalysts, bioactive nanoparticles, nanostructured catalytic membranes, and nanoparticle-enhanced filtration.
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Affiliation(s)
- Nonhlanhla Ngwenya
- Scientific Services Division, Rand Water, Johannesburg, 1170 2000 South Africa.
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Bodhankar SL, Ghosh P. A Cross Sectional Study to Determine Association of the Socio Demographic Risk Factors with Prevalence and Virulence of H. pylori Infection in Salivary Samples of Asymptomatic Subjects by Application of Polymerase Chain Reaction Technique. ACTA ACUST UNITED AC 2012. [DOI: 10.5567/pharmacologia.2012.481.489] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Nam S, Kwon S, Kim MJ, Chae JC, Jae Maeng P, Park JG, Lee GC. Selective detection of viable Helicobacter pylori using ethidium monoazide or propidium monoazide in combination with real-time polymerase chain reaction. Microbiol Immunol 2012; 55:841-6. [PMID: 22004535 DOI: 10.1111/j.1348-0421.2011.00388.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Because Helicobacter pylori has a role in the pathogenesis of gastric cancer, chronic gastritis and peptic ulcer disease, detection of its viable form is very important. The objective of this study was to optimize a PCR method using ethidium monoazide (EMA) or propidium monoazide (PMA) for selective detection of viable H. pylori cells in mixed samples of viable and dead bacteria. Before conducting the real-time PCR using SodB primers of H. pylori, EMA or PMA was added to suspensions of viable and/or dead H. pylori cells at concentrations between 1 and 100 μM. PMA at a concentration of 50 μM induced the highest DNA loss in dead cells with little loss of genomic DNA in viable cells. In addition, selective detection of viable cells in the mixtures of viable and dead cells at various ratios was possible with the combined use of PMA and real-time PCR. In contrast, EMA penetrated the membranes of both viable and dead cells and induced degradation of their genomic DNA. The findings of this study suggest that PMA, but not EMA, can be used effectively to differentiate viable H. pylori from its dead form.
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Affiliation(s)
- Sehee Nam
- Water Analysis and Research Center, K-water, Daejeon 306-711, Korea
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Bellou N, Papathanassiou E, Dobretsov S, Lykousis V, Colijn F. The effect of substratum type, orientation and depth on the development of bacterial deep-sea biofilm communities grown on artificial substrata deployed in the Eastern Mediterranean. BIOFOULING 2012; 28:199-213. [PMID: 22352335 DOI: 10.1080/08927014.2012.662675] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
An increasing number of deep-sea studies have highlighted the importance of deep-sea biofouling, especially in relation to the protection of deep-sea instruments. In this study, the microbial communities developed on different substrata (titanium, aluminum, limestone, shale and neutrino telescope glass) exposed for 155 days at different depths (1500 m, 2500 m, 3500 m and 4500 m) and positions (vertical and horizontal) in the Eastern Mediterranean Deep Sea were compared. Replicated biofilm samples were analyzed using a Terminal Restriction Fragment Length Polymorphisms (T-RFLP) method. The restriction enzymes CfoI and RsaI produced similar total numbers (94, 93) of different T-RFLP peaks (T-RFs) along the vertical transect. In contrast, the mean total T-RF number between each sample according to substratum type and depth was higher in more samples when CfoI was used. The total species richness (S) of the bacterial communities differed significantly between the substrata, and depended on the orientation of each substratum within one depth and throughout the water column (ANOVA). T-RFLP analyses using the Jaccard similarity index showed that within one depth layer, the composition of microbial communities on different substrata was different and highly altered among communities developed on the same substratum but exposed to fouling at different depths. Based on Multidimensional Scaling Analyses (MDS), the study suggests that depth plays an important role in the composition of deep-sea biofouling communities, while substratum type and orientation of substrata throughout the water column are less important. To the authors' knowledge, this is the first study of biofilm development in deep waters, in relation to the effects of substratum type, orientation and depth.
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Affiliation(s)
- Nikoleta Bellou
- Hellenic Centre for Marine Research, Institute of Oceanography, Athens, Greece.
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Wu MY, Sendamangalam V, Xue Z, Seo Y. The influence of biofilm structure and total interaction energy on Escherichia coli retention by Pseudomonas aeruginosa biofilm. BIOFOULING 2012; 28:1119-1128. [PMID: 23075008 DOI: 10.1080/08927014.2012.732070] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The retention of a surrogate pathogenic bacterium, Escherichia coli(T) , in Pseudomonas aeruginosa biofilms (with various EPS excreting capacities) was investigated using a laboratory flow cell system. The structural characteristics of the biofilm, as well as the quantity of E. coli(T) retained in the biofilm, were assessed using confocal laser scanning microscopy coupled with image analysis. In addition, the total interaction energy between E. coli(T) and the P. aeruginosa biofilm was computed with the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, which provided an additional context to explain the pathogen interaction in aquatic biofilms. The correlations between the quantity of detained E. coli(T) cells and the structural characteristics of the biofilm were analysed and the results indicated that the heterogeneity of the biofilm could create a quiescent zone leading to temporary retention of E. coli(T) within the biofilm. Overall, this study provided insights toward understanding the retention of pathogenic bacteria in environmental biofilms.
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Affiliation(s)
- Mau-Yi Wu
- Department of Civil and Engineering , University of Toledo, Toledo, Ohio 43606, USA
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Wingender J. Hygienically Relevant Microorganisms in Biofilms of Man-Made Water Systems. ACTA ACUST UNITED AC 2011. [DOI: 10.1007/978-3-642-19940-0_9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Yonezawa H, Osaki T, Woo T, Kurata S, Zaman C, Hojo F, Hanawa T, Kato S, Kamiya S. Analysis of outer membrane vesicle protein involved in biofilm formation of Helicobacter pylori. Anaerobe 2011; 17:388-90. [PMID: 21515394 DOI: 10.1016/j.anaerobe.2011.03.020] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 03/30/2011] [Accepted: 03/31/2011] [Indexed: 01/26/2023]
Abstract
Helicobacter pylori is one of the most common causes of bacterial infection in humans. Infection with H. pylori is closely associated with gastritis and peptic ulcers and is a risk factor for gastric cancer and mucosa-associated lymphoid tissue lymphoma. H. pylori forms biofilms on glass surfaces at the air-liquid interface in in-vitro batch cultures. We previously reported that strain TK1402 showed a strong biofilm-forming ability in vitro. We also suggested the outer membrane vesicles (OMV) produced by strain TK1402 might be related to its biofilm forming ability. In the present study, we analyzed the protein profile of the OMV produced by strain TK1402 and found a unique 22-kDa protein in TK1402 OMV cultured for 2-3 days. In addition, this protein could not be detected in the OMVs produced by other H. pylori strains. These results suggest that the 22-kDa protein is involved in effective biofilm formation by strain TK1402.
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Affiliation(s)
- Hideo Yonezawa
- Department of Infectious Disease, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka-shi, Tokyo 181-8611, Japan
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Yang FL, Hassanbhai AM, Chen HY, Huang ZY, Lin TL, Wu SH, Ho B. Proteomannans in biofilm of Helicobacter pylori ATCC 43504. Helicobacter 2011; 16:89-98. [PMID: 21435085 DOI: 10.1111/j.1523-5378.2010.00815.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND The human bacterial pathogen Helicobacter pylori forms biofilms. However, the constituents of the biofilm have not been extensively investigated. In this study, we analyzed the carbohydrate and protein components of biofilm formed by H. pylori strain ATCC 43504 (NCTC 11637). MATERIALS AND METHODS Development of H. pylori biofilm was analyzed using scanning electron microscopy (SEM) and quantified using crystal violet staining. The extracted extracellular polysaccharide (EPS) matrix was analyzed using GC-MS and nuclear magnetic resonance (NMR) analyses. Proteomic profiles of biofilms were examined by SDS-PAGE while deletion mutants of upregulated biofilm proteins were constructed and characterized. RESULTS Formation of H. pylori biofilm is time dependent as shown by crystal violet staining assay and SEM. NMR reveals the prevalence of 1,4-mannosyl linkages in both developing and mature biofilms. Proteomic analysis of the biofilm indicates the upregulation of neutrophil-activating protein A (NapA) and several stress-induced proteins. Interestingly, the isogenic mutant napA revealed a different biofilm phenotype that showed reduced aggregated colonial structure when compared to the wild type. CONCLUSIONS This in vitro study shows that mannose-related proteoglycans (proteomannans) are involved in the process of H. pylori biofilm formation while the presence of upregulated NapA in the biofilm implies the potency to increase adhesiveness of H. pylori biofilm. Being a complex matrix of proteins and carbohydrates, which are probably interdependent, the H. pylori biofilm could possibly offer a protective haven for the survival of this gastric bacterial pathogen in the extragastric environments.
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Affiliation(s)
- Feng-Ling Yang
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
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Gião MS, Azevedo NF, Wilks SA, Vieira MJ, Keevil CW. Interaction of Legionella pneumophila and Helicobacter pylori with bacterial species isolated from drinking water biofilms. BMC Microbiol 2011; 11:57. [PMID: 21418578 PMCID: PMC3068934 DOI: 10.1186/1471-2180-11-57] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Accepted: 03/18/2011] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND It is well established that Legionella pneumophila is a waterborne pathogen; by contrast, the mode of Helicobacter pylori transmission remains unknown but water seems to play an important role. This work aims to study the influence of five microorganisms isolated from drinking water biofilms on the survival and integration of both of these pathogens into biofilms. RESULTS Firstly, both pathogens were studied for auto- and co-aggregation with the species isolated from drinking water; subsequently the formation of mono and dual-species biofilms by L. pneumophila or H. pylori with the same microorganisms was investigated. Neither auto- nor co-aggregation was observed between the microorganisms tested. For biofilm studies, sessile cells were quantified in terms of total cells by SYTO 9 staining, viable L. pneumophila or H. pylori cells were quantified using 16 S rRNA-specific peptide nucleic acid (PNA) probes and cultivable cells by standard culture techniques. Acidovorax sp. and Sphingomonas sp. appeared to have an antagonistic effect on L. pneumophila cultivability but not on the viability (as assessed by rRNA content using the PNA probe), possibly leading to the formation of viable but noncultivable (VBNC) cells, whereas Mycobacterium chelonae increased the cultivability of this pathogen. The results obtained for H. pylori showed that M. chelonae and Sphingomonas sp. help this pathogen to maintain cultivability for at least 24 hours. CONCLUSIONS It appears that M. chelonae may have an important role in the survival of both pathogens in drinking water. This work also suggests that the presence of some microorganisms can decrease the cultivability of L. pneumophila but not the viability which indicates that the presence of autochthonous microorganisms can lead to misleading results when the safety of water is assessed by cultivable methods alone.
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Affiliation(s)
- Maria S Gião
- School of Biological Sciences, Life Sciences Building, Highfield Campus, University of Southampton, Southampton SO17 1BJ, UK
- Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar 4710-057, Braga, Portugal
| | - Nuno F Azevedo
- School of Biological Sciences, Life Sciences Building, Highfield Campus, University of Southampton, Southampton SO17 1BJ, UK
- Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar 4710-057, Braga, Portugal
- LEPAE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - Sandra A Wilks
- School of Biological Sciences, Life Sciences Building, Highfield Campus, University of Southampton, Southampton SO17 1BJ, UK
| | - Maria J Vieira
- Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar 4710-057, Braga, Portugal
| | - Charles W Keevil
- School of Biological Sciences, Life Sciences Building, Highfield Campus, University of Southampton, Southampton SO17 1BJ, UK
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Girones R, Ferrús MA, Alonso JL, Rodriguez-Manzano J, Calgua B, Corrêa ADA, Hundesa A, Carratala A, Bofill-Mas S. Molecular detection of pathogens in water--the pros and cons of molecular techniques. WATER RESEARCH 2010; 44:4325-39. [PMID: 20619868 DOI: 10.1016/j.watres.2010.06.030] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 06/10/2010] [Accepted: 06/14/2010] [Indexed: 05/04/2023]
Abstract
Pollution of water by sewage and run-off from farms produces a serious public health problem in many countries. Viruses, along with bacteria and protozoa in the intestine or in urine are shed and transported through the sewer system. Even in highly industrialized countries, pathogens, including viruses, are prevalent throughout the environment. Molecular methods are used to monitor viral, bacterial, and protozoan pathogens, and to track pathogen- and source-specific markers in the environment. Molecular techniques, specifically polymerase chain reaction-based methods, provide sensitive, rapid, and quantitative analytical tools with which to study such pathogens, including new or emerging strains. These techniques are used to evaluate the microbiological quality of food and water, and to assess the efficiency of virus removal in drinking and wastewater treatment plants. The range of methods available for the application of molecular techniques has increased, and the costs involved have fallen. These developments have allowed the potential standardization and automation of certain techniques. In some cases they facilitate the identification, genotyping, enumeration, viability assessment, and source-tracking of human and animal contamination. Additionally, recent improvements in detection technologies have allowed the simultaneous detection of multiple targets in a single assay. However, the molecular techniques available today and those under development require further refinement in order to be standardized and applicable to a diversity of matrices. Water disinfection treatments may have an effect on the viability of pathogens and the numbers obtained by molecular techniques may overestimate the quantification of infectious microorganisms. The pros and cons of molecular techniques for the detection and quantification of pathogens in water are discussed.
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Affiliation(s)
- Rosina Girones
- Department of Microbiology, Faculty of Biology, University of Barcelona. Av. Diagonal 645, 08028 Barcelona, Spain.
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Yonezawa H, Osaki T, Kurata S, Zaman C, Hanawa T, Kamiya S. Assessment of in vitro biofilm formation by Helicobacter pylori. J Gastroenterol Hepatol 2010; 25 Suppl 1:S90-4. [PMID: 20586874 DOI: 10.1111/j.1440-1746.2009.06213.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS Biofilms are surface-bound communities of bacterial cells that are implicated in their survival. As with various bacteria studied to date, Helicobacter pylori can have an alternate lifestyle as a biofilm. We previously reported that strain TK1402 showed a strong biofilm-forming ability in vitro. However, the mechanisms of its biofilm development remain unclear. We analyzed the basic characteristics of the biofilm-forming ability in strain TK1402. METHODS In order to characterize the biofilm-forming ability of the H. pylori strains, auto-aggregation, motility and hydrophobicity, which are important factors in biofilm formation by other bacteria, were analyzed. Further, we tested whether cell growth participated in biofilm formation in strain TK1402. RESULTS There were no significant differences in the auto-aggregation, motility and hydrophobicity of strain TK1402 compared with the other strains. On the other hand, pre-culture of this strain for 24-48 h resulted in decreased biofilm formation. CONCLUSION TK1402 is a strong biofilm-forming strain of H. pylori in Brucella broth supplemented with 7% fetal calf serum. It is possible that biofilm-forming cell growth is a principal factor in biofilm development.
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Affiliation(s)
- Hideo Yonezawa
- Department of Infectious Disease, Kyorin University School of Medicine, Shinkawa, Tokyo, Japan.
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Gião MS, Azevedo NF, Wilks SA, Vieira MJ, Keevil CW. Effect of chlorine on incorporation of Helicobacter pylori into drinking water biofilms. Appl Environ Microbiol 2010; 76:1669-73. [PMID: 19966018 PMCID: PMC2832397 DOI: 10.1128/aem.01378-09] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Accepted: 11/27/2009] [Indexed: 12/25/2022] Open
Abstract
The use of a specific peptide nucleic acid (PNA) probe demonstrated that Helicobacter pylori persisted inside biofilms exposed to low concentrations of chlorine (0.2 and 1.2 mg liter(-1)) for at least 26 days, although no culturable cells were recovered. Coupled with data obtained using viability stains in pure culture, this result suggests that H. pylori can survive chlorination but remain undetectable by culture methods, which can be effectively replaced by PNA hybridization.
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Affiliation(s)
- M S Gião
- Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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Vale FF, Vítor JMB. Transmission pathway of Helicobacter pylori: does food play a role in rural and urban areas? Int J Food Microbiol 2010; 138:1-12. [PMID: 20122750 DOI: 10.1016/j.ijfoodmicro.2010.01.016] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2009] [Revised: 01/13/2010] [Accepted: 01/14/2010] [Indexed: 01/03/2023]
Abstract
Helicobacter pylori is a Gram-negative microaerophilic bacterium that has colonized the human gastric mucosa. This infection is very common and affects more than half of the human population. The prevalence is however unbalanced between rural developing areas (more than 80%) and urban developed areas (less than 40%). H. pylori is responsible for several pathologies, such as gastritis, peptic ulcer and gastric cancer but its transmission pathway is still not clear. The risk factors for H. pylori infection include poor social and economic development; poor hygienic practices; absence of hygienic drinking water; and unsanitary prepared food. There is evidence supporting a gastro-oral, oral-oral and faecal-oral transmission, but no predominant mechanism of transmission has been yet identified. Transmission may occur in a vertical mode (e.g. from parents to child) or in a horizontal mode (across individuals or from environmental contamination). In either case, the involvement of water and food cannot be excluded as vehicles or sources of infection. Indirect evidence of presence of H. pylori in water and food, namely the detection of its DNA and survival studies after artificial contamination of food and water has been described. This paper reviews data both favourable and against the role of water and food in the transmission of H. pylori, exploring their role as a potential transmission vehicle for person-to-person and food-chain transmission. The likelihood of the transmission pathway in developing rural and developed urban areas appears to be different. In developed areas, person-to-person transmission within families appears to be dominant, while in the rural developing areas the transmission pathway appears to be more complex. In this later case, the transmission by contaminated food, water, or via intensive contact between infants and non-parental caretakers may have a greater influence than within-family transmission.
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Affiliation(s)
- F F Vale
- Faculty of Engineering Catholic University of Portugal, Estrada Octávio Pato, Rio de Mouro, Portugal.
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Yonezawa H, Osaki T, Kurata S, Fukuda M, Kawakami H, Ochiai K, Hanawa T, Kamiya S. Outer membrane vesicles of Helicobacter pylori TK1402 are involved in biofilm formation. BMC Microbiol 2009; 9:197. [PMID: 19751530 PMCID: PMC2749055 DOI: 10.1186/1471-2180-9-197] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Accepted: 09/15/2009] [Indexed: 12/12/2022] Open
Abstract
Background Helicobacter pylori forms biofilms on glass surfaces at the air-liquid interface in in vitro batch cultures; however, biofilms of H. pylori have not been well characterized. In the present study, we analyzed the ability of H. pylori strains to form biofilms and characterized the underlying mechanisms of H. pylori biofilm formation. Results Strain TK1402 showed strong biofilm forming ability relative to the other strains in Brucella broth supplemented with 7% FCS. The strong biofilm forming ability of TK1402 is reflected the relative thickness of the biofilms. In addition, outer membrane vesicles (OMV) were detected within the matrix of only the TK1402 biofilms. Biofilm formation was strongly correlated with the production of OMV in this strain. We further observed that strain TK1402 did not form thick biofilms in Brucella broth supplemented with 0.2% β-cyclodextrin. However, the addition of the OMV-fraction collected from TK1402 could enhance biofilm formation. Conclusion The results suggested that OMV produced from TK1402 play an important role in biofilm formation in strain TK1402.
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Affiliation(s)
- Hideo Yonezawa
- Department of Infectious Disease, Kyorin University School of Medicine, Shinkawa, Mitaka, Tokyo, 181-8611, Japan.
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Abstract
Electron microscopic studies have shown that Helicobacter pylori occurs in three stages: spiral forms, coccoid forms and degenerative forms. The spiral forms are viable, culturable, virulent and can colonize experimental animals and induce inflammation. The coccoid forms may also be viable but are nonculturable, less virulent and are less likely to colonize and induce inflammation in experimental animals than the spiral forms. The degenerative forms are pyknotic, nonculturable, coccoid forms of dead H. pylori. These forms cannot be cultured and the cell membrane has disintegrated but gene material can be detected by PCR in water supplies. There is no substantial evidence for viable H. pylori persisting in water supplies. Epidemiological studies suggest that environmental water is a risk factor for H. pylori infection when compared with tap water, and formation of H. pylori biofilm cannot be excluded. Helicobacter pylori does not seem to take part in biofilm formation in the oral cavity even though the bacterium may be detected.
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Affiliation(s)
- Leif Percival Andersen
- Department of Infections Control 9101, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
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Failure to detect Helicobacter pylori DNA in drinking and environmental water in Dhaka, Bangladesh, using highly sensitive real-time PCR assays. Appl Environ Microbiol 2009; 75:3039-44. [PMID: 19304824 DOI: 10.1128/aem.02779-08] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The main transmission pathway of Helicobacter pylori has not been determined, but several reports have described detection of H. pylori DNA in drinking and environmental water, suggesting that H. pylori may be waterborne. To address this possibility, we developed, tested, and optimized two complementary H. pylori-specific real-time PCR assays for quantification of H. pylori DNA in water. The minimum detection level of the assays including collection procedures and DNA extraction was shown to be approximately 250 H. pylori genomes per water sample. Using our assays, we then analyzed samples of drinking and environmental water (n = 75) and natural water biofilms (n = 21) from a high-endemicity area in Bangladesh. We could not identify H. pylori DNA in any of the samples, even though other pathogenic bacteria have been found previously in the same water samples by using the same methodology. A series of control experiments were performed to ensure that the negative results were not falsely caused by PCR inhibition, nonspecific assays, degradation of template DNA, or low detection sensitivity. Our results suggest that it is unlikely that the predominant transmission route of H. pylori in this area is waterborne.
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Dube C, Tanih NF, Ndip RN. Helicobacter pylori in water sources: a global environmental health concern. REVIEWS ON ENVIRONMENTAL HEALTH 2009; 24:1-14. [PMID: 19476289 DOI: 10.1515/reveh.2009.24.1.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Helicobacter pylori are Gram-negative micro-aerophilic motile curve rods that inhabit the gastric mucosa of the human stomach. The bacterium chronically infects billions of people worldwide and is one of the most genetically diverse of bacterial species. More than half of the world population in both developed and developing countries are infected with this organism. Infection usually occurs without overt clinical symptoms, particularly in poor communities. If untreated, the infection can last for decades without causing symptoms. In some communities, however, infection with the organism causes peptic and duodenal ulcers, gastritis, duodenitis, and gastric cancers. How H. pylori initially enters the stomach is not known, but contaminated food particles and water are suspected, with the former physically shielding it from stomach acid. Similarly, the route of transmission of this pathogen is unknown. Several reports have suggested the possibility of waterborne transmission as the organism can survive for a few days in fresh cold water, salt water, distilled water, and tap water. Knowledge of the epidemiology and mode of transmission of H. pylori is important to prevent its spread and may be useful in identifying high risk populations.
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Affiliation(s)
- C Dube
- Microbial Pathogenicity and Molecular Epidemiology Research Group, Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa
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Gião MS, Azevedo NF, Wilks SA, Vieira MJ, Keevil CW. Persistence of Helicobacter pylori in heterotrophic drinking-water biofilms. Appl Environ Microbiol 2008; 74:5898-904. [PMID: 18676697 PMCID: PMC2565978 DOI: 10.1128/aem.00827-08] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Accepted: 07/28/2008] [Indexed: 12/25/2022] Open
Abstract
Although the route of transmission of Helicobacter pylori remains unknown, drinking water has been considered a possible transmission vector. It has been shown previously that, in water, biofilms are a protective niche for several pathogens, protecting them from stressful conditions, such as low carbon concentration, shear stress, and less-than-optimal temperatures. In this work, the influence of these three parameters on the persistence and cultivability of H. pylori in drinking-water biofilms was studied. Autochthonous biofilm consortia were formed in a two-stage chemostat system and then inoculated with the pathogen. Total numbers of H. pylori cells were determined by microscopy using a specific H. pylori 16S rRNA peptide nucleic acid probe, whereas cultivable cells were assessed by standard plating onto selective H. pylori medium. Cultivable H. pylori could not be detected at any time point, but the ability of H. pylori cells to incorporate, undergo morphological transformations, persist, and even agglomerate in biofilms for at least 31 days without a noticeable decrease in the total cell number (on average, the concentration was between 1.54 x 10(6) and 2.25 x 10(6) cells cm(-2)) or in the intracellular rRNA content may indicate that the loss of cultivability was due to entry into a viable but noncultivable state. Unlike previous results obtained for pure-culture H. pylori biofilms, shear stress did not negatively influence the numbers of H. pylori cells attached, suggesting that the autochthonous aquatic bacteria have an important role in retaining this pathogen in the sessile state, possibly by providing suitable microaerophilic environments or linking biomolecules to which the pathogen adheres. Therefore, biofilms appear to provide not only a safe haven for H. pylori but also a concentration mechanism so that subsequent sloughing releases a concentrated bolus of cells that might be infectious and that could escape routine grab sample microbiological analyses and be a cause of concern for public health.
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Affiliation(s)
- M S Gião
- Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar 4710-057, Braga, Portugal
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Cellini L, Grande R, Di Campli E, Di Bartolomeo S, Di Giulio M, Traini T, Trubiani O. Characterization of an Helicobacter pylori environmental strain. J Appl Microbiol 2008; 105:761-9. [PMID: 18410343 DOI: 10.1111/j.1365-2672.2008.03808.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AIMS To investigate the main genotypic virulence markers and the phenotypic features of an environmental Helicobacter pylori strain, named MDC1. METHODS AND RESULTS The H. pylori MDC1 genotypic status was evaluated by PCR amplification. The mosaicism in vacA alleles was expressed by the s1m1 allelic combination, as found in strains which are strong vacuolating cytotoxin producers; the number of cagA variable EPIYA motifs displayed P1P2P3P3 pattern and the iceA1 was recorded between the iceA allelic types and the babA2 gene found in strains causing more severe disease. The biofilm formation was evaluated on a polystyrene surface in static conditions by scanning electron microscopy and confocal scanning laser microscopy. Helicobacter pylori MDC1 displayed a dense mature biofilm with cells in a coccoid morphology persistent in time in which the expression of the luxS gene, related to the quorum-sensing signalling, was always detected. CONCLUSIONS Helicobacter pylori MDC1 strain had the main virulence markers closely related to gastric pathogenesis and displayed a well-structured biofilm which allowed this bacterium to be more protected in the environment. SIGNIFICANCE AND IMPACT OF THE STUDY The persistence of the environmental virulent H. pylori strain in a clustered state suggests a long-term survival of this bacterial community outside of the host, enabling the bacterial transmission with important clinical repercussions.
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Affiliation(s)
- L Cellini
- Department of Biomedical Sciences, University 'G. d'Annunzio', Chieti-Pescara, Italy.
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Survival of gastric and enterohepatic Helicobacter spp. in water: implications for transmission. Appl Environ Microbiol 2008; 74:1805-11. [PMID: 18245254 DOI: 10.1128/aem.02241-07] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Part of the reason for rejecting aquatic environments as possible vectors for the transmission of Helicobacter pylori has been the preference of this microorganism to inhabit the human stomach and hence use a direct oral-oral route for transmission. On the other hand, most enteric bacterial pathogens are well known for being able to use water as an environmental reservoir. In this work, we have exposed 13 strains of seven different Helicobacter spp. (both gastric and enterohepatic) to water and tracked their survival by standard plating methods and membrane integrity assessment. The influence of different plating media and temperatures and the presence of light on recovery was also assessed. There was good correlation between cultivability and membrane integrity results (Pearson's correlation coefficient = 0.916), confirming that the culture method could reliably estimate differences in survival among different Helicobacter spp. The species that survived the longest in water was H. pylori (>96 h in the dark at 25 degrees C), whereas H. felis appeared to be the most sensitive to water (<6 h). A hierarchical cluster analysis demonstrated that there was no relationship between the enterohepatic nature of Helicobacter spp. and an increased time of survival in water. This work assesses for the first time the survival of multiple Helicobacter spp., such has H. mustelae, H. muridarum, H. felis, H. canadensis, H. pullorum, and H. canis, in water under several conditions and concludes that the roles of water in transmission between hosts are likely to be similar for all these species, whether enterohepatic or not.
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Whitacre DM. Risk of waterborne illness via drinking water in the United States. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2008; 192:117-58. [PMID: 18020305 PMCID: PMC7120101 DOI: 10.1007/978-0-387-71724-1_4] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Accepted: 01/12/2007] [Indexed: 05/18/2023]
Abstract
Outbreaks of disease attributable to drinking water are not common in the U.S., but they do still occur and can lead to serious acute, chronic, or sometimes fatal health consequences, particularly in sensitive and immunocompromised populations. From 1971 to 2002, there were 764 documented waterborne outbreaks associated with drinking water, resulting in 575,457 cases of illness and 79 deaths (Blackburn et al. 2004; Calderon 2004); however, the true impact of disease is estimated to be much higher. If properly applied, current protocols in municipal water treatment are effective at eliminating pathogens from water. However, inadequate, interrupted, or intermittent treatment has repeatedly been associated with waterborne disease outbreaks. Contamination is not evenly distributed but rather affected by the number of pathogens in the source water, the age of the distribution system, the quality of the delivered water, and climatic events that can tax treatment plant operations. Private water supplies are not regulated by the USEPA and are generally not treated or monitored, although very few of the municipal systems involved in documented outbreaks exceeded the USEPA's total coliform standard in the preceding 12 mon (Craun et al. 2002). We provide here estimates of waterborne infection and illness risks in the U.S. based on the total number of water systems, source water type, and total populations exposed. Furthermore, we evaluated all possible illnesses associated with the microbial infection and not just gastroenteritis. Our results indicate that 10.7 M infections/yr and 5.4 M illnesses/yr occur in populations served by community groundwater systems; 2.2 M infections/yr and 1.1 M illnesses/yr occur in noncommunity groundwater systems; and 26.0 M infections/yr and 13.0 M illnesses/yr occur in municipal surface water systems. The total estimated number of waterborne illnesses/yr in the U.S. is therefore estimated to be 19.5 M/yr. Others have recently estimated waterborne illness rates of 12M cases/yr (Colford et al. 2006) and 16 M cases/yr (Messner et al. 2006), yet our estimate considers all health outcomes associated with exposure to pathogens in drinking water rather than only gastrointestinal illness. Drinking water outbreaks exemplify known breaches in municipal water treatment and distribution processes and the failure of regulatory requirements to ensure water that is free of human pathogens. Water purification technologies applied at the point-of-use (POU) can be effective for limiting the effects of source water contamination, treatment plant inadequacies, minor intrusions in the distribution system, or deliberate posttreatment acts (i.e., bioterrorism). Epidemiological studies are conflicting on the benefits of POU water treatment. One prospective intervention study found that consumers of reverse-osmosis (POU) filtered water had 20%-35% less gastrointestinal illnesses than those consuming regular tap water, with an excess of 14% of illness due to contaminants introduced in the distribution system (Payment 1991, 1997). Two other studies using randomized, blinded, controlled trials determined that the risks were equal among groups supplied with POU-treated water compared to untreated tap water (Hellard et al. 2001; Colford et al. 2003). For immunocompromised populations, POU water treatment devices are recommended by the CDC and USEPA as one treatment option for reducing risks of Cryptosporidium and other types of infectious agents transmitted by drinking water. Other populations, including those experiencing "normal" life stages such as pregnancy, or those very young or very old, might also benefit from the utilization of additional water treatment options beyond the current multibarrier approach of municipal water treatment.
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Moreno Y, Piqueres P, Alonso JL, Jiménez A, González A, Ferrús MA. Survival and viability of Helicobacter pylori after inoculation into chlorinated drinking water. WATER RESEARCH 2007; 41:3490-3496. [PMID: 17585990 DOI: 10.1016/j.watres.2007.05.020] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Revised: 04/30/2007] [Accepted: 05/04/2007] [Indexed: 05/02/2023]
Abstract
The aim of this work was to assess the effect of chlorine water treatment on Helicobacter pylori and to study the succession of cellular alterations in response to chlorine exposure. H. pylori NCTC 11637 reference strain was used for inoculating water samples. The culturability, substrate responsiveness combined with fluorescent in situ hybridization detection (DVC-FISH assay), RNA content, DNA content, and mRNA changes of H. pylori cells were analyzed. Culturability was lost at 5 min in water with 0.96 mg/l of free chlorine. Viable cells were detected by DVC-FISH after 3h of exposure to chlorine but not after 24h. The percentage of coccoid forms was higher than spiral forms after 40s of chlorine exposure, but even after 24h, FISH detection revealed the presence of spiral cells. After 24h, amplification of the specific H. pylori 16S rDNA gene was achieved. Expression of the vacA gene was detected with the same intensity at all time points tested, demonstrating that these genes are expressed in non-culturable H. pylori cells. Levels of 16S rRNA were constant during the chlorine treatment, so killing of bacteria with chlorine probably does not involve ribosome degradation. According to our results, H. pylori could survive to disinfection practices normally used in drinking water treatment in the viable but non-culturable form, which would allow them to reach final consumption points and, at the same time, enable them to be undetectable by culture methods.
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Affiliation(s)
- Yolanda Moreno
- Departamento de Biotecnología, Universidad Politécnica, Camino de Vera 14, 46022 Valencia, Spain
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