Oral lichen planus (OLP) is a prevalent T-cell mediated inflammatory-immune disease with uncertain etiology. Recently, there is emerging evidence suggesting that oral bacteria may exert a prominent role in the onset and development of OLP. They might promote the initiation and progression of OLP by disrupting the oral epithelia, invading the lamina propria, stimulating pro-inflammatory cytokines production and inducing immune dysfunction. In this review, we will focus on the possible mechanisms of oral bacteria contributing to occurrence and development of OLP, and provide new insights into the bacteria-related diagnosis, prevention and treatment strategies for OLP.

The biofilm structure of Helicobacter pylori is known to enhance its capabilities for antimicrobial resistance. This study aims to investigate the role of the flagellar hook length control protein gene fliK in the biofilm formation of H. pylori. Homologous recombination was employed to knock out the fliK gene in the H. pylori NCTC 11637 strain. The flagella of H. pylori were observed using transmission electron microscopy (TEM), whereas H. pylori motility and growth were examined through semi-solid agar assays and growth curve analyses, respectively. The bacterial biofilm and its constituents were visualized utilizing fluorescence confocal microscopy. Assessments of H. pylori adhesion to gastric mucosal cells, its vacuolar toxicity, and antibiotic resistance were evaluated using co-culture experiments and E-test methods. The fliK gene was successfully knocked out in H. pylori NCTC 11637. The ΔfliK mutant exhibited polyhook structures or lacked typical flagellar morphology, reduced mobility, and a slower bacterial growth rate compared with the wild-type strain. Fluorescence confocal microscopy revealed a decrease in the thickness of the biofilm formed by the ΔfliK strain, along with reductions in polysaccharide and DNA components. The deletion of fliK did not affect vacuolar toxicity or antibiotic resistance but did reduce the adhesive capacity of the bacterium to gastric mucosal cells. The deletion of the fliK gene significantly impairs H. pylori biofilm formation, leading to substantial decreases in biofilm components, bacterial growth, and adhesion capabilities. These findings underscore the importance of fliK in the pathogenicity of H. pylori.IMPORTANCEThe increasing antibiotic resistance of Helicobacter pylori has emerged as a global health concern, with biofilm formation serving as a crucial mechanism underlying this resistance. This study investigates the role of the fliK gene, which encodes the flagellar hook length control protein, in H. pylori biofilm formation. Furthermore, we examined the influence of fliK on H. pylori growth, motility, and cellular adhesion capabilities. Our findings elucidate the molecular mechanisms governing H. pylori biofilm formation and suggest potential therapeutic strategies for addressing H. pylori antibiotic resistance.

The status of family-based H. pylori infection in Yunnan Province is unknown. This study is the first family-based epidemiological survey of H. pylori in the province, aiming to provide new insights into the status of family-based H. pylori infections in Yunnan Province as well as in the country as a whole.

Between 2021 and 2023, 1,176 families with 2,947 family members were tested for H. pylori in six cities in Yunnan Province with different geographic locations and economic status, to assess the status of H. pylori infection, and to clarify the related factors and modes of transmission by means of a questionnaire survey.

In Yunnan Province, the H. pylori infection rate was 31.46% (927/2947) in people and 54.59% (642/1176) in families.On the individual side, living outside of southern Yunnan (e.g., Central OR 1.41, 95% CI 1.10-1.81), having a family member living together for ≥ 1 year (OR 2.43, 95% CI 1.49-3.95), being ≥ 18 years old (e.g., 18-44 years old: OR 3.51, 95% CI 1.98-6.23), and gastrointestinal discomfort within the last 1 year (OR 1.25, 95% CI 1.04-1.50) were independent risk factors for H. pylori infection in the study population in Yunnan Province, whereas an education level of college/university and above (OR 0.62, 95% CI 0.48-0.79), and a gastroscopy within 5 years (OR 0.58, 95% CI 0.46-0.73) were independent protective factors for their H. pylori infection. In terms of family, living outside of southern Yunnan (e.g., Central OR 1.52, 95% CI 1.07-2.18), and having ≥ 3 people living together in the family (e.g., 3-4 people: OR 2.04, 95% CI 1.52-2.72) were independent risk factors for H. pylori infection in study families in Yunnan Province, whereas an annual household income of ≥ 100,000 ( OR 0.68, 95% CI 0.51-0.90), total household living area ≥ 60 m2 (OR 0.62, 95% CI 0.39-0.97), the use of separate meals for intra-household gatherings (OR 0.56, 95% CI 0.38-0.85), and the use of communal spoons and chopsticks (OR 0.38, 95% CI 0.28-0.52) were the independent protective factorse.

The risk factors of Family-Based H. pylori infection in Yunnan province were closely related to demographic characteristics, personal and family living habits. Close contact with infected family members may be the main cause of transmission. Family-based control of H. pylori infection should be regarded in clinical practice.

Chronic atrophic gastritis (CAG) is an important stage of precancerous lesions of gastric cancer. Effective treatment and regulation of CAG are essential to prevent its progression to malignancy. Traditional Chinese medicine (TCM) has shown multi-targeted efficacy in CAG treatment, with advantages in enhancing gastric mucosal barrier defense, improving microcirculation, modulating inflammatory and immune responses, and promoting lesion healing, etc. Clinical studies and meta-analyses indicate that TCM provides significant benefits, with specific Chinese herbal compounds and monomers demonstrating protective effects on the gastric mucosa through mechanisms including anti-inflammation, anti-oxidation, and regulation of cellular proliferation and apoptosis, etc. Finally, it is pointed out that the efficacy of TCM in the treatment of CAG requires standardized research and unified standards, and constantly clarifies and improves the evaluation criteria of each dimension of gastric mucosal barrier function.

Porphyromonas gingivalis (P. gingivalis) is a keystone periodontal pathogen associated with various gastro-intestinal tract cancers. However, whether P. gingivalis can promote oral squamous cell carcinoma (OSCC) and the underlying mechanism associated with such promotion remain unclear.

In this study, OSCC xenograft models were used to evaluate the effects of P. gingivalis on tumor progression. The functional studies were done on several OSCC cell lines in vitro. P. gingivalis-specific 16S rRNA fluorescent in situ hybridization (FISH) was used to test its prevalence in clinical samples.

We found that P. gingivalis increased tumor volume and tumor growth in OSCC nude models. Functional studies demonstrated that P. gingivalis inhibited the apoptosis of OSCC cells by promoting cellular autophagy. P. gingivalis was more prevalent in FISH samples from patients with OSCC than from patients with leukoplakia or healthy subjects (70% vs. 47.2% vs. 33.3%, p = 0.045 and p < 0.001, respectively).

These data suggest that P. gingivalis plays an accelerating role in OSCC progression and contributes to OSCC by enhancing the autophagy pathway to reduce carcinoma apoptosis.

Helicobacter pylori (HP) is a Gram-negative bacterium that infects approximately fifty percent (50%) of individuals worldwide. The coccoid form of HP, a dormant state with altered morphology, has been associated with persistent infections and antibiotic resistance. This study aimed to investigate the prevalence of the coccoid form of HP in patients living with obesity. Sleeve gastrectomy specimens from obese patients and gastric biopsies from non-obese individuals were analyzed. Immunohistochemistry (IHC) staining and histopathological examination were performed to identify and quantify the coccoid forms of HP. Statistical analysis was conducted to compare the results between the two groups. The study included 53 obese patients and 62 non-obese individuals. The percentage of coccoid forms of HP was significantly higher in obese patients compared to non-obese individuals (median 50% vs. 10%, p < 0.001). Type of gastritis was also significantly different between the groups. Obese patients exhibited a higher prevalence of the coccoid form of HP in their gastric mucosa. This finding suggests that the gastric microenvironment in obesity may favor the formation of the coccoid form, potentially impacting the colonization and pathogenicity of HP. The higher prevalence of the coccoid form in obese patients has important clinical implications, as it is more resistant to antibiotics and difficult to eradicate. Alternative treatment strategies may be necessary to effectively manage HP infections in this population. Furthermore, the presence of the coccoid form may increase the risk of HP-associated diseases in obese individuals. Further research is needed to elucidate the underlying mechanisms and explore novel treatment approaches for HP infection in the context of obesity.

Helicobacter pylori is a successful etiologic gastric agent that reaches a prevalence around 80% in Colombia. This bacterium is extremely diverse and has shown a phylogeographic pattern. The objective of this study was to perform an analysis of genomic epidemiology of H. pylori in Colombia. We enriched our set of 29 newly sequenced Colombian H. pylori genomes with additional data from public databases, reaching a total of 221 genomes in our dataset. Phylogenetic characterization was carried out using MLST and whole genome SNP analysis. We also performed a characterized the diversity of virulence factors and mutations associated with antimicrobial resistance. Phylogenetic analyzes showed two new Colombian H. pylori clades. Furthermore, many virulence genotype combinations were found, mutations associated with resistance were found for all the studied antibiotics, highlighting 14.4% of the genomes presented profiles associated with resistance to more than one family of antibiotics. Our analyzes described the genomics of Colombian H. pylori and verify the presence of a population group formed exclusively by Colombian isolates. We demonstrated the great diversity among the isolates and that the analysis by comparative genomics of H. pylori are valuable tools to assess the diversity, virulence, and resistance of H. pylori.

Helicobacter pylori (Hp) infection is highly prevalent globally and poses a significant public health challenge due to its link with chronic gastritis, peptic ulcers, and gastric malignancies. Hp's persistence within the gastric environment, particularly in case of infection with virulent strains, triggers chronic inflammatory responses and mucosal damage. Antibiotic therapy is the primary approach for Hp eradication, but antibiotic resistance and adverse effects hinder treatment efficacy. Emerging evidence suggests that Brassicaceae-derived metabolites could serve as adjunctive therapy for Hp infection, offering potential antimicrobial and anti-inflammatory benefits.

A systematic literature review was conducted following PRISMA guidelines to assess the impact of Brassicaceae-rich diets on Hp infection control. Searches were performed in MEDLINE PubMed, Web of Science, and the Cochrane Library until 18 October 2023, without language or date restrictions. Eligible studies meeting PICOS criteria were included, encompassing populations infected with Hp or Hp-infected human cell cultures, interventions involving Brassicaceae consumption or its bioactive molecules, and outcomes related to Hp infection control, antibiotic therapy interactions, reduction of antibiotic side effects, and inflammation mitigation. Animal studies, cell line experiments, reviews unrelated to the research objectives, and studies on Hp-related gastric cancer were excluded.

Available evidence indicates that Brassicaceae consumption exhibits the potential to reduce Hp colonization but achieving complete eradication of the pathogen remains challenging. Conflicting results regarding the efficacy of broccoli in Hp treatment emerge, with certain investigations suggesting limited effectiveness. Other studies point to a potential for heightened eradication rates when combined with standard triple therapy. Furthermore, promising outcomes are observed with broccoli extract supplements, indicating their role in mitigating Hp-induced gastric mucosal damage. In fact, it is noteworthy that sulforaphane and its derivatives manifest notable reductions in pro-inflammatory markers, indicative of their anti-inflammatory properties. Adverse events associated with antibiotic therapy seem unaffected by sulforaphane derivatives or probiotics. However, individual responses to these treatments vary, underscoring the unpredictability of their efficacy in ameliorating antibiotic therapy-related side effects.

Our systematic review highlights the potential of Brassicaceae-rich diets as adjunctive therapy for Hp infection, offering synergistic interactions with antibiotics and possibly mitigating antibiotic side effects and inflammation. Further research, particularly well-designed randomized trials, is warranted to elucidate the therapeutic efficacy and optimal utilization of Brassicaceae-derived metabolites in managing human Hp-related diseases.

Chronic atrophic gastritis (CAG) is a prevalent digestive system disease characterized by atrophy of the gastric mucosa and the disappearance of inherent gastric glands. According to the theory of Correa's cascade, CAG is an important pathological stage in the transformation from normal condition to gastric carcinoma. In recent years, the global incidence of CAG has been increasing due to pathogenic factors, including Helicobacter pylori infection, bile reflux, and the consumption of processed meats. In this review, we comprehensively described the etiology and clinical diagnosis of CAG. We focused on elucidating the regulatory mechanisms and promising therapeutic targets in CAG, with the expectation of providing insights and theoretical support for future research on CAG.

Helicobacter pylori (H. pylori) stands as the predominant infectious agent linked to the onset of gastritis, peptic ulcer diseases, and gastric cancer (GC). Identified as the exclusive bacterial factor associated with the onset of GC, it is classified as a group 1 carcinogen by the World Health Organization. The elimination of H. pylori plays a crucial role in the primary prevention of GC. While the prevalence has declined in recent decades, H. pylori infection is still highly prevalent in China, accounting for a significant part of the disease burden of GC. Therefore, updated prevalence information for H. pylori infection, especially regional and demographic variations in China, is an important basis for the design of targeted strategies that will be effective for the prevention of GC and application of policies for H. pylori control.

To methodically evaluate the occurrence of H. pylori infection throughout China and establish a reference point for subsequent investigations.

A systematic review and meta-analysis was conducted following established guidelines, as detailed in our methodology section.

Our review synthesized data from 152 studies, covering a sample of 763827 individuals, 314423 of whom were infected with H. pylori. We evaluated infection rates in mainland China and the combined prevalence of H. pylori was 42.8% (95%CI: 40.7-44.9). Subgroup analysis indicated the highest prevalence in Northwest China at 51.3% (95%CI: 45.6-56.9), and in Qinghai Province, the prevalence reached 60.2% (95%CI: 46.5-73.9). The urea breath test, which recorded the highest infection rate, showed a prevalence of 43.7% (95%CI: 41.4-46.0). No notable differences in infection rates were observed between genders. Notably, the prevalence among the elderly was significantly higher at 44.5% (95%CI: 41.9-47.1), compared to children, who showed a prevalence of 27.5% (95%CI: 19.58-34.7).

Between 2014 and 2023, the prevalence of H. pylori infection in China decreased to 42.8%, down from the previous decade. However, the infection rates vary considerably across different geographical areas, among various populations, and by detection methods employed.

Peptic ulcers, affecting approximately 10% of the global population, can result from factors such as stress, alcohol use, smoking, NSAIDs, Helicobacter pylori infection, and genetic predisposition. Plant-based medicines are gaining recognition for their therapeutic potential, including in the treatment of peptic ulcers. Green chemistry methods for the biological synthesis of nanoparticles (NPs) provide a sustainable alternative to traditional chemical techniques. These nanoparticles, particularly metallic NPs and metal oxides synthesized from plant extracts, offer promising anti-ulcer properties. This review highlights research from 2000 to 2024 on the use of green-synthesized nanoparticles and their role in peptic ulcer treatment, focusing on their therapeutic mechanisms and potential benefits. For this purpose, an electronic search of published research and review articles was conducted in PubMed, Scopus, Science Direct, Cochrane databases, and Google Scholar.

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The effectiveness of vonoprazan (VPZ)-based regimens in enhancing Helicobacter pylori (HP) eradication rates is promising. This study evaluated the clinical efficacy of 14-day VPZ-based triple therapy in obese patients infected with HP. A total of 200 obese patients with gastric disorders, confirmed to be HP-positive via gastroscopy and the 13C urea breath test, were retrospectively analyzed. Among them, 118 patients received the 14-day VPZ-based triple regimen (Study group), while 82 patients were treated with the traditional 14-day bismuth-containing proton pump inhibitor-based quadruple regimen (Control group). Baseline characteristics, pretreatment inflammatory indicators, lipid profiles, and gastrointestinal function indicators recorded. The two groups were compared for treatment efficacy, HP eradication rate, gastrointestinal function improvement, and incidence of adverse reactions. The Study group demonstrated a higher overall effective rate compared to the Control group, particularly in HP-strong positive obese patients. No significant differences were observed between the two groups for HP-positive obese patients in terms of total effective rate, HP eradication rate, gastrointestinal function improvement, or adverse reactions incidence. In conclusion, the 14-day VPZ-based triple regimen exhibited superior therapeutic efficacy, higher HP eradication rates, enhanced gastrointestinal function, and reduced adverse reactions in HP-strong positive obese patients, indicating improved overall efficacy and safety.

The rapid urease test (RUT) is widely used to detect Helicobacter pylori infection; however, it is not preferred as a monitoring strategy after eradication owing to its low sensitivity. In this study, we evaluated the diagnostic performance of RUT using the sweeping method, which overcomes the limitations of conventional tissue sampling methods after eradication.

Patients who received H pylori eradication treatment were enrolled. Each of the sweeping and conventional methods was performed on the same patients to compare diagnostic performance. Urea breath test (UBT), histology, and polymerase chain reaction were performed to determine true infection. Logistic regression analysis was conducted to investigate reasons for discrepancies between the results of the 2 methods.

In 216 patients, the eradication success rate was 68.1%, and the sensitivity and specificity of the sweeping method were 0.812 and 0.912, respectively, whereas those of the conventional method were 0.391 and 0.993, respectively (P < .05 for all). The area under the receiver operating characteristic curve for the sweeping method was higher than that for the conventional method (0.862 vs 0.692, P < .001). The mean time to H pylori detection for the sweeping method was 4.7 ± 4.4 minutes and 12.3 ± 16.1 minutes for the conventional method (P < .001). The risk for inconsistent results between the 2 methods was the highest for UBT values of 1.4‰ to 2.4‰ (odds ratio, 3.8; P = .016).

The RUT with the sweeping method could potentially replace the tissue sampling method as a test to confirm H pylori eradication and be an alternative option to UBT for patients requiring endoscopy.

The sustained increase in antibiotic resistance leads to a declining trend in the eradication rate of Helicobacter pylori (H. pylori) infection with antibiotic-based eradication regimens. Administration of a single probiotic shows limited efficacy in eradicating H. pylori infection. This review indicates that faecal microbiota transplantation (FMT), a novel therapeutic approach, either as a monotherapy or adjunctive therapy, exhibits beneficial effects in terms of the eradication of H. pylori infection and the prevention of adverse events. The role of FMT in H. pylori eradication may be associated directly or indirectly with some therapeutic constituents within the faecal suspension, including bacteria, viruses, antimicrobial peptides and metabolites. In addition, variations in donor selection, faecal suspension preparation and delivery methods are believed to be the main factors determining the effectiveness of FMT for the treatment of H. pylori infection. Future research should refine the operational procedures of FMT to achieve optimal efficacy for H. pylori infection and explore the mechanisms by which FMT acts against H. pylori.

This article investigates the link between Helicobacter pylori (H. pylori) infection and cardiovascular and neurological disorders. Recent research suggests that H. pylori may play a role in cardiovascular diseases like atherosclerosis, myocardial infarction, and stroke, as well as neurological diseases including Alzheimer's disease, multiple sclerosis, and Parkinson's disease. Cardiovascular Diseases: H. pylori induces endothelial dysfunction and chronic inflammation, promoting atherosclerotic plaque formation and other cardiac complications. High infection prevalence in cardiovascular patients implies that systemic inflammation from H. pylori accelerates disease progression. Eradication therapies combined with anti-inflammatory and lipid-lowering treatments may reduce cardiovascular risk. Neurological Diseases: H. pylori may contribute to Alzheimer's, multiple sclerosis, and Parkinson's through systemic inflammation, neuroinflammation, and autoimmune responses. Increased infection prevalence in these patients suggests bacterial involvement in disease pathogenesis. The eradication of H. pylori could reduce neuroinflammation and improve outcomes. Discussions and Future Research: Managing H. pylori infection in clinical practice could impact public health and treatment approaches. Further research is needed to clarify these relationships. Longitudinal and mechanistic studies are essential to fully understand H. pylori's role in these conditions. Conclusions: H. pylori infection is a potential risk factor for various cardiovascular and neurological conditions. Additional research is critical for developing effective prevention and treatment strategies. Targeted therapies, including H. pylori eradication combined with anti-inflammatory treatments, could improve clinical outcomes. These findings highlight the need for an integrated clinical approach to include H. pylori evaluation and treatment.

Infection caused by Helicobacter pylori (H. pylori) affects approximately 50% of the global population. It is a major pathogenic factor for chronic gastritis and gastric cancer. Besides, the resistance to antibiotics such as clarithromycin could reduce the eradication rate. Currently, there is an urgent need for a swift, easy to perform, and highly sensitive detection method for H. pylori and clarithromycin resistance.

We used FAM/Digoxin labeled primers to amplify specific H. pylori 23S rRNA fragments by Recombinase Aided Amplification (RAA), and resistance mutations were distinguished using CRISPR/Cas13a system combined with lateral flow strip. Twenty-eight saliva samples were analyzed using qPCR, gene sequencing and this method to evaluate the detection efficiency.

We developed a simultaneous detection method for H. pylori and clarithromycin resistance mutations named sensitive H. pylori easy-read dual detection (SHIELD). The results showed both A2142G and A2143G mutant DNAs causing clarithromycin resistance could be distinguished from the wild type with a concentration of 50 copies/μL, and no cross-reaction with other 5 common gastrointestinal bacteria was observed. For the detection of H. pylori in 28 saliva samples, the positive predictive value of this method was 100% (19/19) in comparison with qPCR. For detecting clarithromycin resistance, the positive predictive value of this method was 84.6% (11/13) compared with gene sequencing.

SHIELD assay showed high sensitivity and specificity in detecting H. pylori and clarithromycin resistance mutations. It could be a potential measure in the rapid detection of H. pylori, large-scale screening and guiding clinical medication.

Helicobacter pylori (H. pylori) is a harmful bacterium that is difficult to conveniently diagnose and effectively eradicate. Chronic H. pylori infection increases the risk of gastrointestinal diseases, even cancers. Despite the known findings, more underlying mechanisms are to be deeply explored to facilitate the development of novel prevention and treatment strategies of H. pylori infection. Long noncoding RNAs (lncRNAs) are RNAs with more than 200 nucleotides. They may be implicated in cell proliferation, inflammation and many other signaling pathways of gastrointestinal cancer progression. The dynamic expression of lncRNAs indicates their potential to be diagnostic or prognostic biomarkers. In this paper, we comprehensively summarize the processes of H. pylori infection and the treatment methods, review the known findings of lncRNA classification and functional mechanisms, elucidate the roles of lncRNAs in H. pylori-related gastrointestinal cancer, and discuss the clinical perspectives of lncRNAs.

Helicobacter pylori infection causes chronic gastritis, ulcers, and gastric cancer, making it a threat to human health. Despite the use of antibiotic therapy, the global prevalence of H. pylori infection remains high, necessitating early eradication measures. Immunotherapy, especially vaccine development, is a promising solution in this direction, albeit the selection of an appropriate animal model is critical in efficient vaccine production. Accordingly, we conducted a literature, search and summarized the commonly used H. pylori strains, H. pylori infection-related animal models, and models for evaluating H. pylori vaccines. Based on factors such as the ability to replicate human diseases, strain compatibility, vaccine types, and eliciting of immune responses, we systematically compared the advantages and disadvantages of different animal models, to obtain the informed recommendations. In addition, we have proposed novel perspectives on H. pylori-related animal models to advance research and vaccine evaluation for the prevention and treatment of diseases such as gastric cancer.

Helicobacter pylori (H. pylori) is the predominant etiological agent of gastritis and disrupts the integrity of the gastric mucosal barrier through various pathogenic mechanisms. After H. pylori invades the gastric mucosa, it interacts with immune cells in the lamina propria. Macrophages are central players in the inflammatory response, and H. pylori stimulates them to secrete a variety of inflammatory factors, leading to the chronic damage of the gastric mucosa. Therefore, the study aims to explore the mechanism of gastric mucosal injury caused by inflammatory factors secreted by macrophages, which may provide a new mechanism for the development of H. pylori-related gastritis.

The expression and secretion of CCL3 from H. pylori infected macrophages were detected by RT-qPCR, Western blot and ELISA. The effect of H. pylori-infected macrophage culture medium and CCL3 on gastric epithelial cells tight junctions were analyzed by Western blot, immunofluorescence and transepithelial electrical resistance. EdU and apoptotic flow cytometry assays were used to detect cell proliferation and apoptosis levels. Dual-luciferase reporter assays and chromatin immunoprecipitation assays were used to study CCL3 transcription factors. Finally, gastric mucosal tissue inflammation and CCL3 expression were analyzed by hematoxylin and eosin staining and immunohistochemistry.

After H. pylori infection, CCL3 expressed and secreted from macrophages were increased. H. pylori-infected macrophage culture medium and CCL3 disrupted gastric epithelial cells tight junctions, while CCL3 neutralizing antibody and receptor inhibitor of CCL3 improved the disruption of tight junctions between cells. In addition, H. pylori-infected macrophage culture medium and CCL3 recombinant proteins stimulated P38 phosphorylation, and P38 phosphorylation inhibitor improved the disruption of tight junctions between cells. Besides, it was identified that STAT1 was a transcription factor of CCL3 and H. pylori stimulated macrophage to secret CCL3 through the JAK1-STAT1 pathway. Finally, after mice were injected with murine CCL3 recombinant protein, the gastric mucosal injury and inflammation were aggravated, and the phosphorylation level of P38 was increased.

In summary, our findings demonstrate that H. pylori infection stimulates macrophages to secrete CCL3 via the JAK1-STAT1 pathway. Subsequently, CCL3 damages gastric epithelial tight junctions through the phosphorylation of P38. This may be a novel mechanism of gastric mucosal injury in H. pylori-associated gastritis.

Helicobacter pylori (H. pylori) can evade the host's immune response and persist for a long time on the gastric mucosa. T helper (Th) cells appear to be involved in the control of H. pylori bacteria but promote mucosal inflammation. In contrast, regulatory T cells (Tregs) may reduce inflammation but promote H. pylori persistence. CC motif chemokine receptor 6 (CCR6) is involved in the migration of various cells into inflamed gastric mucosa. In this study, we examined CCR6+ Th cells and CCR6+ Tregs during H. pylori infection in humans.

Isolation of cells from blood and mucosal biopsies, magnetic separation of В cells, CD4+ and CD4+CCR6+CD45RO+ T cells, antigen-specific activation, B cell response in vitro, flow cytometry, determination of CD4+CD25hiFoxP3+ Tregs and various groups of Th cells.

CD4+CCR6+ blood lymphocytes from healthy donors included Th cells and Tregs. These CCR6+ Th cells produced proinflammatory cytokines and also stimulated plasma cell maturation and antibody production in vitro. H. pylori gastritis and peptic ulcer disease were associated with an increase in the number of circulate CD4+CCR6+CD45RO+ cells and the percentage of Th1, Th17 and Th1/17 cells in this lymphocyte subgroup. In H. pylori-positive patients, circulating CD4+CCR6+ cells contained a higher proportion of H. pylori-specific cells compared with their CD4+CCR6- counterparts. H. pylori infection strongly increased the content of CD4+ lymphocytes in the inflamed gastric mucosa, with the majority of these CD4+ lymphocytes expressing CCR6. CD4+CCR6+ lymphocytes from H. pylori-infected stomach included Tregs and in vivo activated T cells, some of which produced interferon-γ without ex vivo stimulation.

H. pylori infection causes an increase in the number of mature CD4+CCR6+ lymphocytes in the blood, with a pro-inflammatory shift in their composition and enrichment of the gastric mucosa with CD4+CCR6+ lymphocytes, including CCR6+ Th1 cells and Tregs.

Nodular gastritis (NG) represents a frequently observed clinical presentation of Helicobacter pylori (H. pylori) infection in pediatric patients. This investigation aimed to explore the microbiota and histological features of the gastric mucosa in children with H. pylori colonized NG.

The current investigation examined a sample of 120 children who underwent gastroscopy due to symptoms of gastrointestinal distress, which showed that 64 were patients with H. pylori infection. Endoscopic procedures were conducted to acquire mucosal biopsies for the purpose of DNA extraction and histopathological analysis. The 16S rRNA profiling was utilized to examine the gastric mucosal microbiota.

In conjunction with endoscopic evaluation, 26 of 64 patients were diagnosed with NG. The NG group had significantly higher inflammation scores and activity scores on histological assessment than the non-NG group. The NG group exhibited a significant reduction in the richness levels of the five genera. In terms of the predicted functions, the pathways of synthesis and degradation of ketone bodies and phagosome in the NG group were less abundant compared with the non-NG group, while the Wnt signaling pathway was significantly enriched. NG does not increase a microbial community that possesses genotoxic potential within the gastric mucosa.

In conclusion, NG group exhibited significant severe inflammation and reduced abundance levels of several bacterial genera compared to the non-NG group. However, individuals with NG did not have a dysregulated microbial community with genotoxic potential.

Vonoprazan holds significant research promise for Helicobacter pylori eradication, with the goal of determining the most effective drug regimen. In this study, H. pylori patients (426) were enrolled and randomized into 3 groups: an EA14 group (20 mg of esomeprazole qid and 1000 mg of amoxicillin tid for 14 days), a VA14 group (20 mg of vonoprazan bid and 750 mg of amoxicillin qid for 14 days), and a VA10 group (20 mg of vonoprazan bid and 1000 mg of amoxicillin tid for 10 days). Key outcomes encompassed the H. pylori eradication rate, patient adverse effects, and compliance. In the EA14, VA14, and VA10 groups, H. pylori eradication rates were 89.4%, 90.1%, and 88.7% in intention-to-treat analysis, and 94.2%, 94.4%, and 94.6% in per-protocol analysis, respectively. Adverse events incidences were 14.8%, 12.7%, and 5.6%, while compliance rates were 88.7%, 90.9%, and 95.8%, respectively. Notably, the VA10 regimen demonstrated comparable H. pylori eradication rates, adverse effect incidences, and compliance levels to the EA14 and VA14 regimens.

Helicobacter pylori (H. pylori) is the predominant pathogen causing chronic gastric mucosal infections globally. During the period from 2011 to 2022, the global prevalence of H. pylori infection was estimated at 43.1%, while in China, it was slightly higher at approximately 44.2%. Persistent colonization by H. pylori can lead to gastritis, peptic ulcers, and malignancies such as mucosa-associated lymphoid tissue (MALT) lymphomas and gastric adenocarcinomas. Despite eliciting robust immune responses from the host, H. pylori thrives in the gastric mucosa by modulating host immunity, particularly by altering the functions of innate and adaptive immune cells, and dampening inflammatory responses adverse to its survival, posing challenges to clinical management. The interaction between H. pylori and host immune defenses is intricate, involving evasion of host recognition by modifying surface molecules, manipulating macrophage functionality, and modulating T cell responses to evade immune surveillance. This review analyzes the immunopathogenic and immune evasion mechanisms of H. pylori, underscoring the importance of identifying new therapeutic targets and developing effective treatment strategies, and discusses how the development of vaccines against H. pylori offers new hope for eradicating such infections.

The administration of probiotics is an effective approach for treatment of Helicobacter pylori, which is associated with human gastrointestinal diseases and cancers. To explore more effective probiotics for H. pylori infection elimination, bacteria from infant feces were screened in this study. We successfully isolated the Bifidobacterium animalis subsp. lactis strains and evaluated its efficacy to inhibit H. pylori growth in vitro and in vivo. The results showed that a B. animalis strain (named BB18) sustained a high survival rate after incubation in gastric juice. The rapid urease test suggested that B. animalis BB18 reduced pathogen loads in H. pylori-infected Mongolian gerbils. Alleviation of H. pylori infection-induced gastric mucosa damage and decreased levels inflammatory cytokines were observed after the B. animalis BB18 administration. These findings demonstrated that B. animalis BB18 can inhibit H. pylori infection both in vitro and in vivo, suggesting its potential application for the prevention and eradication therapy of H. pylori infection.

Helicobacter pylori is a Gram-negative, spiral-shaped bacterium that infects approximately 50% of the world's population and has been strongly associated with chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoma, and gastric cancer. The elimination of H. pylori is currently considered one of the most effective strategies for the treatment of gastric-related diseases, so antibiotic therapy is the most commonly used regimen for the treatment of H. pylori infection. Although this therapy has some positive effects, antibiotic resistance has become another clinically prominent problem. Therefore, the development of a safe and efficient vaccine has become an important measure to prevent H. pylori infection.

PubMed and ClinicalTrials.gov were systematically searched from January 1980 to March 2023 with search terms-H. pylori vaccine, adjuvants, immunization, pathogenesis, and H. pylori eradication in the title and/or abstract of literature. A total of 5182 documents were obtained. Based on the principles of academic reliability, authority, nearly publicated, and excluded the similar documents, finally, 75 documents were selected, organized, and analyzed.

Most of the candidate antigens used as H. pylori vaccines in these literatures are whole-cell antigens and virulence antigens such as UreB, VacA, CagA, and HspA, and the main types of vaccines for H. pylori are whole bacteria vaccines, vector vaccines, subunit vaccines, nucleic acid vaccines, epitope vaccines, etc. Some vaccines have shown good immune protection in animal trials; however, few vaccines show good in clinical trials. The only H. pylori vaccine passed phase 3 clinical trial is a recombinant subunit vaccine using Urease subunit B (UreB) as the vaccine antigen, and it shows good prophylactic effects. Meanwhile, the adjuvant system for vaccines against this bacterium has been developed considerably. In addition to the traditional mucosal adjuvants such as cholera toxin (CT) and E. coli heat labile enterotoxin (LT), there are also promising safer and more effective mucosal adjuvants. All these advances made safe and effective H. pylori vaccines come into service as early as possible.

This review briefly summarized the advances of H. pylori vaccines from two aspects, candidates of antigens and adjuvants, to provide references for the development of vaccine against this bacterium. We also present our prospects of exosomal vaccines in H. pylori vaccine research, in the hope of inspiring future researchers.

This is the first clinical research to systematically expound the difference between gastric cancer (GC) individuals with Helicobacter pylori and GC individuals without H. pylori from the perspective of multi-omics. This clinical study identified significant genes, microbes, and fecal metabolites, which exhibited nice power for differentiating GC individuals with H. pylori infection from GC individuals without H. pylori infection. This study provides a crucial basis for a better understanding of eradication therapy among the GC population.

Background Helicobacter pylori (H. pylori) is a virulent pathogen causing gastritis and ulcers followed by serious complications. Despite being a heavy burden to eradicate, there are not many studies that assess the comprehension of future physicians regarding this bacterium. The objective of this study was to assess medical students' knowledge and attitude toward H. pylori while evaluating the variations based on their socio-demographic factors at King Saud bin Abdulaziz University for Health Sciences (KSAU-HS) in Riyadh, Saudi Arabia. Methods A cross-sectional study was conducted among students in all four years of medical college. The data was collected by distributing an online questionnaire which included three following sections: demographic data, knowledge regarding H. pylori infection, and attitude toward H. pylori infection. Total knowledge and attitude levels were grouped into three and two categories, respectively, and compared between the respondents' socio-demographics. Results Out of 330 respondents, the majority were females (n=185, 56%), and the mean age was 22.8±2.1 years. There were 184 students (56%) who had an excellent attitude (>70%) and 140 (44%) students had average knowledge (34-70%). The medical students' knowledge level was significantly (p<0.001) different between the participants according to their year of study and gender, with higher scores reported by male students in their clinical years (sixth and fifth years). Conclusion Medical students of KSAU-HS, Riyadh, had an overall average knowledge and excellent attitude towards H. pylori infection, and its prevention and management which emphasize the need for more comprehensive education and awareness programs throughout the medical curriculum to ensure future physicians are well-prepared to address the challenges associated with H. pylori-related health issues.

The bacterium Helicobacter pylori (H. pylori) represents a major risk factor associated with the development of gastric cancer. The anti-oxidant curcumin has been ascribed many benefits to human health, including bactericidal effects. However, these effects are poorly reproducible because the molecule is extremely unstable and water insoluble. Here we solubilized curcumin as either nanoemulsions or chitosan nanocapsules and tested the effects on H. pylori. The nanoemulsions were on average 200 nm in diameter with a PdI ≤ 0.16 and a negative zeta potential (-54 mV), while the nanocapsules were 305 nm in diameter with a PdI ≤ 0.29 and a positive zeta potential (+68 mV). Nanocapsules were safer than nanoemulsions when testing effects on the viability of GES-1 gastric cells. Also, nanocapsules were more efficient than nanoemulsions at inhibiting H. pylori growth (minimal inhibitory concentration: 50 and 75 μM, respectively), whereby chitosan contributed to this activity. Importantly, both formulations effectively diminished H. pylori's adherence to and internalization by GES-1 cells, as well as biofilm formation. In summary, the demonstrated activity of the curcumin nanoformulations described here against H. pylori posit them as having great potential to treat or complement other therapies currently in use against H. pylori infection.

Urease subunit B (UreB), a conserved and key virulence factor of Helicobacter pylori (H. pylori), can induce the host CD4+ T cell immune responses to provide protection, but less is known regarding CD8+ T cell responses. The characteristics of H. pylori-specific CD8+ T cell responses and the mechanism underlying antigen processing and presentation pathways remain unclear. This study was focus on protective antigen recombinant UreB (rUreb) to detect specific CD8+ T cell responses in vitro and elucidate the mechanism of UreB antigen processing and presentation.

The peripheral blood mononuclear cells (PBMCs) collected from H. pylori-infected individuals were stimulated with rUreB in vitro to detect specific CD8+ T cell responses after co-culture with rUreB-pulsed autologous hMDCs. Through blocking assay, we investigated the potential pathway of UreB antigen processing and presentation via the cytosolic pathway or vacuolar pathway. The cytokines production of UreB specific CD8+ T cell were evaluated as well.

We demonstrated UreB can induce specific CD8+ T cell immune responses in H. pylori infected individuals. Importantly, we characterized that UreB were mainly processed by proteasome instead of lysosomal proteases and presented through cytosolic pathway of cross-presentation, which requires endoplasmic reticulum-Golgi transport and newly synthesized MHC-I molecules, to induce functional-specific CD8+ T cell (IFN-γ + TNF-α + Grz A+ Grz B+) responses.

These results suggest that H. pylori UreB induces specific CD8+ T cell responses through cytosolic pathway of cross-presentation in infected individuals.

The relationship between Helicobacter pylori infection and rheumatoid arthritis has been investigated, but the results remain controversial. This study aims to determine the association between the two diseases via a 17-year retrospective cohort study. Using the National Health Insurance Research Database, a nationwide population based in Taiwan, we identified 97,533 individuals with H. pylori infection and matched controls between 2000 and 2017 using propensity score matching at a 1:1 ratio. The adjusted hazard ratio of rheumatoid arthritis was determined by multiple Cox regression. The incidence rate of rheumatoid arthritis was 1.28 per 10,000 person-months in the H. pylori cohort, with a higher risk compared to the control group. In the < 30 years old subgroup, the risk was highest, especially in women < 30 years old with H. pylori infection. Patients with < 1 year follow-up showed 1.58 times higher susceptibility to rheumatoid arthritis. Individuals with follow-ups of 1-5 years and over 5 years demonstrated 1.43 and 1.44 times higher risks of rheumatoid arthritis, respectively. Our study showed H. pylori infection was associated with the development of rheumatoid arthritis. Clinicians should note higher risk, especially < 30 years old. More research needed to understand underlying mechanism.

This study used multilocus sequence typing (MLST) to investigate the prevalence of Helicobacter pylori (H. pylori) mixed infections and H. pylori mixed infections involving unrelated strains; and determined the phylogeographic groups of H. pylori recovered from patients in Ningbo, China. A total of 156 H. pylori isolates were obtained from a convenience sample of 33 patients with culture-positive H. pylori infection. MLST was used to classify 150 H. pylori clinical isolates and 12 methodological control strains (6 clinical isolates and 6 strains of American Type Culture Collection H. pylori) into 43 and 12 sequence types (STs), respectively. In this study, 246 new alleles and 53 new STs were identified by MLST. The prevalence of mixed infections was 41% (11/27). The prevalence of H. pylori mixed infections involving unrelated strains was 46% (5/11) and the prevalence of H. pylori mixed infections involving completely unrelated strains (strains with all 7 housekeeping genes different) was 36% (4/11). A phylogenetic tree was created to determine the evolutionary relationships between different strains. The STs in this study were clustered within the hspEAsia subgroup (98%) and hpEurope group (2%). H. pylori mixed infections were common in Ningbo, China. The H. pylori isolates belonging to the hpEurope group were recovered from three different biopsy samples in a native Chinese patient. Most of H. pylori strains colonizing the antrum, corpus, and duodenum bulb were homologous.

Duodenal ulcer significantly reduces quality of life and safety in children; however, the mechanism of the pathogenesis in children with duodenal ulcer remains unclear. S100A8/A9, which plays a critical role in the occurrence and development of inflammation, has attracted a lot of interest recently. Here, we identified that S100A8/A9 are highly expressed in the serum of children with duodenal ulcers, and this is of excellent diagnostic value. Animal experiments have proved that inhibition of S100A8/A9 can repair ulcer progression. In addition, further study has shown that S100A8/A9, mainly produced by neutrophil, can enhance the apoptosis of intestinal epithelial cells and promote the growth in children with duodenal ulcers. Thus, our research proves the value of S100A8/A9 in the diagnosis and treatment of children with duodenal ulcers.

Even though Helicobacter pylori (H. pylori) is a serious pathogen, its origin is unknown. Poultry (Chicken, Turkey, Quebec, Goose, and Ostrich) are consumed as a regular protein source by a large number of people across the world; therefore, sanitary ways of delivering poultry for food are important for global health. As a result, we looked at the distribution of the pathogenicity cagA, vacA, babA2, oipA, and iceA in H. pylori isolates in poultry meat, as well as their antimicrobial resistance. Wilkins Chalgren anaerobic bacterial medium was used to cultivate 320 raw poultry specimens. Disk diffusion and Multiplex-PCR were used to investigate antimicrobial resistance and genotyping patterns, separately. H. pylori was found in 20 of 320 (6.25%) raw poultry samples. The highest incidence of H. pylori was found in chicken raw meat (15%), whereas the fewest was found in Goose and Quebec (0.00%). Resistance to ampicillin (85%), tetracycline (85%), and amoxicillin (75%) were greatest in H. pylori isolates. The percentage of H. pylori isolates with a MAR value of more than 0.2 was 17/20 (85%). The most prevalent genotypes discovered were VacA s1a (75%), m1a (75%), s2 (70%) and m2 (65%), and cagA (60%). The most typically discovered genotype patterns were s1am1a (45%), s2m1a (45%), and s2m2 (30%). BabA2, OipA + , and OipA- genotypes were found in 40%, 30%, and 30% of the population. In summary, the poultry flesh was polluted by H. pylori, with the babA2, vacA, and cagA genotypes being more prevalent. The simultaneous occurrence of vacA, cagA, iceA, oipA, and babA2 genotypes in antibiotic-resistant H. pylori bacteria implies a serious public health concern about raw poultry eating. In the future, researchers should look into H. pylori's resistance to multiple antibacterial drugs in Iran.

The recognition of pathogen- or damage- associated molecular patterns (PAMPs/DAMPs) signals a series of coordinated responses as part of innate immunity or host cell defense during infection. The inflammasome is an assemblage of multiprotein complexes in the cytosol that activate inflammatory caspases and release pro-inflammatory mediators. This review examines the two-edged sword activity of gasdermin D (GSDMD). Since its discovery in 2015, GSDMD has played a crucial role in the programmed necrotic type of cell death called pyroptosis. Pyroptosis is an important response in host self-protection against danger signals and infection. Although excessive pyroptosis has a deleterious effect on the host, it proves to have a game-changing therapeutic application against pathogenic invasion when controlled. Here, we explore the mechanism utilized by GSDMD, the best studied member of the gasdermin protein family, in host immune defense against many bacteria. While the protein contributes to the clearance of some bacteria, we also discussed results from previous studies and research, that its presence might hinder effective immunity against other pathogens, thus aiding pathogenic invasion and spread.

Breast cancer is one of the leading causes of death in women worldwide. Recent studies have demonstrated that inflammation due to infections with microorganisms could play a role in breast cancer development. One of the known human pathogens, Borrelia burgdorferi, the causative agent of Lyme disease, has been shown to be present in various types of breast cancer and is associated with poor prognosis. We reported that B. burgdorferi can invade breast cancer cells and affect their tumorigenic phenotype. To better understand the genome-wide genetic changes caused by B. burgdorferi, we evaluated the microRNA (miRNA or miR) expression profiles of two triple-negative breast cancer cell lines and one non-tumorigenic mammary cell line before and after B. burgdorferi infection. Using a cancer-specific miRNA panel, four miRNAs (miR-206, 214-3p, 16-5p, and 20b-5p) were identified as potential markers for Borrelia-induced changes, and the results were confirmed by quantitative real-time reverse transcription (qRT-PCR). Among those miRNAs, miR-206 and 214 were the most significantly upregulated miRNAs. The cellular impact of miR-206 and 214 was evaluated using DIANA software to identify related molecular pathways and genes. Analyses showed that the cell cycle, checkpoints, DNA damage-repair, proto-oncogenes, and cancer-related signaling pathways are mostly affected by B. burgdorferi infection. Based on this information, we have identified potential miRNAs which could be further evaluated as biomarkers for tumorigenesis caused by pathogens in breast cancer cells.

Helicobacter pylori infection is an important issue worldwide, and several guidelines have been published for clinicians to achieve successful eradication. However, there are still some patients who remain infected with H. pylori after treatment. Clinicians should identify the reasons that caused treatment failure and find strategies to manage them. We have searched and organized the literature and developed methods to overcome factors that contribute to prior treatment failure, such as poor compliance, inadequate intragastric acid suppression, and antibiotic resistance. To improve compliance, telemedicine or smartphone applications might play a role in the modern world by increasing doctor-patient relationships, while concomitant probiotics could be administered to reduce adverse effects and enhance adherence. For better acid suppression, high-potency and high-dose proton-pump inhibitors or potassium-competitive acid blockers have preferable efficacy. To overcome antibiotic resistance, susceptibility tests either by culture or by genotyping are the most commonly used methods and have been suggested for antibiotic selection before rescue therapy, but empirical therapy according to detailed medical history could be an alternative. Eradication with a longer treatment period (14 days) has a better outcome than shorter period (7 or 10 days). Ultimately, clinicians should select antibiotics based on the patient's history of drug allergy, previous antibiotic exposure, local antibiotic resistance, available medications, and cost. In addition, identifying patients with a high risk of cancer and shared decision-making are also essential for those who have experienced eradication failure.

Even though Helicobacter pylori (H. pylori) is a serious pathogen, its origin is unknown. Poultry (chicken, turkey, quail, goose, and ostrich) is consumed as a regular protein source by many people across the world; therefore, sanitary ways of delivering poultry for food are important for global health. As a result, the distribution of the virulence genes cagA, vacA, babA2, oipA, and iceA in H. pylori isolates in poultry meat, as well as their antibacterial resistance, was investigated. A Wilkins Chalgren anaerobic bacterial medium was used to cultivate 320 samples of raw poultry meat. Disk diffusion and multiplex-PCR were used to investigate both antimicrobial resistance and genotyping patterns. H. pylori was found in 20 of 320 (6.25 %) raw chicken meat samples. The highest incidence of H. pylori was found in chicken raw meat (15%), whereas no isolate was recovered from goose or quail raw meat (0.00%). Resistance to ampicillin (85%), tetracycline (85%), and amoxicillin (75%) were the most commonly detected in the tested H. pylori isolates. The percentage of H. pylori isolates with a multiple antibiotic resistance (MAR) index value of more than 0.2 was 17/20 (85%). The most prevalent genotypes detected were VacA (75%), m1a (75%), s2 (70%) and m2 (65%), and cagA (60%). The most typically detected genotype patterns were s1am1a (45 %), s2m1a (45 %), and s2 m2 (30%). babA2, oipA+, and oipA- genotypes were found in 40%, 30%, and 30% of the population, respectively. In summary, fresh poultry meat was polluted by H. pylori, with the babA2, vacA, and cagA genotypes being more prevalent. The simultaneous occurrence of vacA, cagA, iceA, oipA, and babA2 genotypes in antibiotic-resistant H. pylori bacteria raises a serious public health concern regarding the consumption of raw poultry. Future research should evaluate antimicrobial resistance among H. pylori isolates in Iran.

Helicobacter pylori (H. pylori) is a key pathogen causing several gastrointestinal diseases. Fortunately, H. pylori infection is treatable, which can lower its comorbidities. However, data assessing physicians' awareness of H. pylori is lacking in Saudi Arabia.

To assess the knowledge and awareness of physicians of different specialties who practice in Saudi Arabia about H. pylori infection.

This is a cross-sectional study conducted between May and September 2022 on physicians across all regions in Saudi Arabia using a validated online questionnaire covering their knowledge and awareness of H. pylori infection. An independent t-test, one-way ANOVA, and Games-Howell as a post hoc test were used to analyze the data. A General Linear Model was also employed to determine significant predictors among the variables reliant on H. pylori awareness.

The results showed that the mean awareness score of 474 physicians was 76.99± 6.9, indicating that participants had sufficient knowledge about H. pylori infection. In general, the internal medicine specialists (28.3%) had better awareness of H. pylori infection than the other specialties. Moreover, the university hospital sector performed the best, scoring 80.68±13.3, and the southern region had the highest-ranked physicians with a score of 81.56 ±13.7 in terms of H. pylori awareness. Furthermore, the general linear model revealed a statistical significance (p<0.05) for the following demographic aspects concerning H. pylori awareness: the physicians' age group of 30-39 years, duration of experience of 11-15 years, the hospital sectors of Nation Guards (NGH) and Security Forces (SFH), and the southern and central regions of practice in Saudi Arabia.

Physicians in Saudi Arabia have relatively sufficient awareness of H. pylori; however, they are highly influenced by age, years of experience, the hospital sector involved, and the region where the physicians practice.

A Gram-stain-negative, spiral bacterium (PAGU 1991^T) was isolated from the blood of a patient with diffuse large B-cell lymphoma. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate was very closely related to Helicobacter equorum LMG 23362^T (99.1 % similarity), originally isolated from a faecal sample from a healthy horse. PAGU 1991^T was also very closely related to PAGU 1750 in our strain library (=CCUG 41437) with 99.7 % similarity. Additional phylogenetic analyses based on the 23S rRNA gene sequence and GyrA amino acid sequence further supported the close relationship between the two human isolates (PAGU 1991^T and PAGU 1750) and the horse strain. However, a phylogenetic analysis based on 16S rRNA showed that the two human isolates formed a lineage that was distinct from the horse strain (less than 99.2 % similarity). In silico whole-genome comparisons based on digital DNA-DNA hybridization, average nucleotide identity based on blast and orthologous average nucleotide identity using usearch between the two human isolates and the type strain of H. equorum showed values of less than 52.40, 93.47, and 93.50 %, respectively, whereas those between the two human isolates were 75.8, 97.2, and 97.2 %, respectively. These data clearly demonstrated that the two human isolates formed a single species, distinct from H. equorum. Morphologically, the human isolates could be distinguished by the type of flagella; the human isolates showed a bipolar sheathed flagellum, whereas that of H. equorum was monopolar. Biochemically, the human isolate was characterized by growth at 42 °C under microaerobic conditions and nitrate reduction unability. We conclude that the two human isolates, obtained from geographically and temporally distinct sources, were a novel species, for which we propose the name Helicobacter kumamotonensis sp. nov., with the type strain PAGU 1991^T (=GTC 16810^T=CCUG 75774^T).