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Gassiep I, Burnard D, Bauer MJ, Norton RE, Harris PN. Diagnosis of melioidosis: the role of molecular techniques. Future Microbiol 2021; 16:271-288. [PMID: 33595347 DOI: 10.2217/fmb-2020-0202] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Melioidosis is an emerging infectious disease with an estimated global burden of 4.64 million disability-adjusted life years per year. A major determinant related to poor disease outcomes is delay to diagnosis due to the fact that identification of the causative agent Burkholderia pseudomallei may be challenging. Over the last 25 years, advances in molecular diagnostic techniques have resulted in the potential for rapid and accurate organism detection and identification direct from clinical samples. While these methods are not yet routine in clinical practice, laboratory diagnosis of infectious diseases is transitioning to culture-independent techniques. This review article aims to evaluate molecular methods for melioidosis diagnosis direct from clinical samples and discuss current and future utility and limitations.
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Affiliation(s)
- Ian Gassiep
- University of Queensland Centre for Clinical Research, Royal Brisbane and Woman's Hospital, Herston, Queensland, 4029, Australia.,Department of Infectious Diseases, Mater Hospital Brisbane, South Brisbane, Queensland, 4101, Australia
| | - Delaney Burnard
- University of Queensland Centre for Clinical Research, Royal Brisbane and Woman's Hospital, Herston, Queensland, 4029, Australia
| | - Michelle J Bauer
- University of Queensland Centre for Clinical Research, Royal Brisbane and Woman's Hospital, Herston, Queensland, 4029, Australia
| | - Robert E Norton
- Pathology Queensland, Townsville University Hospital, Townsville, Queensland, 4814, Australia
| | - Patrick N Harris
- University of Queensland Centre for Clinical Research, Royal Brisbane and Woman's Hospital, Herston, Queensland, 4029, Australia.,Pathology Queensland, Royal Brisbane & Women's Hospital, Herston, Queensland, 4029, Australia
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Chomkatekaew C, Boonklang P, Sangphukieo A, Chewapreecha C. An Evolutionary Arms Race Between Burkholderia pseudomallei and Host Immune System: What Do We Know? Front Microbiol 2021; 11:612568. [PMID: 33552023 PMCID: PMC7858667 DOI: 10.3389/fmicb.2020.612568] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/21/2020] [Indexed: 12/18/2022] Open
Abstract
A better understanding of co-evolution between pathogens and hosts holds promise for better prevention and control strategies. This review will explore the interactions between Burkholderia pseudomallei, an environmental and opportunistic pathogen, and the human host immune system. B. pseudomallei causes "Melioidosis," a rapidly fatal tropical infectious disease predicted to affect 165,000 cases annually worldwide, of which 89,000 are fatal. Genetic heterogeneities were reported in both B. pseudomallei and human host population, some of which may, at least in part, contribute to inter-individual differences in disease susceptibility. Here, we review (i) a multi-host-pathogen characteristic of the interaction; (ii) selection pressures acting on B. pseudomallei and human genomes with the former being driven by bacterial adaptation across ranges of ecological niches while the latter are driven by human encounter of broad ranges of pathogens; (iii) the mechanisms that generate genetic diversity in bacterial and host population particularly in sequences encoding proteins functioning in host-pathogen interaction; (iv) reported genetic and structural variations of proteins or molecules observed in B. pseudomallei-human host interactions and their implications in infection outcomes. Together, these predict bacterial and host evolutionary trajectory which continues to generate genetic diversity in bacterium and operates host immune selection at the molecular level.
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Affiliation(s)
| | | | - Apiwat Sangphukieo
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Bangkok, Thailand
- Bioinformatics and Systems Biology Program, School of Bioresource and Technology, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand
| | - Claire Chewapreecha
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Bangkok, Thailand
- Bioinformatics and Systems Biology Program, School of Bioresource and Technology, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand
- Wellcome Sanger Institute, Hinxton, United Kingdom
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Abstract
The causative agent of melioidosis, Burkholderia pseudomallei, a tier 1 select agent, is endemic in Southeast Asia and northern Australia, with increased incidence associated with high levels of rainfall. Increasing reports of this condition have occurred worldwide, with estimates of up to 165,000 cases and 89,000 deaths per year. The ecological niche of the organism has yet to be clearly defined, although the organism is associated with soil and water. The culture of appropriate clinical material remains the mainstay of laboratory diagnosis. Identification is best done by phenotypic methods, although mass spectrometric methods have been described. Serology has a limited diagnostic role. Direct molecular and antigen detection methods have limited availability and sensitivity. Clinical presentations of melioidosis range from acute bacteremic pneumonia to disseminated visceral abscesses and localized infections. Transmission is by direct inoculation, inhalation, or ingestion. Risk factors for melioidosis include male sex, diabetes mellitus, alcohol abuse, and immunosuppression. The organism is well adapted to intracellular survival, with numerous virulence mechanisms. Immunity likely requires innate and adaptive responses. The principles of management of this condition are drainage and debridement of infected material and appropriate antimicrobial therapy. Global mortality rates vary between 9% and 70%. Research into vaccine development is ongoing.
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Affiliation(s)
- I Gassiep
- Pathology Queensland, Townsville Hospital, Townsville, Queensland, Australia
- Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
| | - M Armstrong
- Pathology Queensland, Townsville Hospital, Townsville, Queensland, Australia
| | - R Norton
- Pathology Queensland, Townsville Hospital, Townsville, Queensland, Australia
- Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
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Virulence of the Melioidosis Pathogen Burkholderia pseudomallei Requires the Oxidoreductase Membrane Protein DsbB. Infect Immun 2018; 86:IAI.00938-17. [PMID: 29440370 PMCID: PMC5913862 DOI: 10.1128/iai.00938-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 02/04/2018] [Indexed: 12/26/2022] Open
Abstract
The naturally antibiotic-resistant bacterium Burkholderia pseudomallei is the causative agent of melioidosis, a disease with stubbornly high mortality and a complex, protracted treatment regimen. The worldwide incidence of melioidosis is likely grossly underreported, though it is known to be highly endemic in northern Australia and Southeast Asia. Bacterial disulfide bond (DSB) proteins catalyze the oxidative folding and isomerization of disulfide bonds in substrate proteins. In the present study, we demonstrate that B. pseudomallei membrane protein disulfide bond protein B (BpsDsbB) forms a functional redox relay with the previously characterized virulence mediator B. pseudomallei disulfide bond protein A (BpsDsbA). Genomic analysis of diverse B. pseudomallei clinical isolates demonstrated that dsbB is a highly conserved core gene. Critically, we show that DsbB is required for virulence in B. pseudomallei. A panel of B. pseudomalleidsbB deletion strains (K96243, 576, MSHR2511, MSHR0305b, and MSHR5858) were phenotypically diverse according to the results of in vitro assays that assess hallmarks of virulence. Irrespective of their in vitro virulence phenotypes, two deletion strains were attenuated in a BALB/c mouse model of infection. A crystal structure of a DsbB-derived peptide complexed with BpsDsbA provides the first molecular characterization of their interaction. This work contributes to our broader understanding of DSB redox biology and will support the design of antimicrobial drugs active against this important family of bacterial virulence targets.
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Stundick MV, Albrecht MT, Houchens CR, Smith AP, Dreier TM, Larsen JC. Animal models for Francisella tularensis and Burkholderia species: scientific and regulatory gaps toward approval of antibiotics under the FDA Animal Rule. Vet Pathol 2013; 50:877-92. [PMID: 23628693 DOI: 10.1177/0300985813486812] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The development and regulatory approval of medical countermeasures (MCMs) for the treatment and prevention of bacterial threat agent infections will require the evaluation of products in animal models. To obtain regulatory approval, these models must accurately recapitulate aspects of human disease, including, but not necessarily limited to, route of exposure, time to disease onset, pathology, immune response, and mortality. This article focuses on the state of animal model development for 3 agents for which models are largely immature: Francisella tularensis, Burkholderia mallei, and Burkholderia pseudomallei. An overview of available models and a description of scientific and regulatory gaps are provided.
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Affiliation(s)
- M V Stundick
- US Department of Health and Human Services, Office of the Assistant Secretary for Preparedness and Response, Biomedical Advanced Research and Development Authority, 375 E. St, SW- 12th Floor, Washington, DC 20024, USA.
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Polz MF, Alm EJ, Hanage WP. Horizontal gene transfer and the evolution of bacterial and archaeal population structure. Trends Genet 2013; 29:170-5. [PMID: 23332119 PMCID: PMC3760709 DOI: 10.1016/j.tig.2012.12.006] [Citation(s) in RCA: 262] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 11/29/2012] [Accepted: 12/18/2012] [Indexed: 12/28/2022]
Abstract
Many bacterial and archaeal lineages have a history of extensive and ongoing horizontal gene transfer and loss, as evidenced by the large differences in genome content even among otherwise closely related isolates. How ecologically cohesive populations might evolve and be maintained under such conditions of rapid gene turnover has remained controversial. Here we synthesize recent literature demonstrating the importance of habitat and niche in structuring horizontal gene transfer. This leads to a model of ecological speciation via gradual genetic isolation triggered by differential habitat-association of nascent populations. Further, we hypothesize that subpopulations can evolve through local gene-exchange networks by tapping into a gene pool that is adaptive towards local, continuously changing organismic interactions and is, to a large degree, responsible for the observed rapid gene turnover. Overall, these insights help to explain how bacteria and archaea form populations that display both ecological cohesion and high genomic diversity.
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Affiliation(s)
- Martin F Polz
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Antonov VA, Tkachenko GA, Altukhova VV, Savchenko SS, Zinchenko OV, Viktorov DV, Zamaraev VS, Ilyukhin VI, Alekseev VV. Molecular identification and typing of Burkholderia pseudomallei and Burkholderia mallei: when is enough enough? Trans R Soc Trop Med Hyg 2008; 102 Suppl 1:S134-9. [DOI: 10.1016/s0035-9203(08)70030-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Tuanyok A, Leadem BR, Auerbach RK, Beckstrom-Sternberg SM, Beckstrom-Sternberg JS, Mayo M, Wuthiekanun V, Brettin TS, Nierman WC, Peacock SJ, Currie BJ, Wagner DM, Keim P. Genomic islands from five strains of Burkholderia pseudomallei. BMC Genomics 2008; 9:566. [PMID: 19038032 PMCID: PMC2612704 DOI: 10.1186/1471-2164-9-566] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Accepted: 11/27/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Burkholderia pseudomallei is the etiologic agent of melioidosis, a significant cause of morbidity and mortality where this infection is endemic. Genomic differences among strains of B. pseudomallei are predicted to be one of the major causes of the diverse clinical manifestations observed among patients with melioidosis. The purpose of this study was to examine the role of genomic islands (GIs) as sources of genomic diversity in this species. RESULTS We found that genomic islands (GIs) vary greatly among B. pseudomallei strains. We identified 71 distinct GIs from the genome sequences of five reference strains of B. pseudomallei: K96243, 1710b, 1106a, MSHR668, and MSHR305. The genomic positions of these GIs are not random, as many of them are associated with tRNA gene loci. In particular, the 3' end sequences of tRNA genes are predicted to be involved in the integration of GIs. We propose the term "tRNA-mediated site-specific recombination" (tRNA-SSR) for this mechanism. In addition, we provide a GI nomenclature that is based upon integration hotspots identified here or previously described. CONCLUSION Our data suggest that acquisition of GIs is one of the major sources of genomic diversity within B. pseudomallei and the molecular mechanisms that facilitate horizontally-acquired GIs are common across multiple strains of B. pseudomallei. The differential presence of the 71 GIs across multiple strains demonstrates the importance of these mobile elements for shaping the genetic composition of individual strains and populations within this bacterial species.
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Affiliation(s)
- Apichai Tuanyok
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011-5640, USA.
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Sim SH, Yu Y, Lin CH, Karuturi RKM, Wuthiekanun V, Tuanyok A, Chua HH, Ong C, Paramalingam SS, Tan G, Tang L, Lau G, Ooi EE, Woods D, Feil E, Peacock SJ, Tan P. The core and accessory genomes of Burkholderia pseudomallei: implications for human melioidosis. PLoS Pathog 2008; 4:e1000178. [PMID: 18927621 PMCID: PMC2564834 DOI: 10.1371/journal.ppat.1000178] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Accepted: 09/16/2008] [Indexed: 11/19/2022] Open
Abstract
Natural isolates of Burkholderia pseudomallei (Bp), the causative agent of melioidosis, can exhibit significant ecological flexibility that is likely reflective of a dynamic genome. Using whole-genome Bp microarrays, we examined patterns of gene presence and absence across 94 South East Asian strains isolated from a variety of clinical, environmental, or animal sources. 86% of the Bp K96243 reference genome was common to all the strains representing the Bp “core genome”, comprising genes largely involved in essential functions (eg amino acid metabolism, protein translation). In contrast, 14% of the K96243 genome was variably present across the isolates. This Bp accessory genome encompassed multiple genomic islands (GIs), paralogous genes, and insertions/deletions, including three distinct lipopolysaccharide (LPS)-related gene clusters. Strikingly, strains recovered from cases of human melioidosis clustered on a tree based on accessory gene content, and were significantly more likely to harbor certain GIs compared to animal and environmental isolates. Consistent with the inference that the GIs may contribute to pathogenesis, experimental mutation of BPSS2053, a GI gene, reduced microbial adherence to human epithelial cells. Our results suggest that the Bp accessory genome is likely to play an important role in microbial adaptation and virulence. Melioidosis is a serious infectious disease of humans caused by Burkholderia pseudomallei, a soil bacterium endemic to many areas in South East Asia. Besides humans, B. pseudomallei is also capable of infecting many other species and can be isolated from diverse environmental sources including soil, water, and air. In this study, we used DNA microarrays to probe the stability of the B. pseudomallei genome in a large panel of clinical, animal, and environmental strains. We found that evidence of a highly dynamic B. pseudomallei genome, with up to 14% being variably present across different strains. Surprisingly, strains recovered from human patients were significantly associated with the presence of “genomic islands”, corresponding to regions of DNA directly acquired from other microorganisms. Genes on these genomic islands may thus play an important role in the pathogenesis of human melioidosis.
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Affiliation(s)
- Siew Hoon Sim
- Defense Medical and Environmental Research Institute, DSO National Laboratories, Singapore, Republic of Singapore
| | - Yiting Yu
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | - Chi Ho Lin
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | | | - Vanaporn Wuthiekanun
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Apichai Tuanyok
- Faculty of Medicine, University of Calgary Health Sciences Centre, Calgary, Alberta, Canada
| | - Hui Hoon Chua
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | - Catherine Ong
- Defense Medical and Environmental Research Institute, DSO National Laboratories, Singapore, Republic of Singapore
| | | | - Gladys Tan
- Defense Medical and Environmental Research Institute, DSO National Laboratories, Singapore, Republic of Singapore
| | - Lynn Tang
- Defense Medical and Environmental Research Institute, DSO National Laboratories, Singapore, Republic of Singapore
| | - Gary Lau
- Defense Medical and Environmental Research Institute, DSO National Laboratories, Singapore, Republic of Singapore
| | - Eng Eong Ooi
- Defense Medical and Environmental Research Institute, DSO National Laboratories, Singapore, Republic of Singapore
| | - Donald Woods
- Faculty of Medicine, University of Calgary Health Sciences Centre, Calgary, Alberta, Canada
| | - Edward Feil
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, United Kingdom
| | - Sharon J. Peacock
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Center for Clinical Vaccinology and Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Headington, Oxford, United Kingdom
- * E-mail: (SJP); (PT)
| | - Patrick Tan
- Genome Institute of Singapore, Singapore, Republic of Singapore
- Duke-NUS Graduate Medical School Singapore, Singapore, Republic of Singapore
- * E-mail: (SJP); (PT)
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Burkholderia pseudomallei genome plasticity associated with genomic island variation. BMC Genomics 2008; 9:190. [PMID: 18439288 PMCID: PMC2386483 DOI: 10.1186/1471-2164-9-190] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 04/25/2008] [Indexed: 11/24/2022] Open
Abstract
Background Burkholderia pseudomallei is a soil-dwelling saprophyte and the cause of melioidosis. Horizontal gene transfer contributes to the genetic diversity of this pathogen and may be an important determinant of virulence potential. The genome contains genomic island (GI) regions that encode a broad array of functions. Although there is some evidence for the variable distribution of genomic islands in B. pseudomallei isolates, little is known about the extent of variation between related strains or their association with disease or environmental survival. Results Five islands from B. pseudomallei strain K96243 were chosen as representatives of different types of genomic islands present in this strain, and their presence investigated in other B. pseudomallei. In silico analysis of 10 B. pseudomallei genome sequences provided evidence for the variable presence of these regions, together with micro-evolutionary changes that generate GI diversity. The diversity of GIs in 186 isolates from NE Thailand (83 environmental and 103 clinical isolates) was investigated using multiplex PCR screening. The proportion of all isolates positive by PCR ranged from 12% for a prophage-like island (GI 9), to 76% for a metabolic island (GI 16). The presence of each of the five GIs did not differ between environmental and disease-associated isolates (p > 0.05 for all five islands). The cumulative number of GIs per isolate for the 186 isolates ranged from 0 to 5 (median 2, IQR 1 to 3). The distribution of cumulative GI number did not differ between environmental and disease-associated isolates (p = 0.27). The presence of GIs was defined for the three largest clones in this collection (each defined as a single sequence type, ST, by multilocus sequence typing); these were ST 70 (n = 15 isolates), ST 54 (n = 11), and ST 167 (n = 9). The rapid loss and/or acquisition of gene islands was observed within individual clones. Comparisons were drawn between isolates obtained from the environment and from patients with melioidosis in order to examine the role of genomic islands in virulence and clinical associations. There was no reproducible association between the individual or cumulative presence of five GIs and a range of clinical features in 103 patients with melioidosis. Conclusion Horizontal gene transfer of mobile genetic elements can rapidly alter the gene repertoire of B. pseudomallei. This study confirms the utility of a range of approaches in defining the presence and significance of genomic variation in natural populations of B. pseudomallei.
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Currie BJ. Advances and remaining uncertainties in the epidemiology of Burkholderia pseudomallei and melioidosis. Trans R Soc Trop Med Hyg 2007; 102:225-7. [PMID: 18166205 DOI: 10.1016/j.trstmh.2007.11.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Revised: 11/06/2007] [Accepted: 11/07/2007] [Indexed: 11/25/2022] Open
Abstract
Major advances have been made in molecular studies of Burkholderia pseudomallei and the immunology of melioidosis. However, there remain large gaps in understanding of the epidemiology of this enigmatic disease. Identified global distribution boundaries of melioidosis continue to expand. Recent data suggest Australian strains of B. pseudomallei may be ancestral to those from Southeast Asia, but the ecology of this environmental bacterium remains elusive. Despite the potential for rapidly progressive septicaemia, the critical virulence factors in B. pseudomallei remain to be clarified. Inhalation following aerosolization of B. pseudomallei may account for the high mortality when melioidosis occurs after severe weather events.
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Affiliation(s)
- Bart J Currie
- Menzies School of Health Research, Charles Darwin University, and Northern Territory Clinical School, Flinders University, Darwin, Northern Territory Australia.
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A horizontal gene transfer event defines two distinct groups within Burkholderia pseudomallei that have dissimilar geographic distributions. J Bacteriol 2007; 189:9044-9. [PMID: 17933898 PMCID: PMC2168593 DOI: 10.1128/jb.01264-07] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia pseudomallei is the etiologic agent of melioidosis. Many disease manifestations are associated with melioidosis, and the mechanisms causing this variation are unknown; genomic differences among strains offer one explanation. We compared the genome sequences of two strains of B. pseudomallei: the original reference strain K96243 from Thailand and strain MSHR305 from Australia. We identified a variable homologous region between the two strains. This region was previously identified in comparisons of the genome of B. pseudomallei strain K96243 with the genome of strain E264 from the closely related B. thailandensis. In that comparison, K96243 was shown to possess a horizontally acquired Yersinia-like fimbrial (YLF) gene cluster. Here, we show that the homologous genomic region in B. pseudomallei strain 305 is similar to that previously identified in B. thailandensis strain E264. We have named this region in B. pseudomallei strain 305 the B. thailandensis-like flagellum and chemotaxis (BTFC) gene cluster. We screened for these different genomic components across additional genome sequences and 571 B. pseudomallei DNA extracts obtained from regions of endemicity. These alternate genomic states define two distinct groups within B. pseudomallei: all strains contained either the BTFC gene cluster (group BTFC) or the YLF gene cluster (group YLF). These two groups have distinct geographic distributions: group BTFC is dominant in Australia, and group YLF is dominant in Thailand and elsewhere. In addition, clinical isolates are more likely to belong to group YLF, whereas environmental isolates are more likely to belong to group BTFC. These groups should be further characterized in an animal model.
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Abstract
PURPOSE OF REVIEW Melioidosis is increasingly recognized around the world. Despite several decades of clinical research, the mortality rate for melioidosis remains high. This review focuses on studies that relate to patient management, including risk factors, diagnosis, treatment and prediction of the outcome. A brief summary of studies relating to genomics and genotyping, immunology and pathogenesis is provided. RECENT FINDINGS Involvement in the tsunami of December 2004 is a risk factor for melioidosis, and risk may extend to individuals who were uninjured bystanders. Several standard microbiological techniques used to culture and identify Burkholderia pseudomallei have been evaluated. Polymerase chain reaction has been developed for bacterial identification, although limited evaluation has been performed in the clinical setting. Two trials of antimicrobial therapy provide evidence with which to refine existing treatment protocols. Inexpensive clinical and laboratory predictors for poor outcome have been described. Several putative vaccine candidates have been proposed and studied in animals, but no vaccine is on the immediate horizon. SUMMARY None of the studies reviewed here report strategies that reduce mortality. A key area for future research is the identification of affordable interventions that lower the death rate, and are applicable to low-resource settings.
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Affiliation(s)
- Sharon J Peacock
- Wellcome Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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