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Seng R, Chomkatekaew C, Tandhavanant S, Saiprom N, Phunpang R, Thaipadungpanit J, Batty EM, Day NPJ, Chantratita W, Eoin West T, Thomson NR, Parkhill J, Chewapreecha C, Chantratita N. Genetic diversity, determinants, and dissemination of Burkholderia pseudomallei lineages implicated in melioidosis in Northeast Thailand. Nat Commun 2024; 15:5699. [PMID: 38972886 PMCID: PMC11228029 DOI: 10.1038/s41467-024-50067-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 06/28/2024] [Indexed: 07/09/2024] Open
Abstract
Melioidosis is an often-fatal neglected tropical disease caused by an environmental bacterium Burkholderia pseudomallei. However, our understanding of the disease-causing bacterial lineages, their dissemination, and adaptive mechanisms remains limited. To address this, we conduct a comprehensive genomic analysis of 1,391 B. pseudomallei isolates collected from nine hospitals in northeast Thailand between 2015 and 2018, and contemporaneous isolates from neighbouring countries, representing the most densely sampled collection to date. Our study identifies three dominant lineages, each with unique gene sets potentially enhancing bacterial fitness in the environment. We find that recombination drives lineage-specific gene flow. Transcriptome analyses of representative clinical isolates from each dominant lineage reveal increased expression of lineage-specific genes under environmental conditions in two out of three lineages. This underscores the potential importance of environmental persistence for these dominant lineages. The study also highlights the influence of environmental factors such as terrain slope, altitude, and river direction on the geographical dispersal of B. pseudomallei. Collectively, our findings suggest that environmental persistence may play a role in facilitating the spread of B. pseudomallei, and as a prerequisite for exposure and infection, thereby providing useful insights for informing melioidosis prevention and control strategies.
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Affiliation(s)
- Rathanin Seng
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chalita Chomkatekaew
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Sarunporn Tandhavanant
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Natnaree Saiprom
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rungnapa Phunpang
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Janjira Thaipadungpanit
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Elizabeth M Batty
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Nicholas P J Day
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Wasun Chantratita
- Center for Medical Genomics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - T Eoin West
- Division of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of Washington, Seattle, WA, USA
- Department of Global Health, University of Washington, Seattle, WA, USA
| | - Nicholas R Thomson
- Parasites and Microbes Wellcome Sanger Institute, Cambridge, UK
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Claire Chewapreecha
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
- Parasites and Microbes Wellcome Sanger Institute, Cambridge, UK.
- Previous Affiliations: Bioinformatics and Systems Biology Program, School of Bioresource and Technology, King Mongkut University of Technology Thonburi, Bangkok, Thailand.
| | - Narisara Chantratita
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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Badten AJ, Torres AG. Burkholderia pseudomallei Complex Subunit and Glycoconjugate Vaccines and Their Potential to Elicit Cross-Protection to Burkholderia cepacia Complex. Vaccines (Basel) 2024; 12:313. [PMID: 38543947 PMCID: PMC10975474 DOI: 10.3390/vaccines12030313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/12/2024] [Accepted: 03/14/2024] [Indexed: 04/01/2024] Open
Abstract
Burkholderia are a group of Gram-negative bacteria that can cause a variety of diseases in at-risk populations. B. pseudomallei and B. mallei, the etiological agents of melioidosis and glanders, respectively, are the two clinically relevant members of the B. pseudomallei complex (Bpc). The development of vaccines against Bpc species has been accelerated in recent years, resulting in numerous promising subunits and glycoconjugate vaccines incorporating a variety of antigens. However, a second group of pathogenic Burkholderia species exists known as the Burkholderia cepacia complex (Bcc), a group of opportunistic bacteria which tend to affect individuals with weakened immunity or cystic fibrosis. To date, there have been few attempts to develop vaccines to Bcc species. Therefore, the primary goal of this review is to provide a broad overview of the various subunit antigens that have been tested in Bpc species, their protective efficacy, study limitations, and known or suspected mechanisms of protection. Then, we assess the reviewed Bpc antigens for their amino acid sequence conservation to homologous proteins found in Bcc species. We propose that protective Bpc antigens with a high degree of Bpc-to-Bcc sequence conservation could serve as components of a pan-Burkholderia vaccine capable of protecting against both disease-causing groups.
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Affiliation(s)
- Alexander J. Badten
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA;
- Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Alfredo G. Torres
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA;
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
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Meumann EM, Limmathurotsakul D, Dunachie SJ, Wiersinga WJ, Currie BJ. Burkholderia pseudomallei and melioidosis. Nat Rev Microbiol 2024; 22:155-169. [PMID: 37794173 DOI: 10.1038/s41579-023-00972-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2023] [Indexed: 10/06/2023]
Abstract
Burkholderia pseudomallei, the causative agent of melioidosis, is found in soil and water of tropical and subtropical regions globally. Modelled estimates of the global burden predict that melioidosis remains vastly under-reported, and a call has been made for it to be recognized as a neglected tropical disease by the World Health Organization. Severe weather events and environmental disturbance are associated with increased case numbers, and it is anticipated that, in some regions, cases will increase in association with climate change. Genomic epidemiological investigations have confirmed B. pseudomallei endemicity in newly recognized regions, including the southern United States. Melioidosis follows environmental exposure to B. pseudomallei and is associated with comorbidities that affect the immune response, such as diabetes, and with socioeconomic disadvantage. Several vaccine candidates are ready for phase I clinical trials. In this Review, we explore the global burden, epidemiology and pathophysiology of B. pseudomallei as well as current diagnostics, treatment recommendations and preventive measures, highlighting research needs and priorities.
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Affiliation(s)
- Ella M Meumann
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia.
- Department of Infectious Diseases, Division of Medicine, Royal Darwin Hospital, Darwin, Northern Territory, Australia.
| | - Direk Limmathurotsakul
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- NDM Centre for Global Health Research, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Susanna J Dunachie
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- NDM Centre for Global Health Research, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Willem J Wiersinga
- Division of Infectious Diseases, Center for Experimental Molecular Medicine, Amsterdam University Medical Centers, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Bart J Currie
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
- Department of Infectious Diseases, Division of Medicine, Royal Darwin Hospital, Darwin, Northern Territory, Australia
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Wagner GE, Stanjek TFP, Albrecht D, Lipp M, Dunachie SJ, Föderl-Höbenreich E, Riedel K, Kohler A, Steinmetz I, Kohler C. Deciphering the human antibody response against Burkholderia pseudomallei during melioidosis using a comprehensive immunoproteome approach. Front Immunol 2023; 14:1294113. [PMID: 38146371 PMCID: PMC10749318 DOI: 10.3389/fimmu.2023.1294113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 11/22/2023] [Indexed: 12/27/2023] Open
Abstract
Introduction The environmental bacterium Burkholderia pseudomallei causes the often fatal and massively underreported infectious disease melioidosis. Antigens inducing protective immunity in experimental models have recently been identified and serodiagnostic tools have been improved. However, further elucidation of the antigenic repertoire of B. pseudomallei during human infection for diagnostic and vaccine purposes is required. The adaptation of B. pseudomallei to very different habitats is reflected by a huge genome and a selective transcriptional response to a variety of conditions. We, therefore, hypothesized that exposure of B. pseudomallei to culture conditions mimicking habitats encountered in the human host might unravel novel antigens that are recognized by melioidosis patients. Methods and results In this study, B. pseudomallei was exposed to various stress and growth conditions, including anaerobiosis, acid stress, oxidative stress, iron starvation and osmotic stress. Immunogenic proteins were identified by probing two-dimensional Western blots of B. pseudomallei intracellular and extracellular protein extracts with sera from melioidosis patients and controls and subsequent MALDI-TOF MS. Among B. pseudomallei specific immunogenic signals, 90 % (55/61) of extracellular immunogenic proteins were identified by acid, osmotic or oxidative stress. A total of 84 % (44/52) of intracellular antigens originated from the stationary growth phase, acidic, oxidative and anaerobic conditions. The majority of the extracellular and intracellular protein antigens were identified in only one of the various stress conditions. Sixty-three immunoreactive proteins and an additional 38 candidates from a literature screening were heterologously expressed and subjected to dot blot analysis using melioidosis sera and controls. Our experiments confirmed melioidosis-specific signals in 58 of our immunoproteome candidates. These include 15 antigens with average signal ratios (melioidosis:controls) greater than 10 and another 26 with average ratios greater than 5, including new promising serodiagnostic candidates with a very high signal-to-noise ratio. Conclusion Our study shows that a comprehensive B. pseudomallei immunoproteomics approach, using conditions which are likely to be encountered during infection, can identify novel antibody targets previously unrecognized in human melioidosis.
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Affiliation(s)
- Gabriel E. Wagner
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | | | - Dirk Albrecht
- Institute of Microbiology, Department of Microbial Physiology and Molecular Biology, University of Greifswald, Greifswald, Germany
| | - Michaela Lipp
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Susanna J. Dunachie
- Nuffield Department of Medicine (NDM) Centre for Global Health Research, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- National Institute for Health and Care Research (NIHR) Oxford Biomedical Centre, Oxford University Hospitals National Health Service (NHS) Foundation Trust, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Esther Föderl-Höbenreich
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
- Diagnostic & Research Institute of Pathology, Medical University Graz, Graz, Austria
| | - Katharina Riedel
- Institute of Microbiology, Department of Microbial Physiology and Molecular Biology, University of Greifswald, Greifswald, Germany
| | - Anne Kohler
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine, Greifswald, Germany
| | - Ivo Steinmetz
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine, Greifswald, Germany
| | - Christian Kohler
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine, Greifswald, Germany
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Seng R, Chomkatekaew C, Tandhavanant S, Saiprom N, Phunpang R, Thaipadungpanit J, Batty EM, Day NPJ, Chantratita W, West TE, Thomson NR, Parkhill J, Chewapreecha C, Chantratita N. Genetic diversity, determinants, and dissemination of Burkholderia pseudomallei lineages implicated in melioidosis in northeast Thailand. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.02.543359. [PMID: 38106061 PMCID: PMC10723255 DOI: 10.1101/2023.06.02.543359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Melioidosis is an often-fatal neglected tropical disease caused by an environmental bacterium Burkholderia pseudomallei. However, our understanding of the disease-causing bacterial lineages, their dissemination, and adaptive mechanisms remains limited. To address this, we conducted a comprehensive genomic analysis of 1,391 B. pseudomallei isolates collected from nine hospitals in northeast Thailand between 2015 and 2018, and contemporaneous isolates from neighbouring countries, representing the most densely sampled collection to date. Our study identified three dominant lineages with unique gene sets enhancing bacterial fitness, indicating lineage-specific adaptation strategies. Crucially, recombination was found to drive lineage-specific gene flow. Transcriptome analyses of representative clinical isolates from each dominant lineage revealed heightened expression of lineage-specific genes in environmental versus infection conditions, notably under nutrient depletion, highlighting environmental persistence as a key factor in the success of dominant lineages. The study also revealed the role of environmental factors - slope of terrain, altitude, direction of rivers, and the northeast monsoons - in shaping B. pseudomallei geographical dispersal. Collectively, our findings highlight persistence in the environment as a pivotal element facilitating B. pseudomallei spread, and as a prelude to exposure and infection, thereby providing useful insights for informing melioidosis prevention and control strategies.
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Affiliation(s)
- Rathanin Seng
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chalita Chomkatekaew
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Veterinary Medicine, University of Cambridge, UK
| | - Sarunporn Tandhavanant
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Natnaree Saiprom
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rungnapa Phunpang
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Janjira Thaipadungpanit
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Elizabeth M Batty
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Nicholas PJ Day
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Wasun Chantratita
- Center for Medical Genomics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - T. Eoin West
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Division of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | | | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, UK
| | - Claire Chewapreecha
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK
- Previous Affiliations: Bioinformatics and Systems Biology Program, School of Bioresource and Technology, King Mongkut University of Technology Thonburi, Bangkok, Thailand
| | - Narisara Chantratita
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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Verma G, Singh N, Mohanty A, Patro ARK, Pattnaik D. Coexistence of blaNDM and blaOXA-48 Genes in Carbapenem-Resistant Burkholderia pseudomallei Isolated From Pus: A Rare Phenomenon. Cureus 2023; 15:e50671. [PMID: 38229822 PMCID: PMC10790810 DOI: 10.7759/cureus.50671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2023] [Indexed: 01/18/2024] Open
Abstract
Burkholderia pseudomallei causes melioidosis in both humans as well as animals and is classified as a tier 1 pathogen by the US CDC. Melioidosis is a disease that occurs predominantly in subtropical and tropical regions. It is endemic to northern Australia and parts of Southeast Asia, as well as the Indian subcontinent. Diagnosis can be made through history, clinical examination, imaging, and microbiological studies. We report a case where Burkholderia pseudomallei was isolated froma 41-year-old man who complained of pain in the left hip and the left shoulder and swelling in both lower limbs. Chest X-ray showed bilateral consolidation. USG of the left shoulder and bilateral hips showed a mass in the anterior region of the left upper arm and the lateral region of the left thigh. Pus aspirated from left shoulder grew Burkholderia pseudomallei on culture and was carbapenem-resistant. The isolate harbored two carbapenemase genes, blaNDM and blaOXA-48, which is a novel finding.
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Affiliation(s)
- Gaurav Verma
- Department of Microbiology, Kalinga Institute of Medical Sciences, Bhubaneswar, IND
| | - Nipa Singh
- Department of Microbiology, Kalinga Institute of Medical Sciences, Bhubaneswar, IND
| | - Ambika Mohanty
- Department of General Medicine, Kalinga Institute of Medical Sciences, Bhubaneswar, IND
| | - A Raj Kumar Patro
- Department of Molecular Biology, Kalinga Institute of Medical Sciences, Bhubaneswar, IND
| | - Dipti Pattnaik
- Department of Microbiology, Kalinga Institute of Medical Sciences, Bhubaneswar, IND
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Ghazali AK, Firdaus-Raih M, Uthaya Kumar A, Lee WK, Hoh CC, Nathan S. Transitioning from Soil to Host: Comparative Transcriptome Analysis Reveals the Burkholderia pseudomallei Response to Different Niches. Microbiol Spectr 2023; 11:e0383522. [PMID: 36856434 PMCID: PMC10100664 DOI: 10.1128/spectrum.03835-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 02/06/2023] [Indexed: 03/02/2023] Open
Abstract
Burkholderia pseudomallei, a soil and water saprophyte, is responsible for the tropical human disease melioidosis. A hundred years since its discovery, there is still much to learn about B. pseudomallei proteins that are essential for the bacterium's survival in and interaction with the infected host, as well as their roles within the bacterium's natural soil habitat. To address this gap, bacteria grown under conditions mimicking the soil environment were subjected to transcriptome sequencing (RNA-seq) analysis. A dual RNA-seq approach was used on total RNA from spleens isolated from a B. pseudomallei mouse infection model at 5 days postinfection. Under these conditions, a total of 1,434 bacterial genes were induced, with 959 induced in the soil environment and 475 induced in bacteria residing within the host. Genes encoding metabolism and transporter proteins were induced when the bacteria were present in soil, while virulence factors, metabolism, and bacterial defense mechanisms were upregulated during active infection of mice. On the other hand, capsular polysaccharide and quorum-sensing pathways were inhibited during infection. In addition to virulence factors, reactive oxygen species, heat shock proteins, siderophores, and secondary metabolites were also induced to assist bacterial adaptation and survival in the host. Overall, this study provides crucial insights into the transcriptome-level adaptations which facilitate infection by soil-dwelling B. pseudomallei. Targeting novel therapeutics toward B. pseudomallei proteins required for adaptation provides an alternative treatment strategy given its intrinsic antimicrobial resistance and the absence of a vaccine. IMPORTANCE Burkholderia pseudomallei, a soil-dwelling bacterium, is the causative agent of melioidosis, a fatal infectious disease of humans and animals. The bacterium has a large genome consisting of two chromosomes carrying genes that encode proteins with important roles for survival in diverse environments as well as in the infected host. While a general mechanism of pathogenesis has been proposed, it is not clear which proteins have major roles when the bacteria are in the soil and whether the same proteins are key to successful infection and spread. To address this question, we grew the bacteria in soil medium and then in infected mice. At 5 days postinfection, bacteria were recovered from infected mouse organs and their gene expression was compared against that of bacteria grown in soil medium. The analysis revealed a list of genes expressed under soil growth conditions and a different set of genes encoding proteins which may be important for survival, replication, and dissemination in an infected host. These proteins are a potential resource for understanding the full adaptation mechanism of this pathogen. In the absence of a vaccine for melioidosis and with treatment being reliant on combinatorial antibiotic therapy, these proteins may be ideal targets for designing antimicrobials to treat melioidosis.
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Affiliation(s)
- Ahmad-Kamal Ghazali
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Mohd Firdaus-Raih
- Department of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Asqwin Uthaya Kumar
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Wei-Kang Lee
- Codon Genomics Sdn. Bhd., Seri Kembangan, Selangor, Malaysia
| | - Chee-Choong Hoh
- Codon Genomics Sdn. Bhd., Seri Kembangan, Selangor, Malaysia
| | - Sheila Nathan
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
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Meethai C, Vanaporn M, Intarak N, Lerdsittikul V, Withatanung P, Janesomboon S, Vattanaviboon P, Chareonsudjai S, Wilkinson T, Stevens MP, Stevens JM, Korbsrisate S. Analysis of the role of the QseBC two-component sensory system in epinephrine-induced motility and intracellular replication of Burkholderia pseudomallei. PLoS One 2023; 18:e0282098. [PMID: 36821630 PMCID: PMC9949665 DOI: 10.1371/journal.pone.0282098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 02/07/2023] [Indexed: 02/24/2023] Open
Abstract
Burkholderia pseudomallei is a facultative intracellular bacterial pathogen that causes melioidosis, a severe invasive disease of humans. We previously reported that the stress-related catecholamine hormone epinephrine enhances motility of B. pseudomallei, transcription of flagellar genes and the production of flagellin. It has been reported that the QseBC two-component sensory system regulates motility and virulence-associated genes in other Gram-negative bacteria in response to stress-related catecholamines, albeit disparities between studies exist. We constructed and whole-genome sequenced a mutant of B. pseudomallei with a deletion spanning the predicted qseBC homologues (bpsl0806 and bpsl0807). The ΔqseBC mutant exhibited significantly reduced swimming and swarming motility and reduced transcription of fliC. It also exhibited a defect in biofilm formation and net intracellular survival in J774A.1 murine macrophage-like cells. While epinephrine enhanced bacterial motility and fliC transcription, no further reduction in these phenotypes was observed with the ΔqseBC mutant in the presence of epinephrine. Plasmid-mediated expression of qseBC suppressed bacterial growth, complicating attempts to trans-complement mutant phenotypes. Our data support a role for QseBC in motility, biofilm formation and net intracellular survival of B. pseudomallei, but indicate that it is not essential for epinephrine-induced motility per se.
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Affiliation(s)
- Chatruthai Meethai
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Muthita Vanaporn
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Narin Intarak
- Department of Physiology, Faculty of Dentistry, Genomics and Precision, Chulalongkorn University, Bangkok, Thailand
| | - Varintip Lerdsittikul
- Microbiology Laboratory, Faculty of Veterinary Science, Veterinary Diagnostic Center, Mahidol University, Nakhon Pathom, Thailand
| | - Patoo Withatanung
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Sujintana Janesomboon
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | | | | | - Toby Wilkinson
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom
| | - Mark P. Stevens
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom
| | - Joanne M. Stevens
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom
- * E-mail: (JMS); (SK)
| | - Sunee Korbsrisate
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- * E-mail: (JMS); (SK)
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9
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Aiosa N, Sinha A, Jaiyesimi OA, da Silva RR, Branda SS, Garg N. Metabolomics Analysis of Bacterial Pathogen Burkholderia thailandensis and Mammalian Host Cells in Co-culture. ACS Infect Dis 2022; 8:1646-1662. [PMID: 35767828 DOI: 10.1021/acsinfecdis.2c00233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Tier 1 HHS/USDA Select Agent Burkholderia pseudomallei is a bacterial pathogen that is highly virulent when introduced into the respiratory tract and intrinsically resistant to many antibiotics. Transcriptomic- and proteomic-based methodologies have been used to investigate mechanisms of virulence employed by B. pseudomallei and Burkholderia thailandensis, a convenient surrogate; however, analysis of the pathogen and host metabolomes during infection is lacking. Changes in the metabolites produced can be a result of altered gene expression and/or post-transcriptional processes. Thus, metabolomics complements transcriptomics and proteomics by providing a chemical readout of a biological phenotype, which serves as a snapshot of an organism's physiological state. However, the poor signal from bacterial metabolites in the context of infection poses a challenge in their detection and robust annotation. In this study, we coupled mammalian cell culture-based metabolomics with feature-based molecular networking of mono- and co-cultures to annotate the pathogen's secondary metabolome during infection of mammalian cells. These methods enabled us to identify several key secondary metabolites produced by B. thailandensis during infection of airway epithelial and macrophage cell lines. Additionally, the use of in silico approaches provided insights into shifts in host biochemical pathways relevant to defense against infection. Using chemical class enrichment analysis, for example, we identified changes in a number of host-derived compounds including immune lipids such as prostaglandins, which were detected exclusively upon pathogen challenge. Taken together, our findings indicate that co-culture of B. thailandensis with mammalian cells alters the metabolome of both pathogen and host and provides a new dimension of information for in-depth analysis of the host-pathogen interactions underlying Burkholderia infection.
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Affiliation(s)
- Nicole Aiosa
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Drive, Atlanta, Georgia 30332-2000, United States
| | - Anupama Sinha
- Biotechnology & Bioengineering, Sandia National Laboratories, 7011 East Avenue, Livermore, California 94550, United States
| | - Olakunle A Jaiyesimi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Drive, Atlanta, Georgia 30332-2000, United States
| | - Ricardo R da Silva
- School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Av. do Café─Vila Monte Alegre, 14040-903 Ribeirão Preto-SP, Brazil
| | - Steven S Branda
- Systems Biology, Sandia National Laboratories, 7011 East Avenue, Livermore, California 94550, United States
| | - Neha Garg
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Drive, Atlanta, Georgia 30332-2000, United States.,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, 311 Ferst Drive, ES&T, Atlanta, Georgia 30332, United States
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10
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Quilici G, Berardi A, Fabris C, Ghitti M, Punta M, Gourlay LJ, Bolognesi M, Musco G. Solution Structure of the BPSL1445 Protein of Burkholderia pseudomallei Reveals the SYLF Domain Three-Dimensional Fold. ACS Chem Biol 2022; 17:230-239. [PMID: 34968022 DOI: 10.1021/acschembio.1c00886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The SYLF domain is an evolutionary conserved protein domain with phosphatidylinositol binding ability, whose three-dimensional structure is unknown. Here, we present the solution structure and the dynamics characterization of the SYLF domain of the bacterial BPSL1445 protein. BPSL1445 is a seroreactive antigen and a diagnostic marker of Burkholderia pseudomallei, the etiological agent of melioidosis, a severe infectious disease in the tropics. The BPSL1445 SYLF domain (BPSL1445-SYLF) consists of a β-barrel core, with two flexible loops protruding out of the barrel and three helices packing on its surface. Our structure allows for a more precise definition of the boundaries of the SYLF domain compared to the previously reported one and suggests common ancestry with bacterial EipA domains. We also demonstrate by phosphatidyl-inositol phosphate arrays and nuclear magnetic resonance titrations that BPSL1445-SYLF weakly interacts with phosphoinositides, thus supporting lipid binding abilities of this domain also in prokaryotes.
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Affiliation(s)
- Giacomo Quilici
- Biomolecular NMR Laboratory, I.R.C.C.S. Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy
| | - Andrea Berardi
- Biomolecular NMR Laboratory, I.R.C.C.S. Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy
| | - Chantal Fabris
- Biomolecular NMR Laboratory, I.R.C.C.S. Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy
| | - Michela Ghitti
- Biomolecular NMR Laboratory, I.R.C.C.S. Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy
| | - Marco Punta
- Unit of Immunogenetics, Leukemia Genomics and Immunobiology and Center for Omics Sciences, I.R.C.C.S. Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy
| | - Louise J. Gourlay
- Department of Biosciences, University of Milano, Via Celoria 26, 20133 Milan, Italy
- Centro di Ricerca Pediatrica Romeo ed Enrica Invernizzi, Università degli Studi di Milano, 20133 Milan, Italy
| | - Martino Bolognesi
- Department of Biosciences, University of Milano, Via Celoria 26, 20133 Milan, Italy
- Centro di Ricerca Pediatrica Romeo ed Enrica Invernizzi, Università degli Studi di Milano, 20133 Milan, Italy
| | - Giovanna Musco
- Biomolecular NMR Laboratory, I.R.C.C.S. Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy
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11
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Chewapreecha C, Pensar J, Chattagul S, Pesonen M, Sangphukieo A, Boonklang P, Potisap C, Koosakulnirand S, Feil EJ, Dunachie S, Chantratita N, Limmathurotsakul D, Peacock SJ, Day NPJ, Parkhill J, Thomson NR, Sermswan RW, Corander J. Co-evolutionary Signals Identify Burkholderia pseudomallei Survival Strategies in a Hostile Environment. Mol Biol Evol 2022; 39:6400259. [PMID: 34662416 PMCID: PMC8760936 DOI: 10.1093/molbev/msab306] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The soil bacterium Burkholderia pseudomallei is the causative agent of melioidosis and a significant cause of human morbidity and mortality in many tropical and subtropical countries. The species notoriously survives harsh environmental conditions but the genetic architecture for these adaptations remains unclear. Here we employed a powerful combination of genome-wide epistasis and co-selection studies (2,011 genomes), condition-wide transcriptome analyses (82 diverse conditions), and a gene knockout assay to uncover signals of "co-selection"-that is a combination of genetic markers that have been repeatedly selected together through B. pseudomallei evolution. These enabled us to identify 13,061 mutation pairs under co-selection in distinct genes and noncoding RNA. Genes under co-selection displayed marked expression correlation when B. pseudomallei was subjected to physical stress conditions, highlighting the conditions as one of the major evolutionary driving forces for this bacterium. We identified a putative adhesin (BPSL1661) as a hub of co-selection signals, experimentally confirmed a BPSL1661 role under nutrient deprivation, and explored the functional basis of co-selection gene network surrounding BPSL1661 in facilitating the bacterial survival under nutrient depletion. Our findings suggest that nutrient-limited conditions have been the common selection pressure acting on this species, and allelic variation of BPSL1661 may have promoted B. pseudomallei survival during harsh environmental conditions by facilitating bacterial adherence to different surfaces, cells, or living hosts.
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Affiliation(s)
- Claire Chewapreecha
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Parasites and Microbes Programme, Wellcome Sanger Insitute, Hinxton, United Kingdom
- Bioinformatics & Systems Biology Program, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand
- Corresponding authors: E-mails: ; ;
| | - Johan Pensar
- Department of Mathematics, University of Oslo, Oslo, Norway
- Department of Mathematics and Statistics, Helsinki Institute of Information Technology, University of Helsinki, Helsinki, Finland
| | - Supaksorn Chattagul
- Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand
- Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Maiju Pesonen
- Oslo Centre for Biostatistics and Epidemiology, Oslo University Hospital, Oslo, Norway
| | - Apiwat Sangphukieo
- Bioinformatics & Systems Biology Program, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand
| | - Phumrapee Boonklang
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chotima Potisap
- Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand
| | - Sirikamon Koosakulnirand
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Edward J Feil
- Department of Biology and Biochemistry, The Milner Centre for Evolution, University of Bath, Bath, United Kingdom
| | - Susanna Dunachie
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Narisara Chantratita
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Direk Limmathurotsakul
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Sharon J Peacock
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Nick P J Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Nicholas R Thomson
- Parasites and Microbes Programme, Wellcome Sanger Insitute, Hinxton, United Kingdom
| | - Rasana W Sermswan
- Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand
- Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- Corresponding authors: E-mails: ; ;
| | - Jukka Corander
- Parasites and Microbes Programme, Wellcome Sanger Insitute, Hinxton, United Kingdom
- Department of Mathematics and Statistics, Helsinki Institute of Information Technology, University of Helsinki, Helsinki, Finland
- Department of Biostatistics, University of Oslo, Oslo, Norway
- Corresponding authors: E-mails: ; ;
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12
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Regulation of Glycine Cleavage and Detoxification by a Highly Conserved Glycine Riboswitch in Burkholderia spp. Curr Microbiol 2021; 78:2943-2955. [PMID: 34076709 DOI: 10.1007/s00284-021-02550-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 05/21/2021] [Indexed: 10/21/2022]
Abstract
The glycine riboswitch is a known regulatory element that is unique in having two aptamers that are joined by a linker region. In this study, we investigated a glycine riboswitch located in the 5' untranslated region of a glycine cleavage system homolog (gcvTHP) in Burkholderia spp. Structure prediction using the sequence generated a model with a glycine binding pocket composed of base-triple interactions (G62-A64-A86 and G65-U84-C85) that are supported by A/G minor interactions (A17-C60-G88 and G16-C61-G87, respectively) and two ribose-zipper motifs (C11-G12 interacting with A248-A247 and C153-U154 interacting with A79-A78) which had not been previously reported. The capacity of the riboswitch to bind to glycine was experimentally validated by native gel assays and the crucial role of interactions that make up the glycine binding pocket were proven by mutations of A17U and G16C which resulted in conformational differences that may lead to dysfunction. Using glycine supplemented minimal media, we were able to prove that the expression of the gcvTHP genes found downstream of the riboswitch responded to the glycine concentrations introduced thus confirming the role of this highly conserved Burkholderia riboswitch and its associated genes as a putative glycine detoxification system in Burkholderia spp.
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13
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Phenn J, Pané-Farré J, Meukow N, Klein A, Troitzsch A, Tan P, Fuchs S, Wagner GE, Lichtenegger S, Steinmetz I, Kohler C. RegAB Homolog of Burkholderia pseudomallei is the Master Regulator of Redox Control and involved in Virulence. PLoS Pathog 2021; 17:e1009604. [PMID: 34048488 PMCID: PMC8191878 DOI: 10.1371/journal.ppat.1009604] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 06/10/2021] [Accepted: 05/03/2021] [Indexed: 12/23/2022] Open
Abstract
Burkholderia pseudomallei, the etiological agent of melioidosis in humans and animals, often occupies environmental niches and infection sites characterized by limited concentrations of oxygen. Versatile genomic features enable this pathogen to maintain its physiology and virulence under hypoxia, but the crucial regulatory networks employed to switch from oxygen dependent respiration to alternative terminal electron acceptors (TEA) like nitrate, remains poorly understood. Here, we combined a Tn5 transposon mutagenesis screen and an anaerobic growth screen to identify a two-component signal transduction system with homology to RegAB. We show that RegAB is not only essential for anaerobic growth, but also for full virulence in cell lines and a mouse infection model. Further investigations of the RegAB regulon, using a global transcriptomic approach, identified 20 additional regulators under transcriptional control of RegAB, indicating a superordinate role of RegAB in the B. pseudomallei anaerobiosis regulatory network. Of the 20 identified regulators, NarX/L and a FNR homolog were selected for further analyses and a role in adaptation to anaerobic conditions was demonstrated. Growth experiments identified nitrate and intermediates of the denitrification process as the likely signal activateing RegAB, NarX/L, and probably of the downstream regulators Dnr or NsrR homologs. While deletions of individual genes involved in the denitrification process demonstrated their important role in anaerobic fitness, they showed no effect on virulence. This further highlights the central role of RegAB as the master regulator of anaerobic metabolism in B. pseudomallei and that the complete RegAB-mediated response is required to achieve full virulence. In summary, our analysis of the RegAB-dependent modulon and its interconnected regulons revealed a key role for RegAB of B. pseudomallei in the coordination of the response to hypoxic conditions and virulence, in the environment and the host.
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Affiliation(s)
- Julia Phenn
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine Greifswald, Greifswald, Germany
| | - Jan Pané-Farré
- SYNMIKRO Research Center and Department of Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Nikolai Meukow
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine Greifswald, Greifswald, Germany
| | - Annelie Klein
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine Greifswald, Greifswald, Germany
| | - Anne Troitzsch
- Department for Microbial Physiology and Molecular Biology, University Greifswald, Greifswald, Germany
| | - Patrick Tan
- Genome Institute of Singapore, Singapore, Republic of Singapore
- Duke-NUS Medical School Singapore, Singapore, Republic of Singapore
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Republic of Singapore
| | - Stephan Fuchs
- FG13 Nosocomial Pathogens and Antibiotic Resistances, Robert Koch Institute, Wernigerode, Germany
| | - Gabriel E Wagner
- Institute of Hygiene, Microbiology and Environmental Medicine, Medical University Graz, Graz, Austria
| | - Sabine Lichtenegger
- Institute of Hygiene, Microbiology and Environmental Medicine, Medical University Graz, Graz, Austria
| | - Ivo Steinmetz
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine Greifswald, Greifswald, Germany
- Institute of Hygiene, Microbiology and Environmental Medicine, Medical University Graz, Graz, Austria
| | - Christian Kohler
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine Greifswald, Greifswald, Germany
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14
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Heacock-Kang Y, McMillan IA, Norris MH, Sun Z, Zarzycki-Siek J, Bluhm AP, Cabanas D, Norton RE, Ketheesan N, Miller JF, Schweizer HP, Hoang TT. The Burkholderia pseudomallei intracellular 'TRANSITome'. Nat Commun 2021; 12:1907. [PMID: 33772012 PMCID: PMC7998038 DOI: 10.1038/s41467-021-22169-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 02/26/2021] [Indexed: 01/01/2023] Open
Abstract
Prokaryotic cell transcriptomics has been limited to mixed or sub-population dynamics and individual cells within heterogeneous populations, which has hampered further understanding of spatiotemporal and stage-specific processes of prokaryotic cells within complex environments. Here we develop a 'TRANSITomic' approach to profile transcriptomes of single Burkholderia pseudomallei cells as they transit through host cell infection at defined stages, yielding pathophysiological insights. We find that B. pseudomallei transits through host cells during infection in three observable stages: vacuole entry; cytoplasmic escape and replication; and membrane protrusion, promoting cell-to-cell spread. The B. pseudomallei 'TRANSITome' reveals dynamic gene-expression flux during transit in host cells and identifies genes that are required for pathogenesis. We find several hypothetical proteins and assign them to virulence mechanisms, including attachment, cytoskeletal modulation, and autophagy evasion. The B. pseudomallei 'TRANSITome' provides prokaryotic single-cell transcriptomics information enabling high-resolution understanding of host-pathogen interactions.
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Affiliation(s)
- Yun Heacock-Kang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Ian A McMillan
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Michael H Norris
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
- Department of Geography and Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Zhenxin Sun
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Jan Zarzycki-Siek
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Andrew P Bluhm
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
- Department of Geography and Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Darlene Cabanas
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Robert E Norton
- Townsville Hospital, Townsville, QLD, Australia
- Faculty of Medicine, University of Queensland, Brisbane, Australia
| | - Natkunam Ketheesan
- Science and Technology, University of New England, New South Wales, Australia
| | - Jeff F Miller
- Department of Microbiology, Immunology, and Molecular Genetics, and the California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Herbert P Schweizer
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Tung T Hoang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA.
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15
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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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16
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Welkos S, Blanco I, Okaro U, Chua J, DeShazer D. A DUF4148 family protein produced inside RAW264.7 cells is a critical Burkholderia pseudomallei virulence factor. Virulence 2020; 11:1041-1058. [PMID: 32835600 PMCID: PMC7549894 DOI: 10.1080/21505594.2020.1806675] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/24/2020] [Accepted: 07/27/2020] [Indexed: 11/12/2022] Open
Abstract
Burkholderia pseudomallei: is the etiological agent of the disease melioidosis and is a Tier 1 select agent. It survives and replicates inside phagocytic cells by escaping from the endocytic vacuole, replicating in the cytosol, spreading to other cells via actin polymerization and promoting the fusion of infected and uninfected host cells to form multinucleated giant cells. In this study, we utilized a proteomics approach to identify bacterial proteins produced inside RAW264.7 murine macrophages and host proteins produced in response to B. pseudomallei infection. Cells infected with B. pseudomallei strain K96243 were lysed and the lysate proteins digested and analyzed using nanoflow reversed-phase liquid chromatography and tandem mass spectrometry. Approximately 160 bacterial proteins were identified in the infected macrophages, including BimA, TssA, TssB, Hcp1 and TssM. Several previously uncharacterized B. pseudomallei proteins were also identified, including BPSS1996 and BPSL2748. Mutations were constructed in the genes encoding these novel proteins and their relative virulence was assessed in BALB/c mice. The 50% lethal dose for the BPSS1996 mutant was approximately 55-fold higher than that of the wild type, suggesting that BPSS1996 is required for full virulence. Sera from B. pseudomallei-infected animals reacted with BPSS1996 and it was found to localize to the bacterial surface using indirect immunofluorescence. Finally, we identified 274 host proteins that were exclusively present or absent in infected RAW264.7 cells, including chemokines and cytokines involved in controlling the initial stages of infection.
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Affiliation(s)
- Susan Welkos
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
| | - Irma Blanco
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
| | - Udoka Okaro
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
| | - Jennifer Chua
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
| | - David DeShazer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
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17
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Grund ME, Choi SJ, McNitt DH, Barbier M, Hu G, LaSala PR, Cote CK, Berisio R, Lukomski S. Burkholderia collagen-like protein 8, Bucl8, is a unique outer membrane component of a putative tetrapartite efflux pump in Burkholderia pseudomallei and Burkholderia mallei. PLoS One 2020; 15:e0242593. [PMID: 33227031 PMCID: PMC7682875 DOI: 10.1371/journal.pone.0242593] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 11/06/2020] [Indexed: 12/19/2022] Open
Abstract
Bacterial efflux pumps are an important pathogenicity trait because they extrude a variety of xenobiotics. Our laboratory previously identified in silico Burkholderia collagen-like protein 8 (Bucl8) in the hazardous pathogens Burkholderia pseudomallei and Burkholderia mallei. We hypothesize that Bucl8, which contains two predicted tandem outer membrane efflux pump domains, is a component of a putative efflux pump. Unique to Bucl8, as compared to other outer membrane proteins, is the presence of an extended extracellular region containing a collagen-like (CL) domain and a non-collagenous C-terminus (Ct). Molecular modeling and circular dichroism spectroscopy with a recombinant protein, corresponding to this extracellular CL-Ct portion of Bucl8, demonstrated that it adopts a collagen triple helix, whereas functional assays screening for Bucl8 ligands identified binding to fibrinogen. Bioinformatic analysis of the bucl8 gene locus revealed it resembles a classical efflux-pump operon. The bucl8 gene is co-localized with downstream fusCDE genes encoding fusaric acid (FA) resistance, and with an upstream gene, designated as fusR, encoding a LysR-type transcriptional regulator. Using reverse transcriptase (RT)-qPCR, we defined the boundaries and transcriptional organization of the fusR-bucl8-fusCDE operon. We found exogenous FA induced bucl8 transcription over 80-fold in B. pseudomallei, while deletion of the entire bucl8 locus decreased the minimum inhibitory concentration of FA 4-fold in its isogenic mutant. We furthermore showed that the putative Bucl8-associated pump expressed in the heterologous Escherichia coli host confers FA resistance. On the contrary, the Bucl8-associated pump did not confer resistance to a panel of clinically-relevant antimicrobials in Burkholderia and E. coli. We finally demonstrated that deletion of the bucl8-locus drastically affects the growth of the mutant in L-broth. We determined that Bucl8 is a component of a novel tetrapartite efflux pump, which confers FA resistance, fibrinogen binding, and optimal growth.
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Affiliation(s)
- Megan E. Grund
- Department of Microbiology, Immunology and Cell Biology, School of
Medicine, West Virginia University, Morgantown, WV, United States of
America
| | - Soo J. Choi
- Department of Microbiology, Immunology and Cell Biology, School of
Medicine, West Virginia University, Morgantown, WV, United States of
America
| | - Dudley H. McNitt
- Department of Microbiology, Immunology and Cell Biology, School of
Medicine, West Virginia University, Morgantown, WV, United States of
America
| | - Mariette Barbier
- Department of Microbiology, Immunology and Cell Biology, School of
Medicine, West Virginia University, Morgantown, WV, United States of
America
| | - Gangqing Hu
- Department of Microbiology, Immunology and Cell Biology, School of
Medicine, West Virginia University, Morgantown, WV, United States of
America
- Cancer Center, West Virginia University, Morgantown, WV, United States of
America
- Bioinformatics Core, West Virginia University, Morgantown, WV, United
States of America
| | - P. Rocco LaSala
- Department of Pathology, West Virginia University, Morgantown, WV, United
States of America
| | - Christopher K. Cote
- Bacteriology Division, The United States Army Medical Research Institute
of Infectious Diseases (USAMRIID), Frederick, MD, United States of
America
| | - Rita Berisio
- Institute of Biostructures and Bioimaging, National Research Council,
Naples, Italy
| | - Slawomir Lukomski
- Department of Microbiology, Immunology and Cell Biology, School of
Medicine, West Virginia University, Morgantown, WV, United States of
America
- Cancer Center, West Virginia University, Morgantown, WV, United States of
America
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18
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Functional redundancy of Burkholderia pseudomallei phospholipase C enzymes and their role in virulence. Sci Rep 2020; 10:19242. [PMID: 33159122 PMCID: PMC7648637 DOI: 10.1038/s41598-020-76186-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 10/21/2020] [Indexed: 11/12/2022] Open
Abstract
Phospholipase C (PLC) enzymes are key virulence factors in several pathogenic bacteria. Burkholderia pseudomallei, the causative agent of melioidosis, possesses at least three plc genes (plc1, plc2 and plc3). We found that in culture medium plc1 gene expression increased with increasing pH, whilst expression of the plc3 gene was pH (4.5 to 9.0) independent. Expression of the plc2 gene was not detected in culture medium. All three plc genes were expressed during macrophage infection by B. pseudomallei K96243. Comparing B. pseudomallei wild-type with plc mutants revealed that plc2, plc12 or plc123 mutants showed reduced intracellular survival in macrophages and reduced plaque formation in HeLa cells. However, plc1 or plc3 mutants showed no significant differences in plaque formation compared to wild-type bacteria. These findings suggest that Plc2, but not Plc1 or Plc3 are required for infection of host cells. In Galleria mellonella, plc1, plc2 or plc3 mutants were not attenuated compared to the wild-type strain, but multiple plc mutants showed reduced virulence. These findings indicate functional redundancy of the B. pseudomallei phospholipases in virulence.
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Ross BN, Thiriot JD, Wilson SM, Torres AG. Predicting toxins found in toxin-antitoxin systems with a role in host-induced Burkholderia pseudomallei persistence. Sci Rep 2020; 10:16923. [PMID: 33037311 PMCID: PMC7547725 DOI: 10.1038/s41598-020-73887-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 09/23/2020] [Indexed: 12/19/2022] Open
Abstract
Burkholderia pseudomallei (Bpm) is a bacterial pathogen that causes Melioidosis, a disease with up to 40% mortality and an infection relapse of 15-23% despite antibiotic treatment. Ineffective clearance of Bpm by antibiotics is believed to be due to persistence, a hibernation-like survival mechanism modulated, in part, by toxin-antitoxin systems (TAS). Several organisms possess a repertoire of TASs but defining environmental cues eliciting their activity is hindered by laborious in vitro experiments, especially when there are many toxins with redundant function. Here, we identified which of 103 proteins in Bpm that share features found in toxins of the TAS and repurposed transcriptional data to identify which ones play a role in surviving intracellular host defenses. Putative toxins with the strongest transcriptional response were found to have low conservation between Bpm strains, while toxins that were constitutively expressed were highly conserved. Further examination of highly conserved toxins BPSS0899, BPSS1321, and BPSL1494 showed that they were functional, and their mutation led to reduce survival within macrophages and reduced in vivo persistence-associated pathology (abscesses) during treatment, but did not affect macrophages persistence. These findings highlight the utility of a data-driven approach to select putative toxins and suggests a selective role for some TAS in host survival.
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Affiliation(s)
- Brittany N Ross
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Joseph D Thiriot
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Shane M Wilson
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Alfredo G Torres
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA.
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA.
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Saikh KU, Ranji CM, Ulrich RG, Corea E, De Silva AD, Natesan M. An increase in p62/NBR1 levels in melioidosis patients of Sri Lanka exhibit a characteristic of potential host biomarker. J Med Microbiol 2020; 69:1240-1248. [PMID: 32815800 PMCID: PMC7660894 DOI: 10.1099/jmm.0.001242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 07/23/2020] [Indexed: 12/18/2022] Open
Abstract
Introduction. Melioidosis, caused by Burkholderia pseudomallei, in endemic areas, poses a challenge for treating the diseased populations without accurate diagnosis, and the disease-specific biomarkers linked with the infection have yet to be reported. Due to the invasive nature of the causative agent, Burkholderia pseudomallei, host innate effector mechanisms, including autophagy are known to be activated, resulting in differential expression of cellular proteins and immune markers. Identification of a disease-specific biomarker associated with B. pseudomallei infection will be helpful to facilitate rapid confirmation of melioidosis, which would enable early treatment and therapeutic success.Aim. We aimed to assess the levels of a host autophagy component, p62/NBR1, which function as a cargo-receptor in the process of autophagy activation leading to the degradation of ubiquitin-coated intracellular bacteria in which p62/NBR1 itself is degraded in the clearance of the pathogen. We further probed the extent of intracellular p62/NBR1 degradation and assessed its potential as a melioidosis biomarker.Methodology. We analysed peripheral blood mononuclear cell (PBMC) lysates using an ELISA-based assay for detecting cytosolic autophagy-related proteins p62/NBR1. We measured p62/NBR1 levels in diseased (confirmed B. pseudomallei infection) and non -diseased populations and utilized receiver operating characteristic (ROC) curve and max Youden index analysis for evaluating potential disease biomarker characteristics.Results. Our results revealed a three to fivefold increase in p62/NBR1 levels confirmed melioidosis cases compared to uninfected healthy donors. Comparable to p62/NBR1, levels of cytosolic LC3-I levels also increased, whereas the levels of degraded membrane bound form LC3-II was low, suggesting autophagy deficiency. Proinflammatory serum cytokine response, particularly IL-6, was consistently higher alongside B. pseudomallei infection in comparison to healthy controls.Conclusions. ROC curve and max Youden index analysis suggest that increased p62/NBR1 levels in diseased populations display characteristics of a potential disease biomarker in melioidosis and illustrates that an elevated p62/NBR1 level, in conjunction with B. pseudomallei infection associated with autophagy deficiency.
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Affiliation(s)
- Kamal U. Saikh
- Department of Immunology, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, USA
| | - Cyra M. Ranji
- Department of Immunology, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, USA
| | - Robert G. Ulrich
- Department of Immunology, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, USA
| | - Enoka Corea
- Department of Microbiology, University of Colombo, Colombo, Sri Lanka
| | - Aruna Dharshan De Silva
- Division of Vaccine Discovery, La Jolla Institute of Allergy and Immunology, La Jolla, CA, USA
- Department of Paraclinical Sciences, Faculty of Medicine, Kotelawala Defence University, Ratmalana, Sri Lanka
| | - Mohan Natesan
- Department of Immunology, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, USA
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ScmR, a Global Regulator of Gene Expression, Quorum Sensing, pH Homeostasis, and Virulence in Burkholderia thailandensis. J Bacteriol 2020; 202:JB.00776-19. [PMID: 32312745 DOI: 10.1128/jb.00776-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 04/13/2020] [Indexed: 11/20/2022] Open
Abstract
The nonpathogenic soil saprophyte Burkholderia thailandensis is a member of the Burkholderia pseudomallei /B. thailandensis/B. mallei group, which also comprises the closely related human pathogens B. pseudomallei and Burkholderia mallei responsible for the melioidosis and glanders diseases, respectively. ScmR, a recently identified LysR-type transcriptional regulator in B. thailandensis, acts as a global transcriptional regulator throughout the stationary phase and modulates the production of a wide range of secondary metabolites, including N-acyl-l-homoserine lactones and 4-hydroxy-3-methyl-2-alkylquinolines and virulence in the Caenorhabditis elegans nematode worm host model, as well as several quorum sensing (QS)-dependent phenotypes. We have investigated the role of ScmR in B. thailandensis strain E264 during the exponential phase. We used RNA sequencing transcriptomic analyses to identify the ScmR regulon, which was compared to the QS-controlled regulon, showing a considerable overlap between the ScmR-regulated genes and those controlled by QS. We characterized several genes modulated by ScmR using quantitative reverse transcription-PCR or mini-CTX-lux transcriptional reporters, including the oxalate biosynthetic gene obc1 required for pH homeostasis, the orphan LuxR-type transcriptional regulator BtaR5-encoding gene, and the bsa (Burkholderia secretion apparatus) type III secretion system genes essential for both B. pseudomallei and B. mallei pathogenicity, as well as the scmR gene itself. We confirmed that the transcription of scmR is under QS control, presumably ensuring fine-tuned modulation of gene expression. Finally, we demonstrated that ScmR influences virulence using the fruit fly model host Drosophila melanogaster We conclude that ScmR represents a central component of the B. thailandensis QS regulatory network.IMPORTANCE Coordination of the expression of genes associated with bacterial virulence and environmental adaptation is often dependent on quorum sensing (QS). The QS circuitry of the nonpathogenic bacterium Burkholderia thailandensis, widely used as a model system for the study of the human pathogen Burkholderia pseudomallei, is complex. We found that the LysR-type transcriptional regulator, ScmR, which is highly conserved and involved in the control of virulence/survival factors in the Burkholderia genus, is a global regulator mediating gene expression through the multiple QS systems coexisting in B. thailandensis, as well as QS independently. We conclude that ScmR represents a key QS modulatory network element, ensuring tight regulation of the transcription of QS-controlled genes, particularly those required for acclimatization to the environment.
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22
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Burkholderia pseudomallei pathogenesis and survival in different niches. Biochem Soc Trans 2020; 48:569-579. [PMID: 32167134 DOI: 10.1042/bst20190836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 02/24/2020] [Accepted: 02/25/2020] [Indexed: 01/16/2023]
Abstract
Burkholderia pseudomallei (Bp) is the causative agent of melioidosis, a disease of the tropics with high clinical mortality rates. To date, no vaccines are approved for melioidosis and current treatment relies on antibiotics. Conversely, common misdiagnosis and high pathogenicity of Bp hamper efforts to fight melioidosis. This bacterium can be isolated from a wide range of niches such as waterlogged fields, stagnant water bodies, salt water bodies and from human and animal clinical specimens. Although extensive studies have been undertaken to elucidate pathogenesis mechanisms of Bp, little is known about how a harmless soil bacterium adapts to different environmental conditions, in particular, the shift to a human host to become a highly virulent pathogen. The bacterium has a large genome encoding an armory of factors that assist the pathogen in surviving under stressful conditions and assuming its role as a deadly intracellular pathogen. This review presents an overview of what is currently known about how the pathogen adapts to different environments. With in-depth understanding of Bp adaptation and survival, more effective therapies for melioidosis can be developed by targeting related genes or proteins that play a major role in the bacteria's survival.
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Jitprasutwit S, Jitprasutwit N, Hemsley CM, Onlamoon N, Withatanung P, Muangsombut V, Vattanaviboon P, Stevens JM, Ong C, Stevens MP, Titball RW, Korbsrisate S. Identification of Burkholderia pseudomallei Genes Induced During Infection of Macrophages by Differential Fluorescence Induction. Front Microbiol 2020; 11:72. [PMID: 32153515 PMCID: PMC7047822 DOI: 10.3389/fmicb.2020.00072] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/14/2020] [Indexed: 12/05/2022] Open
Abstract
Burkholderia pseudomallei, the causative agent of melioidosis, can survive and replicate in macrophages. Little is known about B. pseudomallei genes that are induced during macrophage infection. We constructed a B. pseudomallei K96243 promoter trap library with genomic DNA fragments fused to the 5' end of a plasmid-borne gene encoding enhanced green fluorescent protein (eGFP). Microarray analysis showed that the library spanned 88% of the B. pseudomallei genome. The recombinant plasmids were introduced into Burkholderia thailandensis E264, and promoter fusions active during in vitro culture were removed. J774A.1 murine macrophages were infected with the promoter trap library, and J774A.1 cells containing fluorescent bacteria carrying plasmids with active promoters were isolated using flow cytometric-based cell sorting. Candidate macrophage-induced B. pseudomallei genes were identified from the location of the insertions containing an active promoter activity. A proportion of the 138 genes identified in this way have been previously reported to be involved in metabolism and transport, virulence, or adaptation. Novel macrophage-induced B. pseudomallei genes were also identified. Quantitative reverse-transcription PCR analysis of 13 selected genes confirmed gene induction during macrophage infection. Deletion mutants of two macrophage-induced genes from this study were attenuated in Galleria mellonella larvae, suggesting roles in virulence. B. pseudomallei genes activated during macrophage infection may contribute to intracellular life and pathogenesis and merit further investigation toward control strategies for melioidosis.
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Affiliation(s)
- Siroj Jitprasutwit
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Niramol Jitprasutwit
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | | | - Nattawat Onlamoon
- Siriraj Research Group in Immunobiology and Therapeutic Sciences, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Patoo Withatanung
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Veerachat Muangsombut
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | | | - Joanne M. Stevens
- The Roslin Institute, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Catherine Ong
- Defence Medical and Environmental Research Institute, DSO National Laboratories, Singapore, Singapore
| | - Mark P. Stevens
- The Roslin Institute, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Sunee Korbsrisate
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
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24
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Chewapreecha C, Mather AE, Harris SR, Hunt M, Holden MTG, Chaichana C, Wuthiekanun V, Dougan G, Day NPJ, Limmathurotsakul D, Parkhill J, Peacock SJ. Genetic variation associated with infection and the environment in the accidental pathogen Burkholderia pseudomallei. Commun Biol 2019; 2:428. [PMID: 31799430 PMCID: PMC6874650 DOI: 10.1038/s42003-019-0678-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 11/04/2019] [Indexed: 01/09/2023] Open
Abstract
The environmental bacterium Burkholderia pseudomallei causes melioidosis, an important endemic human disease in tropical and sub-tropical countries. This bacterium occupies broad ecological niches including soil, contaminated water, single-cell microbes, plants and infection in a range of animal species. Here, we performed genome-wide association studies for genetic determinants of environmental and human adaptation using a combined dataset of 1,010 whole genome sequences of B. pseudomallei from Northeast Thailand and Australia, representing two major disease hotspots. With these data, we identified 47 genes from 26 distinct loci associated with clinical or environmental isolates from Thailand and replicated 12 genes in an independent Australian cohort. We next outlined the selective pressures on the genetic loci (dN/dS) and the frequency at which they had been gained or lost throughout their evolutionary history, reflecting the bacterial adaptability to a wide range of ecological niches. Finally, we highlighted loci likely implicated in human disease.
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Affiliation(s)
- Claire Chewapreecha
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400 Thailand
- Bioinformatics and Systems Biology Program, School of Bioresource and Technology, King Mongkut’s University of Technology Thonburi, Bangkok, 10150 Thailand
- Wellcome Sanger Institute, Hinxton, CB10 1SA UK
- Department of Medicine, University of Cambridge, Cambridge, CB2 0QQ UK
| | - Alison E. Mather
- Quadram Institute Bioscience, Norwich, NR4 7UQ UK
- Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, NR4 7TJ UK
| | | | - Martin Hunt
- Wellcome Sanger Institute, Hinxton, CB10 1SA UK
| | | | - Chutima Chaichana
- Department of Mathematics, Faculty of Science, King Mongkut’s University of Technology Thonburi, Bangkok, 10140 Thailand
| | - Vanaporn Wuthiekanun
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400 Thailand
| | - Gordon Dougan
- Department of Medicine, University of Cambridge, Cambridge, CB2 0QQ UK
| | - Nicholas P. J. Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400 Thailand
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7LF UK
| | - Direk Limmathurotsakul
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400 Thailand
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7LF UK
| | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES UK
| | - Sharon J. Peacock
- Department of Medicine, University of Cambridge, Cambridge, CB2 0QQ UK
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25
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DeShazer D. A novel contact-independent T6SS that maintains redox homeostasis via Zn 2+ and Mn 2+ acquisition is conserved in the Burkholderia pseudomallei complex. Microbiol Res 2019; 226:48-54. [PMID: 31284944 DOI: 10.1016/j.micres.2019.05.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/08/2019] [Accepted: 05/30/2019] [Indexed: 12/21/2022]
Abstract
The Burkholderia pseudomallei complex consists of six phylogenetically related Gram-negative bacterial species that include environmental saprophytes and mammalian pathogens. These microbes possess multiple type VI secretion systems (T6SS) that provide a fitness advantage in diverse niches by translocating effector molecules into prokaryotic and eukaryotic cells in a contact-dependent manner. Several recent studies have elucidated the regulation and function of T6SS-2, a novel contact-independent member of the T6SS family. Expression of the T6SS-2 gene cluster is repressed by OxyR, Zur and TctR and is activated by GvmR and reactive oxygen species (ROS). The last two genes of the T6SS-2 gene cluster encode a zincophore (TseZ) and a manganeseophore (TseM) that are exported into the extracellular milieu in a contact-independent fashion when microbes encounter oxidative stress. TseZ and TseM bind Zn2+ and Mn2+, respectively, and deliver them to bacteria where they provide protection against the lethal effects of ROS. The TonB-dependent transporters that interact with TseZ and TseM, and actively transport Zn2+ and Mn2+ across the outer membrane, have also been identified. Finally, T6SS-2 provides a contact-independent growth advantage in nutrient limited environments and is critical for virulence in Galleria mellonella larvae, but is dispensable for virulence in rodent models of infection.
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Affiliation(s)
- David DeShazer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, USA.
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26
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Kovacs-Simon A, Hemsley CM, Scott AE, Prior JL, Titball RW. Burkholderia thailandensis strain E555 is a surrogate for the investigation of Burkholderia pseudomallei replication and survival in macrophages. BMC Microbiol 2019; 19:97. [PMID: 31092204 PMCID: PMC6521459 DOI: 10.1186/s12866-019-1469-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 04/30/2019] [Indexed: 02/02/2023] Open
Abstract
Background Burkholderia pseudomallei is a human pathogen causing severe infections in tropical and subtropical regions and is classified as a bio-threat agent. B. thailandensis strain E264 has been proposed as less pathogenic surrogate for understanding the interactions of B. pseudomallei with host cells. Results We show that, unlike B. thailandensis strain E264, the pattern of growth of B. thailandensis strain E555 in macrophages is similar to that of B. pseudomallei. We have genome sequenced B. thailandensis strain E555 and using the annotated sequence identified genes and proteins up-regulated during infection. Changes in gene expression identified more of the known B. pseudomallei virulence factors than changes in protein levels and used together we identified 16% of the currently known B. pseudomallei virulence factors. These findings demonstrate the utility of B. thailandensis strain E555 to study virulence of B. pseudomallei. Conclusions A weakness of studies using B. thailandensis as a surrogate for B. pseudomallei is that the strains used replicate at a slower rate in infected cells. We show that the pattern of growth of B. thailandensis strain E555 in macrophages closely mirrors that of B. pseudomallei. Using this infection model we have shown that virulence factors of B. pseudomallei can be identified as genes or proteins whose expression is elevated on the infection of macrophages. This finding confirms the utility of B. thailandensis strain E555 as a surrogate for B. pseudomallei and this strain should be used for future studies on virulence mechanisms. Electronic supplementary material The online version of this article (10.1186/s12866-019-1469-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- A Kovacs-Simon
- College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.
| | - C M Hemsley
- College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - A E Scott
- CBR Division, Defence Science and Technology Laboratory, Porton Down, Salisbury, SP4 0JQ, UK
| | - J L Prior
- College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.,CBR Division, Defence Science and Technology Laboratory, Porton Down, Salisbury, SP4 0JQ, UK
| | - R W Titball
- College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
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Rossi E, Paroni M, Landini P. Biofilm and motility in response to environmental and host-related signals in Gram negative opportunistic pathogens. J Appl Microbiol 2018; 125:1587-1602. [PMID: 30153375 DOI: 10.1111/jam.14089] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 05/30/2018] [Accepted: 07/20/2018] [Indexed: 12/13/2022]
Abstract
Most bacteria can switch between a planktonic, sometimes motile, form and a biofilm mode, in which bacterial cells can aggregate and attach to a solid surface. The transition between these two forms represents an example of bacterial adaptation to environmental signals and stresses. In 'environmental pathogens', namely, environmental bacteria that are also able to cause disease in animals and humans, signals associated either with the host or with the external environment, such as temperature, oxygen availability, nutrient concentrations etc., play a major role in triggering the switch between the motile and the biofilm mode, via complex regulatory mechanisms that control flagellar synthesis and motility, and production of adhesion factors. In this review article, we present examples of how environmental signals can impact biofilm formation and cell motility in the Gram negative bacteria Pseudomonas aeruginosa, Escherichia coli and in the Burkholderia genus, and how the switch between motile and biofilm mode can be an essential part of a more general process of adaptation either to the host or to the external environment.
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Affiliation(s)
- E Rossi
- Department of Clinical Microbiology, Rigshospitalet, København, Denmark
| | - M Paroni
- Department of Biosciences, Università degli Studi di Milano, Milan, Italy
| | - P Landini
- Department of Biosciences, Università degli Studi di Milano, Milan, Italy
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28
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Losada L, Shea AA, DeShazer D. A MarR family transcriptional regulator and subinhibitory antibiotics regulate type VI secretion gene clusters in Burkholderia pseudomallei. MICROBIOLOGY-SGM 2018; 164:1196-1211. [PMID: 30052173 DOI: 10.1099/mic.0.000697] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Burkholderia pseudomallei, the aetiological agent of melioidosis, is an inhabitant of soil and water in many tropical and subtropical regions worldwide. It possesses six distinct type VI secretion systems (T6SS-1 to T6SS-6), but little is known about most of them, as they are poorly expressed in laboratory culture media. A genetic screen was devised to locate a putative repressor of the T6SS-2 gene cluster and a MarR family transcriptional regulator, termed TctR, was identified. The inactivation of tctR resulted in a 50-fold increase in the expression of an hcp2-lacZ transcriptional fusion, indicating that TctR is a negative regulator of the T6SS-2 gene cluster. Surprisingly, the tctR mutation resulted in a significant decrease in the expression of an hcp6-lacZ transcriptional fusion. B. pseudomallei K96243 and a tctR mutant were grown to logarithmic phase in rich culture medium and RNA was isolated and sequenced in order to identify other genes regulated by TctR. The results identified seven gene clusters that were repressed by TctR, including T6SS-2, and three gene clusters that were significantly activated. A small molecule library consisting of 1120 structurally defined compounds was screened to identify a putative ligand (or ligands) that might bind TctR and derepress transcription of the T6SS-2 gene cluster. Seven compounds, six fluoroquinolones and one quinolone, activated the expression of hcp2-lacZ. Subinhibitory ciprofloxacin also increased the expression of the T6SS-3, T6SS-4 and T6SS-6 gene clusters. This study highlights the complex layers of regulatory control that B. pseudomallei utilizes to ensure that T6SS expression only occurs under very defined environmental conditions.
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Affiliation(s)
- Liliana Losada
- 1J. Craig Venter Institute, Rockville, MD, USA.,†Present address: Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, Rockville, MD, USA
| | - April A Shea
- 2Diagnostic Systems Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, USA.,‡Present address: National Strategic Research Institute, Annapolis Junction, MD, USA
| | - David DeShazer
- 3Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, USA
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29
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Rhodes KA, Somprasong N, Podnecky NL, Mima T, Chirakul S, Schweizer HP. Molecular determinants of Burkholderia pseudomallei BpeEF-OprC efflux pump expression. MICROBIOLOGY-SGM 2018; 164:1156-1167. [PMID: 30024368 DOI: 10.1099/mic.0.000691] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Burkholderia pseudomallei, the cause of melioidosis, is intrinsically resistant to many antibiotics. Acquired multidrug resistance, including resistance to doxycycline and co-trimoxazole used for melioidosis eradication phase therapy, is mainly attributed to constitutive expression of the BpeEF-OprC efflux pump. Constitutive expression of this pump is caused by mutations affecting two highly similar LysR-type transcriptional regulators (LTTR), BpeT and BpeS, but their interaction with the regulatory region governing BpeEF-OprC expression has not yet been studied. The bpeE-bpeF-oprC genes are distally located in the llpE-bpeE-bpeF-oprC operon. The llpE gene encodes a putative lipase/esterase of unknown function. We show that in a bpeT mutant llpE is constitutively co-transcribed with bpeE-bpeF-oprC. As expected from previous studies with B. cenocepacia, deletion of llpE does not affect antibiotic efflux. Using transcriptional bpeE'-lacZ fusions, we demonstrate that the 188 bp bpeT-llpE intergenic region located between bpeT and the llpE-bpeE-bpeF-oprC operon contains regulatory elements needed for control of bpeT and llpE-bpeE-bpeF-oprC operon expression. By native polyacrylamide gel electrophoresis and electrophoretic mobility shift assays with purified recombinant BpeT and BpeS proteins, we show BpeT and BpeS form oligomers that share a 14 bp binding site overlapping the essential region required for llpE-bpeE-bpeF-oprC expression. The binding site contains the conserved T-N11-A LTTR box motif involved in binding of LysR proteins, which in concert with two other possible LTTR boxes may mediate BpeT and BpeS regulation of BpeEF-OprC expression. These studies form the basis for further investigation of BpeEF-OprC expression and regulation at the molecular level by yet unknown external stimuli.
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Affiliation(s)
- Katherine A Rhodes
- 1Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA.,3Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.,2Department of Molecular Genetics and Microbiology, College of Medicine, Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.,†Present address: University of Arizona BIO5 Institute, Tucson, AZ 85721, USA
| | - Nawarat Somprasong
- 1Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA.,2Department of Molecular Genetics and Microbiology, College of Medicine, Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.,3Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Nicole L Podnecky
- 1Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA.,‡Present address: Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Tromsø, 9037 Tromsø, Norway
| | - Takehiko Mima
- 1Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA.,§Present address: Department of Bacteriology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Sunisa Chirakul
- 2Department of Molecular Genetics and Microbiology, College of Medicine, Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.,3Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Herbert P Schweizer
- 3Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.,2Department of Molecular Genetics and Microbiology, College of Medicine, Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.,1Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
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Price EP, Viberg LT, Kidd TJ, Bell SC, Currie BJ, Sarovich DS. Transcriptomic analysis of longitudinal Burkholderia pseudomallei infecting the cystic fibrosis lung. Microb Genom 2018; 4. [PMID: 29989529 PMCID: PMC6159556 DOI: 10.1099/mgen.0.000194] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The melioidosis bacterium, Burkholderia pseudomallei, is increasingly being recognised as a pathogen in patients with cystic fibrosis (CF). We have recently catalogued genome-wide variation of paired, isogenic B. pseudomallei isolates from seven Australasian CF cases, which were collected between 4 and 55 months apart. Here, we extend this investigation by documenting the transcriptomic changes in B. pseudomallei in five cases. Following growth in an artificial CF sputum medium, four of the five paired isolates exhibited significant differential gene expression (DE) that affected between 32 and 792 genes. The greatest number of DE events was observed between the strains from patient CF9, consistent with the hypermutator status of the latter strain, which is deficient in the DNA mismatch repair protein MutS. Two patient isolates harboured duplications that concomitantly increased expression of the β-lactamase-encoding gene penA, and a 35 kb deletion in another abolished expression of 29 genes. Convergent expression profiles in the chronically-adapted isolates identified two significantly downregulated and 17 significantly upregulated loci, including the resistance-nodulation-division (RND) efflux pump BpeEF-OprC, the quorum-sensing hhqABCDE operon, and a cyanide- and pyocyanin-insensitive cytochrome bd quinol oxidase. These convergent pathoadaptations lead to increased expression of pathways that may suppress competing bacterial and fungal pathogens, and that enhance survival in oxygen-restricted environments, the latter of which may render conventional antibiotics less effective in vivo. Treating chronically adapted B. pseudomallei infections with antibiotics designed to target anaerobic infections, such as the nitroimidazole class of antibiotics, may significantly improve pathogen eradication attempts by exploiting this Achilles heel.
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Affiliation(s)
- Erin P Price
- 1Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia.,2Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Linda T Viberg
- 2Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Timothy J Kidd
- 3Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.,4School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
| | - Scott C Bell
- 3Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.,5QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.,6Department of Thoracic Medicine, The Prince Charles Hospital, Chermside, QLD, Australia
| | - Bart J Currie
- 2Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia.,7Department of Infectious Diseases and Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Derek S Sarovich
- 1Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia.,2Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
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31
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Duong LT, Schwarz S, Gross H, Breitbach K, Hochgräfe F, Mostertz J, Eske-Pogodda K, Wagner GE, Steinmetz I, Kohler C. GvmR - A Novel LysR-Type Transcriptional Regulator Involved in Virulence and Primary and Secondary Metabolism of Burkholderia pseudomallei. Front Microbiol 2018; 9:935. [PMID: 29867844 PMCID: PMC5964159 DOI: 10.3389/fmicb.2018.00935] [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: 03/05/2018] [Accepted: 04/23/2018] [Indexed: 01/22/2023] Open
Abstract
Burkholderia pseudomallei is a soil-dwelling bacterium able to survive not only under adverse environmental conditions, but also within various hosts which can lead to the disease melioidosis. The capability of B. pseudomallei to adapt to environmental changes is facilitated by the large number of regulatory proteins encoded by its genome. Among them are more than 60 uncharacterized LysR-type transcriptional regulators (LTTRs). Here we analyzed a B. pseudomallei mutant harboring a transposon in the gene BPSL0117 annotated as a LTTR, which we named gvmR (globally acting virulence and metabolism regulator). The gvmR mutant displayed a growth defect in minimal medium and macrophages in comparison with the wild type. Moreover, disruption of gvmR rendered B. pseudomallei avirulent in mice indicating a critical role of GvmR in infection. These defects of the mutant were rescued by ectopic expression of gvmR. To identify genes whose expression is modulated by GvmR, global transcriptome analysis of the B. pseudomallei wild type and gvmR mutant was performed using whole genome tiling microarrays. Transcript levels of 190 genes were upregulated and 141 genes were downregulated in the gvmR mutant relative to the wild type. Among the most downregulated genes in the gvmR mutant were important virulence factor genes (T3SS3, T6SS1, and T6SS2), which could explain the virulence defect of the gvmR mutant. In addition, expression of genes related to amino acid synthesis, glyoxylate shunt, iron-sulfur cluster assembly, and syrbactin metabolism (secondary metabolite) was decreased in the mutant. On the other hand, inactivation of GvmR increased expression of genes involved in pyruvate metabolism, ATP synthesis, malleobactin, and porin genes. Quantitative real-time PCR verified the differential expression of 27 selected genes. In summary, our data show that GvmR acts as an activating and repressing global regulator that is required to coordinate expression of a diverse set of metabolic and virulence genes essential for the survival in the animal host and under nutrient limitation.
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Affiliation(s)
- Linh Tuan Duong
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine Greifswald, Greifswald, Germany
| | - Sandra Schwarz
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany
| | - Harald Gross
- Department of Pharmaceutical Biology, Pharmaceutical Institute, Eberhard Karls University of Tübingen, Tübingen, Germany.,German Centre for Infection Research, Partner Site Tübingen, Tübingen, Germany
| | - Katrin Breitbach
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine Greifswald, Greifswald, Germany
| | - Falko Hochgräfe
- Competence Center Functional Genomics, Junior Research Group Pathoproteomics, University of Greifswald, Greifswald, Germany
| | - Jörg Mostertz
- Competence Center Functional Genomics, Junior Research Group Pathoproteomics, University of Greifswald, Greifswald, Germany
| | - Kristin Eske-Pogodda
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine Greifswald, Greifswald, Germany
| | - Gabriel E Wagner
- Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Ivo Steinmetz
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine Greifswald, Greifswald, Germany.,Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Christian Kohler
- Friedrich Loeffler Institute of Medical Microbiology, University Medicine Greifswald, Greifswald, Germany
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Abstract
Burkholderia pseudomallei is a Gram-negative environmental bacterium and the aetiological agent of melioidosis, a life-threatening infection that is estimated to account for ∼89,000 deaths per year worldwide. Diabetes mellitus is a major risk factor for melioidosis, and the global diabetes pandemic could increase the number of fatalities caused by melioidosis. Melioidosis is endemic across tropical areas, especially in southeast Asia and northern Australia. Disease manifestations can range from acute septicaemia to chronic infection, as the facultative intracellular lifestyle and virulence factors of B. pseudomallei promote survival and persistence of the pathogen within a broad range of cells, and the bacteria can manipulate the host's immune responses and signalling pathways to escape surveillance. The majority of patients present with sepsis, but specific clinical presentations and their severity vary depending on the route of bacterial entry (skin penetration, inhalation or ingestion), host immune function and bacterial strain and load. Diagnosis is based on clinical and epidemiological features as well as bacterial culture. Treatment requires long-term intravenous and oral antibiotic courses. Delays in treatment due to difficulties in clinical recognition and laboratory diagnosis often lead to poor outcomes and mortality can exceed 40% in some regions. Research into B. pseudomallei is increasing, owing to the biothreat potential of this pathogen and increasing awareness of the disease and its burden; however, better diagnostic tests are needed to improve early confirmation of diagnosis, which would enable better therapeutic efficacy and survival.
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Affiliation(s)
- W Joost Wiersinga
- Department of Medicine, Division of Infectious Diseases, Academic Medical Center, Meibergdreef 9, Rm. G2-132, 1105 AZ Amsterdam, The Netherlands
- Centre for Experimental and Molecular Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Harjeet S Virk
- Centre for Experimental and Molecular Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Alfredo G Torres
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Bart J Currie
- Menzies School of Health Research, Charles Darwin University and Royal Darwin Hospital, Darwin, Australia
| | - Sharon J Peacock
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - David A B Dance
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
- Lao-Oxford-Mahosot Hospital Wellcome Trust Research Unit, Vientiane, Lao People's Democratic Republic
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Direk Limmathurotsakul
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- Department of Tropical Hygiene and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
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Identification of sRNA mediated responses to nutrient depletion in Burkholderia pseudomallei. Sci Rep 2017; 7:17173. [PMID: 29215024 PMCID: PMC5719362 DOI: 10.1038/s41598-017-17356-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/22/2017] [Indexed: 12/16/2022] Open
Abstract
The Burkholderia genus includes many species that are known to survive in diverse environmental conditions including low nutrient environments. One species, Burkholderia pseudomallei is a versatile pathogen that can survive in a wide range of hosts and environmental conditions. In this study, we investigated how a nutrient depleted growth environment evokes sRNA mediated responses by B. pseudomallei. Computationally predicted B. pseudomallei D286 sRNAs were mapped to RNA-sequencing data for cultures grown under two conditions: (1) BHIB as a nutrient rich media reference environment and (2) M9 media as a nutrient depleted stress environment. The sRNAs were further selected to identify potentially cis-encoded systems by investigating their possible interactions with their flanking genes. The mappings of predicted sRNA genes and interactions analysis to their flanking genes identified 12 sRNA candidates that may possibly have cis-acting regulatory roles that are associated to a nutrient depleted growth environment. Our approach can be used for identifying novel sRNA genes and their possible role as cis-mediated regulatory systems.
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34
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Luan OG, Yam H, Samian R, Wajidi MFF, Mahadi NM, Mohamad S, Najimudin N. Hypothetical Protein BPSL3393 of Burkholderia pseudomallei is Involved in Ethanolamine Catabolism. Trop Life Sci Res 2017; 28:57-74. [PMID: 28890761 PMCID: PMC5584837 DOI: 10.21315/tlsr2017.28.2.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Burkholderia pseudomallei is a soil-dwelling bacterium that causes a globally emerging disease called melioidosis. Approximately one third of the in silico annotated genes in its genome are classified as hypothetical genes. This group of genes is difficult to be functionally characterised partly due to the absence of noticeable phenotypes under conventional laboratory settings. A bioinformatic survey of hypothetical genes revealed a gene designated as BPSL3393 that putatively encodes a small protein of 11 kDA with a CoA binding domain. BPSL3393 is conserved in all the B. pseudomallei genomes as well as various in other species within the genus Burkholderia. Taking into consideration that CoA plays a ubiquitous metabolic role in all life forms, characterisation of BPSL3393 may uncover a previously over-looked metabolic feature of B. pseudomallei. The gene was deleted from the genome using a double homologous recombination approach yielding a null mutant. The BPSL3393 mutant showed no difference in growth rate with the wild type under rich and minimal growth conditions. An extensive metabolic phenotyping test was performed involving 95 metabolic substrates. The deletion mutant of BPSL3393 was severely impaired in its ethanolamine metabolism. The growth rate of the mutant was attenuated when ethanolamine was used as the sole carbon source. A transcriptional analysis of the ethanolamine metabolism genes showed that they were down-regulated in the BPSL3393 mutant. This seemed to suggest that BPSL3393 functions as a positive regulator for ethanolamine metabolism.
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Affiliation(s)
- Ooi Gim Luan
- School of Biological Sciences, Universiti Sains Malaysia, 11800 USM Pulau Pinang, Malaysia
| | - Hokchai Yam
- School of Biological Sciences, Universiti Sains Malaysia, 11800 USM Pulau Pinang, Malaysia.,Faculty of Applied Sciences, UCSI University, Jalan Menara Gading, 56000 Kuala Lumpur, Malaysia
| | - Razip Samian
- School of Biological Sciences, Universiti Sains Malaysia, 11800 USM Pulau Pinang, Malaysia
| | | | | | - Suriani Mohamad
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM Pulau Pinang, Malaysia
| | - Nazalan Najimudin
- School of Biological Sciences, Universiti Sains Malaysia, 11800 USM Pulau Pinang, Malaysia
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35
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Relationships Between Resistance and Virulence in Burkholderia pseudomallei. CURRENT TROPICAL MEDICINE REPORTS 2017. [DOI: 10.1007/s40475-017-0119-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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36
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Antibodies against In Vivo-Expressed Antigens Are Sufficient To Protect against Lethal Aerosol Infection with Burkholderia mallei and Burkholderia pseudomallei. Infect Immun 2017; 85:IAI.00102-17. [PMID: 28507073 DOI: 10.1128/iai.00102-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 05/08/2017] [Indexed: 12/22/2022] Open
Abstract
Burkholderia mallei, a facultative intracellular bacterium and tier 1 biothreat, causes the fatal zoonotic disease glanders. The organism possesses multiple genes encoding autotransporter proteins, which represent important virulence factors and targets for developing countermeasures in pathogenic Gram-negative bacteria. In the present study, we investigated one of these autotransporters, BatA, and demonstrate that it displays lipolytic activity, aids in intracellular survival, is expressed in vivo, elicits production of antibodies during infection, and contributes to pathogenicity in a mouse aerosol challenge model. A mutation in the batA gene of wild-type strain ATCC 23344 was found to be particularly attenuating, as BALB/c mice infected with the equivalent of 80 median lethal doses cleared the organism. This finding prompted us to test the hypothesis that vaccination with the batA mutant strain elicits protective immunity against subsequent infection with wild-type bacteria. We discovered that not only does vaccination provide high levels of protection against lethal aerosol challenge with B. mallei ATCC 23344, it also protects against infection with multiple isolates of the closely related organism and causative agent of melioidosis, Burkholderia pseudomallei Passive-transfer experiments also revealed that the protective immunity afforded by vaccination with the batA mutant strain is predominantly mediated by IgG antibodies binding to antigens expressed exclusively in vivo Collectively, our data demonstrate that BatA is a target for developing medical countermeasures and that vaccination with a mutant lacking expression of the protein provides a platform to gain insights regarding mechanisms of protective immunity against B. mallei and B. pseudomallei, including antigen discovery.
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37
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Schroeder CLC, Narra HP, Sahni A, Khanipov K, Patel J, Fofanov Y, Sahni SK. Transcriptional profiling of Rickettsia prowazekii coding and non-coding transcripts during in vitro host-pathogen and vector-pathogen interactions. Ticks Tick Borne Dis 2017; 8:827-836. [PMID: 28709615 DOI: 10.1016/j.ttbdis.2017.06.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/13/2017] [Accepted: 06/15/2017] [Indexed: 01/09/2023]
Abstract
Natural pathogen transmission of Rickettsia prowazekii, the etiologic agent of epidemic typhus, to humans is associated with arthropods, including human body lice, ticks, and ectoparasites of eastern flying squirrel. Recently, we have documented the presence of small RNAs in Rickettsia species and expression of R. prowazekii sRNAs during infection of cultured human microvascular endothelial cells (HMECs), which represent the primary target cells during human infections. Bacterial noncoding transcripts are now well established as critical post-transcriptional regulators of virulence and adaptation mechanisms in varying host environments. Despite their importance, little is known about the expression profile and regulatory activities of R. prowazekii sRNAs (Rp_sRs) in different host cells encountered as part of the natural life-cycle. To investigate the sRNA expression profile of R. prowazekii during infection of arthropod host cells, we employed an approach combining in vitro infection, bioinformatics, RNA sequencing, and PCR-based quantitation. Global analysis of R. prowazekii transcriptome by strand-specific RNA sequencing enabled us to identify 67 cis-acting (antisense) and 26 trans-acting (intergenic) Rp_sRs expressed during the infection of Amblyomma americanum (AAE2) cells. Comparative evaluation of expression during R. prowazekii infection of HMECs and AAE2 cells by quantitative RT-PCR demonstrated significantly higher expression of four selected Rp_sRs in tick AAE2 cells. Examination of the coding transcriptome revealed differential up-regulation of >150 rickettsial genes in either HMECs or AAE2 cells and yielded evidence for host cell-dependent utilization of alternative transcription start sites by 18 rickettsial genes. Our results thus suggest noticeable differences in the expression of both Rp_sRs as well as the coding transcriptome and the exploitation of multiple transcription initiation sites for select genes during the infection of human endothelium and tick vector cells as the host and yield new insights into rickettsial virulence and transmission mechanisms.
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Affiliation(s)
- Casey L C Schroeder
- Department of Pathology, University of Texas Medical Branch, 301 University Boulevard Galveston, TX 77555, USA.
| | - Hema P Narra
- Department of Pathology, University of Texas Medical Branch, 301 University Boulevard Galveston, TX 77555, USA.
| | - Abha Sahni
- Department of Pathology, University of Texas Medical Branch, 301 University Boulevard Galveston, TX 77555, USA.
| | - Kamil Khanipov
- Department of Pharmacology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.
| | - Jignesh Patel
- Department of Pathology, University of Texas Medical Branch, 301 University Boulevard Galveston, TX 77555, USA.
| | - Yuriy Fofanov
- Department of Pharmacology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.
| | - Sanjeev K Sahni
- Department of Pathology, University of Texas Medical Branch, 301 University Boulevard Galveston, TX 77555, USA.
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38
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Perumal Samy R, Stiles BG, Sethi G, Lim LHK. Melioidosis: Clinical impact and public health threat in the tropics. PLoS Negl Trop Dis 2017; 11:e0004738. [PMID: 28493905 PMCID: PMC5426594 DOI: 10.1371/journal.pntd.0004738] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
This review briefly summarizes the geographical distribution and clinical impact of melioidosis, especially in the tropics. Burkholderia pseudomallei (a gram-negative bacterium) is the major causative agent for melioidosis, which is prevalent in Singapore, Malaysia, Thailand, Vietnam, and Northern Australia. Melioidosis patients are increasingly being recognized in other parts of the world. The bacteria are intrinsically resistant to many antimicrobial agents, but prolonged treatment, especially with combinations of antibiotics, may be effective. Despite therapy, the overall case fatality rate of septicemia in melioidosis remains significantly high. Intracellular survival of the bacteria within macrophages may progress to chronic infections, and about 10% of patients suffer relapses. In the coming decades, melioidosis will increasingly afflict travelers throughout many global regions. Clinicians managing travelers returning from the subtropics or tropics with severe pneumonia or septicemia should consider acute melioidosis as a differential diagnosis. Patients with open skin wounds, diabetes, or chronic renal disease are at higher risk for melioidosis and should avoid direct contact with soil and standing water in endemic regions. Furthermore, there are fears that B. pseudomallei may be used as a biological weapon. Technological advancements in molecular diagnostics and antibiotic therapy are improving the disease outcomes in endemic areas throughout Asia. Research and development efforts on vaccine candidates against melioidosis are ongoing.
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Affiliation(s)
- Ramar Perumal Samy
- Department of Physiology, NUS Immunology Programme, Centre for Life Sciences, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore
| | - Bradley G. Stiles
- Integrated Toxicology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - Gautam Sethi
- Department of Pharmacology, Yong Loo Lin School of Medicine, NUHS, National University of Singapore, Singapore
| | - Lina H. K. Lim
- Department of Physiology, NUS Immunology Programme, Centre for Life Sciences, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore
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39
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Chewapreecha C, Holden MTG, Vehkala M, Välimäki N, Yang Z, Harris SR, Mather AE, Tuanyok A, De Smet B, Le Hello S, Bizet C, Mayo M, Wuthiekanun V, Limmathurotsakul D, Phetsouvanh R, Spratt BG, Corander J, Keim P, Dougan G, Dance DAB, Currie BJ, Parkhill J, Peacock SJ. Global and regional dissemination and evolution of Burkholderia pseudomallei. Nat Microbiol 2017; 2:16263. [PMID: 28112723 PMCID: PMC5300093 DOI: 10.1038/nmicrobiol.2016.263] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 12/08/2016] [Indexed: 11/09/2022]
Abstract
The environmental bacterium Burkholderia pseudomallei causes an estimated 165,000 cases of human melioidosis per year worldwide and is also classified as a biothreat agent. We used whole genome sequences of 469 B. pseudomallei isolates from 30 countries collected over 79 years to explore its geographic transmission. Our data point to Australia as an early reservoir, with transmission to Southeast Asia followed by onward transmission to South Asia and East Asia. Repeated reintroductions were observed within the Malay Peninsula and between countries bordered by the Mekong River. Our data support an African origin of the Central and South American isolates with introduction of B. pseudomallei into the Americas between 1650 and 1850, providing a temporal link with the slave trade. We also identified geographically distinct genes/variants in Australasian or Southeast Asian isolates alone, with virulence-associated genes being among those over-represented. This provides a potential explanation for clinical manifestations of melioidosis that are geographically restricted.
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Affiliation(s)
- Claire Chewapreecha
- Department of Medicine, University of Cambridge, UK
- Wellcome Trust Sanger Institute, Cambridge, UK
- Bioinformatics and Systems Biology Program, School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi, Thailand
| | - Matthew T. G. Holden
- Wellcome Trust Sanger Institute, Cambridge, UK
- School of Medicine, University of St Andrew, UK
| | - Minna Vehkala
- Department of Mathematics and Statistics, University of Helsinki, Finland
| | - Niko Välimäki
- Department of Medical and Clinical Genetics, Genome-Scale Biology Research Program, University of Helsinki, Finland
| | - Zhirong Yang
- Department of Mathematics and Statistics, University of Helsinki, Finland
| | | | | | | | - Birgit De Smet
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Laboratory of Microbiology, Faculty of Sciences, Ghent University, Belgium
| | - Simon Le Hello
- Department of Infection and Epidemiology, Enteric bacteria pathogen Unit, Institut Pasteur, Paris, France
| | - Chantal Bizet
- Department of Microbiology, Collection of Institut Pasteur, Institut Pasteur, Paris, France
| | - Mark Mayo
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University and Royal Darwin Hospital, Darwin, Australia
| | - Vanaporn Wuthiekanun
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Direk Limmathurotsakul
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine & Global Health, University of Oxford, UK
| | - Rattanaphone Phetsouvanh
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot, Vientiane, Lao PDR
| | - Brian G Spratt
- Department of Infectious Disease Epidemiology, Imperial College, UK
| | - Jukka Corander
- Department of Mathematics and Statistics, University of Helsinki, Finland
- Department of Biostatistics, University of Oslo, Oslo, Norway
| | - Paul Keim
- Center for Microbial Genetics and Genomics, Northern Arizona University, USA
| | - Gordon Dougan
- Department of Medicine, University of Cambridge, UK
- Wellcome Trust Sanger Institute, Cambridge, UK
| | - David A. B. Dance
- Centre for Tropical Medicine & Global Health, University of Oxford, UK
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot, Vientiane, Lao PDR
- London School of Hygiene and Tropical Medicine, UK
| | - Bart J Currie
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University and Royal Darwin Hospital, Darwin, Australia
| | | | - Sharon J. Peacock
- Department of Medicine, University of Cambridge, UK
- Wellcome Trust Sanger Institute, Cambridge, UK
- London School of Hygiene and Tropical Medicine, UK
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40
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Vanaporn M, Sarkar-Tyson M, Kovacs-Simon A, Ireland PM, Pumirat P, Korbsrisate S, Titball RW, Butt A. Trehalase plays a role in macrophage colonization and virulence of Burkholderia pseudomallei in insect and mammalian hosts. Virulence 2017; 8:30-40. [PMID: 27367830 PMCID: PMC5963195 DOI: 10.1080/21505594.2016.1199316] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/01/2016] [Accepted: 06/03/2016] [Indexed: 10/21/2022] Open
Abstract
Trehalose is a disaccharide formed from two glucose molecules. This sugar molecule can be isolated from a range of organisms including bacteria, fungi, plants and invertebrates. Trehalose has a variety of functions including a role as an energy storage molecule, a structural component of glycolipids and plays a role in the virulence of some microorganisms. There are many metabolic pathways that control the biosynthesis and degradation of trehalose in different organisms. The enzyme trehalase forms part of a pathway that converts trehalose into glucose. In this study we set out to investigate whether trehalase plays a role in both stress adaptation and virulence of Burkholderia pseudomallei. We show that a trehalase deletion mutant (treA) had increased tolerance to thermal stress and produced less biofilm than the wild type B. pseudomallei K96243 strain. We also show that the ΔtreA mutant has reduced ability to survive in macrophages and that it is attenuated in both Galleria mellonella (wax moth larvae) and a mouse infection model. This is the first report that trehalase is important for bacterial virulence.
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Affiliation(s)
- Muthita Vanaporn
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Andrea Kovacs-Simon
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Philip M. Ireland
- CBR Division, Defense Science and Technology Laboratory, Salisbury, UK
| | - Pornpan Pumirat
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sunee Korbsrisate
- Department of Immunology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Richard W. Titball
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Aaron Butt
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
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Techawiwattanaboon T, Chareonsudjai S. A predicted cation transporter protein, BPSS1228, is involved in intracellular behaviour of Burkholderia pseudomallei in a human lung epithelial cell line (A549). FEMS Microbiol Lett 2016; 363:fnw259. [PMID: 28003338 DOI: 10.1093/femsle/fnw259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 06/10/2016] [Accepted: 11/10/2016] [Indexed: 12/15/2022] Open
Abstract
Burkholderia pseudomallei causes melioidosis, a potentially fatal infectious disease in tropical and subtropical countries worldwide. The intracellular behaviour of this pathogen in host cells has been reported to impact the severity of melioidosis, including the development of septicaemia, a consequence of pneumonia melioidosis. We previously identified a predicted cation transporter protein, BPSS1228, that participates in the transitional stage of this intracellular pathogen. For further analysis, in this study B. pseudomallei bpss1228 mutant and complemented strains were constructed and bacterial infectivity on human lung epithelial cells, A549, investigated in vitro Burkholderia pseudomallei bpss1228 mutant showed impaired bacterial adhesion and invasion into A549 cells compared with wild-type strain, while the deficient phenotypes were restored to wild-type levels by the complemented strain. Additionally, the inactivation of bpss1228 in the mutant strain affected flagella-based swimming on a semi-solid surface and resistance to acid stresses simulating intracellular environments. These observations of BPSS1228 relating to B. pseudomallei infection strategies shed a new light on its association with intracellular B. pseudomallei during the interaction with host cells.
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Affiliation(s)
- Teerasit Techawiwattanaboon
- Department of Microbiology, Faculty of Medicine, Melioidosis Research Center and Biofilm Research Group, Khon Kaen University, Khon Kaen, Thailand
| | - Sorujsiri Chareonsudjai
- Department of Microbiology, Faculty of Medicine, Melioidosis Research Center and Biofilm Research Group, Khon Kaen University, Khon Kaen, Thailand
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Custódio R, McLean CJ, Scott AE, Lowther J, Kennedy A, Clarke DJ, Campopiano DJ, Sarkar-Tyson M, Brown AR. Characterization of secreted sphingosine-1-phosphate lyases required for virulence and intracellular survival of Burkholderia pseudomallei. Mol Microbiol 2016; 102:1004-1019. [PMID: 27632710 DOI: 10.1111/mmi.13531] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2016] [Indexed: 01/09/2023]
Abstract
Sphingosine-1-phosphate (S1P), a bioactive sphingolipid metabolite, plays a critical role in the orchestration of immune responses. S1P levels within the mammalian host are tightly regulated, in part through the activity of S1P lyase (S1PL) which catalyses its irreversible degradation. Herein, we describe the identification and characterization of secreted S1PL orthologues encoded by the facultative intracellular bacteria Burkholderia pseudomallei and Burkholderia thailandensis. These bacterial orthologues exhibited S1PL enzymatic activity, functionally complemented an S1PL-deficient yeast strain and conferred resistance to the antimicrobial sphingolipid D-erythro-sphingosine. We report that secretion of these bacterial S1PLs is pH-dependent, and is observed during intracellular infection. S1PL-deficient mutants displayed impaired intracellular replication in murine macrophages (associated with an inability to evade the maturing phagosome) and were significantly attenuated in murine and larval infection models. Furthermore, treatment of Burkholderia-infected macrophages with either S1P or a selective agonist of S1P receptor 1 enhanced bacterial colocalisation with LAMP-1 and reduced their intracellular survival. In summary, our studies confirm bacterial-encoded S1PL as a critical virulence determinant of B. pseudomallei and B. thailandensis, further highlighting the pivotal role of S1P in host-pathogen interactions. In addition, our data suggest that S1P pathway modulators have potential for the treatment of intracellular infection.
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Affiliation(s)
- Rafael Custódio
- Biosciences, College of Life and Environmental Sciences, University of Exeter, UK
| | | | - Andrew E Scott
- Microbiology, Defence Science and Technology Laboratory, Porton Down, UK
| | | | | | | | | | - Mitali Sarkar-Tyson
- Microbiology, Defence Science and Technology Laboratory, Porton Down, UK.,Marshall Centre for Infectious Diseases and Training, School of Pathology and Laboratory Medicine, University of Western Australia, WA 6009, Australia
| | - Alan R Brown
- Biosciences, College of Life and Environmental Sciences, University of Exeter, UK
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Champion OL, Gourlay LJ, Scott AE, Lassaux P, Conejero L, Perletti L, Hemsley C, Prior J, Bancroft G, Bolognesi M, Titball RW. Immunisation with proteins expressed during chronic murine melioidosis provides enhanced protection against disease. Vaccine 2016; 34:1665-71. [PMID: 26917010 DOI: 10.1016/j.vaccine.2016.02.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/29/2016] [Accepted: 02/15/2016] [Indexed: 11/20/2022]
Abstract
There is an urgent need for an effective vaccine against human disease caused by Burkholderia pseudomallei, and although a wide range of candidates have been tested in mice none provide high level protection. We considered this might reflect the inability of these vaccine candidates to protect against chronic disease. Using Q-RT PCR we have identified 6 genes which are expressed in bacteria colonising spleens and lungs of chronically infected mice. Three of the genes (BPSL1897, BPSL3369 and BPSL2287) have been expressed in Escherichia coli and the encoded proteins purified. We have also included BPSL2765, a protein known to induce immune responses associated with a reduced incidence of chronic/recurrent disease in humans. Immunisation of mice with a combination of these antigens resulted in the induction of antibody responses against all of the proteins. Compared with mice immunised with capsular polysaccharide or LolC protein, mice immunised with the combination of chronic stage antigens showed enhanced protection against experimental disease in mice.
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Affiliation(s)
- Olivia L Champion
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Louise J Gourlay
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Andrew E Scott
- Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, UK
| | - Patricia Lassaux
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Laura Conejero
- London School of Hygiene and Tropical Medicine, Keppler Street, London WC1E 7HT, UK
| | - Lucia Perletti
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Claudia Hemsley
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Joann Prior
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK; Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, UK
| | - Gregory Bancroft
- London School of Hygiene and Tropical Medicine, Keppler Street, London WC1E 7HT, UK
| | - Martino Bolognesi
- Department of Biosciences, University of Milan, Milan 20133, Italy; Consiglio Nazionale delle Ricerche, Institute of Biophysics, University of Milan, Milan 20133, Italy
| | - Richard W Titball
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK.
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Willcocks SJ, Denman CC, Atkins HS, Wren BW. Intracellular replication of the well-armed pathogen Burkholderia pseudomallei. Curr Opin Microbiol 2016; 29:94-103. [DOI: 10.1016/j.mib.2015.11.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 11/27/2015] [Accepted: 11/30/2015] [Indexed: 12/31/2022]
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Lau SKP, Lam CW, Curreem SOT, Lee KC, Chow WN, Lau CCY, Sridhar S, Wong SCY, Martelli P, Hui SW, Yuen KY, Woo PCY. Metabolomic profiling of Burkholderia pseudomallei using UHPLC-ESI-Q-TOF-MS reveals specific biomarkers including 4-methyl-5-thiazoleethanol and unique thiamine degradation pathway. Cell Biosci 2015; 5:26. [PMID: 26097677 PMCID: PMC4475313 DOI: 10.1186/s13578-015-0018-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 05/22/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Burkholderia pseudomallei is an emerging pathogen that causes melioidosis, a serious and potentially fatal disease which requires prolonged antibiotics to prevent relapse. However, diagnosis of melioidosis can be difficult, especially in culture-negative cases. While metabolomics represents an uprising tool for studying infectious diseases, there were no reports on its applications to B. pseudomallei. To search for potential specific biomarkers, we compared the metabolomics profiles of culture supernatants of B. pseudomallei (15 strains), B. thailandensis (3 strains), B. cepacia complex (14 strains), P. aeruginosa (4 strains) and E. coli (3 strains), using ultra-high performance liquid chromatography-electrospray ionization-quadruple time-of-flight mass spectrometry (UHPLC-ESI-Q-TOF-MS). Multi- and univariate analyses were used to identify specific metabolites in B. pseudomallei. RESULTS Principal component and partial-least squares discrimination analysis readily distinguished the metabolomes between B. pseudomallei and other bacterial species. Using multi-variate and univariate analysis, eight metabolites with significantly higher levels in B. pseudomallei were identified. Three of the eight metabolites were identified by MS/MS, while five metabolites were unidentified against database matching, suggesting that they may be potentially novel compounds. One metabolite, m/z 144.048, was identified as 4-methyl-5-thiazoleethanol, a degradation product of thiamine (vitamin B1), with molecular formula C6H9NOS by database searches and confirmed by MS/MS using commercially available authentic chemical standard. Two metabolites, m/z 512.282 and m/z 542.2921, were identified as tetrapeptides, Ile-His-Lys-Asp with molecular formula C22H37N7O7 and Pro-Arg-Arg-Asn with molecular formula C21H39N11O6, respectively. To investigate the high levels of 4-methyl-5-thiazoleethanol in B. pseudomallei, we compared the thiamine degradation pathways encoded in genomes of B. pseudomallei and B. thailandensis. While both B. pseudomallei and B. thailandensis possess thiaminase I which catalyzes degradation of thiamine to 4-methyl-5-thiazoleethanol, thiM, which encodes hydroxyethylthiazole kinase responsible for degradation of 4-methyl-5-thiazoleethanol, is present and expressed in B. thailandensis as detected by PCR/RT-PCR, but absent or not expressed in all B. pseudomallei strains. This suggests that the high 4-methyl-5-thiazoleethanol level in B. pseudomallei is likely due to the absence of hydroxyethylthiazole kinase and hence reduced downstream degradation. CONCLUSION Eight novel biomarkers, including 4-methyl-5-thiazoleethanol and two tetrapeptides, were identified in the culture supernatant of B. pseudomallei.
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Affiliation(s)
- Susanna K P Lau
- State Key Laboratory of Emerging Infectious Diseases, Department of Microbiology, The University of Hong Kong, Room 423, University Pathology Building, Queen Mary Hospital, Pok Fu Lam, Hong Kong ; Research Centre of Infection and Immunology, The University of Hong Kong, Pok Fu Lam, Hong Kong ; Carol Yu Centre for Infection, The University of Hong Kong, Pok Fu Lam, Hong Kong ; Department of Microbiology, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Ching-Wan Lam
- Department of Pathology, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Shirly O T Curreem
- Department of Microbiology, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Kim-Chung Lee
- Department of Microbiology, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Wang-Ngai Chow
- Department of Microbiology, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Candy C Y Lau
- Department of Microbiology, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Siddharth Sridhar
- Department of Microbiology, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Sally C Y Wong
- Department of Microbiology, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | | | - Suk-Wai Hui
- Ocean Park Corporation, Aqua City, Hong Kong
| | - Kwok-Yung Yuen
- State Key Laboratory of Emerging Infectious Diseases, Department of Microbiology, The University of Hong Kong, Room 423, University Pathology Building, Queen Mary Hospital, Pok Fu Lam, Hong Kong ; Research Centre of Infection and Immunology, The University of Hong Kong, Pok Fu Lam, Hong Kong ; Carol Yu Centre for Infection, The University of Hong Kong, Pok Fu Lam, Hong Kong ; Department of Microbiology, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Patrick C Y Woo
- State Key Laboratory of Emerging Infectious Diseases, Department of Microbiology, The University of Hong Kong, Room 423, University Pathology Building, Queen Mary Hospital, Pok Fu Lam, Hong Kong ; Research Centre of Infection and Immunology, The University of Hong Kong, Pok Fu Lam, Hong Kong ; Carol Yu Centre for Infection, The University of Hong Kong, Pok Fu Lam, Hong Kong ; Department of Microbiology, The University of Hong Kong, Pok Fu Lam, Hong Kong
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Zimmerman SM, Michel F, Hogan RJ, Lafontaine ER. The Autotransporter BpaB Contributes to the Virulence of Burkholderia mallei in an Aerosol Model of Infection. PLoS One 2015; 10:e0126437. [PMID: 25993100 PMCID: PMC4438868 DOI: 10.1371/journal.pone.0126437] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/02/2015] [Indexed: 02/06/2023] Open
Abstract
Burkholderia mallei is a highly pathogenic bacterium that causes the zoonosis glanders. Previous studies indicated that the genome of the organism contains eight genes specifying autotransporter proteins, which are important virulence factors of Gram-negative bacteria. In the present study, we report the characterization of one of these autotransporters, BpaB. Database searches identified the bpaB gene in ten B. mallei isolates and the predicted proteins were 99-100% identical. Comparative sequence analyses indicate that the gene product is a trimeric autotransporter of 1,090 amino acids with a predicted molecular weight of 105-kDa. Consistent with this finding, we discovered that recombinant bacteria expressing bpaB produce a protein of ≥300-kDa on their surface that is reactive with a BpaB-specific monoclonal antibody. Analysis of sera from mice infected with B. mallei indicated that animals produce antibodies against BpaB during the course of disease, thus establishing production of the autotransporter in vivo. To gain insight on its role in virulence, we inactivated the bpaB gene of B. mallei strain ATCC 23344 and determined the median lethal dose of the mutant in a mouse model of aerosol infection. These experiments revealed that the bpaB mutation attenuates virulence 8-14 fold. Using a crystal violet-based assay, we also discovered that constitutive production of BpaB on the surface of B. mallei promotes biofilm formation. To our knowledge, this is the first report of a biofilm factor for this organism.
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Affiliation(s)
- Shawn M. Zimmerman
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, United States of America
| | - Frank Michel
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia College of Veterinary Medicine, Athens, GA, United States of America
| | - Robert J. Hogan
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, United States of America
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia College of Veterinary Medicine, Athens, GA, United States of America
| | - Eric R. Lafontaine
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, United States of America
- * E-mail:
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Reynolds C, Goudet A, Jenjaroen K, Sumonwiriya M, Rinchai D, Musson J, Overbeek S, Makinde J, Quigley K, Manji J, Spink N, Yos P, Wuthiekanun V, Bancroft G, Robinson J, Lertmemongkolchai G, Dunachie S, Maillere B, Holden M, Altmann D, Boyton R. T Cell Immunity to the Alkyl Hydroperoxide Reductase of Burkholderia pseudomallei: A Correlate of Disease Outcome in Acute Melioidosis. THE JOURNAL OF IMMUNOLOGY 2015; 194:4814-24. [PMID: 25862821 PMCID: PMC4416739 DOI: 10.4049/jimmunol.1402862] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 03/02/2015] [Indexed: 01/09/2023]
Abstract
There is an urgent need for a better understanding of adaptive immunity to Burkholderia pseudomallei, the causative agent of melioidosis that is frequently associated with sepsis or death in patients in Southeast Asia and Northern Australia. The imperative to identify vaccine targets is driven both by the public health agenda in these regions and biological threat concerns. In several intracellular bacterial pathogens, alkyl hydroperoxidase reductases are upregulated as part of the response to host oxidative stress, and they can stimulate strong adaptive immunity. We show that alkyl hydroperoxidase reductase (AhpC) of B. pseudomallei is strongly immunogenic for T cells of ‘humanized’ HLA transgenic mice and seropositive human donors. Some T cell epitopes, such as p6, are able to bind diverse HLA class II heterodimers and stimulate strong T cell immunity in mice and humans. Importantly, patients with acute melioidosis who survive infection show stronger T cell responses to AhpC relative to those who do not. Although the sequence of AhpC is virtually invariant among global B. pseudomallei clinical isolates, a Cambodian isolate varies only in C-terminal truncation of the p6 T cell epitope, raising the possibility of selection by host immunity. This variant peptide is virtually unable to stimulate T cell immunity. For an infection in which there has been debate about centrality of T cell immunity in defense, these observations support a role for T cell immunity to AhpC in disease protection.
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Affiliation(s)
- Catherine Reynolds
- Lung Immunology Group, Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London, London W12 ONN, United Kingdom
| | - Amélie Goudet
- CEA, Institut de Biologie et de Technologies de Saclay, Labex Laboratoire de Recherche sur le Médicament et l'Innovation Thérapeutique and Institut de Recherche Vaccinale, Service d'Ingénierie Moléculaire des Protéines, 91191 Gif sur Yvette, France
| | - Kemajittra Jenjaroen
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Manutsanun Sumonwiriya
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Darawan Rinchai
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40000, Thailand
| | - Julie Musson
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Saskia Overbeek
- Lung Immunology Group, Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London, London W12 ONN, United Kingdom
| | - Julia Makinde
- Lung Immunology Group, Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London, London W12 ONN, United Kingdom
| | - Kathryn Quigley
- Lung Immunology Group, Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London, London W12 ONN, United Kingdom
| | - Jiten Manji
- Lung Immunology Group, Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London, London W12 ONN, United Kingdom
| | - Natasha Spink
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Pagnarith Yos
- Cambodia Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | - Vanaporn Wuthiekanun
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Gregory Bancroft
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - John Robinson
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Ganjana Lertmemongkolchai
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40000, Thailand
| | - Susanna Dunachie
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; Centre for Tropical Medicine, University of Oxford, Oxford OX3 7FZ, United Kingdom; and
| | - Bernard Maillere
- CEA, Institut de Biologie et de Technologies de Saclay, Labex Laboratoire de Recherche sur le Médicament et l'Innovation Thérapeutique and Institut de Recherche Vaccinale, Service d'Ingénierie Moléculaire des Protéines, 91191 Gif sur Yvette, France
| | - Matthew Holden
- School of Medicine, University of St Andrews, St Andrews KY16 9TF, United Kingdom
| | - Daniel Altmann
- Lung Immunology Group, Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London, London W12 ONN, United Kingdom
| | - Rosemary Boyton
- Lung Immunology Group, Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London, London W12 ONN, United Kingdom;
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Adler NRL, Stevens MP, Dean RE, Saint RJ, Pankhania D, Prior JL, Atkins TP, Kessler B, Nithichanon A, Lertmemongkolchai G, Galyov EE. Systematic mutagenesis of genes encoding predicted autotransported proteins of Burkholderia pseudomallei identifies factors mediating virulence in mice, net intracellular replication and a novel protein conferring serum resistance. PLoS One 2015; 10:e0121271. [PMID: 25830295 PMCID: PMC4382181 DOI: 10.1371/journal.pone.0121271] [Citation(s) in RCA: 16] [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: 09/19/2014] [Accepted: 01/29/2015] [Indexed: 01/12/2023] Open
Abstract
Burkholderia pseudomallei is the causative agent of the severe tropical disease melioidosis, which commonly presents as sepsis. The B. pseudomallei K96243 genome encodes eleven predicted autotransporters, a diverse family of secreted and outer membrane proteins often associated with virulence. In a systematic study of these autotransporters, we constructed insertion mutants in each gene predicted to encode an autotransporter and assessed them for three pathogenesis-associated phenotypes: virulence in the BALB/c intra-peritoneal mouse melioidosis model, net intracellular replication in J774.2 murine macrophage-like cells and survival in 45% (v/v) normal human serum. From the complete repertoire of eleven autotransporter mutants, we identified eight mutants which exhibited an increase in median lethal dose of 1 to 2-log10 compared to the isogenic parent strain (bcaA, boaA, boaB, bpaA, bpaC, bpaE, bpaF and bimA). Four mutants, all demonstrating attenuation for virulence, exhibited reduced net intracellular replication in J774.2 macrophage-like cells (bimA, boaB, bpaC and bpaE). A single mutant (bpaC) was identified that exhibited significantly reduced serum survival compared to wild-type. The bpaC mutant, which demonstrated attenuation for virulence and net intracellular replication, was sensitive to complement-mediated killing via the classical and/or lectin pathway. Serum resistance was rescued by in trans complementation. Subsequently, we expressed recombinant proteins of the passenger domain of four predicted autotransporters representing each of the phenotypic groups identified: those attenuated for virulence (BcaA), those attenuated for virulence and net intracellular replication (BpaE), the BpaC mutant with defects in virulence, net intracellular replication and serum resistance and those displaying wild-type phenotypes (BatA). Only BcaA and BpaE elicited a strong IFN-γ response in a restimulation assay using whole blood from seropositive donors and were recognised by seropositive human sera from the endemic area. To conclude, several predicted autotransporters contribute to B. pseudomallei virulence and BpaC may do so by conferring resistance against complement-mediated killing.
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Affiliation(s)
- Natalie R. Lazar Adler
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Mark P. Stevens
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, United Kingdom
| | - Rachel E. Dean
- Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, United Kingdom
| | - Richard J. Saint
- Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, United Kingdom
| | - Depesh Pankhania
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Joann L. Prior
- Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, United Kingdom
| | - Timothy P. Atkins
- Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, United Kingdom
- School of Biosciences, Geoffrey Pope Building, University of Exeter, Exeter, United Kingdom
| | - Bianca Kessler
- The Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Arnone Nithichanon
- The Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Ganjana Lertmemongkolchai
- The Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Edouard E. Galyov
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
- * E-mail:
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49
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Vander Broek CW, Chalmers KJ, Stevens MP, Stevens JM. Quantitative proteomic analysis of Burkholderia pseudomallei Bsa type III secretion system effectors using hypersecreting mutants. Mol Cell Proteomics 2015; 14:905-16. [PMID: 25635268 PMCID: PMC4390269 DOI: 10.1074/mcp.m114.044875] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 01/07/2015] [Indexed: 11/06/2022] Open
Abstract
Burkholderia pseudomallei is an intracellular pathogen and the causative agent of melioidosis, a severe disease of humans and animals. One of the virulence factors critical for early stages of infection is the Burkholderia secretion apparatus (Bsa) Type 3 Secretion System (T3SS), a molecular syringe that injects bacterial proteins, called effectors, into eukaryotic cells where they subvert cellular functions to the benefit of the bacteria. Although the Bsa T3SS itself is known to be important for invasion, intracellular replication, and virulence, only a few genuine effector proteins have been identified and the complete repertoire of proteins secreted by the system has not yet been fully characterized. We constructed a mutant lacking bsaP, a homolog of the T3SS "gatekeeper" family of proteins that exert control over the timing and magnitude of effector protein secretion. Mutants lacking BsaP, or the T3SS translocon protein BipD, were observed to hypersecrete the known Bsa effector protein BopE, providing evidence of their role in post-translational control of the Bsa T3SS and representing key reagents for the identification of its secreted substrates. Isobaric Tags for Relative and Absolute Quantification (iTRAQ), a gel-free quantitative proteomics technique, was used to compare the secreted protein profiles of the Bsa T3SS hypersecreting mutants of B. pseudomallei with the isogenic parent strain and a bsaZ mutant incapable of effector protein secretion. Our study provides one of the most comprehensive core secretomes of B. pseudomallei described to date and identified 26 putative Bsa-dependent secreted proteins that may be considered candidate effectors. Two of these proteins, BprD and BapA, were validated as novel effector proteins secreted by the Bsa T3SS of B. pseudomallei.
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Affiliation(s)
- Charles W Vander Broek
- From the ‡The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - Kevin J Chalmers
- §Dundee Cell Products, James Lindsay Place, Dundee Technopole, Dundee, DD1 5JJ, Scotland, UK
| | - Mark P Stevens
- From the ‡The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - Joanne M Stevens
- From the ‡The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK.;
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Techawiwattanaboon T, Bartpho T, Sermswan RW, Chareonsudjai S. Transcription level analysis of intracellular Burkholderia pseudomallei illustrates the role of BPSL1502 during bacterial interaction with human lung epithelial cells. J Microbiol 2015; 53:134-40. [PMID: 25626369 DOI: 10.1007/s12275-015-4522-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 11/10/2014] [Accepted: 12/05/2014] [Indexed: 01/04/2023]
Abstract
Melioidosis caused by Burkholderia pseudomallei is a globally important disease of increasing concern according to high case-fatality rate and epidemic spreading. The ability of B. pseudomallei to attach and invade host cells and subsequently survive intracellularly has stimulated many questions concerning the comprehension of bacterial pathogenesis progression. Transcription levels of intracellular B. pseudomallei genes in human lung epithelial cells were therefore analyzed using bioinformatic tools, RT-PCR and real time RT-PCR. Here, it is reported that the identification of bpsl1502, encoding B. pseudomallei SurE (stationary phase survival protein E) located in a global transcriptional regulation operon was accomplished. The up-regulation of B. pseudomallei SurE was demonstrated during intracellular survival of A549 cells at 12, 18, and 24 h post-infection. To investigate the role of this protein, a B. pseudomallei SurE defective mutant was constructed. The invasion and initial survival of the SurE mutants within the A549 cells were impaired. There was no difference, however, between the growth of B. pseudomallei SurE mutant as compared to the wild type in Luria-Bertani culture. These data suggest that SurE may assist B. pseudomallei host cells invade and facilitate early intracellular infection but is not crucial during the stationary growth phase. The identification of B. pseudomallei SurE provides more information of bacterial strategy during an early step of the pathogenesis process of melioidosis.
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