Bacteriophages (phages) are being investigated as potential biocontrol agents for the suppression of bacterial diseases in cultivated crops. Jumbo bacteriophages, which possess genomic DNA larger than 200 kbp, generally have a broader host range than other phages and therefore would be useful as biocontrol agents against a wide range of bacterial strains. Thus, the characterization of novel jumbo phages specific for agricultural pathogens would be of importance for the development of phage biocontrol strategies. Herein, we demonstrate that phage S13 requires Burkholderia glumae flagella for its attachment and infection and that loss of B. glumae flagella prevents S13 cellular lysis. As flagella is a known virulence factor, loss of flagella results in a surviving population of B. glumae with reduced virulence. Further experimentation demonstrates that phage S13 can protect rice plants from B. glumae-sponsored destruction in a rice seedling model of infection.IMPORTANCEBacterial plant pathogens threaten many major food crops and inflict large agricultural losses worldwide. B. glumae is a bacterial plant pathogen that causes diseases such as rot, wilt, and blight in several food major crops including rice, tomato, hot pepper, and eggplant. B. glumae infects rice during all developmental stages, causing diseases such as rice seedling rot and bacterial panicle blight (BPB). The B. glumae incidence of rice plant infection is predicted to increase with warming global temperatures, and several different control strategies targeting B. glumae are being explored. These include chemical and antibiotic soil amendment, microbiome manipulation, and the use of partially resistant rice cultivars. However, despite rice growth amelioration, the treatment options for B. glumae plant infections remain limited to cultural practices. Alternatively, phage biocontrol represents a promising new method for eliminating B. glumae from crop soils and improving rice yields.

Agricultural crop yield losses and food destruction due to infections by phytopathogenic bacteria such as Burkholderia gladioli, which causes devastating diseases in onion, mushroom, corn, and rice crops, pose major threats to worldwide food security and cause enormous damage to the global economy. Biocontrol using bacteriophages has emerged as a promising strategy against a number of phytopathogenic species but has never been attempted against B. gladioli due to a lack of quantitative infection models and a scarcity of phages targeting this specific pathogen. In this study, we present a novel, procedurally straightforward, and highly generalizable fully quantitative ex planta maceration model and an accompanying quantitative metric, the ex planta maceration index (xPMI). In utilizing this model to test the ex planta virulence of a panel of 12 strains of B. gladioli in Allium cepa and Agaricus bisporus, we uncover substantial temperature-, host-, and strain-dependent diversity in the virulence of this fascinating pathogenic species. Crucially, we demonstrate that Burkholderia phages KS12 and AH2, respectively, prevent and reduce infection-associated onion tissue destruction, measured through significant (P < 0.0001) reductions in xPMI, by phytopathogenic strains of B. gladioli, thereby demonstrating the potential of agricultural phage biocontrol targeting this problematic microorganism.IMPORTANCEAgricultural crop destruction is increasing due to infections caused by bacteria such as Burkholderia gladioli, which causes plant tissue diseases in onion, mushroom, corn, and rice crops. These bacteria pose a major threat to worldwide food production, which, in turn, damages the global economy. One potential solution being investigated to prevent bacterial infections of plants is "biocontrol" using bacteriophages (or phages), which are bacterial viruses that readily infect and destroy bacterial cells. In this article, we demonstrate that Burkholderia phages KS12 and AH2 prevent or reduce infection-associated plant tissue destruction caused by strains of B. gladioli, thereby demonstrating the inherent potential of agricultural phage biocontrol.

As the intensive development of aquaculture persists, the demand for fishmeal continues to grow; however, since fishery resources are limited, the price of fishmeal remains high. Therefore, there is an urgent need to develop new sources of protein. They are rich in proteins, fatty acids, amino acids, chitin, vitamins, minerals, and antibacterial substances. Maggot meal-based diet is an ideal source of high-quality animal protein and a new type of protein-based immune enhancer with good application prospects in animal husbandry and aquaculture. In the present study, we investigated the effects of three different diets containing maggot protein on the growth and intestinal microflora of Litopenaeus vannamei. The shrimp were fed either a control feed (no fly maggot protein added), FM feed (compound feed with 30% fresh fly maggot protein added), FF feed (fermented fly maggot protein), or HT feed (high-temperature pelleted fly maggot protein) for eight weeks. The results showed that fresh fly maggot protein in the feed was detrimental to shrimp growth, whereas fermented and high-temperature-pelleted fly maggot protein improved shrimp growth and survival. The effects of different fly maggot protein treatments on the intestinal microbiota of L. vannamei also varied. Fermented fly maggot protein feed and high-temperature-pelleted fly maggot protein feed increased the relative abundance of Ruegeria and Pseudomonas, which increased the abundance of beneficial bacteria and thus inhibited the growth of harmful bacteria. In contrast, fresh fly maggot proteins alter the intestinal microbiome, disrupting symbiotic relationships between bacteria, and causing invasion by Vibrio and antibiotic-resistant bacteria. These results suggest that fresh fly maggot proteins affect the composition of intestinal microorganisms, which is detrimental to the intestinal tract of L. vannamei, whereas fermented fly maggot protein feed affected the growth of L. vannamei positively by improving the composition of intestinal microorganisms.

Burkholderia gladioli has been associated with infections in patients with cystic fibrosis, chronic granulomatous disease, and other immunocompromising conditions. The aim of this study was to better depict the outbreak of healthcare-associated bacteremia caused by B. gladioli due to exposure to contaminated multidose vials with saline solutions.

An environmental and epidemiologic investigation was conducted by the Infection Prevention and Control Team (IPCT) to identify the source of the outbreak in three Croatian hospitals.

During a 3-month period, 13 B. gladioli bacteremia episodes were identified in 10 patients in three Croatian hospitals. At the time of the outbreak, all three hospitals used saline products from the same manufacturer. Two 100-ml multidose vials with saline solutions and needleless dispensing pins were positive for B. gladioli. All 13 bacteremia isolates and two isolates from the saline showed the same antimicrobial susceptibility patterns and pulsed-field gel electrophoresis profile, demonstrating clonal relatedness.

When an environmental pathogen causes an outbreak, contamination of intravenous products must be considered. Close communication between the local IPCT and the National Hospital Infection Control Advisory Committee is essential to conduct a prompt and thorough investigation and find the source of the outbreak.

Burkholderia gladioli (B. gladioli) is regarded as a rare opportunistic pathogen. Only a few patients with abscesses caused by B. gladioli infections have been reported, and these are usually abscesses at the incision caused by traumatic surgery.

A 74-year-old male patient with abscesses and pain throughout his body for 1 mo was admitted to our hospital. Some of the abscesses had ruptured with purulent secretions on admission. Color Doppler ultrasound examination of the body surface masses showed mixed masses 75 mm × 19 mm, 58 mm × 17 mm, 17 mm × 7 mm, and 33 mm × 17 mm in size in the muscle tissues of both the right and left forearms, the posterior area of the right knee and the left leg, respectively. Abscess secretions and blood cultures grew B. gladioli. The following 3 methods were used to jointly identify the bacterium: an automatic microbial identification system, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and full-length 16S rDNA sequencing. After 27 d of treatment with meropenem, etimicin, trimethoprim-sulfamethoxazole and other antibiotics, most of his skin abscesses were flat and he was discharged without any symptoms.

This is the first reported case of multiple skin abscesses associated with bacteremia caused by B. gladioli. Our study provides important reference values for the clinical diagnosis and treatment of B. gladioli infections.

To investigate the role of the leading saffron endophyte Burkholderia gladioli strain E39CS3 (BG-E39) in the inhibition of corm-rot and induced systemic resistance (ISR) in the host against the saffron specific pathogen, Fusarium oxysporum.

We studied the interaction between BG-E39 and the corm-rot pathogen F. oxysporum in vitro and in vivo. BG-E39 strongly inhibited both the F. oxysporum strains and other saffron-specific and non-specific pathogens used in this study. Confrontation and microscopic analyses revealed that the endophyte possessed fungicidal activity against the pathogens and effectively induced cell death in the mycelia. The endophyte produced chitinases as well as β-1,3-glucanase that may be involved in the pathogen cell wall degradation. BG-E39 did not cause corm-rot in Crocus sativus and the closely related plant, Gladiolus, thus establishing that it is non-pathogenic to these plants. The endophyte reduced corm-rot through antibiosis and enhanced the endogenous jasmonic acid (JA) levels and expression of JA-regulated and other plant defence genes.

The bacterial endophyte BG-E39 provides resistance to the host plant against F. oxysporum corm-rot in nature.

The current study discovers the role of the saffron endophyte BG-E39 in providing resistance to the host against corm-rot. Therefore, this endophyte is a potential candidate for developing a microbial formulation for the biocontrol of the most common disease of C. sativus.

Burkholderia species have different lifestyles establishing mutualist or pathogenic associations with plants and animals. Changes in the ecological behavior of these bacteria may depend on genetic variations in response to niche adaptation. Here, we studied 15 Burkholderia strains isolated from different environments with respect to genetic and phenotypic traits. By Multilocus Sequence Analysis (MLSA) these isolates fell into 6 distinct groups. MLSA clusters did not correlate with strain antibiotic sensitivity, but with the bacterial ability to produce antimicrobial compounds and control orchid necrosis. Further, the B. seminalis strain TC3.4.2R3, a mutualistic bacterium, was inoculated into orchid plants and the interaction with the host was evaluated by analyzing the plant response and the bacterial oxidative stress response in planta. TC3.4.2R3 responded to plant colonization by increasing its own growth rate and by differential gene regulation upon oxidative stress caused by the plant, while reducing the plant's membrane lipid peroxidation. The bacterial responses to oxidative stress were recapitulated by bacterial exposure to the herbicide paraquat. We suggest that the ability of Burkholderia species to successfully establish in the rhizosphere correlates with genetic variation, whereas traits associated with antibiotic resistance are more likely to be categorized as strain specific.