Genus Burkholderia Research Articles

A Novel Strain Burkholderia theae GS2Y Exhibits Strong Biocontrol Potential Against Fungal Diseases in Tea Plants (Camellia sinensis).

Tea plants (Camellia sinensis) are widely cultivated cash crops. However, fungal diseases lead to significant reductions in both the yield and quality of tea. Therefore, searching for economical, eco-friendly, and efficient biological control measures is crucial for protecting tea plants from pathogenic fungi. The confrontation assays were performed to identify the antagonistic bacteria against tea pathogenic fungi and evaluate the antifungal activity of these bacteria. Here, three tea pathogenic fungi were identified: Colletotrichum siamense HT-1, Diaporthe phaseolorum HT-3, and Fusarium fujikuroi HT-4. Notably, D. phaseolorum was the first to be reported in tea plants in China. Some tea pathogenic fungi showed a high relative abundance, suggesting a potential disease risk in tea plantations. Strain GS2Y, isolated from tea rhizosphere soil, exhibited strong antifungal activity against tea pathogenic fungi and represented a novel species within the genus Burkholderia, designated as Burkholderia theae. GS2Y could directly inhibit tea pathogenic fungi by disrupting the cellular structures and protect tea plants from fungal diseases caused by C. siamense HT-1 and D. phaseolorum HT-3. B. theae GS2Y might function as a potentially valuable resource for biocontrol agents, laying the foundation for the development of strategies to manage fungal diseases in tea plants.

Repeated horizontal acquisition of lagriamide-producing symbionts in Lagriinae beetles.

Microbial symbionts associate with multicellular organisms on a continuum from facultative associations to mutual codependency. In the oldest intracellular symbioses there is exclusive vertical symbiont transmission, and co-diversification of symbiotic partners over millions of years. Such symbionts often undergo genome reduction due to low effective population sizes, frequent population bottlenecks, and reduced purifying selection. Here, we describe multiple independent acquisition events of closely related defensive symbionts followed by genome erosion in a group of Lagriinae beetles. Previous work in Lagria villosa revealed the dominant genome-eroded symbiont of the genus Burkholderia produces the antifungal compound lagriamide, protecting the beetle's eggs and larvae from antagonistic fungi. Here, we use metagenomics to assemble 11 additional genomes of lagriamide-producing symbionts from seven different host species within Lagriinae from five countries, to unravel the evolutionary history of this symbiotic relationship. In each host, we detected one dominant genome-eroded Burkholderia symbiont encoding the lagriamide biosynthetic gene cluster. However, we did not find evidence for host-symbiont co-diversification, or for monophyly of the lagriamide-producing symbionts. Instead, our analyses support a single ancestral acquisition of the gene cluster followed by at least four independent symbiont acquisitions and subsequent genome erosion in each lineage. By contrast, a clade of plant-associated relatives retained large genomes but secondarily lost the lagriamide gene cluster. Our results, therefore, reveal a dynamic evolutionary history with multiple independent symbiont acquisitions characterized by a high degree of specificity, and highlight the importance of the specialized metabolite lagriamide for the establishment and maintenance of this defensive symbiosis.

Identification of Burkholderia cepacia Complex: Comparing Conventional, Automated, and Molecular Methods in a Tertiary Care Center.

Introduction Burkholderia cepacia complex(BCC) is one of the most common polymyxin-resistant Gram-negative bacilli isolated in the clinical microbiological laboratory. They are often underreported when conventional biochemicals are used for identification, due to their similarity to other non-fermenting bacilli. It is essential to identify BCC using simple biochemical tests with good reliability to ease the identification of BCC in resource-limited settings and initiate treatment. Objectives We aim to identify isolates belonging to BCC from other non-fermentersusing simple conventional biochemical tests, automated methods, and polymerase chain reaction (PCR) and analyze antibiotic profiles and treatment outcomes in patients with BCC infection. Materials and methods All samples received at the clinical microbiology laboratory for bacterial culture from March 2023 to March 2024 were included in this study. Samples that grew non-lactose fermenting colonies on MacConkey agar, which were resistant to polymyxin B 300 (PB300) units, were further identified using conventional biochemicals, and lysine decarboxylase test, ornithine decarboxylase test, arginine dihydrolase test, ortho-nitrophenyl-β-galactoside (ONPG) test, urea hydrolysis, triple disc screening test (polymyxin B 300 units, amoxicillin-clavulanic acid 20/10 mcg (AMC20/10), and gentamicin 10 mcg (GEN10)),VITEK MS (bioMérieux, Marcy-l'Etoile, France), VITEK 2 Gram-Negative (GN) Identification (ID) Card(bioMérieux), and PCR targeting groEL sequence was performed for Burkholderia isolates. The antibiotic susceptibility pattern was analyzed using VITEK AST (bioMérieux). Basic patient details were collected from the medical records. Results Using conventional biochemicals and automated methods, 60 isolates were identified belonging to the genus Burkholderia, among which 46 (76.6%) belonged to Burkholderia cepacia complex. The concordance for genus-level identification of Burkholderia with conventional biochemicals, VITEK MS, VITEK 2, and groEL PCRwas found to be 100%. Species-level identification using the listed conventional biochemicals was 28.2% as compared to VITEK MS.All the isolates were susceptible to ceftazidime (n=46,100%). Risk factors included diabetes mellitus (n=19, 41.3%) and indwelling devices such as central venous catheters (CVCs), urinary catheters, and mechanical ventilation. Recovery was seen in 40 (86.9%)patients on treatment with recommended antibiotics. Conclusion Our study shows that the identification of the genus Burkholderia by conventional biochemicals was as efficient as automated and molecular methods. Species identification of BCC was better with automated systems. Infections with BCC commonly occurred in patients with diabetes mellitus and indwelling devices. Treatment with recommended antibiotics showed high recovery rates.

Phosphorus-, potassium-, and silicon-solubilizing bacteria from forest soils can mobilize soil minerals to promote the growth of rice (Oryza sativa L.)

BackgroundForest soils are usually highly weathered and abundant in mineral-weathering bacteria, which have not been used to mobilize soil minerals for crop production. Here, we used an acidic forest soil with low available phosphorus (P), potassium (K), and silicon (Si) to isolate bacteria capable of co-solubilizing P, K, and Si (PKSi-solubilizing) and the model rice plant to test their potential to mobilize soil P, K, and Si for crop nutrition.ResultsSix PKSi-solubilizing strains representative of common mineral-weathering proteobacteria taxa (genera Burkholderia, Paraburkholderia, Collimonas, Pseudomonas, and Agrobacterium) were screened out. They showed diverse P-, K-, or Si-solubilizing activities and produced diverse organic acids. Their mineral-solubilizing activities were positively correlated with the levels of medium pH reduction and gluconic acid production. They promoted the growth of rice seedlings grown in the forest soil by increasing soil available P and Si, plant P, K, and Si cumulative contents and dry weight, and the corresponding root-to-shoot ratios. The growth of rice seedlings alone and with the inoculated PKSi-solubilizing stains in the acidic forest soil did not reduce the soil pH.ConclusionsThe forest soil with low available P, K, and Si is a valuable resource for high-performance PKSi-solubilizing bacteria improving soil fertility and crop nutrition. The PKSi-solubilizing bacteria screened out can promote rice seedling growth by mobilizing P, K, and Si from soil to plant in the acidic soil with low available P, K, and Si. They show potentials to mitigate soil P, K, and Si deficiency and promote crop growth, and to recover soluble P, K, and Si from chemical fertilizers and improve the use efficiency of chemical fertilizers, thus reducing the input of chemical fertilizers. They may retard soil acidification by Si-solubilization and improve soil quality.Graphical

Onion‐pathogenic Burkholderia species: Role and regulation of characterized virulence determinants

AbstractMembers of the bacterial genus Burkholderia are a routine threat to onion production worldwide. In addition to the common onion‐pathogenic species, Burkholderia cepacia, Burkholderia orbicola and Burkholderia gladioli, other Burkholderia species have the potential to cause onion disease. Despite their impacts and long‐known association with onion disease, the virulence mechanisms of onion‐pathogenic Burkholderia are far less well understood than Burkholderia in human and murine infection models. In this review, we will focus on genetically characterized virulence factors in species that contribute to symptom production in onion and other plant hosts. Specifically, we will focus on the variable roles of specialized protein secretion systems (T2SS, T3SS and T4SS) and secreted proteins, thiosulphinate tolerance gene (TTG) clusters and the well‐characterized phytotoxin toxoflavin in virulence. The regulation and roles of LuxI/LuxS quorum‐sensing system and IclR‐type transcriptional regulator, qsmR, as master regulators of secondary metabolite production and virulence factors will also be discussed. The TTG clusters, involved in bacterial tolerance to thiosulphinate defence compounds, exhibit onion tissue‐specific contributions to virulence. This suggests that Burkholderia onion pathogens have tissue‐specific virulence strategies for causing disease.

Repeated horizontal acquisition of lagriamide-producing symbionts in Lagriinae beetles.

Microbial symbionts associate with multicellular organisms on a continuum from facultative associations to mutual codependency. In some of the oldest intracellular symbioses there is exclusive vertical symbiont transmission, and co-diversification of symbiotic partners over millions of years. Such symbionts often undergo genome reduction due to low effective population sizes, frequent population bottlenecks, and reduced purifying selection. Here, we describe multiple independent acquisition events of closely related defensive symbionts followed by genome erosion in a group of Lagriinae beetles. Previous work in Lagria villosa revealed the dominant genome-eroded symbiont of the genus Burkholderia produces the antifungal compound lagriamide and protects the beetle's eggs and larvae from antagonistic fungi. Here, we use metagenomics to assemble 11 additional genomes of lagriamide-producing symbionts from seven different host species within Lagriinae from five countries, to unravel the evolutionary history of this symbiotic relationship. In each host species, we detected one dominant genome-eroded Burkholderia symbiont encoding the lagriamide biosynthetic gene cluster (BGC). Surprisingly, however, we did not find evidence for host-symbiont co-diversification, or for a monophyly of the lagriamide-producing symbionts. Instead, our analyses support at least four independent acquisition events of lagriamide-encoding symbionts and subsequent genome erosion in each of these lineages. By contrast, a clade of plant-associated relatives retained large genomes but secondarily lost the lagriamide BGC. In conclusion, our results reveal a dynamic evolutionary history with multiple independent symbiont acquisitions characterized by high degree of specificity. They highlight the importance of the specialized metabolite lagriamide for the establishment and maintenance of this defensive symbiosis.

Employing Genomic Tools to Explore the Molecular Mechanisms behind the Enhancement of Plant Growth and Stress Resilience Facilitated by a Burkholderia Rhizobacterial Strain.

The rhizobacterial strain BJ3 showed 16S rDNA sequence similarity to species within the Burkholderia genus. Its complete genome sequence revealed a 97% match with Burkholderia contaminans and uncovered gene clusters essential for plant-growth-promoting traits (PGPTs). These clusters include genes responsible for producing indole acetic acid (IAA), osmolytes, non-ribosomal peptides (NRPS), volatile organic compounds (VOCs), siderophores, lipopolysaccharides, hydrolytic enzymes, and spermidine. Additionally, the genome contains genes for nitrogen fixation and phosphate solubilization, as well as a gene encoding 1-aminocyclopropane-1-carboxylate (ACC) deaminase. The treatment with BJ3 enhanced root architecture, boosted vegetative growth, and accelerated early flowering in Arabidopsis. Treated seedlings also showed increased lignin production and antioxidant capabilities, as well as notably increased tolerance to water deficit and high salinity. An RNA-seq transcriptome analysis indicated that BJ3 treatment significantly activated genes related to immunity induction, hormone signaling, and vegetative growth. It specifically activated genes involved in the production of auxin, ethylene, and salicylic acid (SA), as well as genes involved in the synthesis of defense compounds like glucosinolates, camalexin, and terpenoids. The expression of AP2/ERF transcription factors was markedly increased. These findings highlight BJ3's potential to produce various bioactive metabolites and its ability to activate auxin, ethylene, and SA signaling in Arabidopsis, positioning it as a new Burkholderia strain that could significantly improve plant growth, stress resilience, and immune function.

Glyphosate resistance and biodegradation by Burkholderia cenocepacia CEIB S5-2.

Glyphosate is a broad spectrum and non-selective herbicide employed to control different weeds in agricultural and urban zones and to facilitate the harvest of various crops. Currently, glyphosate-based formulations are the most employed herbicides in agriculture worldwide. Extensive use of glyphosate has been related to environmental pollution events and adverse effects on non-target organisms, including humans. Reducing the presence of glyphosate in the environment and its potential adverse effects requires the development of remediation and treatment alternatives. Bioremediation with microorganisms has been proposed as a feasible alternative for treating glyphosate pollution. The present study reports the glyphosate resistance profile and degradation capacity of the bacterial strain Burkholderia cenocepacia CEIB S5-2, isolated from an agricultural field in Morelos-México. According to the agar plates and the liquid media inhibition assays, the bacterial strain can resist glyphosate exposure at high concentrations, 2000mg·L-1. In the degradation assays, the bacterial strain was capable of fast degrading glyphosate (50mg·L-1) and the primary degradation metabolite aminomethylphosphonic acid (AMPA) in just eight hours. The analysis of the genomic data of B. cenocepacia CEIB S5-2 revealed the presence of genes that encode enzymes implicated in glyphosate biodegradation through the two metabolic pathways reported, sarcosine and AMPA. This investigation provides novel information about the potential of species of the genus Burkholderia in the degradation of the herbicide glyphosate and its main degradation metabolite (AMPA). Furthermore, the analysis of genomic information allowed us to propose for the first time a metabolic route related to the degradation of glyphosate in this bacterial group. According to the findings of this study, B. cenocepacia CEIB S5-2 displays a great glyphosate biodegradation capability and has the potential to be implemented in glyphosate bioremediation approaches.

Genome Wide Identification, Characterization and Evolutionary Analysis of T6SS in Burkholderia cenocepacia Strains

Pathogens of the Burkholderia genus are causing diseases in a diverse variety of hosts. After the discovery of T6SS, it was found to play a pivotal role in virulence and other pathogenicity factors in different pathogenic Burkholderia species. For this study, three strains of Burkholderia cenocepacia were selected from different ecological niches; J2315 from humans, MC0-3 from the rhizosphere of maize, and YG-3 from the Populus tree. The sequenced genomes were retrieved from PATRIC. It was found that B. cenocepacia J2315 and MC0-3 strains had only 1 cluster of T6SS in their genomes while the YG-3 strain had 3 clusters. The circular genomic map and phylogenetic tree suggested major differences in T6SS clusters 2 and 3 of the YG-3 strain from other clusters. From the results obtained in the study and reviewing the literature, it was concluded that all 3 strains harbor T6SS-1 type cluster that is involved in causing virulence in eukaryotic organisms and several bacterial species. This factor of causing virulence in the bacteria species might be helpful for B. cenocepacia strains J2315, MC0-3 and YG-3 in survival and niche adaptation.

Wild mushrooms as potential reservoirs of plant pathogenic bacteria: a case study on Burkholderia gladioli.

Fruit bodies (sporocarps) of wild mushrooms growing in natural environments play a substantial role in the preservation of microbial communities, for example, clinical and food-poisoning bacteria. However, the role of wild mushrooms as natural reservoirs of plant pathogenic bacteria remains almost entirely unknown. Furthermore, bacterial transmission from a mushroom species to agricultural plants has rarely been recorded in the literature. In September 2021, a creamy-white Gram-negative bacterial strain was isolated from the sporocarp of Suillus luteus (slippery jack) growing in Bermuda grass (Cynodon dactylon) lawn in Southern Iran. A similar strain was isolated from the same fungus in the same area in September 2022. Both strains were identified as Burkholderia gladioli based on phenotypic features as well as phylogeny of 16S rRNA and three housekeeping genes. The strains were not only pathogenic on white button mushrooms (Agaricus bisporus) but also induced hypersensitive reaction (HR) on tobacco and common bean leaves and caused soft rot on a set of diverse plant species, that is, chili pepper, common bean pod, cucumber, eggplant, garlic, gladiolus, narcissus, onion, potato, spring onion, okra, kohlrabi, mango, and watermelon. Isolation of plant pathogenic B. gladioli strains from sporocarp of S. luteus in two consecutive years in the same area could be indicative of the role of this fungus in the preservation of the bacterium in the natural environment. B. gladioli associated with naturally growing S. luteus could potentially invade neighboring agricultural crops, for example, vegetables and ornamentals. The potential role of wild mushrooms as natural reservoirs of phytopathogenic bacteria is further discussed.IMPORTANCEThe bacterial genus Burkholderia contains biologically heterogeneous strains that can be isolated from diverse habitats, that is, soil, water, diseased plant material, and clinical specimens. In this study, two Gram-negative pectinolytic bacterial strains were isolated from the sporocarps of Suillus luteus in September 2021 and 2022. Molecular phylogenetic analyses revealed that both strains belonged to the complex species Burkholderia gladioli, while the pathovar status of the strains remained undetermined. Biological investigations accomplished with pathogenicity and host range assays showed that B. gladioli strains isolated from S. luteus in two consecutive years were pathogenic on a set of diverse plant species ranging from ornamentals to both monocotyledonous and dicotyledonous vegetables. Thus, B. gladioli could be considered an infectious pathogen capable of being transmitted from wild mushrooms to annual crops. Our results raise a hypothesis that wild mushrooms could be considered as potential reservoirs for phytopathogenic B. gladioli.

Transposon sequencing reveals the essential gene set and genes enabling gut symbiosis in the insect symbiont Caballeronia insecticola.

Caballeronia insecticola is a bacterium belonging to the Burkholderia genus sensu lato, which is able to colonize multiple environments like soils and the gut of the bean bug Riptortus pedestris. We constructed a saturated Himar1 mariner transposon library and revealed by transposon-sequencing that 498 protein-coding genes constitute the essential genome of Caballeronia insecticola for growth in free-living conditions. By comparing essential gene sets of Caballeronia insecticola and seven related Burkholderia s.l. strains, only 120 common genes were identified, indicating that a large part of the essential genome is strain-specific. In order to reproduce specific nutritional conditions that are present in the gut of Riptortus pedestris, we grew the mutant library in minimal media supplemented with candidate gut nutrients and identified several condition-dependent fitness-defect genes by transposon-sequencing. To validate the robustness of the approach, insertion mutants in six fitness genes were constructed and their growth deficiency in media supplemented with the corresponding nutrient was confirmed. The mutants were further tested for their efficiency in Riptortus pedestris gut colonization, confirming that gluconeogenic carbon sources, taurine and inositol, are nutrients consumed by the symbiont in the gut. Thus, our study provides insights about specific contributions provided by the insect host to the bacterial symbiont.

Isolation and Characterization of Phosphate Solubilizing Bacteria from Upland Rice Cultivation Areas in Bangka Regency

The availability of phosphorus (P) in ultisol acid soils presents a significant challenge due to its attachment to aluminum (Al) or iron (Fe) compounds. A potential solution to address this issue is the utilization of phosphate solubilizing bacteria (PSB). Therefore, this study aimed to analyze the potential of PSB originating from upland rice cultivation on ultisol soils. The bacterial isolates were obtained from soil samples taken from the rhizosphere area and root tissue of upland rice plants cultivated in Payabenua and Saing Villages, Bangka Regency. The pathogenicity testing encompassed hypersensitivity and hemolysis tests, while the P solubilization included the evaluation of the phosphate solubilizing index (PSI) and P dissolution. Subsequently, the selected isolates were subjected to phosphatase enzyme and organic acid content assessment. The results showed a total of 120 isolates, predominantly distributed in the Payabenua area and primarily consisting of endophytic bacteria. Among the six selected isolates, genus Burkholderia dominated four isolates, while the remaining isolates belonged to genus Serratia. Furthermore, in Burkholderia vietnamiensis, the solubility value of P in AlPO4 and Ca3(PO4)2 liquid media exhibited a range of 0.0013 to 0.0344% and 0.0008 to 0.1842%, respectively.

Comparative Genome Analyses Provide Insight into the Antimicrobial Activity of Endophytic Burkholderia.

Endophytic bacteria are endosymbionts that colonize a portion of plants without harming the plant for at least a part of its life cycle. Bacterial endophytes play an essential role in promoting plant growth using multiple mechanisms. The genus Burkholderia is an important member among endophytes and encompasses bacterial species with high genetic versatility and adaptability. In this study, the endophytic characteristics of Burkholderia species are investigated via comparative genomic analyses of several endophytic Burkholderia strains with pathogenic Burkholderia strains. A group of bacterial genes was identified and predicted as the putative endophytic behavior genes of Burkholderia. Multiple antimicrobial biosynthesis genes were observed in these endophytic bacteria; however, certain important pathogenic and virulence genes were absent. The majority of resistome genes were distributed relatively evenly among the endophytic and pathogenic bacteria. All known types of secretion systems were found in the studied bacteria. This includes T3SS and T4SS, which were previously thought to be disproportionately represented in endophytes. Additionally, questionable CRISPR-Cas systems with an orphan CRISPR array were prevalent, suggesting that intact CRISPR-Cas systems may not exist in symbiotes of Burkholderia. This research not only sheds light on the antimicrobial activities that contribute to biocontrol but also expands our understanding of genomic variations in Burkholderia's endophytic and pathogenic bacteria.

Expected and Unexpected Products from the Biochemical Oxidation of Bacterial Alkylquinolones with CYP4F11.

2-Alkylquinolones are a class of microbial natural products primarily produced in the Pseudomonas and Burkholderia genera that play a key role in modulating quorum sensing. Bacterial alkylquinolones were synthesized and then subjected to oxidative biotransformation using human cytochrome P450 enzyme CYP4F11, heterologously expressed in the fission yeast Schizosaccharomyces pombe. This yielded a range of hydroxylated and carboxylic acid derivatives which had undergone ω-oxidation of the 2-alkyl chain, the structures of which were determined by analysis of NMR and MS data. Oxidation efficiency depended on chain length, with a chain length of eight or nine carbon atoms proving optimal for high yields. Homology modeling suggested that Glu233 was relevant for binding, due to the formation of a hydrogen bond from the quinolone nitrogen to Glu233, and in this position only the longer alkyl chains could come close enough to the heme moiety for effective oxidation. In addition to the direct oxidation products, a number of esters were also isolated, which was attributed to the action of endogenous yeast enzymes on the newly formed ω-hydroxy-alkylquinolones. ω-Oxidation of the alkyl chain significantly reduced the antimicrobial and antibiofilm activity of the quinolones.

Human Breast Tissue Microbiota Reveals Unique Microbial Signatures that Correlate with Prognostic Features in Adult Ethiopian Women with Breast Cancer.

Breast cancer (BC) is the leading cause of cancer mortality among women in Ethiopia. Overall, women of African ancestry have the highest death toll due to BC compared to other racial/ethnic groups. The cause of the disparity in mortality is unclear. Recently, studies conducted in the United States and other high-income countries highlighted the role of microbial dysbiosis in BC initiation, tumor growth, and treatment outcome. However, the extent to which inter-individual differences in the makeup of microbiota are associated with clinical and histopathological outcomes in Ethiopian women has not been studied. The goal of our study was to profile the microbiome in breast tumor and normal adjacent to tumor (NAT) tissues of the same donor and to identify associations between microbial composition and abundance and clinicopathological factors in Ethiopian women with BC. We identified 14 microbiota genera in breast tumor tissues that were distinct from NAT tissues, of which Sphingobium, Anaerococcus, Corynebacterium, Delftia, and Enhydrobacter were most significantly decreased in breast tumors compared to NAT tissues. Several microbial genera significantly differed by clinicopathological factors in Ethiopian women with BC. Specifically, the genus Burkholderia more strongly correlated with aggressive triple negative (TNBC) and basal-like breast tumors. The genera Alkanindiges, Anoxybacillus, Leifsonia, and Exiguobacterium most strongly correlated with HER2-E tumors. Luminal A and luminal B tumors also correlated with Anoxybacillus but not as strongly as HER2-E tumors. A relatively higher abundance of the genus Citrobacter most significantly correlated with advanced-stage breast tumors compared to early-stage tumors. This is the first study to report an association between breast microbial dysbiosis and clinicopathological factors in Ethiopian women.

Bacteriophage steering of Burkholderia cenocepacia toward reduced virulence and increased antibiotic sensitivity.

Antibiotic resistance in bacteria is a growing global concern and has spurred increasing efforts to find alternative therapeutics, such as the use of bacterial viruses, or bacteriophages. One promising approach is to use phages that not only kill pathogenic bacteria but also select phage-resistant survivors that are newly sensitized to traditional antibiotics, in a process called "phage steering." Members of the bacterial genus Burkholderia, which includes various human pathogens, are highly resistant to most antimicrobial agents, including serum immune components, antimicrobial peptides, and polymixin-class antibiotics. However, the application of phages in combination with certain antibiotics can produce synergistic effects that more effectively kill pathogenic bacteria. Herein, we demonstrate that Burkholderia cenocepacia serum resistance is due to intact lipopolysaccharide (LPS) and membranes, and phage-induced resistance altering LPS structure can enhance bacterial sensitivity not only to immune components in serum but also to membrane-associated antibiotics such as colistin. IMPORTANCE Bacteria frequently encounter selection pressure from both antibiotics and lytic phages, but little is known about the interactions between antibiotics and phages. This study provides new insights into the evolutionary trade-offs between phage resistance and antibiotic sensitivity. The creation of phage resistance through changes in membrane structure or lipopolysaccharide composition can simultaneously be a major cause of antibiotic sensitivity. Our results provide evidence of synergistic therapeutic efficacy in phage-antibiotic interactions and have implications for the future clinical use of phage steering in phage therapy applications.

Showing the limitations of available phenotypic assays to detect Burkholderia pseudomallei from clinical specimens in Nigeria.

The genus Burkholderia comprises Gram-negative bacteria that are metabolically complex and versatile, often thriving in hostile settings. Burkholderia pseudomallei , the causative agent of melioidosis, is a prominent member of the genus and a clinical pathogen in tropical and sub-tropical regions. This pathogen is well known for its multidrug resistance and possible bioweapon potential. There is currently no report of the pathogen from clinical specimens in Nigeria, which might be due to misdiagnosis with phenotypic assays. This study aims to explore the accuracy of the use of phenotypic assays to diagnose B. pseudomallei in Nigeria. Two hundred and seventeen clinical samples and 28 Gram-negative clinical isolates were collected and analysed using Ashdown's selective agar and monoclonal antibody-based latex agglutination. Species-level identification was achieved using the analytical profile index (API) 20NE system. The susceptibility of the isolates to nine different antimicrobial agents was determined using the disc diffusion method. A total of seventy-four culture-positive isolates were obtained using Ashdown's selective agar. Twenty-two of these isolates were believed to be B. pseudomallei through the monoclonal antibody-based latex agglutination test and the API 20NE system subsequently identified 14 isolates as Burkholderia . The predominant Burkholderia species was B. cepacia with an isolation rate of 30.8 % (8/26). No isolate was distinctively identified as B. pseudomallei but five isolates were strongly suspected to be B. pseudomallei with similarity indices ranging from 81.9-91.3 %. Other bacterial species with definitive identity include Aeromonas sp., Sphingomonas sp. and Pseudomonas aeruginosa . The antibiotic susceptibility results revealed an overall resistance to amoxicillin-clavullanic acid of 71.4 %, to cefepime of 33.3 %, to trimethoprim-sulfamethoxazole of 38.1 %, to piperacillin-tazobactam of 33.3 %, to imipenem of 66.7 %, to doxycycline of 57.1% and to ceftazidime of 66.7 %. The highest intermediate resistance was observed for cefepime and piperacillin-tazobactam with a value of 66.7 % each, while there was no intermediate resistance for gentamicin, colistin and imipenem. Our findings, therefore, show that phenotypic assays alone are not sufficient in the diagnosis of melioidosis. Additionally, they provide robust support for present and future decisions to expand diagnostic capability for melioidosis beyond phenotypic assays in low-resource settings.

Influence of biosurfactants in the recovery of REE from monazite using Burkholderia thailandensis

The demand of rare earth elements (REE) has grown over the past decades due to their importance in high technology devices such as wind turbines, superconductors, rechargeable batteries, autocatalytic converters, magnets, or LED lighting. The development of clean mining processes is gaining interest and the biomining of REE is mainly focused on monazite using phosphate solubilizing microorganisms. The members of the genus Burkholderia can dissolve phosphorous from inorganic rocks. Furthermore, several species of Burkholderia are able to produce biosurfactants named rhamnolipids. Nevertheless, rhamnolipid interactions with REE have been poorly investigated.The aim of the present work is the study of the solubilization of monazite and the recovery of REE using the bacterium Burkholderia thailandensis, and the influence of the rhamnolipids produced by the bacteria in the REE mobilization. B. thailandensis grown in nutrient broth with 1% monazite (w/v) reached 8.3 mg·l−1 REE after 15 days.To produce rhamnolipids, B. thailandensis was grown in medium supplemented with 10% glycerol and the biosurfactants were extracted. The critical micelle concentration (CMC) was determined: 94.45 mg·l−1 for commercial rhamnolipids and 60.41 mg·l−1 for purified rhamnolipids. The maximum REE solubilization was obtained at CMC reaching 9.36 mg·l−1 with commercial rhamnolipids and 5.13 mg·l−1 with rhamnolipids produced by B. thailandensis E264.

The conductive gel for hospital use as a culture medium for the genus Burkholderia

The Burkholderia genus is a group of gram-negative bacteria that inhabit soil, water, plant and animal tissues; within this genus are B. pseudomallei, B. cepacia, and B. contaminants, which can cause multiple infections. The objective is to describe a prospective series and study whether the use of hospital gel contributed to the development of infection in patients. Methods: Descriptive and prospective study of the series with positive cultures for the genus Burkholderia from 2019 to 2023 in a hospital in Colombia. Results: 27 cases with isolation of Burkholderia, 74.07% Burkholderia cepacea and 25.93% Burkholderia pseudomallei, 68.85% male and 31.15% female, 78.57% from urban areas and 21 43% rural, 62.96% had a history of chronic diseases. The mean hours of culture positivity was 40.64 hours (SD ± 23.19), 14.81% presented pneumonia, 7.40% soft tissue infections, 55.55% sepsis and 22.24 % others, the mean hospital stay was 7.92 days, 100% underwent diagnostic procedures using hospital gel, B. Cepacea and B. pseudomallei growth was obtained in the gel and identification by molecular tests reported Burkholderia contaminants, the mortality of this study was 22.22%. Conclusion: The random culture carried out on the gel in different areas of the hospital obtained growth of Burkholderia, for which procedures and possible solutions are reconsidered to avoid the growth of this germ in this medium and the diagnostic strengthening in the laboratory. 81% presented pneumonia, 7.40% soft tissue infections, 55.55% sepsis and 22.24% others, the mean hospital stay was 7.92 days, 100% underwent diagnostic procedures with the use of gel hospital, B. Cepacea and B. pseudomallei growth was obtained in the gel and the identification by molecular tests reported Burkholderia contaminants, the mortality of this study was 22.22%.

Effects of filling methods on the degradation of ethyl acetate and the microbial community in biofilters

Two biofilters (BFs) for treating ethyl acetate (EA) were constructed with magnetite, activated carbon, perlite and gravel added via layered filling (BF1) or mixed filling (BF2). This study demonstrated the effect of filling method on the degradation of EA and the microbial community in the BFs. The results indicated that the EA removal efficiency (RE) of BF1 and BF2 reached 86.3 ± 3.0 % and 88.9 ± 2.1 %, respectively, under low inlet load (L-IL; (224 g/(m3·h)). Meanwhile, BF2 exhibited stabler RE than BF1 at high IL. BF1 achieved the highest REs of total phosphorus (TP), total nitrogen (TN) and ammonia nitrogen (NH4+-N) under moderate inlet load (M-IL; 336 g/(m3·h)), with average values of 95.8 ± 3.5 %, 83.4 ± 0.4 %, and 85.7 ± 0.3 %, respectively. The removal of TP, TN and NH4+-N in BF2 was superior than BF1 at L-IL and M-IL condition. Moreover, the genera Burkholderia, Acinetobacter, unclassified_Rhizobiales and unclassified_Burkholderiales were the dominant EA-degrading bacteria in BF1, while the EA-degrading bacteria in BF2 were dominated by unclassified_Chloroflexi, unclassified_Bacteroidetes and unclassified_Anaerolineaceae. Furthermore, the mechanism investigation of the mechanism revealed that the types of filling method affect EA degradation by shifting the abundance and diversity of key microorganisms in biodegradation. This study provides an effective strategy for improving the biodegradation efficiency of volatile organic compounds VOCs.