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Trends in Microbiology Jan 2024is a Gram negative, facultative intracellular bacterium that resides in the rhizosphere of tropical soils. causes melioidosis, which is transmitted by cutaneous entry,...
is a Gram negative, facultative intracellular bacterium that resides in the rhizosphere of tropical soils. causes melioidosis, which is transmitted by cutaneous entry, ingestion, or inhalation of contaminated soil or water. Infection with can cause a wide array of clinical symptoms such as pneumonia, bone, joint, skin, genitourinary, and central nervous system infections, as well as parotid abscesses in children. Mammalian virulence is linked to the intracellular life cycle, which begins with attachment and internalization by host cells. can infect a wide range of eukaryotic cells, including macrophages, monocytes, and neutrophils, as well as nonphagocytic cells. Once internalized, a type 3 secretion system (T3SS) facilitates escape from the phagosome, and the bacteria replicate in the cytoplasm. Autotransporter protein BimA mediates actin polymerization, enabling to spread, cell to cell, using actin-based motility. This process, coupled with the activity of a type 6 secretion system (T6SS-5), results in host membrane fusion and the formation of multinucleated giant cells. Capsule polysaccharides also contribute to virulence and evasion of host innate immunity. Treatment of infections is complicated by the organism’s intrinsic resistance to multiple classes of antimicrobials, largely due to an abundance of efflux pumps and reduced outer membrane permeability. While is commonly associated with endemic ‘hotspots’ in southeast Asia and northern Australia, there is increasing evidence that it is likely endemic in a large range of tropical and subtropical areas, including regions in Africa, South America, the Middle East, Central America, and the Caribbean. Soil and climate conditions favorable for survival are also found in additional areas worldwide. Consequently, it is important for clinical and public health laboratories located outside of high-endemicity areas to be aware of , as well as for improved diagnostic and reporting methods.
Topics: Burkholderia pseudomallei; Burkholderia
PubMed: 37634974
DOI: 10.1016/j.tim.2023.07.008 -
Frontiers in Immunology 2021() causes melioidosis, a potentially fatal disease for which no licensed vaccine is available thus far. The host-pathogen interactions in infection largely remain the... (Review)
Review
() causes melioidosis, a potentially fatal disease for which no licensed vaccine is available thus far. The host-pathogen interactions in infection largely remain the tip of the iceberg. The pathological manifestations are protean ranging from acute to chronic involving one or more visceral organs leading to septic shock, especially in individuals with underlying conditions similar to COVID-19. Pathogenesis is attributed to the intracellular ability of the bacterium to 'step into' the host cell's cytoplasm from the endocytotic vacuole, where it appears to polymerize actin filaments to spread across cells in the closer vicinity. effectively evades the host's surveillance armory to remain latent for prolonged duration also causing relapses despite antimicrobial therapy. Therefore, eradication of intracellular is highly dependent on robust cellular immune responses. However, it remains ambiguous why certain individuals in endemic areas experience asymptomatic seroconversion, whereas others succumb to sepsis-associated sequelae. Here, we propose key insights on how the host's surveillance radars get commandeered by .
Topics: Animals; Burkholderia pseudomallei; Host Microbial Interactions; Humans; Immunologic Surveillance; Melioidosis; Virulence
PubMed: 34456925
DOI: 10.3389/fimmu.2021.718719 -
Indian Journal of Medical Microbiology 2020Two cases of Burkholderia pseudomallei septic arthritis are presented with a brief review of the literature. B. pseudomallei septic arthritis most commonly occurs in... (Review)
Review
Two cases of Burkholderia pseudomallei septic arthritis are presented with a brief review of the literature. B. pseudomallei septic arthritis most commonly occurs in diabetics and other immunocompromised patients and may prove fatal despite appropriate therapy. Clinical and microbiological suspicion of B. pseudomallei infection may help in providing appropriate empirical therapy.
Topics: Aged; Arthritis, Infectious; Burkholderia pseudomallei; Diabetes Mellitus, Type 2; Humans; Male; Melioidosis; Middle Aged
PubMed: 32883939
DOI: 10.4103/ijmm.IJMM_20_74 -
Secondary metabolites from the Burkholderia pseudomallei complex: structure, ecology, and evolution.Journal of Industrial Microbiology &... Oct 2020Bacterial secondary metabolites play important roles in promoting survival, though few have been carefully studied in their natural context. Numerous gene clusters code... (Review)
Review
Bacterial secondary metabolites play important roles in promoting survival, though few have been carefully studied in their natural context. Numerous gene clusters code for secondary metabolites in the genomes of members of the Bptm group, made up of three closely related species with distinctly different lifestyles: the opportunistic pathogen Burkholderia pseudomallei, the non-pathogenic saprophyte Burkholderia thailandensis, and the host-adapted pathogen Burkholderia mallei. Several biosynthetic gene clusters are conserved across two or all three species, and this provides an opportunity to understand how the corresponding secondary metabolites contribute to survival in different contexts in nature. In this review, we discuss three secondary metabolites from the Bptm group: bactobolin, malleilactone (and malleicyprol), and the 4-hydroxy-3-methyl-2-alkylquinolines, providing an overview of each of their biosynthetic pathways and insight into their potential ecological roles. Results of studies on these secondary metabolites provide a window into how secondary metabolites contribute to bacterial survival in different environments, from host infections to polymicrobial soil communities.
Topics: Biosynthetic Pathways; Burkholderia; Burkholderia mallei; Burkholderia pseudomallei; Lactones; Multigene Family
PubMed: 33052546
DOI: 10.1007/s10295-020-02317-0 -
Clinical Infectious Diseases : An... Jan 2000
Topics: Adult; Burkholderia pseudomallei; Ceftazidime; Cephalosporins; Child; Humans; Melioidosis
PubMed: 10619778
DOI: 10.1086/313577 -
Journal of Clinical Microbiology Dec 2016Melioidosis is a potentially fatal infection caused by the bacterium Burkholderia pseudomallei Clinical diagnosis of melioidosis can be challenging since there is no... (Review)
Review
Melioidosis is a potentially fatal infection caused by the bacterium Burkholderia pseudomallei Clinical diagnosis of melioidosis can be challenging since there is no pathognomonic clinical syndrome, and the organism is often misidentified by methods used routinely in clinical laboratories. Although the disease is more prevalent in Thailand and northern Australia, sporadic cases may be encountered in areas where it is not endemic, including the United States. Since the organism is considered a tier 1 select agent according to the Centers for Disease Control and Prevention and the U.S. Department of Agriculture Animal and Plant Health Inspection Service, clinical laboratories must be proficient at rapidly recognizing isolates suspicious for B. pseudomallei, be able to safely perform necessary rule-out tests, and to refer suspect isolates to Laboratory Response Network reference laboratories. In this minireview, we report a case of melioidosis encountered at our institution and discuss the laboratory challenges encountered when dealing with clinical isolates suspicious for B. pseudomallei or clinical specimens from suspected melioidosis cases.
Topics: Aged; Aneurysm, Infected; Anti-Bacterial Agents; Bacterial Typing Techniques; Burkholderia pseudomallei; Drug Resistance, Multiple, Bacterial; Female; Humans; Melioidosis; Microbial Sensitivity Tests
PubMed: 27654336
DOI: 10.1128/JCM.01636-16 -
Microbiology Spectrum Sep 2021Burkholderia pseudomallei is an opportunistic pathogen that is responsible for the disease melioidosis in humans and animals. The microbe is a tier 1 select agent...
Burkholderia pseudomallei is an opportunistic pathogen that is responsible for the disease melioidosis in humans and animals. The microbe is a tier 1 select agent because it is highly infectious by the aerosol route, it is inherently resistant to multiple antibiotics, and no licensed vaccine currently exists. Naturally acquired infections result from contact with contaminated soil or water sources in regions of endemicity. There have been few reports investigating the molecular mechanism(s) utilized by B. pseudomallei to survive and persist in ecological niches harboring microbial competitors. Here, we report the isolation of Gram-positive bacteria from multiple environmental sources and show that ∼45% of these isolates are inhibited by B. pseudomallei in head-to-head competition assays. Two competition-deficient B. pseudomallei transposon mutants were identified that contained insertion mutations in the operon. This large biosynthetic gene cluster encodes the enzymes that produce a family of secondary metabolites called 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs). Liquid chromatography and mass spectrometry conducted on filter-sterilized culture supernatants revealed five HMAQs and -oxide derivatives that were produced by the parental strain but were absent in an isogenic deletion mutant. The results demonstrate that B. pseudomallei inhibits the growth of environmental Gram-positive bacteria in a contact-independent manner via the production of HMAQs by the operon. Burkholderia pseudomallei naturally resides in water, soil, and the rhizosphere and its success as an opportunistic pathogen is dependent on the ability to persist in these harsh habitats long enough to come into contact with a susceptible host. In addition to adapting to limiting nutrients and diverse chemical and physical challenges, B. pseudomallei also has to interact with a variety of microbial competitors. Our research shows that one of the ways in which B. pseudomallei competes with Gram-positive environmental bacteria is by exporting a diverse array of closely related antimicrobial secondary metabolites.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Burkholderia pseudomallei; Gram-Positive Bacteria; Microbial Interactions; Mutagenesis, Insertional; Operon; Secondary Metabolism
PubMed: 34160272
DOI: 10.1128/Spectrum.00102-21 -
Current Opinion in Microbiology Apr 2020
Review
Topics: Animals; Biological Evolution; Burkholderia pseudomallei; Genome, Bacterial; Glanders; Host Microbial Interactions; Humans; Melioidosis; Movement; Mutation; Rhizosphere; Type III Secretion Systems; Type VI Secretion Systems; Virulence; Virulence Factors
PubMed: 32028234
DOI: 10.1016/j.mib.2019.12.004 -
Microbiology and Immunology 1993
Review
Topics: Animals; Burkholderia pseudomallei; Climate; Environmental Microbiology; Humans; Melioidosis
PubMed: 7507550
DOI: 10.1111/j.1348-0421.1993.tb01712.x -
Microbial Genomics Feb 2021, a soil-dwelling Gram-negative bacterium, is the causative agent of the endemic tropical disease melioidosis. Clinical manifestations of infection range from acute or...
, a soil-dwelling Gram-negative bacterium, is the causative agent of the endemic tropical disease melioidosis. Clinical manifestations of infection range from acute or chronic localized infection in a single organ to fulminant septicaemia in multiple organs. The diverse clinical manifestations are attributed to various factors, including the genome plasticity across strains. We previously characterized strains isolated in Malaysia and noted different levels of virulence in model hosts. We hypothesized that the difference in virulence might be a result of variance at the genome level. In this study, we sequenced and assembled four Malaysian clinical isolates, UKMR15, UKMPMC2000, UKMD286 and UKMH10. Phylogenomic analysis showed that Malaysian subclades emerged from the Asian subclade, suggesting that the Malaysian strains originated from the Asian region. Interestingly, the low-virulence strain, UKMH10, was the most distantly related compared to the other Malaysian isolates. Genomic island (GI) prediction analysis identified a new island of 23 kb, GI9c, which is present in and , but not . Genes encoding known virulence factors were present across all four genomes, but comparative analysis of the total gene content across the Malaysian strains identified 104 genes that are absent in UKMH10. We propose that these genes may encode novel virulence factors, which may explain the reduced virulence of this strain. Further investigation on the identity and role of these 104 proteins may aid in understanding pathogenicity to guide the design of new therapeutics for treating melioidosis.
Topics: Bacterial Typing Techniques; Burkholderia pseudomallei; Genome Size; Genome, Bacterial; Genomic Islands; Genomics; High-Throughput Nucleotide Sequencing; Humans; Malaysia; Melioidosis; Multilocus Sequence Typing; Phylogeny; Virulence Factors; Whole Genome Sequencing
PubMed: 33565959
DOI: 10.1099/mgen.0.000527