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Cheng S, Fleres G, Chen L, Liu G, Hao B, Newbrough A, Driscoll E, Shields RK, Squires KM, Chu TY, Kreiswirth BN, Nguyen MH, Clancy CJ. Within-Host Genotypic and Phenotypic Diversity of Contemporaneous Carbapenem-Resistant Klebsiella pneumoniae from Blood Cultures of Patients with Bacteremia. mBio 2022; 13:e0290622. [PMID: 36445082 PMCID: PMC9765435 DOI: 10.1128/mbio.02906-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 10/24/2022] [Indexed: 12/02/2022] Open
Abstract
It is unknown whether bacterial bloodstream infections (BSIs) are commonly caused by single organisms or mixed microbial populations. We hypothesized that contemporaneous carbapenem-resistant Klebsiella pneumoniae (CRKP) strains from blood cultures of individual patients are genetically and phenotypically distinct. We determined short-read whole-genome sequences of 10 sequence type 258 (ST258) CRKP strains from blood cultures in each of 6 patients (Illumina HiSeq). Strains clustered by patient by core genome and pan-genome phylogeny. In 5 patients, there was within-host strain diversity by gene mutations, presence/absence of antibiotic resistance or virulence genes, and/or plasmid content. Accessory gene phylogeny revealed strain diversity in all 6 patients. Strains from 3 patients underwent long-read sequencing for genome completion (Oxford Nanopore) and phenotypic testing. Genetically distinct strains within individuals exhibited significant differences in carbapenem and other antibiotic responses, capsular polysaccharide (CPS) production, mucoviscosity, and/or serum killing. In 2 patients, strains differed significantly in virulence during mouse BSIs. Genetic or phenotypic diversity was not observed among strains recovered from blood culture bottles seeded with index strains from the 3 patients and incubated in vitro at 37°C. In conclusion, we identified genotypic and phenotypic variant ST258 CRKP strains from blood cultures of individual patients with BSIs, which were not detected by the clinical laboratory or in seeded blood cultures. The data suggest a new paradigm of CRKP population diversity during BSIs, at least in some patients. If validated for BSIs caused by other bacteria, within-host microbial diversity may have implications for medical, microbiology, and infection prevention practices and for understanding antibiotic resistance and pathogenesis. IMPORTANCE The long-standing paradigm for pathogenesis of bacteremia is that, in most cases, a single organism passes through a bottleneck and establishes itself in the bloodstream (single-organism hypothesis). In keeping with this paradigm, standard practice in processing positive microbiologic cultures is to test single bacterial strains from morphologically distinct colonies. This study is the first genome-wide analysis of within-host diversity of Klebsiella pneumoniae strains recovered from individual patients with bloodstream infections (BSIs). Our finding that positive blood cultures comprised genetically and phenotypically heterogeneous carbapenem-resistant K. pneumoniae strains challenges the single-organism hypothesis and suggests that at least some BSIs are caused by mixed bacterial populations that are unrecognized by the clinical laboratory. The data support a model of pathogenesis in which pressures in vivo select for strain variants with particular antibiotic resistance or virulence attributes and raise questions about laboratory protocols and treatment decisions directed against single strains.
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Affiliation(s)
- Shaoji Cheng
- University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | | | - Liang Chen
- Hackensack Meridian Health Center for Discovery and Innovation, Nutley, New Jersey, USA
| | - Guojun Liu
- University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Binghua Hao
- University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | | | | | - Ryan K. Shields
- University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | | | - Ting-yu Chu
- Hackensack Meridian Health Center for Discovery and Innovation, Nutley, New Jersey, USA
| | - Barry N. Kreiswirth
- Hackensack Meridian Health Center for Discovery and Innovation, Nutley, New Jersey, USA
| | - M. Hong Nguyen
- University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Cornelius J. Clancy
- University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania, USA
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2
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Shafiq M, Ke B, Li X, Zeng M, Yuan Y, He D, Deng X, Jiao X. Genomic diversity of resistant and virulent factors of Burkholderia pseudomallei clinical strains recovered from Guangdong using whole genome sequencing. Front Microbiol 2022; 13:980525. [PMID: 36386717 PMCID: PMC9649843 DOI: 10.3389/fmicb.2022.980525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 10/04/2022] [Indexed: 02/05/2023] Open
Abstract
Background Burkholderia pseudomallei (B. pseudomallei) is a highly infectious agent and causes melioidosis, in both humans and animals, which is endemic in Southeast Asia and Northern Australia. Objectives This study aims to determine the molecular epidemiology, resistant determinants, and genomic diversity of the clinical isolates of B. pseudomallei to further elucidate the phylogenetic and evolutionary relationship of the strains with those in other endemic regions. Methods In this study, we obtained eight clinical B. pseudomallei isolates from Guangdong province from 2018 to 2019. All the isolates were sequenced using the Illumina NovaSeq platform. The draft genomes of B. pseudomallei were further used to find antibiotic-resistant genes (ARGs), virulence factors, and gene mutations. Multilocus sequence typing (MLST) and single nucleotide polymorphism (SNP) analysis were performed to characterize the diversity and epidemiology of the strains. Results All isolates were susceptible to antibiotics commonly used for melioidosis treatment. Class D beta-lactamases genes OXA-57 and OXA-59, as well as various mutation factors such as amrA, amrB, omp38, gyrA, and ceoB were identified. MLST analysis of the B. pseudomallei strains identified eight different sequence types (STs): ST1774, ST1775, ST271, ST562, ST46, ST830, ST1325, and ST10. Phylogenetic analysis found that the strains used in this study showed high genetic diversity. We also report 165 virulence factors among B. pseudomallei strains responsible for different neurological disorders, pneumonia, skin lesions, and abscesses. All strains recovered in this study were susceptible to commonly used antibiotics. However, high genetic diversity exists among the isolates. The surveillance, diagnosis, and clinical features of melioidosis varied in different geographical locations. These regional differences in the clinical manifestations have implications for the practical management of the disease. Conclusion The present study reports the identification of different mutation and virulence factors among B. pseudomallei strains responsible for different neurological disorders, pneumonia, skin lesions, and abscesses.
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Affiliation(s)
- Muhammad Shafiq
- Department of Cell Biology and Genetics, Shantou University Medical College, Shantou, China
| | - Bixia Ke
- Center for Disease Control and Prevention of Guangdong Province, Chinese Academy of Sciences, Guangzhou, China
| | - Xin Li
- Department of Cell Biology and Genetics, Shantou University Medical College, Shantou, China
| | - Mi Zeng
- Department of Cell Biology and Genetics, Shantou University Medical College, Shantou, China
| | - Yumeng Yuan
- Department of Cell Biology and Genetics, Shantou University Medical College, Shantou, China
| | - Dongmei He
- Center for Disease Control and Prevention of Guangdong Province, Chinese Academy of Sciences, Guangzhou, China
| | - Xiaoling Deng
- Center for Disease Control and Prevention of Guangdong Province, Chinese Academy of Sciences, Guangzhou, China
| | - Xiaoyang Jiao
- Department of Cell Biology and Genetics, Shantou University Medical College, Shantou, China
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Genotyping of Burkholderia pseudomallei Isolated From Patients in South-Western Coastal Region of India. Curr Microbiol 2022; 79:226. [PMID: 35731378 DOI: 10.1007/s00284-022-02905-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 05/16/2022] [Indexed: 11/03/2022]
Abstract
Burkholderia pseudomallei is the causative agent of melioidosis. Various tools have been used to determine the genetic diversity in B. pseudomallei isolates. In this study, Random Amplified Polymorphic DNA (RAPD)-PCR and flagellin gene (fliC) based PCR-Restriction Fragment Length Polymorphism (RFLP) were used to genotype Indian clinical B. pseudomallei isolates. A total of 89 clinical isolates could be grouped in 6 groups (A through F) by RAPD-PCR analysis. Some of the isolates in various groups had identical banding pattern suggesting them to be epidemiologically related. The RAPD groups also correlated with MLST sequence types suggesting the utility of this easy to do typing method. The PCR- RFLP analysis suggested Type III to be the predominant type which is different from other RFLP types reported from Southeast Asia. In conclusion, the results of this study show that RAPD-PCR, a simple genotyping method, may be used for analyzing the B. pseudomallei isolates and also establish epidemiological relevant relatedness among them. The results of fliC PCR-RFLP further suggest the Indian isolates are different from other Southeast Asian isolates.
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Oslan SNH, Yusoff AH, Mazlan M, Lim SJ, Khoo JJ, Oslan SN, Ismail A. Comprehensive approaches for the detection of Burkholderia pseudomallei and diagnosis of melioidosis in human and environmental samples. Microb Pathog 2022; 169:105637. [PMID: 35710088 DOI: 10.1016/j.micpath.2022.105637] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 06/06/2022] [Accepted: 06/10/2022] [Indexed: 11/16/2022]
Abstract
Melioidosis is endemic in Southeast Asia and northern Australia. The causative agent of melioidosis is a Gram-negative bacterium, Burkholderia pseudomallei. Its invasion can be fatal if melioidosis is not treated promptly. It is intrinsically resistant to a variety of antibiotics. In this paper, we present a comprehensive overview of the current trends on melioidosis cases, treatments, B. pseudomallei virulence factors, and molecular techniques to detect the bacterium from different samples. The clinical and microbial diagnosis methods of identification and detection of B. pseudomallei are commonly used for the rapid diagnosis and typing of strains, such as polymerase chain reaction or multi-locus sequence typing. The genotyping strategies and techniques have been constantly evolving to identify genomic loci linked to or associated with this human disease. More research strategies for detecting and controlling melioidosis should be encouraged and conducted to understand the current situation. In conclusion, we review existing diagnostic methodologies for melioidosis detection and provide insights on prospective diagnostic methods for the bacterium.
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Affiliation(s)
- Siti Nur Hazwani Oslan
- Faculty of Food Science and Nutrition, Universiti Malaysia Sabah, Jalan UMS, 88400, Kota Kinabalu, Sabah, Malaysia.
| | - Abdul Hafidz Yusoff
- Gold Rare Earth and Material Technopreneurship Centre (GREAT), Faculty of Bioengineering and Technology, Universiti Malaysia Kelantan, Jeli Campus, Jeli, 17600, Kelantan, Malaysia.
| | - Mazlina Mazlan
- Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, 43400 UPM, Serdang, Selangor, Malaysia.
| | - Si Jie Lim
- Enzyme Technology and X-Ray Crystallography Laboratory, VacBio 5, Institute of Bioscience, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia; Enzyme and Microbial Technology (EMTech) Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
| | - Jing Jing Khoo
- Tropical Infectious Diseases Research and Education Centre (TIDREC), High Impact Research Building, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Siti Nurbaya Oslan
- Enzyme Technology and X-Ray Crystallography Laboratory, VacBio 5, Institute of Bioscience, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia; Enzyme and Microbial Technology (EMTech) Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia; Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
| | - Aziah Ismail
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia.
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Abstract
Within-host adaptation is a hallmark of chronic bacterial infections, involving substantial genomic changes. Recent large-scale genomic data from prolonged infections allow the examination of adaptive strategies employed by different pathogens and open the door to investigate whether they converge toward similar strategies. Here, we compiled extensive data of whole-genome sequences of bacterial isolates belonging to miscellaneous species sampled at sequential time points during clinical infections. Analysis of these data revealed that different species share some common adaptive strategies, achieved by mutating various genes. Although the same genes were often mutated in several strains within a species, different genes related to the same pathway, structure, or function were changed in other species utilizing the same adaptive strategy (e.g., mutating flagellar genes). Strategies exploited by various bacterial species were often predicted to be driven by the host immune system, a powerful selective pressure that is not species specific. Remarkably, we find adaptive strategies identified previously within single species to be ubiquitous. Two striking examples are shifts from siderophore-based to heme-based iron scavenging (previously shown for Pseudomonas aeruginosa) and changes in glycerol-phosphate metabolism (previously shown to decrease sensitivity to antibiotics in Mycobacterium tuberculosis). Virulence factors were often adaptively affected in different species, indicating shifts from acute to chronic virulence and virulence attenuation during infection. Our study presents a global view on common within-host adaptive strategies employed by different bacterial species and provides a rich resource for further studying these processes.
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Affiliation(s)
- Yair E Gatt
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hanah Margalit
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
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Abstract
B. pseudomallei causes significant morbidity and mortality, but its geographic prevalence and genetic diversity are not well characterized, especially in the Western Hemisphere. A better understanding of the genetic relationships among clinical and environmental isolates will improve knowledge of the population structure of this bacterium as well as the ability to conduct epidemiological investigations of cases of melioidosis. Burkholderia pseudomallei is a Gram-negative bacterium that causes the sapronotic disease melioidosis. An outbreak in 2003 in the state of Ceara, Brazil, resulted in subsequent surveillance and environmental sampling which led to the recognition of B. pseudomallei as an endemic pathogen in that area. From 2003 to 2015, 24 clinical and 12 environmental isolates were collected across Ceara along with one from the state of Alagoas. Using next-generation sequencing, multilocus sequence typing, and single nucleotide polymorphism analysis, we characterized the genomic diversity of this collection to better understand the population structure of B. pseudomallei associated with Ceara. We found that the isolates in this collection form a distinct subclade compared to other examples from the Western Hemisphere. Substantial genetic diversity among the clinical and environmental isolates was observed, with 14 sequence types (STs) identified among the 37 isolates. Of the 31,594 core single-nucleotide polymorphisms (SNPs) identified, a high proportion (59%) were due to recombination. Because recombination events do not follow a molecular clock, the observation of high occurrence underscores the importance of identifying and removing recombination SNPs prior to evolutionary reconstructions and inferences in public health responses to B. pseudomallei outbreaks. Our results suggest long-term B. pseudomallei prevalence in this recently recognized region of melioidosis endemicity. IMPORTANCEB. pseudomallei causes significant morbidity and mortality, but its geographic prevalence and genetic diversity are not well characterized, especially in the Western Hemisphere. A better understanding of the genetic relationships among clinical and environmental isolates will improve knowledge of the population structure of this bacterium as well as the ability to conduct epidemiological investigations of cases of melioidosis.
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Using Land Runoff to Survey the Distribution and Genetic Diversity of Burkholderia pseudomallei in Vientiane, Laos. Appl Environ Microbiol 2021; 87:AEM.02112-20. [PMID: 33257313 PMCID: PMC7851688 DOI: 10.1128/aem.02112-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Melioidosis is a disease of significant public health importance that is being increasingly recognized globally. The majority of cases arise through direct percutaneous exposure to its etiological agent, Burkholderia pseudomallei In the Lao People's Democratic Republic (Laos), the presence and environmental distribution of B. pseudomallei are not well characterized, though recent epidemiological surveys of the bacterium have indicated that B. pseudomallei is widespread throughout the environment in the center and south of the country and that rivers can act as carriers and potential sentinels for the bacterium. The spatial and genetic distribution of B. pseudomallei within Vientiane Capital, from where the majority of cases diagnosed to date have originated, remains an important knowledge gap. We sampled surface runoff from drain catchment areas throughout urban Vientiane to determine the presence and local population structure of the bacterium. B. pseudomallei was detected in drainage areas throughout the capital, indicating it is widespread in the environment and that exposure rates in urban Vientiane are likely more frequent than previously thought. Whole-genome comparative analysis demonstrated that Lao B. pseudomallei isolates are highly genetically diverse, suggesting the bacterium is well-established and not a recent introduction. Despite the wide genome diversity, one environmental survey isolate was highly genetically related to a Lao melioidosis patient isolate collected 13 years prior to the study. Knowledge gained from this study will augment understanding of B. pseudomallei phylogeography in Asia and enhance public health awareness and future implementation of infection control measures within Laos.IMPORTANCE The environmental bacterium B. pseudomallei is the etiological agent of melioidosis, a tropical disease with one model estimating a global annual incidence of 165,000 cases and 89,000 deaths. In the Lao People's Democratic Republic (Laos), the environmental distribution and population structure of B. pseudomallei remain relatively undefined, particularly in Vientiane Capital from where most diagnosed cases have originated. We used surface runoff as a proxy for B. pseudomallei dispersal in the environment and performed whole-genome sequencing (WGS) to examine the local population structure. Our data confirmed that B. pseudomallei is widespread throughout Vientiane and that surface runoff might be useful for future environmental monitoring of the bacterium. B. pseudomallei isolates were also highly genetically diverse, suggesting the bacterium is well-established and endemic in Laos. These findings can be used to improve awareness of B. pseudomallei in the Lao environment and demonstrates the epidemiological and phylogeographical insights that can be gained from WGS.
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Zhu X, Chen H, Li S, Wang LC, Wu DR, Wang XM, Chen RS, Li ZJ, Liu ZG. Molecular Characteristics of Burkholderia pseudomallei Collected From Humans in Hainan, China. Front Microbiol 2020; 11:778. [PMID: 32457710 PMCID: PMC7223694 DOI: 10.3389/fmicb.2020.00778] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 04/01/2020] [Indexed: 12/21/2022] Open
Abstract
Melioidosis is a common infectious disease in Southeast Asia and Northern Australia. In Hainan, several cases have been reported, but no systematic study has yet been done on the molecular epidemiology profiles of the organism. An investigation of the molecular epidemiology links and population structure of Burkholderia pseudomallei would help to better understand the clonally of the isolates and differences among them. In this study, multilocus variable-number tandem repeat analysis (MLVA), and multilocus sequence typing (MLST) were applied to examine the epidemiological relatedness and population structure of 166 B. pseudomallei isolates obtained during 2002–2014 in Hainan, China. Both the MLVA_4 and MLST approaches had high discriminatory power for this population, with diversity indices of 0.9899 and 0.9457, respectively. However, the MLVA_4 assay showed a higher discriminatory power than the MLST approach, and a variable-number tandem repeat (VNTR3 933) found by the MLVA approach was the most useful in discriminating strains from this province. A total of 166 strains yielded 99 MLVA_4 genotypes, of which 34 genotypes were shared by 101 isolates, for a clustering rate of 60.8% (101/166), which suggested that some cases may have a common source. Additionally, 65 isolates showed distinct genotypes, indicating that more than 39.2% (65/166) of melioidosis cases in Hainan had epidemiologically unrelated or sporadic characteristics. The 166 isolates were resolved into 48 STs, of which five STs (ST55, -70, -46, -50, and -58) were here found to be predominant. Phylogenetic analysis of 116 isolates conducted using the eBURST v3 segregated the 48 STs into eight groups with ST50 as predicted founder, and 21 STs were found to be singletons, which suggest that the strains in the Hainan region represent a high diversity of ST clones, indicating that many B. pseudomallei clone groups are endemic to this region. Moreover, ST50 had 5 SLV, 7 DLV, 6 TLV, and 29 satellite STs and formed a radial expansion pattern, suggesting that the melioidosis epidemic in this study was mainly caused by the clonal expansion of ST 50. Phylogenetic analysis on global scale suggests that China’s isolates are closely related to isolates from Southeast Asia, particularly from Thailand and Malaysia.
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Affiliation(s)
- Xiong Zhu
- Sanya People's Hospital, Sanya, China
| | - Hai Chen
- Sanya People's Hospital, Sanya, China
| | - Sha Li
- Sanya People's Hospital, Sanya, China
| | | | | | | | - Ru-Shou Chen
- The Third People's Hospital of Hainan Province, Sanya, China
| | - Zhen-Jun Li
- State Key Laboratory for Infectious Disease Prevention and Control, China Center for Disease Control and Prevention, National Institute for Communicable Disease Control and Prevention, Beijing, China
| | - Zhi-Guo Liu
- Sanya People's Hospital, Sanya, China.,State Key Laboratory for Infectious Disease Prevention and Control, China Center for Disease Control and Prevention, National Institute for Communicable Disease Control and Prevention, Beijing, China
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Whole-genome sequencing of Burkholderia pseudomallei from an urban melioidosis hot spot reveals a fine-scale population structure and localised spatial clustering in the environment. Sci Rep 2020; 10:5443. [PMID: 32214186 PMCID: PMC7096523 DOI: 10.1038/s41598-020-62300-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 12/17/2019] [Indexed: 11/12/2022] Open
Abstract
Melioidosis is a severe disease caused by the environmental bacterium Burkholderia pseudomallei that affects both humans and animals throughout northern Australia, Southeast Asia and increasingly globally. While there is a considerable degree of genetic diversity amongst isolates, B. pseudomallei has a robust global biogeographic structure and genetic populations are spatially clustered in the environment. We examined the distribution and local spread of B. pseudomallei in Darwin, Northern Territory, Australia, which has the highest recorded urban incidence of melioidosis globally. We sampled soil and land runoff throughout the city centre and performed whole-genome sequencing (WGS) on B. pseudomallei isolates. By combining phylogenetic analyses, Bayesian clustering and spatial hot spot analysis our results demonstrate that some sequence types (STs) are widespread in the urban Darwin environment, while others are highly spatially clustered over a small geographic scale. This clustering matches the spatial distribution of clinical cases for one ST. Results also demonstrate a greater overall isolate diversity recovered from drains compared to park soils, further supporting the role drains may play in dispersal of B. pseudomallei STs in the environment. Collectively, knowledge gained from this study will allow for better understanding of B. pseudomallei phylogeography and melioidosis source attribution, particularly on a local level.
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Pearson T, Sahl JW, Hepp CM, Handady K, Hornstra H, Vazquez AJ, Settles E, Mayo M, Kaestli M, Williamson CHD, Price EP, Sarovich DS, Cook JM, Wolken SR, Bowen RA, Tuanyok A, Foster JT, Drees KP, Kidd TJ, Bell SC, Currie BJ, Keim P. Pathogen to commensal? Longitudinal within-host population dynamics, evolution, and adaptation during a chronic >16-year Burkholderia pseudomallei infection. PLoS Pathog 2020; 16:e1008298. [PMID: 32134991 PMCID: PMC7077878 DOI: 10.1371/journal.ppat.1008298] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 03/17/2020] [Accepted: 01/02/2020] [Indexed: 12/14/2022] Open
Abstract
Although acute melioidosis is the most common outcome of Burkholderia pseudomallei infection, we have documented a case, P314, where disease severity lessened with time, and the pathogen evolved towards a commensal relationship with the host. In the current study, we used whole-genome sequencing to monitor this long-term symbiotic relationship to better understand B. pseudomallei persistence in P314's sputum despite intensive initial therapeutic regimens. We collected and sequenced 118 B. pseudomallei isolates from P314's airways over a >16-year period, and also sampled the patient's home environment, recovering six closely related B. pseudomallei isolates from the household water system. Using comparative genomics, we identified 126 SNPs in the core genome of the 124 isolates or 162 SNPs/indels when the accessory genome was included. The core SNPs were used to construct a phylogenetic tree, which demonstrated a close relationship between environmental and clinical isolates and detailed within-host evolutionary patterns. The phylogeny had little homoplasy, consistent with a strictly clonal mode of genetic inheritance. Repeated sampling revealed evidence of genetic diversification, but frequent extinctions left only one successful lineage through the first four years and two lineages after that. Overall, the evolution of this population is nonadaptive and best explained by genetic drift. However, some genetic and phenotypic changes are consistent with in situ adaptation. Using a mouse model, P314 isolates caused greatly reduced morbidity and mortality compared to the environmental isolates. Additionally, potentially adaptive phenotypes emerged and included differences in the O-antigen, capsular polysaccharide, motility, and colony morphology. The >13-year co-existence of two long-lived lineages presents interesting hypotheses that can be tested in future studies to provide additional insights into selective pressures, niche differentiation, and microbial adaptation. This unusual melioidosis case presents a rare example of the evolutionary progression towards commensalism by a highly virulent pathogen within a single human host.
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Affiliation(s)
- Talima Pearson
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Jason W. Sahl
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Crystal M. Hepp
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Karthik Handady
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Heidie Hornstra
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Adam J. Vazquez
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Erik Settles
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Mark Mayo
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Mirjam Kaestli
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Charles H. D. Williamson
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Erin P. Price
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Derek S. Sarovich
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - James M. Cook
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Spenser R. Wolken
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Richard A. Bowen
- Department of Biomedical Sciences, Colorado State University, Colorado, United States of America
| | - Apichai Tuanyok
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Jeffrey T. Foster
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Kevin P. Drees
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Timothy J. Kidd
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Scott C. Bell
- Department of Thoracic Medicine, The Prince Charles Hospital, Chermside, and QIMR Berghofer Medical Research Institute, Queensland, Australia
| | - Bart J. Currie
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Infectious Diseases Department and Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Paul Keim
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
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Aziz A, Currie BJ, Mayo M, Sarovich DS, Price EP. Comparative genomics confirms a rare melioidosis human-to-human transmission event and reveals incorrect phylogenomic reconstruction due to polyclonality. Microb Genom 2020; 6:e000326. [PMID: 31958055 PMCID: PMC7067207 DOI: 10.1099/mgen.0.000326] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 12/18/2019] [Indexed: 01/13/2023] Open
Abstract
Human-to-human transmission of the melioidosis bacterium, Burkholderia pseudomallei, is exceedingly rare, with only a handful of suspected cases documented to date. Here, we used whole-genome sequencing (WGS) to characterize one such unusual B. pseudomallei transmission event, which occurred between a breastfeeding mother with mastitis and her child. Two strains corresponding to multilocus sequence types (STs)-259 and -261 were identified in the mother's sputum from both the primary culture sweep and in purified colonies, confirming an unusual polyclonal infection in this patient. In contrast, primary culture sweeps of the mother's breast milk and the child's cerebrospinal fluid and blood samples contained only ST-259, indicating monoclonal transmission to the child. Analysis of purified ST-259 isolates showed no genetic variation between mother and baby isolates, providing the strongest possible evidence of B. pseudomallei human-to-human transmission, probably via breastfeeding. Next, phylogenomic analysis of all isolates, including the mother's mixed ST-259/ST-261 sputum sample, was performed to investigate the effects of mixtures on phylogenetic inference. Inclusion of this mixture caused a dramatic reduction in the number of informative SNPs, resulting in branch collapse of ST-259 and ST-261 isolates, and several instances of incorrect topology in a global B. pseudomallei phylogeny, resulting in phylogenetic incongruence. Although phylogenomics can provide clues about the presence of mixtures within WGS datasets, our results demonstrate that this methodology can lead to phylogenetic misinterpretation if mixed genomes are not correctly identified and omitted. Using current bioinformatic tools, we demonstrate a robust method for bacterial mixture identification and strain parsing that avoids these pitfalls.
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Affiliation(s)
- Ammar Aziz
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Bart J. Currie
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
- Infectious Diseases Department, Royal Darwin Hospital, Darwin, NT, Australia
| | - Mark Mayo
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Derek S. Sarovich
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, QLD, Australia
- Sunshine Coast Health Institute, Birtinya, QLD, Australia
| | - Erin P. Price
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, QLD, Australia
- Sunshine Coast Health Institute, Birtinya, QLD, Australia
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Rachlin A, Kleinecke M, Kaestli M, Mayo M, Webb JR, Rigas V, Shilton C, Benedict S, Dyrting K, Currie BJ. A cluster of melioidosis infections in hatchling saltwater crocodiles ( Crocodylus porosus) resolved using genome-wide comparison of a common north Australian strain of Burkholderia pseudomallei. Microb Genom 2019; 5. [PMID: 31433287 PMCID: PMC6755496 DOI: 10.1099/mgen.0.000288] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Burkholderia pseudomallei is a Gram-negative saprophytic bacillus and the aetiological agent of melioidosis, a disease of public-health importance throughout Southeast Asia and northern Australia. Infection can occur in humans and a wide array of animal species, though zoonotic transmission and case clusters are rare. Despite its highly plastic genome and extensive strain diversity, fine-scale investigations into the population structure of B. pseudomallei indicate there is limited geographical dispersal amongst sequence types (STs). In the ‘Top End’ of northern Australia, five STs comprise 90 % of the overall abundance, the most prevalent and widespread of which is ST-109. In May 2016, ST-109 was implicated in two fatal cases of melioidosis in juvenile saltwater crocodiles at a wildlife park near Darwin, Australia. To determine the probable source of infection, we sampled the crocodile enclosures and analysed the phylogenetic relatedness of crocodile and culture-positive ST-109 environmental park isolates against an additional 135 ST-109 B. pseudomallei isolates from the Top End. Collectively, our whole-genome sequencing (WGS) and pathology findings confirmed B. pseudomallei detected in the hatchling incubator as the likely source of infection, with zero SNPs identified between clinical and environmental isolates. Our results also demonstrate little variation across the ST-109 genome, with SNPs in recombinogenic regions and one suspected case of ST homoplasy accounting for nearly all observed diversity. Collectively, this study supports the use of WGS for outbreak source attribution in highly recombinogenic pathogens, and confirms the epidemiological and phylogenetic insights that can be gained from high-resolution sequencing platforms.
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Affiliation(s)
- Audrey Rachlin
- Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory 0811, Australia
- *Correspondence: Audrey Rachlin,
| | - Mariana Kleinecke
- Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory 0811, Australia
| | - Mirjam Kaestli
- Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory 0811, Australia
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory 0811, Australia
| | - Mark Mayo
- Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory 0811, Australia
| | - Jessica R. Webb
- Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory 0811, Australia
| | - Vanessa Rigas
- Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory 0811, Australia
| | - Cathy Shilton
- Berrimah Veterinary Laboratory, Department of Primary Industry, Fisheries and Mines, Berrimah Farm, Makagon Road, Berrimah, Northern Territory 0828, Australia
| | - Suresh Benedict
- Berrimah Veterinary Laboratory, Department of Primary Industry, Fisheries and Mines, Berrimah Farm, Makagon Road, Berrimah, Northern Territory 0828, Australia
| | - Kitman Dyrting
- Berrimah Veterinary Laboratory, Department of Primary Industry, Fisheries and Mines, Berrimah Farm, Makagon Road, Berrimah, Northern Territory 0828, Australia
| | - Bart J. Currie
- Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory 0811, Australia
- Royal Darwin Hospital and Northern Territory Medical Program, Darwin, Northern Territory 0811, Australia
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Multi locus sequence typing of Burkholderia pseudomallei isolates from India unveils molecular diversity and confers regional association in Southeast Asia. PLoS Negl Trop Dis 2018; 12:e0006558. [PMID: 29949580 PMCID: PMC6053238 DOI: 10.1371/journal.pntd.0006558] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 07/19/2018] [Accepted: 05/23/2018] [Indexed: 11/29/2022] Open
Abstract
Objectives Burkholderia pseudomallei, the causative agent for melioidosis, has become a public health problem in India and across the world. Melioidosis can be difficult to diagnose because of the inconsistent clinical presentations of the disease. This study aims to determine the genetic diversity among the clinical isolates of B. pseudomaelli from India in order to establish a molecular epidemiology and elucidate the Southeast Asian association. Methods Molecular typing using multi locus sequence typing was performed on thirty one archived B. pseudomallei clinical isolates, previously characterised from specimens obtained from patients admitted to the Christian Medical College & Hospital, Vellore from 2015 to 2016. Further investigations into the genetic heterogeneity and evolution at a regional and global level were performed using insilico tools. Results Multi locus sequence typing (MLST) of the isolates from systemic and localized forms of melioidosis, including blood, pus, tissue, and urine specimens, revealed twenty isolates with novel sequence types and eleven with previously reported sequence types. High genetic diversity was observed using MLST with a strong association within the Southeast Asian region. Conclusions Molecular typing of B. pseudomallei clinical isolates using MLST revealed high genetic diversity and provided a baseline molecular epidemiology of the disease in India with a strong Southeast Asian association of the strains. Future studies should focus on whole genome based Single-Nucleotide-Polymorphism (SNP) which has the advantage of a high discriminatory power, to further understand the novel sequence types reported in this study. Burkholderia pseudomallei, a gram negative bacteria, is the causative agent for melioidosis. Annually, around 165,000 people suffer from melioidosis worldwide. B. pseudomallei is present in wet soil and stagnant water. It enters the human body via percutaneous inoculation, inhalation, aspiration, and occasionally ingestion. Clinical presentations of B. pseudomallei vary by geographical region. Melioidosis occurs predominantly in Southeast Asia, northern Australia, South Asia (including India), and China. Occasional cases occur in other countries around the world. Melioidosis has become a public health problem in India, due to the increasing numbers of people affected in various parts of the country. This study provides baseline data on the genetic diversity among B. pseudomallei isolates from different clinical samples (blood, pus, tissue and urine) of patients admitted to a tertiary care hospital using signature nucleotide sequences via multi locus sequence typing (MLST). Further, this study shows a relationship among B. pseudomallei previously reported in various Southeast Asian countries over the years from 1935 and 1947 with those seen in current clinical cases.
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Zueter AR, Rahman ZA, Abumarzouq M, Harun A. Multilocus sequence types of clinical Burkholderia pseudomallei isolates from peninsular Malaysia and their associations with disease outcomes. BMC Infect Dis 2018; 18:5. [PMID: 29291714 PMCID: PMC5748966 DOI: 10.1186/s12879-017-2912-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 12/13/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Previous studies on the Burkholderia pseudomallei genetic diversity among clinical isolates from melioidosis-endemic areas have identified genetic factors contributing to differential virulence. Although it has been ruled out in Australian and Thai B. pseudomallei populations, it remains unclear whether B. pseudomallei sequence types (STs) correlate with disease in Malaysian patients with melioidosis. METHODS In this study, multi-locus sequence typing (MLST) was performed on clinical B. pseudomallei isolates collected from Kelantan state of Malaysia, patients' clinical data were reviewed and then genotype-risk correlations were investigated. RESULTS Genotyping of 83 B. pseudomallei isolates revealed 32 different STs, of which 13(40%) were novel. The frequencies of the STs among the 83 isolates ranged from 1 to 12 observations, and ST54, ST371 and ST289 were predominant. All non-novel STs reported in this study have also been identified in other Asian countries. Based on the MLST data analysis, the phylogenetic tree showed clustering of the STs with each other, as well as with the STs from Southeast Asia and China. No evidence for associations between any of B. pseudomallei STs and clinical melioidosis presentation was detected. In addition, the bacterial genotype clusters in relation with each clinical outcome were statistically insignificant, and no risk estimate was reported. This study has expanded the data for B. pseudomallei on MLST database map and provided insights into the molecular epidemiology of melioidosis in Peninsular Malaysia. CONCLUSION This study concurs with previous reports concluding that infecting strain type plays no role in determining disease presentation.
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Affiliation(s)
- Abdel Rahman Zueter
- Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, The Hashemite University, Zarqa, Jordan. .,Department of Medical Microbiology and Parasitology, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia.
| | - Zaidah Abdul Rahman
- Department of Medical Microbiology and Parasitology, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Mahmoud Abumarzouq
- Department of Orthopedic, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Azian Harun
- Department of Medical Microbiology and Parasitology, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia
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Bandeira TDJPG, Castelo-Branco DDSCM, Rocha MFG, Cordeiro RDA, Ocadaque CJ, Paiva MDAN, Brilhante RSN, Sidrim JJC. Clinical and environmental isolates of Burkholderia pseudomallei from Brazil: Genotyping and detection of virulence gene. ASIAN PAC J TROP MED 2017; 10:945-951. [PMID: 29111189 DOI: 10.1016/j.apjtm.2017.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 08/13/2017] [Accepted: 09/11/2017] [Indexed: 10/18/2022] Open
Abstract
OBJECTIVE To evaluate the genetic diversity of clinical and environmental isolates of Burkholderia pseudomallei (B. pseudomallei) recovered in Ceará, Brazil, and screen these isolates for the presence of type three secretion system virulence gene. METHODS Nineteen B. pseudomallei isolates (9 from clinical cases and 10 from soils) were analyzed. Random amplified polymorphic DNA was performed with primers OPQ-2, OPQ-4 and OPQ-16 to evaluate the genetic diversity, and type three secretion system gene was detected through polymerase chain reaction. RESULTS Random amplified polymorphic DNA showed a genetic relatedness of approximately 50% among the tested B. pseudomallei isolates, which were grouped into two clades, of which the biggest ones comprised 18/19 isolates for primer OPQ-2, and 17/19 isolates for primer OPQ-16. Primer OPQ-4 grouped the isolates into three clades comprising 1/19, 3/19 and 15/19 isolates. Additionally, type three secretion system gene was detected in all tested isolates. CONCLUSIONS This is an effort to type B. pseudomallei strains from Ceará, which is important for better understanding this pathogen, contributing for the epidemiological surveillance of melioidosis in this endemic region.
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Affiliation(s)
- Tereza de Jesus Pinheiro Gomes Bandeira
- Specialized Medical Mycology Center, Postgraduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza, Ceará, Brazil; Christus School of Medicine, Fortaleza, Ceará, Brazil
| | | | - Marcos Fábio Gadelha Rocha
- Specialized Medical Mycology Center, Postgraduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza, Ceará, Brazil; Postgraduate Program in Veterinary Sciences, State University of Ceará, Fortaleza, Ceará, Brazil
| | - Rossana de Aguiar Cordeiro
- Specialized Medical Mycology Center, Postgraduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Crister José Ocadaque
- Specialized Medical Mycology Center, Postgraduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Manoel de Araújo Neto Paiva
- Specialized Medical Mycology Center, Postgraduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza, Ceará, Brazil; Federal Institute of Education, Science and Technology of Ceará, Acaraú, Ceará, Brazil
| | - Raimunda Sâmia Nogueira Brilhante
- Specialized Medical Mycology Center, Postgraduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza, Ceará, Brazil.
| | - José Júlio Costa Sidrim
- Specialized Medical Mycology Center, Postgraduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza, Ceará, Brazil
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Price EP, Currie BJ, Sarovich DS. Genomic Insights Into the Melioidosis Pathogen, Burkholderia pseudomallei. CURRENT TROPICAL MEDICINE REPORTS 2017. [DOI: 10.1007/s40475-017-0111-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Sarovich DS, Chapple SNJ, Price EP, Mayo M, Holden MTG, Peacock SJ, Currie BJ. Whole-genome sequencing to investigate a non-clonal melioidosis cluster on a remote Australian island. Microb Genom 2017; 3:e000117. [PMID: 29026657 PMCID: PMC5610713 DOI: 10.1099/mgen.0.000117] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Accepted: 04/20/2017] [Indexed: 12/22/2022] Open
Abstract
Melioidosis is a tropical disease caused by the bacterium Burkholderia pseudomallei. Outbreaks are uncommon and can generally be attributed to a single point source and strain. We used whole-genome sequencing to analyse B. pseudomallei isolates collected from an historical 2-year long case cluster that occurred in a remote northern Australian indigenous island community, where infections were previously linked to a contaminated communal water supply. We analysed the genome-wide relatedness of the two most common multilocus sequence types (STs) involved in the outbreak, STs 125 and 126. This analysis showed that although these STs were closely related on a whole-genome level, they demonstrated evidence of multiple recombination events that were unlikely to have occurred over the timeframe of the outbreak. Based on epidemiological and genetic data, we also identified two additional patients not previously associated with this outbreak. Our results confirm the previous hypothesis that a single unchlorinated water source harbouring multiple B. pseudomallei strains was linked to the outbreak, and that increased melioidosis risk in this community was associated with Piper methysticum root (kava) consumption.
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Affiliation(s)
- Derek S Sarovich
- 1Global and Tropical Health Division, Menzies School of Health Research, Darwin, Australia.,2Centre for Animal Health Innovation, University of the Sunshine Coast, Sippy Downs, Australia
| | - Stephanie N J Chapple
- 1Global and Tropical Health Division, Menzies School of Health Research, Darwin, Australia.,3Melbourne Medical School, University of Melbourne, Melbourne, Australia
| | - Erin P Price
- 1Global and Tropical Health Division, Menzies School of Health Research, Darwin, Australia.,2Centre for Animal Health Innovation, University of the Sunshine Coast, Sippy Downs, Australia
| | - Mark Mayo
- 1Global and Tropical Health Division, Menzies School of Health Research, Darwin, Australia
| | - Matthew T G Holden
- 4School of Medicine, Medical and Biological Sciences, University of St Andrews, St Andrews, UK.,5Wellcome Trust Sanger Institute, Cambridge, UK
| | - Sharon J Peacock
- 5Wellcome Trust Sanger Institute, Cambridge, UK.,6Department of Medicine, University of Cambridge, Cambridge, UK
| | - Bart J Currie
- 1Global and Tropical Health Division, Menzies School of Health Research, Darwin, Australia.,7Department of Infectious Diseases and Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Australia
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Viberg LT, Sarovich DS, Kidd TJ, Geake JB, Bell SC, Currie BJ, Price EP. Within-Host Evolution of Burkholderia pseudomallei during Chronic Infection of Seven Australasian Cystic Fibrosis Patients. mBio 2017; 8:e00356-17. [PMID: 28400528 PMCID: PMC5388805 DOI: 10.1128/mbio.00356-17] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 03/15/2017] [Indexed: 12/14/2022] Open
Abstract
Cystic fibrosis (CF) is a genetic disorder characterized by progressive lung function decline. CF patients are at an increased risk of respiratory infections, including those by the environmental bacterium Burkholderia pseudomallei, the causative agent of melioidosis. Here, we compared the genomes of B. pseudomallei isolates collected between ~4 and 55 months apart from seven chronically infected CF patients. Overall, the B. pseudomallei strains showed evolutionary patterns similar to those of other chronic infections, including emergence of antibiotic resistance, genome reduction, and deleterious mutations in genes involved in virulence, metabolism, environmental survival, and cell wall components. We documented the first reported B. pseudomallei hypermutators, which were likely caused by defective MutS. Further, our study identified both known and novel molecular mechanisms conferring resistance to three of the five clinically important antibiotics for melioidosis treatment. Our report highlights the exquisite adaptability of microorganisms to long-term persistence in their environment and the ongoing challenges of antibiotic treatment in eradicating pathogens in the CF lung. Convergent evolution with other CF pathogens hints at a degree of predictability in bacterial evolution in the CF lung and potential targeted eradication of chronic CF infections in the future.IMPORTANCEBurkholderia pseudomallei, the causative agent of melioidosis, is an environmental opportunistic bacterium that typically infects immunocompromised people and those with certain risk factors such as cystic fibrosis (CF). Patients with CF tend to develop chronic melioidosis infections, for reasons that are not well understood. This report is the first to describe B. pseudomallei evolution within the CF lung during chronic infection. We show that the pathways by which B. pseudomallei adapts to the CF lung are similar to those seen in better-studied CF pathogens such as Pseudomonas aeruginosa, Staphylococcus aureus, and Burkholderia cepacia complex species. Adaptations include the accumulation of antibiotic resistance, loss of nonessential genes, metabolic alterations, and virulence factor attenuation. Known and novel mechanisms of resistance to three of the five antibiotics used in melioidosis treatment were identified. Similar pathways of evolution in CF pathogens, including B. pseudomallei, provide exciting avenues for more-targeted treatment of chronic, recalcitrant infections.
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Affiliation(s)
- Linda T Viberg
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Derek S Sarovich
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
- Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Timothy J Kidd
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, Northern Ireland
- Child Health Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - James B Geake
- Department of Respiratory Medicine, The Lyell McEwin Hospital, Elizabeth Vale, South Australia, Australia
| | - Scott C Bell
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
- Department of Thoracic Medicine, The Prince Charles Hospital, Chermside, Queensland, Australia
| | - Bart J Currie
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
- Department of Infectious Diseases and Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Erin P Price
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
- Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
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Chapple SNJ, Sarovich DS, Holden MTG, Peacock SJ, Buller N, Golledge C, Mayo M, Currie BJ, Price EP. Whole-genome sequencing of a quarter-century melioidosis outbreak in temperate Australia uncovers a region of low-prevalence endemicity. Microb Genom 2016; 2:e000067. [PMID: 28348862 PMCID: PMC5343139 DOI: 10.1099/mgen.0.000067] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 05/11/2016] [Indexed: 12/22/2022] Open
Abstract
Melioidosis, caused by the highly recombinogenic bacterium Burkholderia pseudomallei, is a disease with high mortality. Tracing the origin of melioidosis outbreaks and understanding how the bacterium spreads and persists in the environment are essential to protecting public and veterinary health and reducing mortality associated with outbreaks. We used whole-genome sequencing to compare isolates from a historical quarter-century outbreak that occurred between 1966 and 1991 in the Avon Valley, Western Australia, a region far outside the known range of B. pseudomallei endemicity. All Avon Valley outbreak isolates shared the same multilocus sequence type (ST-284), which has not been identified outside this region. We found substantial genetic diversity among isolates based on a comparison of genome-wide variants, with no clear correlation between genotypes and temporal, geographical or source data. We observed little evidence of recombination in the outbreak strains, indicating that genetic diversity among these isolates has primarily accrued by mutation. Phylogenomic analysis demonstrated that the isolates confidently grouped within the Australian B. pseudomallei clade, thereby ruling out introduction from a melioidosis-endemic region outside Australia. Collectively, our results point to B. pseudomallei ST-284 being present in the Avon Valley for longer than previously recognized, with its persistence and genomic diversity suggesting long-term, low-prevalence endemicity in this temperate region. Our findings provide a concerning demonstration of the potential for environmental persistence of B. pseudomallei far outside the conventional endemic regions. An expected increase in extreme weather events may reactivate latent B. pseudomallei populations in this region.
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Affiliation(s)
- Stephanie N. J. Chapple
- Melbourne Medical School, University of Melbourne, Melbourne, Victoria, Australia
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Derek S. Sarovich
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Matthew T. G. Holden
- School of Medicine, Medical and Biological Sciences, University of St Andrews, St Andrews, UK
- Wellcome Trust Sanger Institute, University of Cambridge, Cambridge, UK
| | - Sharon J. Peacock
- Wellcome Trust Sanger Institute, University of Cambridge, Cambridge, UK
- University of Cambridge, Cambridge, UK
| | - Nicky Buller
- Department of Agriculture and Food Western Australia, Perth, Western Australia, Australia
| | - Clayton Golledge
- Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Mark Mayo
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Bart J. Currie
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Department of Infectious Diseases and Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Erin P. Price
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
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Rachlin A, Dittrich S, Phommasone K, Douangnouvong A, Phetsouvanh R, Newton PN, Dance DAB. Investigation of Recurrent Melioidosis in Lao People's Democratic Republic by Multilocus Sequence Typing. Am J Trop Med Hyg 2016; 94:1208-1211. [PMID: 27001759 PMCID: PMC4889735 DOI: 10.4269/ajtmh.15-0909] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Accepted: 02/15/2016] [Indexed: 12/25/2022] Open
Abstract
Melioidosis is an infectious disease caused by the saprophytic bacterium Burkholderia pseudomallei In northeast Thailand and northern Australia, where the disease is highly endemic, a range of molecular tools have been used to study its epidemiology and pathogenesis. In the Lao People's Democratic Republic (Laos) where melioidosis has been recognized as endemic since 1999, no such studies have been undertaken. We used a multilocus sequence typing scheme specific for B. pseudomallei to investigate nine cases of culture-positive recurrence occurring in 514 patients with melioidosis between 2010 and 2015: four were suspected to be relapses while the other five represented reinfections. In addition, two novel sequence types of the bacterium were identified. The low overall recurrence rates (2.4%) and proportions of relapse and reinfection in the Laos are consistent with those described in the recent literature, reflecting the effective use of appropriate antimicrobial therapy.
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Affiliation(s)
| | - Sabine Dittrich
- London School of Hygiene and Tropical Medicine, London, United Kingdom; Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic; Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
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Multilocus sequence typing of 102 Burkholderia pseudomallei strains isolated from China. Epidemiol Infect 2016; 144:1917-23. [PMID: 26744829 DOI: 10.1017/s0950268815003052] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The phylogenetic and epidemiological relationships of 102 Burkholderia pseudomallei clinical isolates from different geographical and population sources in China were investigated by multilocus sequence typing (MLST). The MLST data were analysed using the e-BURST algorithm, and an unweighted pair-group method with arithmetic mean dendrogram was constructed based on the pair-wise differences in the allelic profiles of the strains. Forty-one sequence types (STs) were identified, of which eight were novel (ST1341, ST1345, ST1346, ST1347, ST1348, ST1349, ST1350, ST1351). No geographical-specific or host population-specific phylogenetic lineages were identified. ST46, ST50, ST55, ST58, ST70 and ST1095 predominated, but ~44% of isolates were assigned to 45 STs illustrating high genetic diversity in the strain collection. Additionally, the phylogenetic relationships of the dominant STs in China showed significant linkeage with B. pseudomallei isolates from Thailand. Analysis of the gmhD allele suggests high genetic variation in B. pseudomallei in China.
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Unprecedented Melioidosis Cases in Northern Australia Caused by an Asian Burkholderia pseudomallei Strain Identified by Using Large-Scale Comparative Genomics. Appl Environ Microbiol 2015; 82:954-63. [PMID: 26607593 DOI: 10.1128/aem.03013-15] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/13/2015] [Indexed: 11/20/2022] Open
Abstract
Melioidosis is a disease of humans and animals that is caused by the saprophytic bacterium Burkholderia pseudomallei. Once thought to be confined to certain locations, the known presence of B. pseudomallei is expanding as more regions of endemicity are uncovered. There is no vaccine for melioidosis, and even with antibiotic administration, the mortality rate is as high as 40% in some regions that are endemic for the infection. Despite high levels of recombination, phylogenetic reconstruction of B. pseudomallei populations using whole-genome sequencing (WGS) has revealed surprisingly robust biogeographic separation between isolates from Australia and Asia. To date, there have been no confirmed autochthonous melioidosis cases in Australia caused by an Asian isolate; likewise, no autochthonous cases in Asia have been identified as Australian in origin. Here, we used comparative genomic analysis of 455 B. pseudomallei genomes to confirm the unprecedented presence of an Asian clone, sequence type 562 (ST-562), in Darwin, northern Australia. First observed in Darwin in 2005, the incidence of melioidosis cases attributable to ST-562 infection has steadily risen, and it is now a common strain in Darwin. Intriguingly, the Australian ST-562 appears to be geographically restricted to a single locale and is genetically less diverse than other common STs from this region, indicating a recent introduction of this clone into northern Australia. Detailed genomic and epidemiological investigations of new clinical and environmental B. pseudomallei isolates in the Darwin region and ST-562 isolates from Asia will be critical for understanding the origin, distribution, and dissemination of this emerging clone in northern Australia.
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Miller RR, Hird TJ, Tang P, Zlosnik JEA. Whole-Genome Sequencing of Three Clonal Clinical Isolates of B. cenocepacia from a Patient with Cystic Fibrosis. PLoS One 2015; 10:e0143472. [PMID: 26599356 PMCID: PMC4658001 DOI: 10.1371/journal.pone.0143472] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 11/05/2015] [Indexed: 11/29/2022] Open
Abstract
Burkholderia cepacia complex bacteria are amongst the most feared of pathogens in cystic fibrosis (CF). The BCC comprises at least 20 distinct species that can cause chronic and unpredictable lung infections in CF. Historically the species B. cenocepacia has been the most prevalent in CF infections and has been associated in some centers with high rates of mortality. Modeling chronic infection by B. cenocepacia in the laboratory is challenging and no models exist which effectively recapitulate CF disease caused by BCC bacteria. Therefore our understanding of factors that contribute towards the morbidity and mortality caused by this organism is limited. In this study we used whole-genome sequencing to examine the evolution of 3 clonal clinical isolates of B. cenocepacia from a patient with cystic fibrosis. The first isolate was from the beginning of infection, and the second two almost 10 years later during the final year of the patients’ life. These isolates also demonstrated phenotypic heterogeneity, with the first isolate displaying the mucoid phenotype (conferred by the overproduction of exopolysaccharide), while one of the later two was nonmucoid. In addition we also sequenced a nonmucoid derivative of the initial mucoid isolate, acquired in the laboratory by antibiotic pressure. Examination of sequence data revealed that the two late stage isolates shared 20 variant nucleotides in common compared to the early isolate. However, despite their isolation within 10 months of one another, there was also considerable variation between the late stage isolates, including 42 single nucleotide variants and three deletions. Additionally, no sequence differences were identified between the initial mucoid isolate and its laboratory acquired nonmucoid derivative, however transcript analysis indicated at least partial down regulation of genes involved in exopolysaccharide production. Our study examines the progression of B. cenocepacia throughout chronic infection, including establishment of sub-populations likely evolved from the original isolate, suggestive of parallel evolution. Additionally, the lack of sequence differences between two of the isolates with differing mucoid phenotypes suggests that other factors, such as gene regulation, come into play in establishing the mucoid phenotype.
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Affiliation(s)
- Ruth R. Miller
- School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada
- British Columbia Centre for Disease Control, University of British Columbia, Canada, Vancouver, British Columbia, Canada
| | - Trevor J. Hird
- Centre for Understanding and Preventing Infection in Children, Department of Pediatrics, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Patrick Tang
- British Columbia Centre for Disease Control, University of British Columbia, Canada, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - James E. A. Zlosnik
- Centre for Understanding and Preventing Infection in Children, Department of Pediatrics, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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Draft Genome Sequences of Burkholderia pseudomallei and Staphylococcus aureus, Isolated from a Patient with Chronic Rhinosinusitis. GENOME ANNOUNCEMENTS 2015; 3:3/5/e01075-15. [PMID: 26430027 PMCID: PMC4591299 DOI: 10.1128/genomea.01075-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Here, we report the draft genome sequences of Burkholderia pseudomallei and Staphylococcus aureus causing chronic rhinosinusitis. Whole-genome sequencing determined the B. pseudomallei as sequence type (ST) 1381 and the S. aureus as ST8. B. pseudomallei possessed the blaOXA-59 gene. This study illustrates the potential emergence of B. pseudomallei in cases of chronic rhinosinusitis.
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Whole-Genome Sequences of Five Burkholderia pseudomallei Isolates from Australian Cystic Fibrosis Patients. GENOME ANNOUNCEMENTS 2015; 3:3/2/e00254-15. [PMID: 25883282 PMCID: PMC4400425 DOI: 10.1128/genomea.00254-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We report here five improved high-quality draft genomes of Burkholderia pseudomallei isolated from Australian cystic fibrosis (CF) patients. This pathogen is rarely seen in CF patients. These genomes will be used to better understand chronic carriage of B. pseudomallei in the CF lung and the within-host evolution of longitudinal isolates from these patients.
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Tracing melioidosis back to the source: using whole-genome sequencing to investigate an outbreak originating from a contaminated domestic water supply. J Clin Microbiol 2015; 53:1144-8. [PMID: 25631791 DOI: 10.1128/jcm.03453-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Melioidosis, a disease of public health importance in Southeast Asia and northern Australia, is caused by the Gram-negative soil bacillus Burkholderia pseudomallei. Melioidosis is typically acquired through environmental exposure, and case clusters are rare, even in regions where the disease is endemic. B. pseudomallei is classed as a tier 1 select agent by the Centers for Disease Control and Prevention; from a biodefense perspective, source attribution is vital in an outbreak scenario to rule out a deliberate release. Two cases of melioidosis within a 3-month period at a residence in rural northern Australia prompted an investigation to determine the source of exposure. B. pseudomallei isolates from the property's groundwater supply matched the multilocus sequence type of the clinical isolates. Whole-genome sequencing confirmed the water supply as the probable source of infection in both cases, with the clinical isolates differing from the likely infecting environmental strain by just one single nucleotide polymorphism (SNP) each. For the first time, we report a phylogenetic analysis of genomewide insertion/deletion (indel) data, an approach conventionally viewed as problematic due to high mutation rates and homoplasy. Our whole-genome indel analysis was concordant with the SNP phylogeny, and these two combined data sets provided greater resolution and a better fit with our epidemiological chronology of events. Collectively, this investigation represents a highly accurate account of source attribution in a melioidosis outbreak and gives further insight into a frequently overlooked reservoir of B. pseudomallei. Our methods and findings have important implications for outbreak source tracing of this bacterium and other highly recombinogenic pathogens.
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