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Li W, Liang H, He W, Gao X, Wu Z, Hu T, Lin X, Wang M, Zhong Y, Zhang H, Ge L, Jin X, Xiao L, Zou Y. Genomic and functional diversity of cultivated Bifidobacterium from human gut microbiota. Heliyon 2024; 10:e27270. [PMID: 38463766 PMCID: PMC10923715 DOI: 10.1016/j.heliyon.2024.e27270] [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] [Received: 08/27/2023] [Revised: 02/14/2024] [Accepted: 02/27/2024] [Indexed: 03/12/2024] Open
Abstract
The genus Bifidobacterium widely exists in human gut and has been increasingly used as the adjuvant probiotics for the prevention and treatment of diseases. However, the functional differences of Bifidobacterium genomes from different regions of the world remain unclear. We here describe an extensive study on the genomic characteristics and function annotations of 1512 genomes (clustered to 849 non-redundant genomes) of Bifidobacterium cultured from human gut. The distribution of some carbohydrate-active enzymes varied among different Bifidobacterium species and continents. More than 36% of the genomes of B. pseudocatenulatum harbored biosynthetic gene clusters of lanthipeptide-class-iv. 99.76% of the cultivated genomes of Bifidobacterium harbored genes of bile salt hydrolase. Most genomes of B. adolescentis, and all genomes of B. dentium harbored genes involved in gamma-aminobutyric acid synthesis. B. longum subsp. infantis were characterized harboring most genes related to human milk oligosaccharide utilization. Significant differences between the distribution of antibiotic resistance genes among different species and continents revealed the importance to use antibiotics precisely in the clinical treatment. Phages infecting Bifidobacterium and horizontal gene transfers occurring in genomes of Bifidobacterium were dependent on species and region sources, and might help Bifidobacterium adapt to the environment. In addition, the distribution of Bifidobacterium in human gut was found varied from different regions of the world. This study represents a comprehensive view of characteristics and functions of genomes of cultivated Bifidobacterium from human gut, and enables clinical advances in the future.
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Affiliation(s)
- Wenxi Li
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
- BGI Research, Shenzhen, 518083, China
| | | | - Wenxin He
- BGI Research, Shenzhen, 518083, China
| | | | - Zhinan Wu
- BGI Research, Shenzhen, 518083, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | | | - Xiaoqian Lin
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
- BGI Research, Shenzhen, 518083, China
| | - Mengmeng Wang
- BGI Research, Shenzhen, 518083, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yiyi Zhong
- BGI Research, Shenzhen, 518083, China
- BGI Precision Nutrition (Shenzhen) Technology Co., Ltd, Shenzhen, China
| | - Haifeng Zhang
- BGI Research, Shenzhen, 518083, China
- BGI Precision Nutrition (Shenzhen) Technology Co., Ltd, Shenzhen, China
| | - Lan Ge
- BGI Research, Shenzhen, 518083, China
- BGI Precision Nutrition (Shenzhen) Technology Co., Ltd, Shenzhen, China
| | - Xin Jin
- BGI Research, Shenzhen, 518083, China
| | - Liang Xiao
- BGI Research, Shenzhen, 518083, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- BGI Research, Qingdao, 266555, China
- Shenzhen Engineering Laboratory of Detection and Intervention of human intestinal microbiome, BGI-Shenzhen, Shenzhen, China
| | - Yuanqiang Zou
- BGI Research, Shenzhen, 518083, China
- Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark
- BGI Research, Qingdao, 266555, China
- Shenzhen Engineering Laboratory of Detection and Intervention of human intestinal microbiome, BGI-Shenzhen, Shenzhen, China
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2
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Jenkins CH, Scott AE, O’Neill PA, Norville IH, Prior JL, Ireland PM. The Arabinose 5-Phosphate Isomerase KdsD Is Required for Virulence in Burkholderia pseudomallei. J Bacteriol 2023; 205:e0003423. [PMID: 37458584 PMCID: PMC10448790 DOI: 10.1128/jb.00034-23] [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: 01/27/2023] [Accepted: 06/06/2023] [Indexed: 08/25/2023] Open
Abstract
Burkholderia pseudomallei is the causative agent of melioidosis, which is endemic primarily in Southeast Asia and northern Australia but is increasingly being seen in other tropical and subtropical regions of the world. Melioidosis is associated with high morbidity and mortality rates, which is mediated by the wide range of virulence factors encoded by B. pseudomallei. These virulence determinants include surface polysaccharides such as lipopolysaccharide (LPS) and capsular polysaccharides (CPS). Here, we investigated a predicted arabinose-5-phosphate isomerase (API) similar to KdsD in B. pseudomallei strain K96243. KdsD is required for the production of the highly conserved 3-deoxy-d-manno-octulosonic acid (Kdo), a key sugar in the core region of LPS. Recombinant KdsD was expressed and purified, and API activity was determined. Although a putative API paralogue (KpsF) is also predicted to be encoded, the deletion of kdsD resulted in growth defects, loss of motility, reduced survival in RAW 264.7 murine macrophages, and attenuation in a BALB/c mouse model of melioidosis. Suppressor mutations were observed during a phenotypic screen for motility, revealing single nucleotide polymorphisms or indels located in the poorly understood CPS type IV cluster. Crucially, suppressor mutations did not result in reversion of attenuation in vivo. This study demonstrates the importance of KdsD for B. pseudomallei virulence and highlights further the complex nature of the polysaccharides it produces. IMPORTANCE The intrinsic resistance of B. pseudomallei to many antibiotics complicates treatment. This opportunistic pathogen possesses a wide range of virulence factors, resulting in severe and potentially fatal disease. Virulence factors as targets for drug development offer an alternative approach to combat pathogenic bacteria. Prior to initiating early drug discovery approaches, it is important to demonstrate that disruption of the target gene will prevent the development of disease. This study highlights the fact that KdsD is crucial for virulence of B. pseudomallei in an animal model of infection and provides supportive phenotypic characterization that builds a foundation for future therapeutic development.
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Affiliation(s)
- Christopher H. Jenkins
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory, Salisbury, Wiltshire, United Kingdom
| | - Andrew E. Scott
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory, Salisbury, Wiltshire, United Kingdom
| | - Paul A. O’Neill
- University of Exeter Sequencing Service, Exeter, United Kingdom
| | - Isobel H. Norville
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory, Salisbury, Wiltshire, United Kingdom
- Biosciences Department, University of Exeter, Exeter, United Kingdom
| | - Joann L. Prior
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory, Salisbury, Wiltshire, United Kingdom
- Biosciences Department, University of Exeter, Exeter, United Kingdom
- Southampton General Hospital, Southampton, United Kingdom
| | - Philip M. Ireland
- Chemical, Biological and Radiological Division, Defence Science and Technology Laboratory, Salisbury, Wiltshire, United Kingdom
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3
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Abstract
The soil saprophyte, Burkholderia pseudomallei, is the causative agent of melioidosis, a disease endemic in South East Asia and northern Australia. Exposure to B. pseudomallei by either inhalation or inoculation can lead to severe disease. B. pseudomallei rapidly shifts from an environmental organism to an aggressive intracellular pathogen capable of rapidly spreading around the body. The expression of multiple virulence factors at every stage of intracellular infection allows for rapid progression of infection. Following invasion or phagocytosis, B. pseudomallei resists host-cell killing mechanisms in the phagosome, followed by escape using the type III secretion system. Several secreted virulence factors manipulate the host cell, while bacterial cells undergo a shift in energy metabolism allowing for overwhelming intracellular replication. Polymerisation of host cell actin into “actin tails” propels B. pseudomallei to the membranes of host cells where the type VI secretion system fuses host cells into multinucleated giant cells (MNGCs) to facilitate cell-to-cell dissemination. This review describes the various mechanisms used by B. pseudomallei to survive within cells.
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Affiliation(s)
- Nicole M Bzdyl
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Clare L Moran
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Justine Bendo
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Mitali Sarkar-Tyson
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Perth, Western Australia, 6009, Australia
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4
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DeMers HL, Nualnoi T, Thorkildson P, Hau D, Hannah EE, Green HR, Pandit SG, Gates-Hollingsworth MA, Boutthasavong L, Luangraj M, Woods KL, Dance D, AuCoin DP. Detection and Quantification of the Capsular Polysaccharide of Burkholderia pseudomallei in Serum and Urine Samples from Melioidosis Patients. Microbiol Spectr 2022; 10:e0076522. [PMID: 35924843 PMCID: PMC9430648 DOI: 10.1128/spectrum.00765-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/30/2022] [Indexed: 11/20/2022] Open
Abstract
Burkholderia pseudomallei is the causative agent of melioidosis, a life-threatening disease common in Southeast Asia and northern Australia. Melioidosis often presents with nonspecific symptoms and has a fatality rate of upwards of 70% when left untreated. The gold standard for diagnosis is culturing B. pseudomallei from patient samples. Bacterial culture, however, can take up to 7 days, and its sensitivity is poor, at roughly 60%. The successful administration of appropriate antibiotics is reliant on rapid and accurate diagnosis. Hence, there is a genuine need for new diagnostics for this deadly pathogen. The Active Melioidosis Detect (AMD) lateral flow immunoassay (LFI) detects the capsular polysaccharide (CPS) of B. pseudomallei. The assay is designed for use on various clinical samples, including serum and urine; however, there are limited data to support which clinical matrices are the best candidates for detecting CPS. In this study, concentrations of CPS in paired serum and urine samples from melioidosis patients were determined using a quantitative antigen capture enzyme-linked immunosorbent assay. In parallel, samples were tested with the AMD LFI, and the results of the two immunoassays were compared. Additionally, centrifugal concentration was performed on a subset of urine samples to determine if this method may improve detection when CPS levels are initially low or undetectable. The results indicate that while CPS levels varied within the two matrices, there tended to be higher concentrations in urine. The AMD LFI detected CPS in 40.5% of urine samples, compared to 6.5% of serum samples, suggesting that urine is a preferable matrix for point-of-care diagnostic assays. IMPORTANCE Melioidosis is very challenging to diagnose. There is a clear need for a point-of-care assay for the detection of B. pseudomallei antigen directly from patient samples. The Active Melioidosis Detect lateral flow immunoassay detects the capsular polysaccharide (CPS) of B. pseudomallei and is designed for use on various clinical samples, including serum and urine. However, there are limited data regarding which clinical matrix is preferable for the detection of CPS. This study addresses this question by examining quantitative CPS levels in paired serum and urine samples and relating them to clinical parameters. Additionally, centrifugal concentration was performed on a subset of urine samples to determine whether this might enable the detection of CPS in samples in which it was initially present at low or undetectable levels. These results provide valuable insights into the detection of CPS in patients with melioidosis and suggest potential ways forward in the diagnosis and treatment of this challenging disease.
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Affiliation(s)
- Haley L. DeMers
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, Reno, Nevada, USA
| | - Teerapat Nualnoi
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, Reno, Nevada, USA
| | - Peter Thorkildson
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, Reno, Nevada, USA
| | - Derrick Hau
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, Reno, Nevada, USA
| | - Emily E. Hannah
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, Reno, Nevada, USA
| | - Heather R. Green
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, Reno, Nevada, USA
| | - Sujata G. Pandit
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, Reno, Nevada, USA
| | | | - Latsaniphone Boutthasavong
- Lao-Oxford-Mahosot Hospital Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
| | - Manophab Luangraj
- Lao-Oxford-Mahosot Hospital Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
| | - Kate L. Woods
- Lao-Oxford-Mahosot Hospital Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
| | - David Dance
- Lao-Oxford-Mahosot Hospital Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - David P. AuCoin
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, Reno, Nevada, USA
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5
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Sajeev S, Hamza M, Sivaraman GK, Ghatak S, Ojha R, Mendem SK, Murugesan D, Raisen C, Shome BR, Holmes MA. Genomic insights of beta-lactamase producing Klebsiella quasipneumoniae subsp. similipneumoniae belonging to sequence type 1699 from retail market fish, India. Arch Microbiol 2022; 204:454. [PMID: 35781844 DOI: 10.1007/s00203-022-03071-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 06/07/2022] [Accepted: 06/13/2022] [Indexed: 11/25/2022]
Abstract
Klebsiella quasipneumoniae is a recently described species and often misidentified as Klebsiella pneumoniae. Here, we report the genomic characterization of Klebsiella quasipneumoniae subsp. similipneumoniae (India238 strain) isolated from fish. The annotated genome acknowledged the presence of blaCTX-M-15, blaOKP-B-1, fosA5, oqxAB and virulence genes. The strain with ST1699 and serotypes KL52 and OL103 also harboured insertion sequences (ISs): ISKpn26 and ISEc9. Three complete phage genomes were identified in contigs 1 and 6 of the bacterial genome, enhancing the prospects of genome manipulation. The study highlights the pitfall of conventional microbiological identification methods to distinguish K. pneumoniae and K. quasipneumoniae. This is the first Indian study documenting the incidence of extended-spectrum beta-lactamase (ESBL)-producing K. quasipneumoniae subsp. similipneumoniae from a non-clinical environment, equipped with virulomes and associated mobile genetic elements. Given that fish can act as a potential vector for transmission of antimicrobial resistance genes, our findings have paramount importance on human health.
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Affiliation(s)
- Sudha Sajeev
- Microbiology, Fermentation and Biotechnology Division, ICAR-Central Institute of Fisheries Technology, Cochin, Kerala, India
| | - Muneeb Hamza
- Microbiology, Fermentation and Biotechnology Division, ICAR-Central Institute of Fisheries Technology, Cochin, Kerala, India
| | - Gopalan Krishnan Sivaraman
- Microbiology, Fermentation and Biotechnology Division, ICAR-Central Institute of Fisheries Technology, Cochin, Kerala, India.
| | - Sandeep Ghatak
- Division of Animal Health, ICAR Research Complex for NEH Region, Umiam, India.
| | - Rakshit Ojha
- Department of Disease Investigation, ICAR-National Institute of Veterinary Epidemiology and Disease Informatics, Bengaluru, Karnataka, India
| | - Suresh Kumar Mendem
- Department of Disease Investigation, ICAR-National Institute of Veterinary Epidemiology and Disease Informatics, Bengaluru, Karnataka, India
| | - Devi Murugesan
- Department of Disease Investigation, ICAR-National Institute of Veterinary Epidemiology and Disease Informatics, Bengaluru, Karnataka, India
| | - Claire Raisen
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Bibek R Shome
- Department of Disease Investigation, ICAR-National Institute of Veterinary Epidemiology and Disease Informatics, Bengaluru, Karnataka, India
| | - Mark A Holmes
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
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6
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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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7
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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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8
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Corell A, Yilmaz A, Almotairi FS, Farahmand D. Intracranial Manifestation of Melioidosis: A Case Report and Long-Term Follow-Up. Cureus 2020; 12:e12367. [PMID: 33527048 PMCID: PMC7843157 DOI: 10.7759/cureus.12367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Primary neurological melioidosis is rare with fewer than 50 cases reported world-wide. We report the first documented case of primary neurological melioidosis in Sweden, a 32-year old male who previously lived in Thailand for six years and recently moved to Sweden. He presented with headache, irritability and lack of concentration. Investigation with computerized tomography (CT) and subsequent magnetic resonance imaging (MRI) showed epidural fluid that was interpreted as a chronic epidural hematoma. He underwent surgical evacuation of the epidural collection that was found to be a white collection mixed with pus and bacterial culture results were positive for Burkholderia pseudomallei.
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9
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Menon N, Mariappan V, Vellasamy KM, Samudi C, See JX, Ganesh PS, Saeidi A, Vadivelu J, Shankar EM. Experimental exposure of Burkholderia pseudomallei crude culture filtrate upregulates PD-1 on T lymphocytes. Access Microbiol 2020; 2:acmi000110. [PMID: 32974575 PMCID: PMC7494189 DOI: 10.1099/acmi.0.000110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 01/30/2020] [Indexed: 12/11/2022] Open
Abstract
Burkholderia pseudomallei is the causative agent for melioidosis. Because of its intracellular nature, the bacterium is capable of replicating within a plethora of eukaryotic cell lines. B. pseudomallei can remain dormant within host cells without symptoms for years, causing recrudescent infections. Here, we investigated the pathogenesis mechanism behind the suppression of T cell responses by B. pseudomallei . Peripheral blood mononuclear cells (1×106 cells/well) isolated by Ficoll Paque (Sigma-Aldrich) density gradient centrifugation were incubated with optimized concentrations of bacterial crude culture filtrate antigens (CFAs) (10 ug ml-1) and heat-killed bacteria [1 : 10 multiplicity of infection (m.o.i.)]. Following incubation, cells were investigated for surface expression of coinhibitory molecules by flow cytometry. We found that B. pseudomallei induced the upregulation of programmed death 1 (PD-1), a molecule responsible for T cell exhaustion, on T cells in vitro following exposure to crude CFAs of B. pseudomallei . This upregulation of PD-1 probably contributes to poor immune surveillance and disease pathogenesis.
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Affiliation(s)
- Nivedita Menon
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Vanitha Mariappan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Kumutha M Vellasamy
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Chandramathi Samudi
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Jia-Xiang See
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia
| | - P Sankar Ganesh
- Department of Life Sciences, Central University of Tamil Nadu, Thiruvarur 610 005, Tamilnadu, India
| | - Alireza Saeidi
- Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia.,Present address: Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Esaki Muthu Shankar
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur, Malaysia.,Present address: Department of Life Sciences, Central University of Tamil Nadu, Tamilnadu, Thiruvarur, India
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10
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Norris MH, Tran HTT, Walker MA, Bluhm AP, Zincke D, Trung TT, Thi NV, Thi NP, Schweizer HP, Unger F, Blackburn JK, Hang NTT. Distribution of Serological Response to Burkholderia pseudomallei in Swine from Three Provinces of Vietnam. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17145203. [PMID: 32708490 PMCID: PMC7399857 DOI: 10.3390/ijerph17145203] [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] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/09/2020] [Accepted: 07/16/2020] [Indexed: 01/18/2023]
Abstract
(1) Background: Burkholderia pseudomallei is an environmentally mediated saprophytic pathogen that can cause severe disease in humans. It is well known that B. pseudomallei survives in tropical moist soil environments worldwide, but melioidosis is gaining recognition as a public and veterinary health issue in Vietnam. The contribution of animals to human disease is unknown, necessitating further investigation. (2) Methods: Swine sera were collected from two populations, one grazing and one commercially farmed, from three provinces in Vietnam. ELISAs utilizing B. pseudomallei capsular polysaccharide (CPS), outer polysaccharide (OPS), and Hcp1 protein were used to screen serum samples. Positive samples were mapped to the commune level. Seroprevalence calculations and pig population estimates were used to approximate number of swine exposures per commune. (3) Results: Grazing pigs from Hoa Binh had significantly higher seropositivity levels (11.4%, 95% CI: 9.7–13.1) compared to farmed pigs from Ha Tinh and Nghe An (4%, 95% CI: 3.3–4.7). Average swine seropositivity rates were ~6.3% (95% CI: 5–7.9), higher than previously identified in Vietnam (~0.88%). (4) Conclusions: Initial serological sampling identified a significant number of seropositive and potential melioidosis infections occurring in swine in Vietnam. This work is a critical step in understanding the role swine may play in the epidemiology of human melioidosis in Vietnam.
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Affiliation(s)
- Michael H. Norris
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
- Correspondence:
| | - Hang Thi Thu Tran
- National Institute of Veterinary Research, Hanoi 10000, Vietnam; (H.T.T.T.); (N.V.T.); (N.P.T.); (N.T.T.H.)
| | - Morgan A. Walker
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
| | - Andrew P. Bluhm
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
| | - Diansy Zincke
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
| | - Trinh Thanh Trung
- VNU-Institute of Microbiology and Biotechnology, Vietnam National University, Hanoi 10000, Vietnam;
| | - Nga Vu Thi
- National Institute of Veterinary Research, Hanoi 10000, Vietnam; (H.T.T.T.); (N.V.T.); (N.P.T.); (N.T.T.H.)
| | - Ngoc Pham Thi
- National Institute of Veterinary Research, Hanoi 10000, Vietnam; (H.T.T.T.); (N.V.T.); (N.P.T.); (N.T.T.H.)
| | - Herbert P. Schweizer
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32611, USA
| | - Fred Unger
- International Livestock Research Institute, Hanoi 10000, Vietnam;
| | - Jason K. Blackburn
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
| | - Nguyen Thi Thu Hang
- National Institute of Veterinary Research, Hanoi 10000, Vietnam; (H.T.T.T.); (N.V.T.); (N.P.T.); (N.T.T.H.)
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11
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Abstract
The causative agent of melioidosis, Burkholderia pseudomallei, a tier 1 select agent, is endemic in Southeast Asia and northern Australia, with increased incidence associated with high levels of rainfall. Increasing reports of this condition have occurred worldwide, with estimates of up to 165,000 cases and 89,000 deaths per year. The ecological niche of the organism has yet to be clearly defined, although the organism is associated with soil and water. The culture of appropriate clinical material remains the mainstay of laboratory diagnosis. Identification is best done by phenotypic methods, although mass spectrometric methods have been described. Serology has a limited diagnostic role. Direct molecular and antigen detection methods have limited availability and sensitivity. Clinical presentations of melioidosis range from acute bacteremic pneumonia to disseminated visceral abscesses and localized infections. Transmission is by direct inoculation, inhalation, or ingestion. Risk factors for melioidosis include male sex, diabetes mellitus, alcohol abuse, and immunosuppression. The organism is well adapted to intracellular survival, with numerous virulence mechanisms. Immunity likely requires innate and adaptive responses. The principles of management of this condition are drainage and debridement of infected material and appropriate antimicrobial therapy. Global mortality rates vary between 9% and 70%. Research into vaccine development is ongoing.
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Affiliation(s)
- I Gassiep
- Pathology Queensland, Townsville Hospital, Townsville, Queensland, Australia
- Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
| | - M Armstrong
- Pathology Queensland, Townsville Hospital, Townsville, Queensland, Australia
| | - R Norton
- Pathology Queensland, Townsville Hospital, Townsville, Queensland, Australia
- Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
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12
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Alwis PA, Treerat P, Gong L, Deveson Lucas D, Allwood EM, Prescott M, Devenish RJ, Adler B, Boyce JD. Disruption of the Burkholderia pseudomallei two-component signal transduction system BbeR-BbeS leads to increased extracellular DNA secretion and altered biofilm formation. Vet Microbiol 2020; 242:108603. [PMID: 32122607 DOI: 10.1016/j.vetmic.2020.108603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 02/03/2020] [Indexed: 10/25/2022]
Abstract
Two-component signal transduction systems (TCSTS) are abundant among prokaryotes and regulate important functions, including drug resistance and virulence. The Gram-negative bacterium Burkholderia pseudomallei, which causes the severe infectious disease melioidosis, encodes 136 putative TCSTS components. In silico analyses of these TCSTS indicated that the predicted BbeR-BbeS system (BPSL1036-BPSL1037) displayed significant amino acid sequence similarity to the Shigella flexneri virulence-associated OmpR-EnvZ osmoregulator. To assess the function of the B. pseudomallei BbeR-BbeS system, we constructed by allelic exchange a ΔbbeRS double mutant strain lacking both genes, and single ΔbbeR and ΔbbeS mutants. All three mutant strains caused disease in the BALB/c acute melioidosis model at the same rate as the wild-type strain, displayed unchanged swarming motility on semi-solid medium, and were unaffected for viability on high-osmolarity media. However, when cultured at 37 °C for at least 14 days, ΔbbeS and ΔbbeR colonies developed a distinct, hypermucoid morphology absent in similarly-cultured wild-type colonies. At both 30 °C and 37 °C, these hypermucoid strains produced wild-type levels of type I capsule but released increased quantities of extracellular DNA (eDNA). Upon static growth in liquid medium, all B. pseudomallei strains produced pellicle biofilms that contained DNA in close association with bacterial cells; however, the ΔbbeS and ΔbbeR strains produced increased biofilms with altered microscopic architecture compared to the wild-type. Unusually, while the ΔbbeS and ΔbbeR single-deletion mutants displayed clear phenotypes, the ΔbbeRS double-deletion mutant was indistinguishable from the wild-type strain. We propose that BbeR-BbeS indirectly affects eDNA secretion and biofilm formation through cross-talk with one or more other TCSTS.
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Affiliation(s)
- Priyangi A Alwis
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia; Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Puthayalai Treerat
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia; Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Lan Gong
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
| | - Deanna Deveson Lucas
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia; Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Elizabeth M Allwood
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia; Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Mark Prescott
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
| | - Rodney J Devenish
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
| | - Ben Adler
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia; Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - John D Boyce
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia; Department of Microbiology, Monash University, Melbourne, Victoria, Australia.
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13
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Pearson T, Sahl JW, Hepp CM, Handady K, Hornstra H, Vazquez AJ, Settles E, Mayo M, Kaestli M, Williamson CHD, Price EP, Sarovich DS, Cook JM, Wolken SR, Bowen RA, Tuanyok A, Foster JT, Drees KP, Kidd TJ, Bell SC, Currie BJ, Keim P. Pathogen to commensal? Longitudinal within-host population dynamics, evolution, and adaptation during a chronic >16-year Burkholderia pseudomallei infection. PLoS Pathog 2020; 16:e1008298. [PMID: 32134991 PMCID: PMC7077878 DOI: 10.1371/journal.ppat.1008298] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 03/17/2020] [Accepted: 01/02/2020] [Indexed: 12/14/2022] Open
Abstract
Although acute melioidosis is the most common outcome of Burkholderia pseudomallei infection, we have documented a case, P314, where disease severity lessened with time, and the pathogen evolved towards a commensal relationship with the host. In the current study, we used whole-genome sequencing to monitor this long-term symbiotic relationship to better understand B. pseudomallei persistence in P314's sputum despite intensive initial therapeutic regimens. We collected and sequenced 118 B. pseudomallei isolates from P314's airways over a >16-year period, and also sampled the patient's home environment, recovering six closely related B. pseudomallei isolates from the household water system. Using comparative genomics, we identified 126 SNPs in the core genome of the 124 isolates or 162 SNPs/indels when the accessory genome was included. The core SNPs were used to construct a phylogenetic tree, which demonstrated a close relationship between environmental and clinical isolates and detailed within-host evolutionary patterns. The phylogeny had little homoplasy, consistent with a strictly clonal mode of genetic inheritance. Repeated sampling revealed evidence of genetic diversification, but frequent extinctions left only one successful lineage through the first four years and two lineages after that. Overall, the evolution of this population is nonadaptive and best explained by genetic drift. However, some genetic and phenotypic changes are consistent with in situ adaptation. Using a mouse model, P314 isolates caused greatly reduced morbidity and mortality compared to the environmental isolates. Additionally, potentially adaptive phenotypes emerged and included differences in the O-antigen, capsular polysaccharide, motility, and colony morphology. The >13-year co-existence of two long-lived lineages presents interesting hypotheses that can be tested in future studies to provide additional insights into selective pressures, niche differentiation, and microbial adaptation. This unusual melioidosis case presents a rare example of the evolutionary progression towards commensalism by a highly virulent pathogen within a single human host.
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Affiliation(s)
- Talima Pearson
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Jason W. Sahl
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Crystal M. Hepp
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Karthik Handady
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Heidie Hornstra
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Adam J. Vazquez
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Erik Settles
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Mark Mayo
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Mirjam Kaestli
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Charles H. D. Williamson
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Erin P. Price
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Derek S. Sarovich
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - James M. Cook
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Spenser R. Wolken
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Richard A. Bowen
- Department of Biomedical Sciences, Colorado State University, Colorado, United States of America
| | - Apichai Tuanyok
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Jeffrey T. Foster
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Kevin P. Drees
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Timothy J. Kidd
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Scott C. Bell
- Department of Thoracic Medicine, The Prince Charles Hospital, Chermside, and QIMR Berghofer Medical Research Institute, Queensland, Australia
| | - Bart J. Currie
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Infectious Diseases Department and Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Paul Keim
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
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14
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Ferro P, Vaz-Moreira I, Manaia CM. Betaproteobacteria are predominant in drinking water: are there reasons for concern? Crit Rev Microbiol 2019; 45:649-667. [PMID: 31686572 DOI: 10.1080/1040841x.2019.1680602] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Betaproteobacteria include some of the most abundant and ubiquitous bacterial genera that can be found in drinking water, including mineral water. The combination of physiology and ecology traits place some Betaproteobacteria in the list of potential, yet sometimes neglected, opportunistic pathogens that can be transmitted by water or aqueous solutions. Indeed, some drinking water Betaproteobacteria with intrinsic and sometimes acquired antibiotic resistance, harbouring virulence factors and often found in biofilm structures, can persist after water disinfection and reach the consumer. This literature review summarises and discusses the current knowledge about the occurrence and implications of Betaproteobacteria in drinking water. Although the sparse knowledge on the ecology and physiology of Betaproteobacteria thriving in tap or bottled natural mineral/spring drinking water (DW) is an evidence of this review, it is demonstrated that DW holds a high diversity of Betaproteobacteria, whose presence may not be innocuous. Frequently belonging to genera also found in humans, DW Betaproteobacteria are ubiquitous in different habitats, have the potential to resist antibiotics either due to intrinsic or acquired mechanisms, and hold different virulence factors. The combination of these factors places DW Betaproteobacteria in the list of candidates of emerging opportunistic pathogens. Improved bacterial identification of clinical isolates associated with opportunistic infections and additional genomic and physiological studies may contribute to elucidate the potential impact of these bacteria.
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Affiliation(s)
- Pompeyo Ferro
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Porto, Portugal
| | - Ivone Vaz-Moreira
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Porto, Portugal
| | - Célia M Manaia
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Porto, Portugal
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15
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Kim S, Jo S, Kim MS, Shin DH. A Study of a Potent Inhibitor Against a GDP-6-Deoxy-α-d- Manno-Heptose Biosynthesis Pathway as Antibiotic Candidates. Microb Drug Resist 2019; 26:385-390. [PMID: 31613705 DOI: 10.1089/mdr.2019.0144] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The GDP-6-deoxy-α-d-manno-heptose is a key building block molecule in constructing lipopolysaccharide of Gram-negative bacteria. Therefore, blockage of the biosynthesis pathway of GDP-6-deoxy-α-d-manno-heptose is lethal or increases antibiotics susceptibility to pathogens. In this study, we assayed d-glycero-α-d-manno-heptose-1-phosphate guanylyltransferase (HddC) from Yersinia pseudotuberculosis (Yp) using an efficient assay method supplying its natural substrate. Using the method, 102 chemical compounds were tested to search inhibitory compounds and electrospray ionization mass spectrometry was used to detect the HddC from Y. pseudotuberculosis (YpHddC) reaction product, GDP-d-glycero-α-d-manno-heptose. Interestingly, one promising lead, ethyl 5-({[(5-benzyl-1, 3, 4-oxadiazol-2-yl) thio] acetyl} amino)-4-cyano-3-methyl-2-thiophenecarboxylate (Chembridge 7929959), was discovered. The inhibitory activity of the lead compound against YpHddC has been proven by blocking its nucleotidyltransferase activity transferring the GMP moiety to α-d-mannose-1-phosphate (αM1P). Chembridge 7929959 shows that the half maximal inhibitory concentration (IC50) is 0.222 μM indicating its affinity with αM1P.
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Affiliation(s)
- Suwon Kim
- Department of pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, Republic of Korea
| | - Seri Jo
- Department of pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, Republic of Korea
| | - Mi-Sun Kim
- Department of pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, Republic of Korea
| | - Dong Hae Shin
- Department of pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, Republic of Korea
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16
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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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17
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Transcriptome analysis of Burkholderia pseudomallei SCV reveals an association with virulence, stress resistance and intracellular persistence. Genomics 2019; 112:501-512. [PMID: 30980902 DOI: 10.1016/j.ygeno.2019.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 03/18/2019] [Accepted: 04/01/2019] [Indexed: 01/16/2023]
Abstract
Differences in expression of potential virulence and survival genes were associated with B. pseudomallei colony morphology variants. Microarray was used to investigate B. pseudomallei transcriptome alterations among the wild type and small colony variant (SCV) pre- and post-exposed to A549 cells. SCV pre- and post-exposed have lower metabolic requirements and consume lesser energy than the wild type pre- and post-exposed to A549. However, both the wild type and SCV limit their metabolic activities post- infection of A549 cells and this is indicated by the down-regulation of genes implicated in the metabolism of amino acids, carbohydrate, lipid, and other amino acids. Many well-known virulence and survival factors, including T3SS, fimbriae, capsular polysaccharides and stress response were up-regulated in both the wild type and SCV pre- and post-exposed to A549 cells. Microarray analysis demonstrated essential differences in bacterial response associated with virulence and survival pre- and post-exposed to A549 cells.
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18
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DeShazer D, Lovett S, Richardson J, Koroleva G, Kuehl K, Amemiya K, Sun M, Worsham P, Welkos S. Bacteriophage-associated genes responsible for the widely divergent phenotypes of variants of Burkholderia pseudomallei strain MSHR5848. J Med Microbiol 2019; 68:263-278. [PMID: 30628877 DOI: 10.1099/jmm.0.000908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
PURPOSE Burkholderia pseudomallei, the tier 1 agent of melioidosis, is a saprophytic microbe that causes endemic infections in tropical regions such as South-East Asia and Northern Australia. It is globally distributed, challenging to diagnose and treat, infectious by several routes including inhalation, and has potential for adversarial use. B. pseudomallei strain MSHR5848 produces two colony variants, smooth (S) and rough (R), which exhibit a divergent range of morphological, biochemical and metabolic phenotypes, and differ in macrophage and animal infectivity. We aimed to characterize two major phenotypic differences, analyse gene expression and study the regulatory basis of the variation. METHODOLOGY Phenotypic expression was characterized by DNA and RNA sequencing, microscopy, and differential bacteriology. Regulatory genes were identified by cloning and bioinformatics.Results/Key findings. Whereas S produced larger quantities of extracellular DNA, R was upregulated in the production of a unique chromosome 1-encoded Siphoviridae-like bacteriophage, φMSHR5848. Exploratory transcriptional analyses revealed significant differences in variant expression of genes encoding siderophores, pili assembly, type VI secretion system cluster 4 (T6SS-4) proteins, several exopolysaccharides and secondary metabolites. A single 3 base duplication in S was the only difference that separated the variants genetically. It occurred upstream of a cluster of bacteriophage-associated genes on chromosome 2 that were upregulated in S. The first two genes were involved in regulating expression of the multiple phenotypes distinguishing S and R. CONCLUSION Bacteriophage-associated proteins have a major role in the phenotypic expression of MSHR5848. The goals are to determine the regulatory basis of this phenotypic variation and its role in pathogenesis and environmental persistence of B. pseudomallei.
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Affiliation(s)
- David DeShazer
- 1Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Sean Lovett
- 2Center for Genome Sciences, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Joshua Richardson
- 2Center for Genome Sciences, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Galina Koroleva
- 2Center for Genome Sciences, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA.,†Present address: Room 7N109, Center for Human Immunology, Autoimmunity and Inflammation, National Institute of Allergy and Infectious Diseases, 10 Center Drive, Bethesda, MD 20814, USA
| | - Kathleen Kuehl
- 3Pathology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Kei Amemiya
- 1Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Mei Sun
- 4United States Army Medical Research and Materiel Command (USAMRMC), Frederick, MD, USA
| | - Patricia Worsham
- 1Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
| | - Susan Welkos
- 1Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, USA
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19
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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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20
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Bi Y, Pei G, Sun T, Chen Z, Chen L, Zhang W. Regulation Mechanism Mediated by Trans-Encoded sRNA Nc117 in Short Chain Alcohols Tolerance in Synechocystis sp. PCC 6803. Front Microbiol 2018; 9:863. [PMID: 29780373 PMCID: PMC5946031 DOI: 10.3389/fmicb.2018.00863] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 04/13/2018] [Indexed: 11/13/2022] Open
Abstract
Microbial small RNAs (sRNAs) play essential roles against many stress conditions in cyanobacteria. However, little is known on their regulatory mechanisms on biofuels tolerance. In our previous sRNA analysis, a trans-encoded sRNA Nc117 was found involved in the tolerance to ethanol and 1-butanol in Synechocystis sp. PCC 6803. However, its functional mechanism is yet to be determined. In this study, functional characterization of sRNA Nc117 was performed. Briefly, the exact length of the trans-encoded sRNA Nc117 was determined to be 102 nucleotides using 3′ RACE, and the positive regulation of Nc117 on short chain alcohols tolerance was further confirmed. Then, computational target prediction and transcriptomic analysis were integrated to explore the potential targets of Nc117. A total of 119 up-regulated and 116 down-regulated genes were identified in nc117 overexpression strain compared with the wild type by comparative transcriptomic analysis, among which the upstream regions of five genes were overlapped with those predicted by computational target approach. Based on the phenotype analysis of gene deletion and overexpression strains under short chain alcohols stress, one gene slr0007 encoding D-glycero-alpha-D-manno-heptose 1-phosphate guanylyltransferase was determined as a potential target of Nc117, suggesting that the synthesis of LPS or S-layer glycoprotein may be responsible for the tolerance enhancement. As the first reported trans-encoded sRNA positively regulating biofuels tolerance in cyanobacteria, this study not only provided evidence for a new regulatory mechanism of trans-encoded sRNA in cyanobacteria, but also valuable information for rational construction of high-tolerant cyanobacterial chassis.
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Affiliation(s)
- Yanqi Bi
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Ministry of Education of the People's Republic of China, Tianjin, China.,Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China
| | - Guangsheng Pei
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Ministry of Education of the People's Republic of China, Tianjin, China.,Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China
| | - Tao Sun
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Ministry of Education of the People's Republic of China, Tianjin, China.,Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China
| | - Zixi Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Ministry of Education of the People's Republic of China, Tianjin, China.,Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China
| | - Lei Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Ministry of Education of the People's Republic of China, Tianjin, China.,Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China
| | - Weiwen Zhang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Ministry of Education of the People's Republic of China, Tianjin, China.,Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China.,Center for Biosafety Research and Strategy, Tianjin University, Tianjin, China
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21
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Mangalea MR, Borlee GI, Borlee BR. The Current Status of Extracellular Polymeric Substances Produced by Burkholderia pseudomallei. CURRENT TROPICAL MEDICINE REPORTS 2017. [DOI: 10.1007/s40475-017-0118-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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22
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General assay for enzymes in the heptose biosynthesis pathways using electrospray ionization mass spectrometry. Appl Microbiol Biotechnol 2017; 101:4521-4532. [DOI: 10.1007/s00253-017-8148-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 01/12/2017] [Accepted: 01/25/2017] [Indexed: 10/20/2022]
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23
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Shea AA, Bernhards RC, Cote CK, Chase CJ, Koehler JW, Klimko CP, Ladner JT, Rozak DA, Wolcott MJ, Fetterer DP, Kern SJ, Koroleva GI, Lovett SP, Palacios GF, Toothman RG, Bozue JA, Worsham PL, Welkos SL. Two stable variants of Burkholderia pseudomallei strain MSHR5848 express broadly divergent in vitro phenotypes associated with their virulence differences. PLoS One 2017; 12:e0171363. [PMID: 28187198 PMCID: PMC5302386 DOI: 10.1371/journal.pone.0171363] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 01/18/2017] [Indexed: 12/12/2022] Open
Abstract
Burkholderia pseudomallei (Bp), the agent of melioidosis, causes disease ranging from acute and rapidly fatal to protracted and chronic. Bp is highly infectious by aerosol, can cause severe disease with nonspecific symptoms, and is naturally resistant to multiple antibiotics. However, no vaccine exists. Unlike many Bp strains, which exhibit random variability in traits such as colony morphology, Bp strain MSHR5848 exhibited two distinct and relatively stable colony morphologies on sheep blood agar plates: a smooth, glossy, pale yellow colony and a flat, rough, white colony. Passage of the two variants, designated "Smooth" and "Rough", under standard laboratory conditions produced cultures composed of > 99.9% of the single corresponding type; however, both could switch to the other type at different frequencies when incubated in certain nutritionally stringent or stressful growth conditions. These MSHR5848 derivatives were extensively characterized to identify variant-associated differences. Microscopic and colony morphology differences on six differential media were observed and only the Rough variant metabolized sugars in selective agar. Antimicrobial susceptibilities and lipopolysaccharide (LPS) features were characterized and phenotype microarray profiles revealed distinct metabolic and susceptibility disparities between the variants. Results using the phenotype microarray system narrowed the 1,920 substrates to a subset which differentiated the two variants. Smooth grew more rapidly in vitro than Rough, yet the latter exhibited a nearly 10-fold lower lethal dose for mice than Smooth. Finally, the Smooth variant was phagocytosed and replicated to a greater extent and was more cytotoxic than Rough in macrophages. In contrast, multiple locus sequence type (MLST) analysis, ribotyping, and whole genome sequence analysis demonstrated the variants' genetic conservation; only a single consistent genetic difference between the two was identified for further study. These distinct differences shown by two variants of a Bp strain will be leveraged to better understand the mechanism of Bp phenotypic variability and to possibly identify in vitro markers of infection.
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Affiliation(s)
- A. A. Shea
- Diagnostic Systems Division, USAMRIID, Frederick, Maryland, United States of America
| | - R. C. Bernhards
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland, United States of America
| | - C. K. Cote
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland, United States of America
| | - C. J. Chase
- Diagnostic Systems Division, USAMRIID, Frederick, Maryland, United States of America
| | - J. W. Koehler
- Diagnostic Systems Division, USAMRIID, Frederick, Maryland, United States of America
| | - C. P. Klimko
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland, United States of America
| | - J. T. Ladner
- Center for Genome Sciences, USAMRIID, Frederick, Maryland, United States of America
| | - D. A. Rozak
- Diagnostic Systems Division, USAMRIID, Frederick, Maryland, United States of America
| | - M. J. Wolcott
- Diagnostic Systems Division, USAMRIID, Frederick, Maryland, United States of America
| | - D. P. Fetterer
- Biostatistical Services Division, USAMRIID, Frederick, Maryland, United States of America
| | - S. J. Kern
- Biostatistical Services Division, USAMRIID, Frederick, Maryland, United States of America
| | - G. I. Koroleva
- Center for Genome Sciences, USAMRIID, Frederick, Maryland, United States of America
| | - S. P. Lovett
- Center for Genome Sciences, USAMRIID, Frederick, Maryland, United States of America
| | - G. F. Palacios
- Center for Genome Sciences, USAMRIID, Frederick, Maryland, United States of America
| | - R. G. Toothman
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland, United States of America
| | - J. A. Bozue
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland, United States of America
| | - P. L. Worsham
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland, United States of America
| | - S. L. Welkos
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland, United States of America
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24
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Jitprasutwit N, Zainal-Abidin N, Vander Broek C, Kurian D, Korbsrisate S, Stevens MP, Stevens JM. Identification of Candidate Host Cell Factors Required for Actin-Based Motility of Burkholderia pseudomallei. J Proteome Res 2016; 15:4675-4685. [PMID: 27934296 DOI: 10.1021/acs.jproteome.6b00760] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Intracellular actin-based motility of the melioidosis pathogen Burkholderia pseudomallei requires the bacterial factor BimA. Located at one pole of the bacterium, BimA recruits and polymerizes cellular actin to promote bacterial motility within and between cells. Here, we describe an affinity approach coupled with mass spectrometry to identify cellular proteins recruited to BimA-expressing bacteria under conditions that promote actin polymerization. We identified a group of cellular proteins that are recruited to the B. pseudomallei surface in a BimA-dependent manner, a subset of which were independently validated with specific antisera including the ubiquitous scaffold protein Ras GTPase-activating-like protein (IQGAP1). IQGAP1 integrates several key cellular signaling pathways including those involved in actin dynamics and has been shown to be involved in the adhesion of attaching and effacing Escherichia coli to infected cells and invasion of host cells by Salmonella enterica serovar Typhimurium. Although a direct interaction between BimA and IQGAP1 could not be detected using either conventional pulldown or yeast two hybrid techniques, confocal microscopy revealed that IQGAP1 is recruited to B. pseudomallei actin tails in infected cells, and siRNA-mediated knockdown highlighted a role for this protein in controlling the length and actin density of B. pseudomallei actin tails.
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Affiliation(s)
- Niramol Jitprasutwit
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh , Easter Bush, Midlothian, EH25 9RG, United Kingdom.,Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University Bangkok, 73170 Thailand
| | - Nurhamimah Zainal-Abidin
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh , Easter Bush, Midlothian, EH25 9RG, United Kingdom
| | - Charles Vander Broek
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh , Easter Bush, Midlothian, EH25 9RG, United Kingdom
| | - Dominic Kurian
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh , Easter Bush, Midlothian, EH25 9RG, United Kingdom
| | - Sunee Korbsrisate
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University Bangkok, 73170 Thailand
| | - Mark P Stevens
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh , Easter Bush, Midlothian, EH25 9RG, United Kingdom
| | - Joanne M Stevens
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh , Easter Bush, Midlothian, EH25 9RG, United Kingdom
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25
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Abstract
A 2-year longitudinal microbiome study of 22 patients who underwent colectomy with an ileal pouch anal anastomosis detected significant increases in distinct populations of Bacteroides during 9 of 11 patient visits that coincided with inflammation (pouchitis). Oligotyping and metagenomic short-read annotation identified Bacteroides populations that occurred in early samples, bloomed during inflammation, and reappeared after antibiotic treatment. Targeted cultivation of Bacteroides isolates from the same individual at multiple time points and from several patients detected subtle genomic changes, including the identification of rapidly evolving genomic elements that differentiate isogenic strains of Bacteroides fragilis from the mucosa versus lumen. Each patient harbored Bacteroides spp. that are closely related to commonly occurring clinical isolates, including Bacteroides ovatus, B. thetaiotaomicron, B. vulgatus, and B. fragilis, which contained unique loci in different patients for synthesis of capsular polysaccharides. The presence of unique Bacteroides capsular polysaccharide loci within different hosts and between the lumen and mucosa may represent adaptations to stimulate, suppress, and evade host-specific immune responses at different microsites of the ileal pouch. This longitudinal study provides an opportunity to describe shifts in the microbiomes of individual patients who suffer from ulcerative colitis (UC) prior to and following inflammation. Pouchitis serves as a model for UC with a predictable incidence of disease onset and enables prospective longitudinal investigations of UC etiology prior to inflammation. Because of insufficient criteria for predicting which patients will develop UC or pouchitis, the interpretation of cross-sectional study designs suffers from lack of information about the microbiome structure and host gene expression patterns that directly correlate with the onset of disease. Our unique longitudinal study design allows each patient to serve as their own control, providing information about the state of the microbiome and host prior to and during the course of disease. Of significance to the broader community, this study identifies microbial strains that may have genetic elements that trigger the onset of disease in susceptible hosts.
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26
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Vivoli M, Isupov MN, Nicholas R, Hill A, Scott AE, Kosma P, Prior JL, Harmer NJ. Unraveling the B. pseudomallei Heptokinase WcbL: From Structure to Drug Discovery. ACTA ACUST UNITED AC 2016; 22:1622-32. [PMID: 26687481 PMCID: PMC4691232 DOI: 10.1016/j.chembiol.2015.10.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 10/20/2015] [Accepted: 10/31/2015] [Indexed: 11/25/2022]
Abstract
Gram-negative bacteria utilize heptoses as part of their repertoire of extracellular polysaccharide virulence determinants. Disruption of heptose biosynthesis offers an attractive target for novel antimicrobials. A critical step in the synthesis of heptoses is their 1-O phosphorylation, mediated by kinases such as HldE or WcbL. Here, we present the structure of WcbL from Burkholderia pseudomallei. We report that WcbL operates through a sequential ordered Bi-Bi mechanism, loading the heptose first and then ATP. We show that dimeric WcbL binds ATP anti-cooperatively in the absence of heptose, and cooperatively in its presence. Modeling of WcbL suggests that heptose binding causes an elegant switch in the hydrogen-bonding network, facilitating the binding of a second ATP molecule. Finally, we screened a library of drug-like fragments, identifying hits that potently inhibit WcbL. Our results provide a novel mechanism for control of substrate binding and emphasize WcbL as an attractive anti-microbial target for Gram-negative bacteria.
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Affiliation(s)
- Mirella Vivoli
- Department of Biosciences, University of Exeter, Henry Wellcome Building, Stocker Road, Exeter EX4 4QD, UK
| | - Michail N Isupov
- Department of Biosciences, University of Exeter, Henry Wellcome Building, Stocker Road, Exeter EX4 4QD, UK
| | - Rebecca Nicholas
- Department of Biosciences, University of Exeter, Henry Wellcome Building, Stocker Road, Exeter EX4 4QD, UK
| | - Andrew Hill
- Department of Biosciences, University of Exeter, Henry Wellcome Building, Stocker Road, Exeter EX4 4QD, UK
| | - Andrew E Scott
- Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire SP4 0JQ, UK
| | - Paul Kosma
- University of Natural Resources and Life Sciences-Vienna, Muthgasse 18, 1190 Vienna, Austria
| | - Joann L Prior
- Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire SP4 0JQ, UK
| | - Nicholas J Harmer
- Department of Biosciences, University of Exeter, Henry Wellcome Building, Stocker Road, Exeter EX4 4QD, UK.
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27
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Araújo WL, Creason AL, Mano ET, Camargo-Neves AA, Minami SN, Chang JH, Loper JE. Genome Sequencing and Transposon Mutagenesis of Burkholderia seminalis TC3.4.2R3 Identify Genes Contributing to Suppression of Orchid Necrosis Caused by B. gladioli. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2016; 29:435-446. [PMID: 26959838 DOI: 10.1094/mpmi-02-16-0047-r] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
From a screen of 36 plant-associated strains of Burkholderia spp., we identified 24 strains that suppressed leaf and pseudobulb necrosis of orchid caused by B. gladioli. To gain insights into the mechanisms of disease suppression, we generated a draft genome sequence from one suppressive strain, TC3.4.2R3. The genome is an estimated 7.67 megabases in size, with three replicons, two chromosomes, and the plasmid pC3. Using a combination of multilocus sequence analysis and phylogenomics, we identified TC3.4.2R3 as B. seminalis, a species within the Burkholderia cepacia complex that includes opportunistic human pathogens and environmental strains. We generated and screened a library of 3,840 transposon mutants of strain TC3.4.2R3 on orchid leaves to identify genes contributing to plant disease suppression. Twelve mutants deficient in suppression of leaf necrosis were selected and the transposon insertions were mapped to eight loci. One gene is in a wcb cluster that is related to synthesis of extracellular polysaccharide, a key determinant in bacterial-host interactions in other systems, and the other seven are highly conserved among Burkholderia spp. The fundamental information developed in this study will serve as a resource for future research aiming to identify mechanisms contributing to biological control.
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Affiliation(s)
- Welington L Araújo
- 1 Laboratory of Molecular Biology and Microbial Ecology, Department of Microbiology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Allison L Creason
- 2 Department of Botany and Plant Pathology; and
- 3 Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR, U.S.A
| | - Emy T Mano
- 1 Laboratory of Molecular Biology and Microbial Ecology, Department of Microbiology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Aline A Camargo-Neves
- 1 Laboratory of Molecular Biology and Microbial Ecology, Department of Microbiology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
- 4 Interdisciplinary Center for Biotechnology, University of Mogi das Cruzes, Mogi das Cruzes, Brazil
| | - Sonia N Minami
- 4 Interdisciplinary Center for Biotechnology, University of Mogi das Cruzes, Mogi das Cruzes, Brazil
| | - Jeff H Chang
- 2 Department of Botany and Plant Pathology; and
- 3 Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR, U.S.A
- 5 Center for Genome Research and Biocomputing, Oregon State University; and
| | - Joyce E Loper
- 2 Department of Botany and Plant Pathology; and
- 3 Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR, U.S.A
- 6 USDA-Agricultural Research Service, Horticultural Crops Laboratory, Corvallis, Oregon, U.S.A
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28
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Harmer NJ, Chahwan R. Isotype switching: Mouse IgG3 constant region drives increased affinity for polysaccharide antigens. Virulence 2016; 7:623-6. [PMID: 27224549 PMCID: PMC4991320 DOI: 10.1080/21505594.2016.1193278] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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29
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Aschenbroich SA, Lafontaine ER, Hogan RJ. Melioidosis and glanders modulation of the innate immune system: barriers to current and future vaccine approaches. Expert Rev Vaccines 2016; 15:1163-81. [PMID: 27010618 DOI: 10.1586/14760584.2016.1170598] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Burkholderia pseudomallei and Burkholderia mallei are pathogenic bacteria causing fatal infections in animals and humans. Both organisms are classified as Tier 1 Select Agents owing to their highly fatal nature, potential/prior use as bioweapons, severity of disease via respiratory exposure, intrinsic resistance to antibiotics, and lack of a current vaccine. Disease manifestations range from acute septicemia to chronic infection, wherein the facultative intracellular lifestyle of these organisms promotes persistence within a broad range of hosts. This ability to thrive intracellularly is thought to be related to exploitation of host immune response signaling pathways. There are currently considerable gaps in our understanding of the molecular strategies employed by these pathogens to modulate these pathways and evade intracellular killing. A better understanding of the specific molecular basis for dysregulation of host immune responses by these organisms will provide a stronger platform to identify novel vaccine targets and develop effective countermeasures.
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Affiliation(s)
- Sophie A Aschenbroich
- a Department of Pathology , College of Veterinary Medicine, University of Georgia , Athens , GA , USA
| | - Eric R Lafontaine
- b Department of Infectious Diseases , College of Veterinary Medicine, University of Georgia , Athens , GA , USA
| | - Robert J Hogan
- b Department of Infectious Diseases , College of Veterinary Medicine, University of Georgia , Athens , GA , USA.,c Department of Veterinary Biosciences and Diagnostic Imaging , College of Veterinary Medicine, University of Georgia , Athens , GA , USA
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30
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David J, Bell RE, Clark GC. Mechanisms of Disease: Host-Pathogen Interactions between Burkholderia Species and Lung Epithelial Cells. Front Cell Infect Microbiol 2015; 5:80. [PMID: 26636042 PMCID: PMC4649042 DOI: 10.3389/fcimb.2015.00080] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/30/2015] [Indexed: 11/17/2022] Open
Abstract
Members of the Burkholderia species can cause a range of severe, often fatal, respiratory diseases. A variety of in vitro models of infection have been developed in an attempt to elucidate the mechanism by which Burkholderia spp. gain entry to and interact with the body. The majority of studies have tended to focus on the interaction of bacteria with phagocytic cells with a paucity of information available with regard to the lung epithelium. However, the lung epithelium is becoming more widely recognized as an important player in innate immunity and the early response to infections. Here we review the complex relationship between Burkholderia species and epithelial cells with an emphasis on the most pathogenic species, Burkholderia pseudomallei and Burkholderia mallei. The current gaps in knowledge in our understanding are highlighted along with the epithelial host-pathogen interactions that offer potential opportunities for therapeutic intervention.
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Affiliation(s)
- Jonathan David
- Microbiology, Biomedical Sciences, Defence Science and Technology Laboratory Salisbury, UK
| | - Rachel E Bell
- Microbiology, Biomedical Sciences, Defence Science and Technology Laboratory Salisbury, UK ; Division of Immunology, Infection and Inflammatory Disease, Centre for Molecular and Cellular Biology of Inflammation, King's College London London, UK
| | - Graeme C Clark
- Microbiology, Biomedical Sciences, Defence Science and Technology Laboratory Salisbury, UK
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31
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Gaudesi D, Peri C, Quilici G, Gori A, Ferrer-Navarro M, Conchillo-Solé O, Thomas R, Nithichanon A, Lertmemongkolchai G, Titball R, Daura X, Colombo G, Musco G. Structure-based design of a B cell antigen from B. pseudomallei. ACS Chem Biol 2015; 10:803-12. [PMID: 25495888 DOI: 10.1021/cb500831y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Burkholderia pseudomallei is the etiological agent of melioidosis, a severe endemic disease in South-East Asia, causing septicemia and organ failure with high mortality rates. Current treatments and diagnostic approaches are largely ineffective. The development of new diagnostic tools and vaccines toward effective therapeutic opportunities against B. pseudomallei is therefore an urgent priority. In the framework of a multidisciplinary project tackling melioidosis through reverse and structural vaccinology, BPSL1050 was identified as a candidate for immunodiagnostic and vaccine development based on its reactivity against the sera of melioidosis patients. We determined its NMR solution structure and dynamics, and by novel computational methods we predicted immunogenic epitopes that once synthesized were able to elicit the production of antibodies inducing the agglutination of the bacterium and recognizing both BPSL1050 and B. pseudomallei crude extracts. Overall, these results hold promise for novel chemical biology approaches in the discovery of new diagnostic and prophylactic tools against melioidosis.
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Affiliation(s)
- Davide Gaudesi
- Biomolecular
NMR Laboratory, Division of Genetics and Cell Biology, S. Raffaele Scientific Institute, Milan, Italy
| | - Claudio Peri
- Department
of Computational Biology, Institute for Molecular Recognition Chemistry, Italian National Research Council, Milan, Italy
| | - Giacomo Quilici
- Biomolecular
NMR Laboratory, Division of Genetics and Cell Biology, S. Raffaele Scientific Institute, Milan, Italy
| | - Alessandro Gori
- Department
of Computational Biology, Institute for Molecular Recognition Chemistry, Italian National Research Council, Milan, Italy
| | - Mario Ferrer-Navarro
- Institute
of Biotechnology and Biomedicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Oscar Conchillo-Solé
- Institute
of Biotechnology and Biomedicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Rachael Thomas
- College
of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Arnone Nithichanon
- Center
for Research and Development of Medical Diagnostic Laboratories (CMDL),
Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Ganjana Lertmemongkolchai
- Center
for Research and Development of Medical Diagnostic Laboratories (CMDL),
Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Richard Titball
- College
of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Xavier Daura
- Institute
of Biotechnology and Biomedicine, Universitat Autònoma de Barcelona, Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Giorgio Colombo
- Department
of Computational Biology, Institute for Molecular Recognition Chemistry, Italian National Research Council, Milan, Italy
| | - Giovanna Musco
- Biomolecular
NMR Laboratory, Division of Genetics and Cell Biology, S. Raffaele Scientific Institute, Milan, Italy
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32
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Stone JK, DeShazer D, Brett PJ, Burtnick MN. Melioidosis: molecular aspects of pathogenesis. Expert Rev Anti Infect Ther 2014; 12:1487-99. [PMID: 25312349 DOI: 10.1586/14787210.2014.970634] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Burkholderia pseudomallei is a gram-negative bacterium that causes melioidosis, a multifaceted disease that is highly endemic in southeast Asia and northern Australia. This facultative intracellular pathogen possesses a large genome that encodes a wide array of virulence factors that promote survival in vivo by manipulating host cell processes and disarming elements of the host immune system. Antigens and systems that play key roles in B. pseudomallei virulence include capsular polysaccharide, lipopolysaccharide, adhesins, specialized secretion systems, actin-based motility and various secreted factors. This review provides an overview of the current and steadily expanding knowledge regarding the molecular mechanisms used by this organism to survive within a host and their contribution to the pathogenesis of melioidosis.
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Affiliation(s)
- Joshua K Stone
- Department of Microbiology and Immunology, University of South Alabama, 610 Clinic Drive, Mobile, AL 36688, USA
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33
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Vivoli M, Novak HR, Littlechild JA, Harmer NJ. Determination of protein-ligand interactions using differential scanning fluorimetry. J Vis Exp 2014:51809. [PMID: 25285605 PMCID: PMC4692391 DOI: 10.3791/51809] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
A wide range of methods are currently available for determining the dissociation constant between a protein and interacting small molecules. However, most of these require access to specialist equipment, and often require a degree of expertise to effectively establish reliable experiments and analyze data. Differential scanning fluorimetry (DSF) is being increasingly used as a robust method for initial screening of proteins for interacting small molecules, either for identifying physiological partners or for hit discovery. This technique has the advantage that it requires only a PCR machine suitable for quantitative PCR, and so suitable instrumentation is available in most institutions; an excellent range of protocols are already available; and there are strong precedents in the literature for multiple uses of the method. Past work has proposed several means of calculating dissociation constants from DSF data, but these are mathematically demanding. Here, we demonstrate a method for estimating dissociation constants from a moderate amount of DSF experimental data. These data can typically be collected and analyzed within a single day. We demonstrate how different models can be used to fit data collected from simple binding events, and where cooperative binding or independent binding sites are present. Finally, we present an example of data analysis in a case where standard models do not apply. These methods are illustrated with data collected on commercially available control proteins, and two proteins from our research program. Overall, our method provides a straightforward way for researchers to rapidly gain further insight into protein-ligand interactions using DSF.
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Chirakul S, Bartpho T, Wongsurawat T, Taweechaisupapong S, Karoonutaisiri N, Talaat AM, Wongratanacheewin S, Ernst RK, Sermswan RW. Characterization of BPSS1521 (bprD), a regulator of Burkholderia pseudomallei virulence gene expression in the mouse model. PLoS One 2014; 9:e104313. [PMID: 25111708 PMCID: PMC4128674 DOI: 10.1371/journal.pone.0104313] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 07/07/2014] [Indexed: 11/19/2022] Open
Abstract
The Gram-negative saprophytic bacterium Burkholderia pseudomallei is the causative agent of melioidosis, a severe infectious disease of both humans and animals. Severity of the disease is thought to be dependent on both the health status of the host, including diabetes mellitus and kidney disease, and bacterial-derived factors. To identify the bacterial factors important during an acute infection, gene expression profiles in the spleen, lung, and liver of BALB/c (Th2 prototype) and C57BL/6 mice (Th1 prototype) were determined using DNA microarrays. This analysis identified BPSS1521 (bprD), a predicted transcriptional regulator located in the type III secretion system (T3SS-3) operon, to be up regulated, specifically in C57BL/6 mice. BALB/c mice infected with a bprD mutant showed a shorter time to death and increased inflammation, as determined by histopathological analysis and enumeration of bacteria in the spleen. Elevated numbers of multinucleated giant cells (MNGCs), which is the hallmark of melioidosis, were detected in both the wild-type and the bprD mutants; a similar elevation occurs in melioidosis patients. One striking observation was the increased expression of BPSS1520 (bprC), located downstream of bprD, in the bprD mutant. BprC is a regulator of T6SS-1 that is required for the virulence of B. pseudomallei in murine infection models. Deletion of bprD led to the overexpression of bprC and a decreased time to death. bprD expression was elevated in C57BL/6--as compared to BALB/c--mice, suggesting a role for BprD in the natural resistance of C57BL/6 mice to B. pseudomallei. Ultimately, this analysis using mice with different immune backgrounds may enhance our understanding of the outcomes of infection in a variety of models.
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Affiliation(s)
- Sunisa Chirakul
- Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand
- Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | | | - Thidathip Wongsurawat
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathumthani, Thailand
| | | | - Nitsara Karoonutaisiri
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathumthani, Thailand
| | - Adel M. Talaat
- Department of Pathobiology, SVM, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Surasakdi Wongratanacheewin
- Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland-Baltimore, Baltimore, Maryland, United States of America
| | - Rasana W. Sermswan
- Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand
- Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
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Alavi P, Starcher MR, Thallinger GG, Zachow C, Müller H, Berg G. Stenotrophomonas comparative genomics reveals genes and functions that differentiate beneficial and pathogenic bacteria. BMC Genomics 2014; 15:482. [PMID: 24939220 PMCID: PMC4101175 DOI: 10.1186/1471-2164-15-482] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 06/11/2014] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND In recent years, the number of human infections caused by opportunistic pathogens has increased dramatically. Plant rhizospheres are one of the most typical natural reservoirs for these pathogens but they also represent a great source for beneficial microbes with potential for biotechnological applications. However, understanding the natural variation and possible differences between pathogens and beneficials is the main challenge in furthering these possibilities. The genus Stenotrophomonas contains representatives found to be associated with human and plant host. RESULTS We used comparative genomics as well as transcriptomic and physiological approaches to detect significant borders between the Stenotrophomonas strains: the multi-drug resistant pathogenic S. maltophilia and the plant-associated strains S. maltophilia R551-3 and S. rhizophila DSM14405T (both are biocontrol agents). We found an overall high degree of sequence similarity between the genomes of all three strains. Despite the notable similarity in potential factors responsible for host invasion and antibiotic resistance, other factors including several crucial virulence factors and heat shock proteins were absent in the plant-associated DSM14405T. Instead, S. rhizophila DSM14405T possessed unique genes for the synthesis and transport of the plant-protective spermidine, plant cell-wall degrading enzymes, and high salinity tolerance. Moreover, the presence or absence of bacterial growth at 37°C was identified as a very simple method in differentiating between pathogenic and non-pathogenic isolates. DSM14405T is not able to grow at this human-relevant temperature, most likely in great part due to the absence of heat shock genes and perhaps also because of the up-regulation at increased temperatures of several genes involved in a suicide mechanism. CONCLUSIONS While this study is important for understanding the mechanisms behind the emerging pattern of infectious diseases, it is, to our knowledge, the first of its kind to assess the risk of beneficial strains for biotechnological applications. We identified certain traits typical of pathogens such as growth at the human body temperature together with the production of heat shock proteins as opposed to a temperature-regulated suicide system that is harnessed by beneficials.
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Affiliation(s)
- Peyman Alavi
- />Graz University of Technology; Environmental Biotechnology, Petersgasse 12, 8010 Graz, Austria
| | - Margaret R Starcher
- />Graz University of Technology; Environmental Biotechnology, Petersgasse 12, 8010 Graz, Austria
| | - Gerhard G Thallinger
- />Institute for Genomics and Bioinformatics, Graz University of Technology, Graz, Austria
| | - Christin Zachow
- />Institute for Genomics and Bioinformatics, Graz University of Technology, Graz, Austria
| | - Henry Müller
- />Graz University of Technology; Environmental Biotechnology, Petersgasse 12, 8010 Graz, Austria
| | - Gabriele Berg
- />Graz University of Technology; Environmental Biotechnology, Petersgasse 12, 8010 Graz, Austria
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Duval BD, Elrod MG, Gee JE, Chantratita N, Tandhavanant S, Limmathurotsakul D, Hoffmaster AR. Evaluation of a latex agglutination assay for the identification of Burkholderia pseudomallei and Burkholderia mallei. Am J Trop Med Hyg 2014; 90:1043-6. [PMID: 24710616 PMCID: PMC4047727 DOI: 10.4269/ajtmh.14-0025] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cases of melioidosis and glanders are rare in the United States, but the etiologic agents of each disease (Burkholderia pseudomallei and Burkholderia mallei, respectively) are classified as Tier 1 select agents because of concerns about their potential use as bioterrorism agents. A rapid, highly sensitive, and portable assay for clinical laboratories and field use is required. Our laboratory has further evaluated a latex agglutination assay for its ability to identify B. pseudomallei and B. mallei isolates. This assay uses a monoclonal antibody that specifically recognizes the capsular polysaccharide produced by B. pseudomallei and B. mallei, but is absent in closely related Burkholderia species. A total of 110 B. pseudomallei and B. mallei were tested, and 36 closely related Burkholderia species. The latex agglutination assay was positive for 109 of 110 (99.1% sensitivity) B. pseudomallei and B. mallei isolates tested.
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Affiliation(s)
- Brea D Duval
- Bacterial Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia; 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; Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mindy G Elrod
- Bacterial Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia; 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; Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Jay E Gee
- Bacterial Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia; 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; Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Narisara Chantratita
- Bacterial Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia; 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; Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sarunporn Tandhavanant
- Bacterial Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia; 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; Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Direk Limmathurotsakul
- Bacterial Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia; 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; Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Alex R Hoffmaster
- Bacterial Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia; 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; Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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Houghton RL, Reed DE, Hubbard MA, Dillon MJ, Chen H, Currie BJ, Mayo M, Sarovich DS, Theobald V, Limmathurotsakul D, Wongsuvan G, Chantratita N, Peacock SJ, Hoffmaster AR, Duval B, Brett PJ, Burtnick MN, AuCoin DP. Development of a prototype lateral flow immunoassay (LFI) for the rapid diagnosis of melioidosis. PLoS Negl Trop Dis 2014; 8:e2727. [PMID: 24651568 PMCID: PMC3961207 DOI: 10.1371/journal.pntd.0002727] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 01/18/2014] [Indexed: 11/18/2022] Open
Abstract
Burkholderia pseudomallei is a soil-dwelling bacterium and the causative agent of melioidosis. Isolation of B. pseudomallei from clinical samples is the “gold standard” for the diagnosis of melioidosis; results can take 3–7 days to produce. Alternatively, antibody-based tests have low specificity due to a high percentage of seropositive individuals in endemic areas. There is a clear need to develop a rapid point-of-care antigen detection assay for the diagnosis of melioidosis. Previously, we employed In vivo Microbial Antigen Discovery (InMAD) to identify potential B. pseudomallei diagnostic biomarkers. The B. pseudomallei capsular polysaccharide (CPS) and numerous protein antigens were identified as potential candidates. Here, we describe the development of a diagnostic immunoassay based on the detection of CPS. Following production of a CPS-specific monoclonal antibody (mAb), an antigen-capture immunoassay was developed to determine the concentration of CPS within a panel of melioidosis patient serum and urine samples. The same mAb was used to produce a prototype Active Melioidosis Detect Lateral Flow Immunoassay (AMD LFI); the limit of detection of the LFI for CPS is comparable to the antigen-capture immunoassay (∼0.2 ng/ml). The analytical reactivity (inclusivity) of the AMD LFI was 98.7% (76/77) when tested against a large panel of B. pseudomallei isolates. Analytical specificity (cross-reactivity) testing determined that 97.2% of B. pseudomallei near neighbor species (35/36) were not reactive. The non-reactive B. pseudomallei strain and the reactive near neighbor strain can be explained through genetic sequence analysis. Importantly, we show the AMD LFI is capable of detecting CPS in a variety of patient samples. The LFI is currently being evaluated in Thailand and Australia; the focus is to optimize and validate testing procedures on melioidosis patient samples prior to initiation of a large, multisite pre-clinical evaluation. Burkholderia pseudomallei is an environmental bacterium and the cause of melioidosis. Culture of patient samples is the “gold standard” diagnostic test, but may take up to 7 days to complete. Melioidosis has a 10–40% case fatality rate depending on the geographic location. Delays in diagnosis could lead to administration of ineffective antimicrobial therapy, since B. pseudomallei is resistant to empiric antibiotic regimens. Therefore, we have developed a lateral flow immunoassay that can be used in the clinical setting to diagnose melioidosis in 15 minutes. The test promises to provide improved management of patients with melioidosis.
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Affiliation(s)
| | - Dana E. Reed
- Department of Microbiology and Immunology, University of Nevada School of Medicine, Reno, Nevada, United States of America
| | - Mark A. Hubbard
- Department of Microbiology and Immunology, University of Nevada School of Medicine, Reno, Nevada, United States of America
| | - Michael J. Dillon
- Department of Microbiology and Immunology, University of Nevada School of Medicine, Reno, Nevada, United States of America
| | - Hongjing Chen
- InBios International, Inc., Seattle, Washington, United States of America
| | - Bart J. Currie
- Menzies School of Health Research and Northern Territory Clinical School, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Mark Mayo
- Menzies School of Health Research and Northern Territory Clinical School, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Derek S. Sarovich
- Menzies School of Health Research and Northern Territory Clinical School, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Vanessa Theobald
- Menzies School of Health Research and Northern Territory Clinical School, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Direk Limmathurotsakul
- Department of Tropical Hygiene, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Gumphol Wongsuvan
- Department of Clinical Pathology, Sappasithiprasong Hospital, Ubon Ratchathani, Thailand
| | - Narisara Chantratita
- Department of Microbiology and Immunology, and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sharon J. Peacock
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Department of Microbiology and Immunology, Mahidol University, Bangkok, Thailand, and Department of Medicine, Cambridge University, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Alex R. Hoffmaster
- Bacterial Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Brea Duval
- Bacterial Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Paul J. Brett
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama, United States of America
| | - Mary N. Burtnick
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama, United States of America
| | - David P. AuCoin
- Department of Microbiology and Immunology, University of Nevada School of Medicine, Reno, Nevada, United States of America
- * E-mail:
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Vivoli M, Ayres E, Beaumont E, Isupov MN, Harmer NJ. Structural insights into WcbI, a novel polysaccharide-biosynthesis enzyme. IUCRJ 2014; 1:28-38. [PMID: 25075317 PMCID: PMC4104973 DOI: 10.1107/s205225251302695x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 09/30/2013] [Indexed: 06/03/2023]
Abstract
Capsular polysaccharides (CPSs) are protective structures on the surfaces of many Gram-negative bacteria. The principal CPS of the human pathogen and Tier 1 select agent Burkholderia pseudomallei consists of a linear repeat of --3)--2-O-acetyl-6-deoxy-β-d-manno-heptopyranose-(1-. This CPS is critical to the virulence of this emerging pathogen and represents a key target for the development of novel therapeutics. wcbI is one of several genes in the CPS biosynthetic cluster whose deletion leads to significant attenuation of the pathogen; unlike most others, it has no homologues of known function and no detectable sequence similarity to any protein with an extant structure. Here, the crystal structure of WcbI bound to its proposed product, coenzyme A, is reported at 1.38 Å resolution, solved using the halide-soak method with multiple anomalous dispersion. This structure reveals that WcbI incorporates a previously described 100-amino-acid subdomain into a novel, principally helical fold (310 amino acids). This fold adopts a cradle-like structure, with a deep binding pocket for CoA in the loop-rich cradle. Structural analysis and biophysical assays suggest that WcbI functions as an acetyltransferase enzyme, whilst biochemical tests suggest that another functional module might be required to assist its activity in forming the mature B. pseudomallei capsule.
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Affiliation(s)
- Mirella Vivoli
- College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, England
| | - Emily Ayres
- College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, England
| | - Edward Beaumont
- College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, England
| | - Michail N. Isupov
- College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, England
| | - Nicholas J. Harmer
- College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, England
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Ooi WF, Ong C, Nandi T, Kreisberg JF, Chua HH, Sun G, Chen Y, Mueller C, Conejero L, Eshaghi M, Ang RML, Liu J, Sobral BW, Korbsrisate S, Gan YH, Titball RW, Bancroft GJ, Valade E, Tan P. The condition-dependent transcriptional landscape of Burkholderia pseudomallei. PLoS Genet 2013; 9:e1003795. [PMID: 24068961 PMCID: PMC3772027 DOI: 10.1371/journal.pgen.1003795] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 07/29/2013] [Indexed: 12/25/2022] Open
Abstract
Burkholderia pseudomallei (Bp), the causative agent of the often-deadly infectious disease melioidosis, contains one of the largest prokaryotic genomes sequenced to date, at 7.2 Mb with two large circular chromosomes (1 and 2). To comprehensively delineate the Bp transcriptome, we integrated whole-genome tiling array expression data of Bp exposed to >80 diverse physical, chemical, and biological conditions. Our results provide direct experimental support for the strand-specific expression of 5,467 Sanger protein-coding genes, 1,041 operons, and 766 non-coding RNAs. A large proportion of these transcripts displayed condition-dependent expression, consistent with them playing functional roles. The two Bp chromosomes exhibited dramatically different transcriptional landscapes — Chr 1 genes were highly and constitutively expressed, while Chr 2 genes exhibited mosaic expression where distinct subsets were expressed in a strongly condition-dependent manner. We identified dozens of cis-regulatory motifs associated with specific condition-dependent expression programs, and used the condition compendium to elucidate key biological processes associated with two complex pathogen phenotypes — quorum sensing and in vivo infection. Our results demonstrate the utility of a Bp condition-compendium as a community resource for biological discovery. Moreover, the observation that significant portions of the Bp virulence machinery can be activated by specific in vitro cues provides insights into Bp's capacity as an “accidental pathogen”, where genetic pathways used by the bacterium to survive in environmental niches may have also facilitated its ability to colonize human hosts. Bacterial transcriptomes are dynamic, context-specific and condition-dependent. Infection by the soil bacterium, Burkholderia pseudomallei, causes melioidosis, an often fatal infectious disease of humans and animals. Possessing a large multi-chromosomal genome, B. pseudomallei is able to persist and survive in a multitude of environments. To obtain a comprehensive overview of B. pseudomallei expressed transcripts, we initiated whole-genome transcriptome profiling covering a broad spectrum of conditions and exposures — a so-called “condition compendium”. Using the compendium, we confirmed many previously-annotated genes and operons, and also identified hundreds of novel transcripts including anti-sense transcripts and non-coding RNAs. By systematically examining genes exhibiting highly similar expression patterns, we ascribed putative functions to previously uncharacterized genes, and identified novel regulatory elements controlling these expression patterns. We also used the compendium to elucidate candidate virulence pathways associated with quorum-sensing and infection in mice. Our study showcases the power of a B. pseudomallei condition compendium as a valuable resource for understanding microbial physiology and the pathogenesis of melioidosis.
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Affiliation(s)
- Wen Fong Ooi
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | - Catherine Ong
- 2DMERI@DSO, DSO National Laboratories, Singapore, Republic of Singapore
| | - Tannistha Nandi
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | | | - Hui Hoon Chua
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | - Guangwen Sun
- School of Applied Science, Republic Polytechnic, Singapore, Republic of Singapore
| | - Yahua Chen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore
| | - Claudia Mueller
- College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Laura Conejero
- Department of Immunology and Infection, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Majid Eshaghi
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | - Roy Moh Lik Ang
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | - Jianhua Liu
- Genome Institute of Singapore, Singapore, Republic of Singapore
| | - Bruno W. Sobral
- Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, Virginia, United States of America
| | - Sunee Korbsrisate
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Yunn Hwen Gan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore
| | - Richard W. Titball
- College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Gregory J. Bancroft
- Department of Immunology and Infection, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Eric Valade
- Institut de Recherche Biomédicale des Armées/CRSSA, La Tronche, France
- Ecole du Val-de-Grâce, Paris, France
| | - Patrick Tan
- Genome Institute of Singapore, Singapore, Republic of Singapore
- Duke-NUS Graduate Medical School, Singapore, Republic of Singapore
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Republic of Singapore
- * E-mail:
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Exploiting the Burkholderia pseudomallei acute phase antigen BPSL2765 for structure-based epitope discovery/design in structural vaccinology. ACTA ACUST UNITED AC 2013; 20:1147-56. [PMID: 23993463 DOI: 10.1016/j.chembiol.2013.07.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/14/2013] [Accepted: 07/23/2013] [Indexed: 11/20/2022]
Abstract
We solved the crystal structure of Burkholderia pseudomallei acute phase antigen BPSL2765 in the context of a structural vaccinology study, in the area of melioidosis vaccine development. Based on the structure, we applied a recently developed method for epitope design that combines computational epitope predictions with in vitro mapping experiments and successfully identified a consensus sequence within the antigen that, when engineered as a synthetic peptide, was selectively immunorecognized to the same extent as the recombinant protein in sera from melioidosis-affected subjects. Antibodies raised against the consensus peptide were successfully tested in opsonization bacterial killing experiments and antibody-dependent agglutination tests of B. pseudomallei. Our strategy represents a step in the development of immunodiagnostics, in the production of specific antibodies and in the optimization of antigens for vaccine development, starting from structural and physicochemical principles.
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Within-host evolution of Burkholderia pseudomallei over a twelve-year chronic carriage infection. mBio 2013; 4:mBio.00388-13. [PMID: 23860767 PMCID: PMC3735121 DOI: 10.1128/mbio.00388-13] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Burkholderia pseudomallei causes the potentially fatal disease melioidosis. It is generally accepted that B. pseudomallei is a noncommensal bacterium and that any culture-positive clinical specimen denotes disease requiring treatment. Over a 23-year study of melioidosis cases in Darwin, Australia, just one patient from 707 survivors has developed persistent asymptomatic B. pseudomallei carriage. To better understand the mechanisms behind this unique scenario, we performed whole-genome analysis of two strains isolated 139 months apart. During this period, B. pseudomallei underwent several adaptive changes. Of 23 point mutations, 78% were nonsynonymous and 43% were predicted to be deleterious to gene function, demonstrating a strong propensity for positive selection. Notably, a nonsense mutation inactivated the universal stress response sigma factor RpoS, with pleiotropic implications. The genome underwent substantial reduction, with four deletions in chromosome 2 resulting in the loss of 221 genes. The deleted loci included genes involved in secondary metabolism, environmental survival, and pathogenesis. Of 14 indels, 11 occurred in coding regions and 9 resulted in frameshift mutations that dramatically affected predicted gene products. Disproportionately, four indels affected lipopolysaccharide biosynthesis and modification. Finally, we identified a frameshift mutation in both P314 isolates within wcbR, an important component of the capsular polysaccharide I locus, suggesting virulence attenuation early in infection. Our study illustrates a unique clinical case that contrasts a high-consequence infectious agent with a long-term commensal infection and provides further insights into bacterial evolution within the human host. Some bacterial pathogens establish long-term infections that are difficult or impossible to eradicate with current treatments. Rapid advances in genome sequencing technologies provide a powerful tool for understanding bacterial persistence within the human host. Burkholderia pseudomallei is considered a highly pathogenic bacterium because infection is commonly fatal. Here, we document within-host evolution of B. pseudomallei in a unique case of human infection with ongoing chronic carriage. Genomic comparison of isolates obtained 139 months (11.5 years) apart showed a strong signal of adaptation within the human host, including inactivation of virulence and immunogenic factors, and deletion of pathways involved in environmental survival. Two global regulatory genes were mutated in the 139-month isolate, indicating extensive regulatory changes favoring bacterial persistence. Our study provides insights into B. pseudomallei pathogenesis and, more broadly, identifies parallel evolutionary mechanisms that underlie chronic persistence of all bacterial pathogens.
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Reliability of automated biochemical identification of Burkholderia pseudomallei is regionally dependent. J Clin Microbiol 2013; 51:3076-8. [PMID: 23784129 DOI: 10.1128/jcm.01290-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Misidentifications of Burkholderia pseudomallei as Burkholderia cepacia by Vitek 2 have occurred. Multidimensional scaling ordination of biochemical profiles of 217 Malaysian and Australian B. pseudomallei isolates found clustering of misidentified B. pseudomallei isolates from Malaysian Borneo. Specificity of B. pseudomallei identification in Vitek 2 and potentially other automated identification systems is regionally dependent.
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Choh LC, Ong GH, Vellasamy KM, Kalaiselvam K, Kang WT, Al-Maleki AR, Mariappan V, Vadivelu J. Burkholderia vaccines: are we moving forward? Front Cell Infect Microbiol 2013; 3:5. [PMID: 23386999 PMCID: PMC3564208 DOI: 10.3389/fcimb.2013.00005] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 01/20/2013] [Indexed: 11/29/2022] Open
Abstract
The genus Burkholderia consists of diverse species which includes both "friends" and "foes." Some of the "friendly" Burkholderia spp. are extensively used in the biotechnological and agricultural industry for bioremediation and biocontrol. However, several members of the genus including B. pseudomallei, B. mallei, and B. cepacia, are known to cause fatal disease in both humans and animals. B. pseudomallei and B. mallei are the causative agents of melioidosis and glanders, respectively, while B. cepacia infection is lethal to cystic fibrosis (CF) patients. Due to the high rate of infectivity and intrinsic resistance to many commonly used antibiotics, together with high mortality rate, B. mallei and B. pseudomallei are considered to be potential biological warfare agents. Treatments of the infections caused by these bacteria are often unsuccessful with frequent relapse of the infection. Thus, we are at a crucial stage of the need for Burkholderia vaccines. Although the search for a prophylactic therapy candidate continues, to date development of vaccines has not advanced beyond research to human clinical trials. In this article, we review the current research on development of safe vaccines with high efficacy against B. pseudomallei, B. mallei, and B. cepacia. It can be concluded that further research will enable elucidation of the potential benefits and risks of Burkholderia vaccines.
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Affiliation(s)
| | | | | | | | | | | | | | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of MalayaKuala Lumpur, Malaysia
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Neutrophil extracellular traps exhibit antibacterial activity against burkholderia pseudomallei and are influenced by bacterial and host factors. Infect Immun 2012; 80:3921-9. [PMID: 22927051 DOI: 10.1128/iai.00806-12] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Burkholderia pseudomallei is the causative pathogen of melioidosis, of which a major predisposing factor is diabetes mellitus. Polymorphonuclear neutrophils (PMNs) kill microbes extracellularly by the release of neutrophil extracellular traps (NETs). PMNs play a key role in the control of melioidosis, but the involvement of NETs in killing of B. pseudomallei remains obscure. Here, we showed that bactericidal NETs were released from human PMNs in response to B. pseudomallei in a dose- and time-dependent manner. B. pseudomallei-induced NET formation required NADPH oxidase activation but not phosphatidylinositol-3 kinase, mitogen-activated protein kinases, or Src family kinase signaling pathways. B. pseudomallei mutants defective in the virulence-associated Bsa type III protein secretion system (T3SS) or capsular polysaccharide I (CPS-I) induced elevated levels of NETs. NET induction by such mutants was associated with increased bacterial killing, phagocytosis, and oxidative burst by PMNs. Taken together the data imply that T3SS and the capsule may play a role in evading the induction of NETs. Importantly, PMNs from diabetic subjects released NETs at a lower level than PMNs from healthy subjects. Modulation of NET formation may therefore be associated with the pathogenesis and control of melioidosis.
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