1
|
Burkholderia Aortic Aneurysm: A Case Report and Review of the Literature. Case Rep Infect Dis 2017; 2017:6206395. [PMID: 29238621 PMCID: PMC5697124 DOI: 10.1155/2017/6206395] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 10/03/2017] [Accepted: 10/11/2017] [Indexed: 11/17/2022] Open
Abstract
Melioidosis is a frequently fatal infection caused by the Gram-negative bacillus Burkholderia pseudomallei endemic to Southeast Asia and Northern Australia. It is a rare imported pathogen in the United States and is a potential bioterror agent. We report the case of an 82-year-old previously healthy man who presented with 2 weeks of fever and epigastric pain after he returned from the Philippines. A diagnosis of nondissecting mycotic aneurysm in the descending thoracic aorta was made with the help of CT angiogram and positive blood cultures. The patient completely recovered with a 6-month antibiotic therapy followed by surgical repair of the aneurysm. Given the slight increase in the number of melioidosis cases reported by CDC since 2008, melioidosis might be considered an emerging infectious disease in the United States. The purpose of this report is to raise awareness of the disease among clinicians as well as travelers.
Collapse
|
2
|
Perumal Samy R, Stiles BG, Sethi G, Lim LHK. Melioidosis: Clinical impact and public health threat in the tropics. PLoS Negl Trop Dis 2017; 11:e0004738. [PMID: 28493905 PMCID: PMC5426594 DOI: 10.1371/journal.pntd.0004738] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
This review briefly summarizes the geographical distribution and clinical impact of melioidosis, especially in the tropics. Burkholderia pseudomallei (a gram-negative bacterium) is the major causative agent for melioidosis, which is prevalent in Singapore, Malaysia, Thailand, Vietnam, and Northern Australia. Melioidosis patients are increasingly being recognized in other parts of the world. The bacteria are intrinsically resistant to many antimicrobial agents, but prolonged treatment, especially with combinations of antibiotics, may be effective. Despite therapy, the overall case fatality rate of septicemia in melioidosis remains significantly high. Intracellular survival of the bacteria within macrophages may progress to chronic infections, and about 10% of patients suffer relapses. In the coming decades, melioidosis will increasingly afflict travelers throughout many global regions. Clinicians managing travelers returning from the subtropics or tropics with severe pneumonia or septicemia should consider acute melioidosis as a differential diagnosis. Patients with open skin wounds, diabetes, or chronic renal disease are at higher risk for melioidosis and should avoid direct contact with soil and standing water in endemic regions. Furthermore, there are fears that B. pseudomallei may be used as a biological weapon. Technological advancements in molecular diagnostics and antibiotic therapy are improving the disease outcomes in endemic areas throughout Asia. Research and development efforts on vaccine candidates against melioidosis are ongoing.
Collapse
Affiliation(s)
- Ramar Perumal Samy
- Department of Physiology, NUS Immunology Programme, Centre for Life Sciences, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore
| | - Bradley G. Stiles
- Integrated Toxicology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - Gautam Sethi
- Department of Pharmacology, Yong Loo Lin School of Medicine, NUHS, National University of Singapore, Singapore
| | - Lina H. K. Lim
- Department of Physiology, NUS Immunology Programme, Centre for Life Sciences, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore
| |
Collapse
|
3
|
Sanongkiet S, Ponnikorn S, Udomsangpetch R, Tungpradabkul S. Burkholderia pseudomallei rpoS mediates iNOS suppression in human hepatocyte (HC04) cells. FEMS Microbiol Lett 2016; 363:fnw161. [PMID: 27324398 PMCID: PMC4936256 DOI: 10.1093/femsle/fnw161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2016] [Indexed: 12/20/2022] Open
Abstract
Burkholderia pseudomallei is an intracellular Gram-negative bacterial pathogen and the causative agent of melioidosis, a widespread disease in Southeast Asia. Reactive nitrogen, in an intermediate form of nitric oxide (NO), is one of the first lines of defense used by host cells to eliminate intracellular pathogens, through the stimulation of inducible nitric oxide synthase (iNOS). Studies in phagocytotic cells have shown that the iNOS response is muted in B. pseudomallei infection, and implicated the rpoS sigma factor as a key regulatory factor mediating suppression. The liver is a main visceral organ affected by B. pseudomallei, and there is little knowledge about the interaction of liver cells and B. pseudomallei. This study investigated the induction of iNOS, as well as autophagic flux and light-chain 3 (LC3) localization in human liver (HC04) cells in response to infection with B. pseudomallei and its rpoS deficient mutant. Results showed that the rpoS mutant was unable to suppress iNOS induction and that the mutant showed less induction of autophagy and lower co-localization with LC3, and this was coupled with a lower intracellular growth rate. Combining these results suggest that B. pseudomallei rpoS is an important factor in establishing infection in liver cells. This study investigated the induction of nitric oxide synthase (iNOS) in human hepatocyte cells (HC-04) infected with wild-type Burkholderia pseudomallei or an rpoS mutant. RpoS was implicated in the ability to suppress iNOS induction and with the induction of autophagy, indicating that it plays an important role in B. pseudomallei interactions with liver cells.
Collapse
Affiliation(s)
- Sucharat Sanongkiet
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Saranyoo Ponnikorn
- Chulabhorn International College of Medicine, Thammasart University, Rangsit campus, Pathumthani 12120, Thailand
| | - Rachanee Udomsangpetch
- Center for Innovation Development and Technology Transfer, Faculty of Medical Technology, Mahidol University, Salaya, Nakhon Pathom 73170, Thailand
| | - Sumalee Tungpradabkul
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| |
Collapse
|
4
|
Moustafa DA, Scarff JM, Garcia PP, Cassidy SKB, DiGiandomenico A, Waag DM, Inzana TJ, Goldberg JB. Recombinant Salmonella Expressing Burkholderia mallei LPS O Antigen Provides Protection in a Murine Model of Melioidosis and Glanders. PLoS One 2015; 10:e0132032. [PMID: 26148026 PMCID: PMC4492786 DOI: 10.1371/journal.pone.0132032] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 06/09/2015] [Indexed: 11/18/2022] Open
Abstract
Burkholderia pseudomallei and Burkholderia mallei are the etiologic agents of melioidosis and glanders, respectively. These bacteria are highly infectious via the respiratory route and can cause severe and often fatal diseases in humans and animals. Both species are considered potential agents of biological warfare; they are classified as category B priority pathogens. Currently there are no human or veterinary vaccines available against these pathogens. Consequently efforts are directed towards the development of an efficacious and safe vaccine. Lipopolysaccharide (LPS) is an immunodominant antigen and potent stimulator of host immune responses. B. mallei express LPS that is structurally similar to that expressed by B. pseudomallei, suggesting the possibility of constructing a single protective vaccine against melioidosis and glanders. Previous studies of others have shown that antibodies against B. mallei or B. pseudomallei LPS partially protect mice against subsequent lethal virulent Burkholderia challenge. In this study, we evaluated the protective efficacy of recombinant Salmonella enterica serovar Typhimurium SL3261 expressing B. mallei O antigen against lethal intranasal infection with Burkholderia thailandensis, a surrogate for biothreat Burkholderia spp. in a murine model that mimics melioidosis and glanders. All vaccine-immunized mice developed a specific antibody response to B. mallei and B. pseudomallei O antigen and to B. thailandensis and were significantly protected against challenge with a lethal dose of B. thailandensis. These results suggest that live-attenuated SL3261 expressing B. mallei O antigen is a promising platform for developing a safe and effective vaccine.
Collapse
Affiliation(s)
- Dina A. Moustafa
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Pediatrics, Emory University School of Medicine and Children’s Hospital of Atlanta, Inc., Atlanta, Georgia, United States of America
| | - Jennifer M. Scarff
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Preston P. Garcia
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Sara K. B. Cassidy
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Antonio DiGiandomenico
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Infectious Diseases, MedImmune, LLC, Gaithersburg, Maryland, United States of America
| | - David M. Waag
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland, United States of America
| | - Thomas J. Inzana
- Virginia-Maryland Regional College of Veterinary Medicine and Virginia Tech-Carilion School of Medicine, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Joanna B. Goldberg
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Pediatrics, Emory University School of Medicine and Children’s Hospital of Atlanta, Inc., Atlanta, Georgia, United States of America
- * E-mail:
| |
Collapse
|
5
|
Characterization of the Burkholderia mallei tonB Mutant and Its Potential as a Backbone Strain for Vaccine Development. PLoS Negl Trop Dis 2015; 9:e0003863. [PMID: 26114445 PMCID: PMC4482651 DOI: 10.1371/journal.pntd.0003863] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 06/01/2015] [Indexed: 01/24/2023] Open
Abstract
Background In this study, a Burkholderia mallei tonB mutant (TMM001) deficient in iron acquisition was constructed, characterized, and evaluated for its protective properties in acute inhalational infection models of murine glanders and melioidosis. Methodology/Principal Findings Compared to the wild-type, TMM001 exhibits slower growth kinetics, siderophore hyper-secretion and the inability to utilize heme-containing proteins as iron sources. A series of animal challenge studies showed an inverse correlation between the percentage of survival in BALB/c mice and iron-dependent TMM001 growth. Upon evaluation of TMM001 as a potential protective strain against infection, we found 100% survival following B. mallei CSM001 challenge of mice previously receiving 1.5 x 104 CFU of TMM001. At 21 days post-immunization, TMM001-treated animals showed significantly higher levels of B. mallei-specific IgG1, IgG2a and IgM when compared to PBS-treated controls. At 48 h post-challenge, PBS-treated controls exhibited higher levels of serum inflammatory cytokines and more severe pathological damage to target organs compared to animals receiving TMM001. In a cross-protection study of acute inhalational melioidosis with B. pseudomallei, TMM001-treated mice were significantly protected. While wild type was cleared in all B. mallei challenge studies, mice failed to clear TMM001. Conclusions/Significance Although further work is needed to prevent chronic infection by TMM001 while maintaining immunogenicity, our attenuated strain demonstrates great potential as a backbone strain for future vaccine development against both glanders and melioidosis. Burkholderia mallei and B. pseudomallei are the causative agents of glanders and melioidosis, respectively. In addition to the recent rise in cases of glanders and the endemicity of melioidosis worldwide, these pathogens have gained attention as potential bioweapons. Further, these pathogens have huge potential for aerosol delivery and often produce fatal infection amongst untreated individuals. Both pathogens are difficult to treat, and even with antibiotic intervention, patients relapse or get re-infected. A big challenge for vaccine development against these pathogens includes identification of broadly protective antigens and a better understanding of the correlates of protection from both acute and chronic infections. Our study is the first to demonstrate significant protection against a lethal challenge with both Burkholderia species. Because TMM001 persists in immunized mice, we propose that this attenuated organism is a promising backbone-based strain from which a legitimate vaccine candidate can be generated.
Collapse
|
6
|
Schully KL, Bell MG, Ward JM, Keane-Myers AM. Oropharyngeal aspiration of Burkholderia mallei and Burkholderia pseudomallei in BALB/c mice. PLoS One 2014; 9:e115066. [PMID: 25503969 PMCID: PMC4263729 DOI: 10.1371/journal.pone.0115066] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 11/18/2014] [Indexed: 01/22/2023] Open
Abstract
Burkholderia mallei and Burkholderia pseudomallei are potentially lethal pathogens categorized as biothreat agents due, in part, to their ability to be disseminated via aerosol. There are no protective vaccines against these pathogens and treatment options are limited and cumbersome. Since disease severity is greatest when these agents are inhaled, efforts to develop pre- or post-exposure prophylaxis focus largely on inhalation models of infection. Here, we demonstrate a non-invasive and technically simple method for affecting the inhalational challenge of BALB/c mice with B. pseudomallei and B. mallei. In this model, two investigators utilized common laboratory tools such as forceps and a micropipette to conduct and characterize an effective and reproducible inhalational challenge of BALB/c mice with B. mallei and B. pseudomallei. Challenge by oropharyngeal aspiration resulted in acute disease. Additionally, 50% endpoints for B. pseudomallei K96243 and B. mallei ATCC 23344 were nearly identical to published aerosol challenge methods. Furthermore, the pathogens disseminated to all major organs typically targeted by these agents where they proliferated. The pro-inflammatory cytokine production in the proximal and peripheral fluids demonstrated a rapid and robust immune response comparable to previously described murine and human studies. These observations demonstrate that OA is a viable alternative to aerosol exposure.
Collapse
Affiliation(s)
- Kevin L. Schully
- Naval Medical Research Center-Frederick, Frederick, Maryland, United States of America
| | - Matthew G. Bell
- Naval Medical Research Center-Frederick, Frederick, Maryland, United States of America
| | - Jerrold M. Ward
- Global Vet Pathology, Montgomery Village, Maryland, United States of America
| | - Andrea M. Keane-Myers
- Naval Medical Research Center-Frederick, Frederick, Maryland, United States of America
- * E-mail:
| |
Collapse
|
7
|
Ding CH, Hussin S, Tzar MN, Rahman MM, Ramli SR. A case of mycotic aneurysm due to Burkholderia pseudomallei. Pak J Med Sci 2013; 29:666-8. [PMID: 24353601 PMCID: PMC3809241 DOI: 10.12669/pjms.292.2815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 01/10/2013] [Indexed: 11/15/2022] Open
Abstract
Burkholderia pseudomallei is an free-living gram-negative bacterium causing melioidosis and is endemic in Southeast Asia. A 56-year-old diabetic construction worker with a 1-month history of abdominal pain and 1-day history of high-grade fever was found to have a left non-dissecting infrarenal mycotic aortic aneurysm by abdominal computerized tomography scan. Bacteriological examination of his blood yielded Burkholderia pseudomallei. The patient was treated with right axillo-bifemoral bypass with excision of aneurysm and high-dose intravenous ceftazidime for two weeks, followed by oral trimethoprim/sulfamethoxazole and oral doxycycline for a minimum of five months.
Collapse
Affiliation(s)
- C H Ding
- C. H. Ding, Department of Medical Microbiology & Immunology, Faculty of Medicine, National University of Malaysia, 56000 Cheras, Kuala Lumpur, Malaysia
| | - S Hussin
- S. Hussin, Department of Medical Microbiology & Immunology, Faculty of Medicine, National University of Malaysia, 56000 Cheras, Kuala Lumpur, Malaysia
| | - M N Tzar
- M. N. Tzar, Department of Medical Microbiology & Immunology, Faculty of Medicine, National University of Malaysia, 56000 Cheras, Kuala Lumpur, Malaysia
| | - M M Rahman
- M. M. Rahman, Department of Medical Microbiology & Immunology, Faculty of Medicine, National University of Malaysia, 56000 Cheras, Kuala Lumpur, Malaysia
| | - S R Ramli
- S. R. Ramli, Department of Pathology, Hospital Raja Permaisuri Bainun, 30990 Ipoh, Perak, Malaysia
| |
Collapse
|
8
|
Abd Aziz AG, Sedelnikova SE, Ruzheinikov SN, Thorpe S, Mohamed R, Nathan S, Rafferty JB, Baker PJ, Rice DW. Crystallization and preliminary X-ray analysis of the receiver domain of a putative response regulator, BPSL0128, from Burkholderia pseudomallei. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:917-22. [PMID: 22869122 PMCID: PMC3412773 DOI: 10.1107/s1744309112025791] [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: 03/30/2012] [Accepted: 06/06/2012] [Indexed: 11/10/2022]
Abstract
bpsl0128, a gene encoding a putative response regulator from Burkholderia pseudomallei strain D286, has been cloned into a pETBLUE-1 vector system, overexpressed in Escherichia coli and purified. The full-length protein is degraded during purification to leave a fragment corresponding to the putative receiver domain, and crystals of this protein that diffracted to beyond 1.75 Å resolution have been grown by the hanging-drop vapour-diffusion technique using PEG 6000 as the precipitant. The crystals belonged to one of the enantiomorphic pair of space groups P3(1)21 and P3(2)21, with unit-cell parameters a = b = 65.69, c = 105.01 Å and either one or two molecules in the asymmetric unit.
Collapse
Affiliation(s)
- Abd Ghani Abd Aziz
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, England
| | - Svetlana E. Sedelnikova
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, England
| | - Sergey N. Ruzheinikov
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, England
| | - Simon Thorpe
- Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, England
| | - Rahmah Mohamed
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor D.E., Malaysia
- Malaysia Genome Institute, Jalan Bangi, 43000 Kajang, Selangor D.E., Malaysia
| | - Sheila Nathan
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor D.E., Malaysia
- Malaysia Genome Institute, Jalan Bangi, 43000 Kajang, Selangor D.E., Malaysia
| | - John B. Rafferty
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, England
| | - Patrick J. Baker
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, England
| | - David W. Rice
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, England
| |
Collapse
|
9
|
AuCoin DP, Reed DE, Marlenee NL, Bowen RA, Thorkildson P, Judy BM, Torres AG, Kozel TR. Polysaccharide specific monoclonal antibodies provide passive protection against intranasal challenge with Burkholderia pseudomallei. PLoS One 2012; 7:e35386. [PMID: 22530013 PMCID: PMC3328442 DOI: 10.1371/journal.pone.0035386] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 03/16/2012] [Indexed: 01/22/2023] Open
Abstract
Burkholderia pseudomallei is a Gram-negative bacillus that is the causative agent of melioidosis. The bacterium is inherently resistant to many antibiotics and mortality rates remain high in endemic areas. The lipopolysaccharide (LPS) and capsular polysaccharide (CPS) are two surface-associated antigens that contribute to pathogenesis. We previously developed two monoclonal antibodies (mAbs) specific to the CPS and LPS; the CPS mAb was shown to identify antigen in serum and urine from melioidosis patients. The goal of this study was to determine if passive immunization with CPS and LPS mAbs alone and in combination would protect mice from a lethal challenge with B. pseudomallei. Intranasal (i.n.) challenge experiments were performed with B. pseudomallei strains 1026b and K96423. Both mAbs provided significant protection when administered alone. A combination of mAbs was protective when low doses were administered. In addition, combination therapy provided a significant reduction in spleen colony forming units (cfu) compared to results when either the CPS or LPS mAbs were administered alone.
Collapse
Affiliation(s)
- David P AuCoin
- Department of Microbiology and Immunology, University of Nevada School of Medicine, Reno, Nevada, United States of America.
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Abstract
Detection of microbial antigens in clinical samples can lead to rapid diagnosis of an infection and administration of appropriate therapeutics. A major barrier in diagnostics development is determining which of the potentially hundreds or thousands of antigens produced by a microbe are actually present in patient samples in detectable amounts against a background of innumerable host proteins. In this report, we describe a strategy, termed in vivo microbial antigen discovery (InMAD), that we used to identify circulating bacterial antigens. This technique starts with “InMAD serum,” which is filtered serum that has been harvested from BALB/c mice infected with a bacterial pathogen. The InMAD serum, which is free of whole bacterial cells, is used to immunize syngeneic BALB/c mice. The resulting “InMAD immune serum” contains antibodies specific for the soluble microbial antigens present in sera from the infected mice. The InMAD immune serum is then used to probe blots of bacterial lysates or bacterial proteome arrays. Bacterial antigens that are reactive with the InMAD immune serum are precisely the antigens to target in an antigen immunoassay. By employing InMAD, we identified multiple circulating antigens that are secreted or shed during infection using Burkholderia pseudomallei and Francisella tularensis as model organisms. Potential diagnostic targets identified by the InMAD approach included bacterial proteins, capsular polysaccharide, and lipopolysaccharide. The InMAD technique makes no assumptions other than immunogenicity and has the potential to be a broad discovery platform to identify diagnostic targets from microbial pathogens. Effective treatment of microbial infection is critically dependent on early diagnosis and identification of the etiological agent. One means for rapid diagnosis is immunoassay for antigens that are shed into body fluids during infection. Immunoassays can be inexpensive, rapid, and adaptable to a point-of-care format. A major impediment to immunoassay for diagnosis of infectious disease is identification of appropriate antigen targets. This report describes a strategy that can be used for identification of microbial antigens that are shed into serum during infection by the biothreats Burkholderia pseudomallei and Francisella tularensis. Termed InMAD (in vivo microbial antigen discovery), the strategy has the potential for application to a broad spectrum of microbial pathogens.
Collapse
|
11
|
Structural and biological diversity of lipopolysaccharides from Burkholderia pseudomallei and Burkholderia thailandensis. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2009; 16:1420-8. [PMID: 19692625 DOI: 10.1128/cvi.00472-08] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Burkholderia pseudomallei, the etiological agent of melioidosis, is a facultative intracellular pathogen. As B. pseudomallei is a gram-negative bacterium, its outer membrane contains lipopolysaccharide (LPS) molecules, which have been shown to have low-level immunological activities in vitro. In this study, the biological activities of B. pseudomallei LPS were compared to those of Burkholderia thailandensis LPS, and it was found that both murine and human macrophages produced levels of tumor necrosis factor alpha, interleukin-6 (IL-6), and IL-10 in response to B. pseudomallei LPS that were lower than those in response to B. thailandensis LPS in vitro. In order to elucidate the molecular mechanisms underlying the low-level immunological activities of B. pseudomallei LPS, its lipid A moiety was characterized using mass spectrometry. The major lipid A species identified in B. pseudomallei consists of a biphosphorylated disaccharide backbone, which is modified with 4-amino-4-deoxy-arabinose (Ara4N) at both phosphates and penta-acylated with fatty acids (FA) C(14:0)(3-OH), C(16:0)(3-OH), and either C(14:0) or C(14:0)(2-OH). In contrast, the major lipid A species identified in B. thailandensis was a mixture of tetra- and penta-acylated structures with differing amounts of Ara4N and FA C(14:0)(3-OH). Lipid A species acylated with FA C(14:0)(2-OH) were unique to B. pseudomallei and not found in B. thailandensis. Our data thus indicate that B. pseudomallei synthesizes lipid A species with long-chain FA C(14:0)(2-OH) and Ara4N-modified phosphate groups, allowing it to evade innate immune recognition.
Collapse
|
12
|
Vellasamy KM, Vasu C, Puthucheary SD, Vadivelu J. Comparative analysis of extracellular enzymes and virulence exhibited by Burkholderia pseudomallei from different sources. Microb Pathog 2009; 47:111-7. [PMID: 19524661 DOI: 10.1016/j.micpath.2009.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Revised: 06/02/2009] [Accepted: 06/04/2009] [Indexed: 10/20/2022]
Abstract
To evaluate the potential role of extracellular proteins in the pathogenicity and virulence of Burkholderia pseudomallei, the activities of several enzymes in the culture filtrates of nine clinical and six environmental isolates were investigated in vitro and in vivo in ICR strain of mice. The production of protease, phosphatase, phospholipase C, superoxide dismutase, catalase and peroxidase were detected in the culture filtrates of all the 15 isolates at different time points of growth 4-24h. Over time, activity of each enzyme at each time point varied. Profile of secretion was similar among the 15 isolates irrespective of source, that is clinical or environmental. Catalase, phosphatase and phospholipase C were found to be increased in 60-100% of the isolates post-passage in mice. In vivo inoculation studies in ICR mice demonstrated a wide difference in their ability to cause bacteraemia, splenic or external abscesses and mortality rate ranged from few days to several weeks.
Collapse
|
13
|
Defense Against Biological Weapons (Biodefense). NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES, NIH 2009. [PMCID: PMC7122899 DOI: 10.1007/978-1-60327-297-1_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Biological warfare (germ warfare) is defined as the use of any disease-causing organism or toxin(s) found in nature as weapons of war with the intent to destroy an adversary. Though rare, the use of biological weapons has occurred throughout the centuries.
Collapse
|
14
|
Abstract
AIMS The objective of this study was development of a dose-response model for exposure to Burkholderia pseudomallei in different animal hosts and analysis of the results. The data sets with which the model was developed were taken from the open literature. METHODS AND RESULTS All data sets were initially tested for a trend between dose and outcome using the Cochran-Armitage test. Only data showing a statistically significant trend were subjected to further analysis (fitting with parametric dose-response relationships). Dose-response relationships (exponential, beta-Poisson and log-probit) were fit to data using the method of maximum likelihood estimation. CONCLUSIONS Dose-response analysis of BALB/c mice, C57BL/6 mice, guinea pigs and diabetic rats showed that BALB/c mice exposed intranasally (i.n.) and guinea pigs exposed intraperitoneally (i.p.) are significantly more sensitive to B. pseudomallei than C57BL/6 mice exposed i.n. and diabetic rats exposed i.p. SIGNIFICANCE AND IMPACT OF THE STUDY The results confirmed the findings of a study of outbreak data that the diabetic population is more susceptible to infection with B. pseudomallei than the general population. The low dose prediction from best fit dose-response models can be used to draw guidelines for public health decision making processes, including consideration of sensitive subpopulations.
Collapse
Affiliation(s)
- S B Tamrakar
- Department of Civil, Architectural and Environmental Engineering, Drexel University, Philadelphia, PA, USA.
| | | |
Collapse
|
15
|
Korbsrisate S, Tomaras AP, Damnin S, Ckumdee J, Srinon V, Lengwehasatit I, Vasil ML, Suparak S. Characterization of two distinct phospholipase C enzymes from Burkholderia pseudomallei. MICROBIOLOGY-SGM 2007; 153:1907-1915. [PMID: 17526847 DOI: 10.1099/mic.0.2006/003004-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Burkholderia pseudomallei is a serious bacterial pathogen that can cause a lethal infection in humans known as melioidosis. In this study two of its phospholipase C (PLC) enzymes (Plc-1 and Plc-2) were characterized. Starting with a virulent strain, two single mutants were constructed, each with one plc gene inactivated, and one double mutant with both plc genes inactivated. The single plc mutants exhibited decreased extracellular PLC activity in comparison to the wild-type strain, thereby demonstrating that the two genes encoded functional extracellular PLCs. Growth comparisons between the wild-type and PLC mutants in egg-yolk-supplemented medium indicated that both PLCs contributed to egg-yolk phospholipid utilization. Both PLCs hydrolysed phosphatidylcholine and sphingomyelin but neither was haemolytic for human erythrocytes. Experimental infections of eukaryotic cells demonstrated that Plc-1 itself had no effect on plaque-forming efficiency but it had an additive effect on increasing the efficiency of Plc-2 to form plaques. Only Plc-2 had a significant role in host cell cytotoxicity. In contrast, neither Plc-1 nor Plc-2 appeared to play any role in multinucleated giant cell (MNGC) formation or induction of apoptotic death in the cells studied. These data suggested that PLCs contribute, at least in part, to B. pseudomallei virulence and support the view that Plc-1 and Plc-2 are not redundant virulence factors.
Collapse
Affiliation(s)
- Sunee Korbsrisate
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Andrew P Tomaras
- Department of Microbiology, University of Colorado at Denver and Health Sciences Center Aurora, CO 80045, USA
| | - Suwat Damnin
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Jutturong Ckumdee
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Varintip Srinon
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | | | - Michael L Vasil
- Department of Microbiology, University of Colorado at Denver and Health Sciences Center Aurora, CO 80045, USA
| | - Supaporn Suparak
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| |
Collapse
|
16
|
Lee SH, Chong CE, Lim BS, Chai SJ, Sam KK, Mohamed R, Nathan S. Burkholderia pseudomallei animal and human isolates from Malaysia exhibit different phenotypic characteristics. Diagn Microbiol Infect Dis 2007; 58:263-70. [PMID: 17350202 DOI: 10.1016/j.diagmicrobio.2007.01.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Revised: 01/02/2007] [Accepted: 01/11/2007] [Indexed: 11/25/2022]
Abstract
Burkholderia pseudomallei is a Gram-negative saprophytic soil bacterium, which is the etiologic agent of melioidosis, a severe and fatal infectious disease occurring in human and animals. Distinct clinical and animal isolates have been shown to exhibit differences in phenotypic trait such as growth rate, colony morphology, antimicrobial resistance, and virulence. This study was carried out to gain insight into the intrinsic differences between 4 clinical and 6 animal B. pseudomallei isolates from Malaysia. The 16S rRNA-encoding genes from these 10 isolates of B. pseudomallei were sequenced to confirm the identity of these isolates along with the avirulent Burkholderia thailandensis. The nucleotide sequences indicated that the 16S rRNA-encoding genes among the 10 B. pseudomallei isolates were identical to each other. However, the nucleotide sequence differences in the 16S rRNA-encoding genes appeared to be B. pseudomallei and B. thailandensis specific. The growth rate of all B. pseudomallei isolates was determined by generating growth curves at 37 degrees C for 72 h. The isolates were found to differ in growth rates with doubling time varying from 1.5 to 2.3 h. In addition, the B. pseudomallei isolates exhibited considerable variation in colony morphology when grown on Ashdown media, brain-heart infusion agar, and Luria-Bertani agar over 9 days of observation. Antimicrobial susceptibility tests indicated that 80% of the isolates examined were Amp(R) Cb(R) Kn(R) Gm(R) Chl(S) Te(S). Virulence of the B. pseudomallei clinical and animal isolates was evaluated in B. pseudomallei-susceptible BALB/c mice. Most of the clinical isolates were highly virulent. However, virulence did not correlate with isolate origin since 2 of the animal isolates were also highly virulent.
Collapse
MESH Headings
- Animals
- Base Sequence
- Burkholderia pseudomallei/classification
- Burkholderia pseudomallei/genetics
- Burkholderia pseudomallei/isolation & purification
- Burkholderia pseudomallei/physiology
- Colony Count, Microbial
- DNA, Bacterial/chemistry
- DNA, Bacterial/genetics
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- Disease Models, Animal
- Genes, rRNA/genetics
- Humans
- Malaysia
- Melioidosis/microbiology
- Melioidosis/veterinary
- Mice
- Mice, Inbred BALB C
- Microbial Sensitivity Tests
- Molecular Sequence Data
- Phylogeny
- RNA, Bacterial/genetics
- RNA, Ribosomal, 16S/genetics
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
- Spleen/microbiology
- Survival Analysis
- Virulence
Collapse
Affiliation(s)
- Song-Hua Lee
- Faculty of Science and Technology, School of Biosciences and Biotechnology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan, Malaysia
| | | | | | | | | | | | | |
Collapse
|
17
|
Arjcharoen S, Wikraiphat C, Pudla M, Limposuwan K, Woods DE, Sirisinha S, Utaisincharoen P. Fate of a Burkholderia pseudomallei lipopolysaccharide mutant in the mouse macrophage cell line RAW 264.7: possible role for the O-antigenic polysaccharide moiety of lipopolysaccharide in internalization and intracellular survival. Infect Immun 2007; 75:4298-304. [PMID: 17576760 PMCID: PMC1951188 DOI: 10.1128/iai.00285-07] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia pseudomallei is a facultative intracellular gram-negative bacterium that can survive and multiply inside macrophages. One of the mechanisms by which B. pseudomallei escapes macrophage killing is by interfering with the expression of inducible nitric oxide synthase (iNOS). However, the bacterial components that modulate antimicrobial activity of the macrophage have not been fully elucidated. In the present study, we demonstrated that B. pseudomallei strain SRM117, a lipopolysaccharide (LPS) mutant that lacks the O-antigenic polysaccharide moiety, was more susceptible to macrophage killing during the early phase of infection than the parental wild-type strain (1026b). Unlike the wild type, the LPS mutant could readily stimulate Y701-STAT-1 phosphorylation (pY701-STAT-1) and interferon-regulatory factor 1 (IRF-1) expression, both of which are essential transcription factors of iNOS. Neutralizing antibody against beta interferon was able to inhibit the phosphorylation of Y701-STAT-1 and the expression of IRF-1 and iNOS, all of which resulted in an increased rate of intracellular replication. These data suggest that the O-antigenic polysaccharide moiety of B. pseudomallei modulates the host cell response, which in turn controls the intracellular fate of B. pseudomallei inside macrophages.
Collapse
Affiliation(s)
- S Arjcharoen
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | | | | | | | | | | | | |
Collapse
|
18
|
Maurelli AT. Black holes, antivirulence genes, and gene inactivation in the evolution of bacterial pathogens. FEMS Microbiol Lett 2007; 267:1-8. [PMID: 17233672 DOI: 10.1111/j.1574-6968.2006.00526.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The evolution of bacterial pathogens from nonpathogenic ancestors is marked principally by the acquisition of virulence gene clusters on plasmids and pathogenicity islands via horizontal gene transfer. The flip side of this evolutionary force is the equally important adaptation of the newly minted pathogen to its new host niche. Pathoadaptive mutations take the form of modification of gene expression such that the pathogen is better fit to survive within the new niche. This mini-review describes the concept of pathoadaptation by loss of gene function. In this process, genes that are no longer compatible with the novel lifestyle of the pathogen are selectively inactivated either by point mutation, insertion, or deletion. These genes are called 'antivirulence genes'. Selective pressure sometimes leads to the deletion of large regions of the genome that contain antivirulence genes generating 'black holes' in the pathogen genome. Inactivation of antivirulence genes leads to a pathogen that is highly adapted to its host niche. Identification of antivirulence genes for a particular pathogen can lead to a better understanding of how it became a pathogen and the types of genetic traits that need to be silenced in order for the pathogen to colonize its new host niche successfully.
Collapse
Affiliation(s)
- Anthony T Maurelli
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University, Bethesda, MD 20814-4799, USA.
| |
Collapse
|
19
|
The Burkholderia pseudomallei serine protease MprA is autoproteolytically activated to produce a highly stable enzyme. Enzyme Microb Technol 2007. [DOI: 10.1016/j.enzmictec.2006.09.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
20
|
Bottex C, Gauthier YP, Hagen RM, Finke EJ, Splettstösser WD, Thibault FM, Neubauer H, Vidal DR. Attempted passive prophylaxis with a monoclonal anti-Burkholderia pseudomallei exopolysaccharide antibody in a murine model of melioidosis. Immunopharmacol Immunotoxicol 2006; 27:565-83. [PMID: 16435577 DOI: 10.1080/08923970500493995] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Melioidosis is a severe gram-negative infection caused by the facultative intracellular bacterium Burkholderia pseudomallei, which is responsible for a broad spectrum of symptoms in both humans and animals. No licensed vaccine currently exists. This study evaluated the protective effect of a monoclonal antibody (Mab Ps6F6) specific to B. pseudomallei exopolysaccharide in an outbred murine model of sub-acute melioidosis. When administered before the infectious challenge, Ps6F6 significantly increased resistance to infection and restrained bacterial burden in the spleen over a 30-days period. Patterns of IFN-gamma production were similar in the treated and non treated groups of mice. However, Ps6F6 lowered IFN-gamma levels over the duration of the assay period, except on day 1, suggesting a transient and rapid production of IFN-gamma under Ps6F6 control. Minor but persisting increases occurred in IL-12 levels while TNF-alpha was detected only in the controls at the later stages of infection. No IL-10 secretion was detected in both groups of mice. These data suggest that passive prophylaxis with Mab Ps6F6 provide a moderate and transient induction of inflammatory responses in infected mice but failed to trigger a sterilizing protective immunity.
Collapse
Affiliation(s)
- Chantal Bottex
- Centre de Recherches du Service de Santé des Armées Emile Pardé, Unité de Microbiologie, La Tronche, France.
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Parthasarathy N, DeShazer D, England M, Waag DM. Polysaccharide microarray technology for the detection of Burkholderia pseudomallei and Burkholderia mallei antibodies. Diagn Microbiol Infect Dis 2006; 56:329-32. [PMID: 16765554 PMCID: PMC7127370 DOI: 10.1016/j.diagmicrobio.2006.04.018] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Revised: 04/14/2006] [Accepted: 04/27/2006] [Indexed: 11/22/2022]
Abstract
A polysaccharide microarray platform was prepared by immobilizing Burkholderia pseudomallei and Burkholderia mallei polysaccharides. This polysaccharide array was tested with success for detecting B. pseudomallei and B. mallei serum (human and animal) antibodies. The advantages of this microarray technology over the current serodiagnosis of the above bacterial infections were discussed.
Collapse
Affiliation(s)
- Narayanan Parthasarathy
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, USA.
| | | | | | | |
Collapse
|
22
|
Ulrich RL, Ulrich MP, Schell MA, Kim HS, DeShazer D. Development of a polymerase chain reaction assay for the specific identification of Burkholderia mallei and differentiation from Burkholderia pseudomallei and other closely related Burkholderiaceae. Diagn Microbiol Infect Dis 2006; 55:37-45. [PMID: 16546342 DOI: 10.1016/j.diagmicrobio.2005.11.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Revised: 11/14/2005] [Accepted: 11/29/2005] [Indexed: 11/17/2022]
Abstract
Burkholderia mallei and Burkholderia pseudomallei, the etiologic agents responsible for glanders and melioidosis, respectively, are genetically and phenotypically similar and are category B biothreat agents. We used an in silico approach to compare the B. mallei ATCC 23344 and B. pseudomallei K96243 genomes to identify nucleotide sequences unique to B. mallei. Five distinct B. mallei DNA sequences and/or genes were identified and evaluated for polymerase chain reaction (PCR) assay development. Genomic DNAs from a collection of 31 B. mallei and 34 B. pseudomallei isolates, obtained from various geographic, clinical, and environmental sources over a 70-year period, were tested with PCR primers targeted for each of the B. mallei ATCC 23344-specific nucleotide sequences. Of the 5 chromosomal targets analyzed, only PCR primers designed to bimA(Bm) were specific for B. mallei. These primers were used to develop a rapid PCR assay for the definitive identification of B. mallei and differentiation from all other bacteria.
Collapse
Affiliation(s)
- Ricky L Ulrich
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702-5011, USA
| | | | | | | | | |
Collapse
|
23
|
Healey GD, Elvin SJ, Morton M, Williamson ED. Humoral and cell-mediated adaptive immune responses are required for protection against Burkholderia pseudomallei challenge and bacterial clearance postinfection. Infect Immun 2005; 73:5945-51. [PMID: 16113315 PMCID: PMC1231116 DOI: 10.1128/iai.73.9.5945-5951.2005] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Burkholderia pseudomallei, the causative agent of melioidosis, is a gram-negative bacillus endemic to areas of southeast Asia and northern Australia. Presently, there is no licensed vaccine for B. pseudomallei and the organism is refractive to antibiotic therapy. The bacterium is known to survive and multiply inside both phagocytic and nonphagocytic host cells and may be able to spread directly from cell to cell. Current vaccine delivery systems are unlikely to induce the correct immune effectors to stimulate a protective response to the organism. In this study, we have developed a procedure to utilize dendritic cells as a vaccine delivery vector to induce cell-mediated immune responses to B. pseudomallei. Dendritic cells were produced by culturing murine bone marrow progenitor cells in medium containing granulocyte-macrophage colony-stimulating factor and tumor necrosis factor alpha. Purified dendritic cells were pulsed with heat-killed whole-cell B. pseudomallei and used to immunize syngeneic mice. Strong cellular immune responses were elicited by this immunization method, although antibody responses were low. Booster immunizations of either a second dose of dendritic cells or heat-killed B. pseudomallei were administered to increase the immune response. Immunized animals were challenged with fully virulent B. pseudomallei, and protection was demonstrated in those with strong humoral and cell-mediated immunity. These results indicate the importance of both cell-mediated and humoral immune mechanisms in protection against intracellular pathogens.
Collapse
Affiliation(s)
- Gareth D Healey
- Host-Pathogen Analysis, Bldg. 7A, Rm. 201, DSTL, Porton Down, Salisbury SP4 0JQ, United Kingdom.
| | | | | | | |
Collapse
|
24
|
Taweechaisupapong S, Kaewpa C, Arunyanart C, Kanla P, Homchampa P, Sirisinha S, Proungvitaya T, Wongratanacheewin S. Virulence of Burkholderia pseudomallei does not correlate with biofilm formation. Microb Pathog 2005; 39:77-85. [PMID: 16084684 DOI: 10.1016/j.micpath.2005.06.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 06/06/2005] [Accepted: 06/07/2005] [Indexed: 11/16/2022]
Abstract
Burkholderia pseudomallei is the causative agent of melioidosis but currently the pathogenesis of the disease is still poorly understood. One of the virulent factors of gram-negative bacteria is the ability to produce biofilm to evade host defense. As B. pseudomallei has also been reported to develop the biofilm [1], in the present study, we therefore, quantified the biofilm formation in 50 strains of B. pseudomallei and compared with 50 strains of its avirulent counterpart Burkholderia thailandensis using a modified microtiter-plate test. The results showed that the quantity of biofilm produced by B. pseudomallei was statistically higher (P< 0.01) than that of B. thailandensis (means and SEs of the corrected OD630 were 2.17+/-0.29 and 0.59+/-0.05, respectively). Transmission electron micrographs of the B. pseudomallei strain with high biofilm formation exhibited microcolonies of bacterial cells surrounded by dense extracellular slime matrix comparing with only trace quantity in the low biofilm-producing strain or the biofilm mutants generated by Tn5-OT182 mutagenesis. However, no correlation could be observed between the biofilm formation and virulence, judging from the LD50 values in BALB/c mice. The data obtained with these naturally occurring Burkholderia species and the biofilm mutants are incompatible with the possibility that the biofilm plays a role in the pathogenesis of B. pseudomallei infection.
Collapse
Affiliation(s)
- Suwimol Taweechaisupapong
- Department of Oral Diagnosis, Faculty of Dentistry, Khon Kaen University, Khon Kaen, 40002, Thailand.
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Keluangkhot V, Pethsouvanh R, Strobel M. Mélioïdose. Med Mal Infect 2005; 35:469-75. [PMID: 16253457 DOI: 10.1016/j.medmal.2005.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Accepted: 08/01/2005] [Indexed: 10/25/2022]
Abstract
Melioidosis is an emerging zoonosis, due to Burkholderia pseudomallei, which is a highly invasive, resistant, and resilient soil bacteria, transmitted by cutaneous or airborne route, and is a potential weapon for bioterrorism. Although the agent has been identified all over the world, the human disease is endemic only in SE Asia and Northern Australia, and gained recent interest after the December 2004 tsunami. Human infection can be a very severe systemic disease (mortality 20 to 80%), with protean expression, but the lung is the most affected organ (50%). Pathophysiology remains unclear. Diabetes mellitus is a major risk factor, and is present in half the Asian patients with melioidosis. Recommended antibiotic regimens are expensive, and in severe disease should be prolonged to 20 weeks to reduce the risk of relapse. Prospects for prevention are limited, and no vaccine is available yet.
Collapse
Affiliation(s)
- V Keluangkhot
- Institut de la francophonie pour la médecine tropicale, BP 9519, Vientiane, Laos
| | | | | |
Collapse
|
26
|
Abstract
Melioidosis, caused by the gram-negative saprophyte Burkholderia pseudomallei, is a disease of public health importance in southeast Asia and northern Australia that is associated with high case-fatality rates in animals and humans. It has the potential for epidemic spread to areas where it is not endemic, and sporadic case reports elsewhere in the world suggest that as-yet-unrecognized foci of infection may exist. Environmental determinants of this infection, apart from a close association with rainfall, are yet to be elucidated. The sequencing of the genome of a strain of B. pseudomallei has recently been completed and will help in the further identification of virulence factors. The presence of specific risk factors for infection, such as diabetes, suggests that functional neutrophil defects are important in the pathogenesis of melioidosis; other studies have defined virulence factors (including a type III secretion system) that allow evasion of killing mechanisms by phagocytes. There is a possible role for cell-mediated immunity, but repeated environmental exposure does not elicit protective humoral or cellular immunity. A vaccine is under development, but economic constraints may make vaccination an unrealistic option for many regions of endemicity. Disease manifestations are protean, and no inexpensive, practical, and accurate rapid diagnostic tests are commercially available; diagnosis relies on culture of the organism. Despite the introduction of ceftazidime- and carbapenem-based intravenous treatments, melioidosis is still associated with a significant mortality attributable to severe sepsis and its complications. A long course of oral eradication therapy is required to prevent relapse. Studies exploring the role of preventative measures, earlier clinical identification, and better management of severe sepsis are required to reduce the burden of this disease.
Collapse
Affiliation(s)
- Allen C Cheng
- Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | | |
Collapse
|
27
|
Monastyrskaya G, Fushan A, Abaev I, Filyukova O, Kostina M, Pecherskih E, Sverdlov E. Genome-wide comparison reveals great inter- and intraspecies variability in B. pseudomallei and B. mallei pathogens. Res Microbiol 2005; 155:781-93. [PMID: 15501656 DOI: 10.1016/j.resmic.2004.05.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Accepted: 05/24/2004] [Indexed: 10/26/2022]
Abstract
Burkholderia mallei and B. pseudomallei, closely related Gram-negative bacteria, are causative agents of serious infectious diseases of humans and animals: glanders and melioidosis, respectively. Despite numerous studies of these pathogens, the detailed mechanism of their pathogenesis is still unknown. The problem is even more complicated due to natural variability of B. pseudomallei and B. mallei strains, the understanding of which is a prerequisite for rational design of tools for diagnostics, prophylaxis and therapy of the diseases. Using a subtractive hybridization technique, we compared the genomes of B. pseudomallei C-141 and B. mallei C-5 strains. A subtracted library of DNA fragments specific for B. pseudomallei C-141 and absent from B. mallei C-5 was obtained and analyzed. A variety of differences have been detected and mapped on the recently sequenced genome of B. pseudomallei K96243. A comparative sequence analysis also revealed considerable genomic differences between B. pseudomallei C-141 and B. mallei ATCC 23344 strains sequenced at The Institute for Genomic Research (TIGR). We also observed significant genomic differences between B. pseudomallei C-141 and B. pseudomallei K96243. Some of the differential DNA fragments displayed similarity to different mobile elements which have not yet been described for B. pseudomallei, whereas the others matched various prophage components, components of active transport systems, different enzymes and transcription regulators. A substantial proportion of the differential clones had no database matches either at the nucleotide or protein level. The results provide evidence for great genome-wide variability of B. pseudomallei, further confirmed by Southern blot analysis of various B. pseudomallei strains. The data obtained can be useful for future development of efficient diagnostic tools allowing rapid identification of species, strains and isolates of B. mallei and B. pseudomallei.
Collapse
Affiliation(s)
- Galina Monastyrskaya
- Laboratory of Structure and Functions of Human Genes, M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow V-437, Russia.
| | | | | | | | | | | | | |
Collapse
|
28
|
Ulrich RL, DeShazer D, Brueggemann EE, Hines HB, Oyston PC, Jeddeloh JA. Role of quorum sensing in the pathogenicity of Burkholderia pseudomallei. J Med Microbiol 2004; 53:1053-1064. [PMID: 15496380 DOI: 10.1099/jmm.0.45661-0] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Burkholderia pseudomallei is the causative agent of human and animal melioidosis. The role of quorum sensing (QS) in the in vivo pathogenicity of B. pseudomallei via inhalational exposure of BALB/c mice and intraperitoneal challenge of Syrian hamsters has not been reported. This investigation demonstrates that B. pseudomallei encodes a minimum of three luxI and five luxR homologues that are involved in animal pathogenicity. Mass spectrometry analysis of culture supernatants revealed that wild-type B. pseudomallei and the luxI mutants synthesized numerous signalling molecules, including N-octanoyl-homoserine lactone, N-decanoyl-homoserine lactone, N-(3-hydroxyoctanoyl)-l-homoserine lactone, N-(3-hydroxydecanoyl)-l-homoserine lactone and N-(3-oxotetradecanoyl)-l-homoserine lactone, which was further confirmed by heterologous expression of the B. pseudomallei luxI alleles in Escherichia coli. Mutagenesis of the B. pseudomallei QS system increased the time to death and reduced organ colonization of aerosolized BALB/c mice. Further, intraperitoneal challenge of Syrian hamsters with the B. pseudomallei QS mutants resulted in a significant increase in the LD50. Using semi-quantitative plate assays, preliminary analysis suggests that QS does not affect lipase, protease and phospholipase C biosynthesis/secretion in B. pseudomallei. The findings of the investigation demonstrate that B. pseudomallei encodes multiple luxIR genes, and disruption of the QS alleles reduces animal pathogenicity, but does not affect exoproduct secretion.
Collapse
Affiliation(s)
- Ricky L Ulrich
- Bacteriology Division1 and Toxinology/Aerobiology Division2, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, MD 21702-5011, USA 3Microbiology, Dstl, CBS Porton Down, Salisbury SP4 0JQ, UK 4Orion Genomics, Center for Emerging Technologies, 4041 Forest Park, St. Louis, MO 63108, USA
| | - David DeShazer
- Bacteriology Division1 and Toxinology/Aerobiology Division2, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, MD 21702-5011, USA 3Microbiology, Dstl, CBS Porton Down, Salisbury SP4 0JQ, UK 4Orion Genomics, Center for Emerging Technologies, 4041 Forest Park, St. Louis, MO 63108, USA
| | - Ernst E Brueggemann
- Bacteriology Division1 and Toxinology/Aerobiology Division2, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, MD 21702-5011, USA 3Microbiology, Dstl, CBS Porton Down, Salisbury SP4 0JQ, UK 4Orion Genomics, Center for Emerging Technologies, 4041 Forest Park, St. Louis, MO 63108, USA
| | - Harry B Hines
- Bacteriology Division1 and Toxinology/Aerobiology Division2, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, MD 21702-5011, USA 3Microbiology, Dstl, CBS Porton Down, Salisbury SP4 0JQ, UK 4Orion Genomics, Center for Emerging Technologies, 4041 Forest Park, St. Louis, MO 63108, USA
| | - Petra C Oyston
- Bacteriology Division1 and Toxinology/Aerobiology Division2, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, MD 21702-5011, USA 3Microbiology, Dstl, CBS Porton Down, Salisbury SP4 0JQ, UK 4Orion Genomics, Center for Emerging Technologies, 4041 Forest Park, St. Louis, MO 63108, USA
| | - Jeffrey A Jeddeloh
- Bacteriology Division1 and Toxinology/Aerobiology Division2, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter Street, Fort Detrick, MD 21702-5011, USA 3Microbiology, Dstl, CBS Porton Down, Salisbury SP4 0JQ, UK 4Orion Genomics, Center for Emerging Technologies, 4041 Forest Park, St. Louis, MO 63108, USA
| |
Collapse
|
29
|
Valade E, Thibault FM, Gauthier YP, Palencia M, Popoff MY, Vidal DR. The PmlI-PmlR quorum-sensing system in Burkholderia pseudomallei plays a key role in virulence and modulates production of the MprA protease. J Bacteriol 2004; 186:2288-94. [PMID: 15060030 PMCID: PMC412159 DOI: 10.1128/jb.186.8.2288-2294.2004] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia pseudomallei is the causative agent of melioidosis, an often fatal infection of humans and animals. The virulence of this pathogen is thought to depend on a number of secreted proteins, including the MprA metalloprotease. We observed that MprA is produced upon entry into the stationary phase, when the cell density is high, and this prompted us to study cell density-dependent regulation in B. pseudomallei. A search of the B. pseudomallei genome led to identification of a quorum-sensing system involving the LuxI-LuxR homologs PmlI-PmlR. PmlI directed the synthesis of an N-acylhomoserine lactone identified as N-decanoylhomoserine lactone. A B. pseudomallei pmlI mutant was significantly less virulent than the parental strain in a murine model of infection by the intraperitoneal, subcutaneous, and intranasal routes. Inactivation of pmlI resulted in overproduction of MprA at the onset of the stationary phase. A wild-type phenotype was restored following complementation with pmlI or addition of cell-free culture supernatant. In contrast, there was no significant difference between the virulence of a B. pseudomallei mprA mutant and the virulence of the wild-type strain. These results suggest that the PmlI-PmlR quorum-sensing system of B. pseudomallei is essential for full virulence in a mouse model and downregulates the production of MprA at a high cell density.
Collapse
Affiliation(s)
- E Valade
- Unité de Microbiologie, Département de biologie des agents transmissibles, Centre de Recherches du Service de Santé des Armées Emile Pardé, 38702 La Tronche, France.
| | | | | | | | | | | |
Collapse
|
30
|
Abstract
Melioidosis, which is infection with the gram-negative bacterium Burkholderia pseudomallei, is an important cause of sepsis in east Asia and northern Australia. In northeastern Thailand, melioidosis accounts for 20% of all community-acquired septicaemias, and causes death in 40% of treated patients. B pseudomallei is an environmental saprophyte found in wet soils. It mostly infects adults with an underlying predisposing condition, mainly diabetes mellitus. Melioidosis is characterised by formation of abscesses, especially in the lungs, liver, spleen, skeletal muscle, and prostate. In a third of paediatric cases in southeast Asia, the disease presents as parotid abscess. In northern Australia, 4% of patients present with brain stem encephalitis. Ceftazidime is the treatment of choice for severe melioidosis, but response to high dose parenteral treatment is slow (median time to abatement of fever 9 days). Maintenance antibiotic treatment is with a four-drug regimen of chloramphenicol, doxycycline, and trimethoprim-sulfamethoxazole, or with amoxicillin-clavulanate in children and pregnant women. However, even with 20 weeks' antibiotic treatment, 10% of patients relapse. With improvements in health care and diagnostic microbiology in endemic areas of Asia, and increased travel, melioidosis will probably be recognised increasingly during the next decade.
Collapse
|
31
|
O'Brien CR, Krockenberger MB, Martin P, Parkes H, Kidd M, Malik R. Disseminated melioidosis in two cats. J Feline Med Surg 2003; 5:83-9. [PMID: 12670433 PMCID: PMC10822220 DOI: 10.1016/s1098-612x(02)00094-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2002] [Indexed: 10/27/2022]
Abstract
Melioidosis was diagnosed in two cats at necropsy. The first cat presented with jaundice and anaemia but died of overwhelming sepsis soon after admission, despite blood transfusion and other supportive measures. The second cat died several days after developing neurological signs; an infected digital wound may have been the primary focus of infection in this patient. The cats had presumably acquired the infection in Malaysia and northern Australia, respectively, and in both cases disease may have represented reactivation of a latent infection brought on by the stress of relocation. The epidemiology, clinical presentation, diagnosis and treatment of melioidosis are discussed from a feline perspective.
Collapse
Affiliation(s)
- C R O'Brien
- University Veterinary Centre Sydney, Faculty of Veterinary Science, The University of Sydney, NSW, Australia
| | | | | | | | | | | |
Collapse
|
32
|
Smith-Vaughan HC, Gal D, Lawrie PM, Winstanley C, Sriprakash KS, Currie BJ. Ubiquity of putative type III secretion genes among clinical and environmental Burkholderia pseudomallei isolates in Northern Australia. J Clin Microbiol 2003; 41:883-5. [PMID: 12574307 PMCID: PMC149695 DOI: 10.1128/jcm.41.2.883-885.2003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Type III secretion (TTSI) genes of an HRP (hypersensitivity response and pathogenicity)-like locus were present in all 116 Northern Australian Burkholderia pseudomallei isolates tested but were not detected in other common environmental Burkholderia species. PCR of TTS1 genes may prove valuable as a diagnostic test [corrected].
Collapse
|
33
|
Brett PJ, Burtnick MN, Woods DE. The wbiA locus is required for the 2-O-acetylation of lipopolysaccharides expressed by Burkholderia pseudomallei and Burkholderia thailandensis. FEMS Microbiol Lett 2003; 218:323-8. [PMID: 12586411 DOI: 10.1111/j.1574-6968.2003.tb11536.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Burkholderia pseudomallei and Burkholderia thailandensis express similar O-antigens (O-PS II) in which their 6-deoxy-alpha-L-talopyranosyl (L-6dTalp) residues are variably substituted with O-acetyl groups at the O-2 or O-4 positions. In previous studies we demonstrated that the protective monoclonal antibody, Pp-PS-W, reacted with O-PS II expressed by wild-type B. pseudomallei strains but not by a B. pseudomallei wbiA null mutant. In the present study we demonstrate that WbiA activity is required for the acetylation of the L-6dTalp residues at the O-2 position and that structural modification of O-PS II molecules at this site is critical for recognition by Pp-PS-W.
Collapse
Affiliation(s)
- Paul J Brett
- Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Centre, 3330 Hospital Drive NW, T2N 4N1, Calgary, AB, Canada
| | | | | |
Collapse
|
34
|
Abstract
The ability of certain pathogens to infect multiple hosts has led to the development of genetically tractable nonvertebrate hosts to elucidate the molecular mechanisms of interactions between these pathogens and their hosts. The use of plant, insect, nematode, and protozoan hosts to study human pathogens has facilitated the elucidation of molecular nature of pathogenesis and host responses. Analyses of virulence of multihost pathogens on their respective hosts revealed that pathogens utilize many universal offensive strategies to overcome host defenses, irrespective of the evolutionary lineage of the host. Likewise, genetic dissections of the defense response of the nonvertebrate hosts have also shown that key features underlying host defense responses are highly conserved. This review summarizes how the information gained from the analysis of cross-species infections contributes to our understanding of host-pathogen interactions.
Collapse
Affiliation(s)
- Man-Wah Tan
- Department of Genetics, Stanford University School of Medicine, California 94305, USA.
| |
Collapse
|
35
|
Jeddeloh JA, Fritz DL, Waag DM, Hartings JM, Andrews GP. Biodefense-driven murine model of pneumonic melioidosis. Infect Immun 2003; 71:584-7. [PMID: 12496217 PMCID: PMC143420 DOI: 10.1128/iai.71.1.584-587.2003] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A whole-body mouse model of pneumonic melioidosis was established for future evaluation of biodefense vaccine candidates. The aerosol 50% lethal doses of Burkholderia pseudomallei strain 1026b for BALB/c and C57BL/6 mice and the times to death, dissemination in organs, and tissue loads after exposure of the mice to low- and high-dose aerosols are reported. In addition, rpsL mutant backgrounds were attenuated in this acute model of disease.
Collapse
Affiliation(s)
- J A Jeddeloh
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702-5011, USA.
| | | | | | | | | |
Collapse
|
36
|
Ulett GC, Ketheesan N, Clair TW, McElnea CL, Barnes JL, Hirst RG. Analogous cytokine responses to Burkholderia pseudomallei strains contrasting in virulence correlate with partial cross-protection in immunized mice. Infect Immun 2002; 70:3953-8. [PMID: 12065542 PMCID: PMC128107 DOI: 10.1128/iai.70.7.3953-3958.2002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cytokine mRNA levels were assessed in Burkholderia pseudomallei-susceptible BALB/c mice and B. pseudomallei-resistant C57BL/6 mice following administration of a sublethal dose of less virulent (LV) B. pseudomallei, a candidate immunogen tested for protection against a highly virulent (HV) challenge. Compared on the basis of the bacterial loads, the cytokine patterns induced by HV and LV B. pseudomallei were similar, involving gamma interferon, interleukin-10, and other cytokines. Partial cross-protection between B. pseudomallei strains is shown to be associated with cytokine profiles involving both type 1 and type 2 cytokines.
Collapse
Affiliation(s)
- Glen C Ulett
- Department of Microbiology and Immunology, School of Medicine, James Cook University, Townsville, Queensland, Australia 4811.
| | | | | | | | | | | |
Collapse
|
37
|
Lengren J, Withey G, Hack J. A of the breast present at screening mammography. Breast 2002; 11:91-3. [PMID: 14965652 DOI: 10.1054/brst.2001.0385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2001] [Accepted: 07/23/2001] [Indexed: 11/18/2022] Open
Abstract
A previously well 54-year-old woman presented for screening mammography with a 3-day history of an inflamed lump in her right breast. She was subsequently admitted to hospital with acute melioidosis where right breast abscesses were drained. Following recovery and discharge, she was reviewed at the mammographic screening unit where her previous abnormal mammogram was found to be due to melioidosis. To our knowledge this is the first reported case of melioidosis of the breast and its appearance on mammography and ultrasound are described.
Collapse
Affiliation(s)
- J Lengren
- Breastscreen Townsville, Queensland, Australia
| | | | | |
Collapse
|
38
|
Müller S, Feldman MF, Cornelis GR. The Type III secretion system of Gram-negative bacteria: a potential therapeutic target? Expert Opin Ther Targets 2001; 5:327-339. [PMID: 12540268 DOI: 10.1517/14728222.5.3.327] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Several pathogenic Gram-negative bacteria, including Salmonella, Shigella, Yersinia, Pseudomonas aeruginosa and enteropathogenic Escherichia coli harbour a complex attack system called 'Type III secretion' which is, in every case, an essential virulence determinant. This system, activated by contact with an eukaryotic cell membrane, allows bacteria to inject bacterial proteins across the two bacterial membranes and the eukaryotic cell membrane, to reach the cell's cytosol and destroy or subvert the host cell. The Type III virulence mechanism consists of a secretion apparatus, made up of about 25 proteins, and a set of effector proteins released by this apparatus. The mechanism of protein secretion is highly conserved among the different bacteria, although they cause a variety of diseases with different symptoms and severities, from fatal septicaemia to mild diarrhoea or from fulgurant diarrhoea to chronic infection of the lung. This review focuses on the proteins that make up the secretion machinery and examine if it could be a potential target for novel antimicrobials.
Collapse
Affiliation(s)
- Simone Müller
- Université Catholique de Louvain, 74 Avenue Hippocrate, UCL 74.49, B-1200 Brussels, Belgium.
| | | | | |
Collapse
|
39
|
Gauthier YP, Hagen RM, Brochier GS, Neubauer H, Splettstoesser WD, Finke EJ, Vidal DR. Study on the pathophysiology of experimental Burkholderia pseudomallei infection in mice. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2001; 30:53-63. [PMID: 11172992 DOI: 10.1111/j.1574-695x.2001.tb01550.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Burkholderia pseudomallei is the etiological agent of melioidosis, a potentially fatal disease occurring in man and animals. The aim of this study was to investigate the pathophysiological course of experimental melioidosis, and to identify the target organs, in an animal model. For this purpose SWISS mice were infected intraperitoneally with the virulent strain B. pseudomallei 6068. The bacterial load of various organs was quantified daily by bacteriological analysis and by an enzyme-linked immunosorbent assay (ELISA) based on a monoclonal antibody specific to B. pseudomallei exopolysaccharide (EPS). Electron microscopic investigation of the spleen was performed to locate the bacteria at the cellular level. In this model of acute melioidosis, B. pseudomallei had a marked organ tropism for liver and spleen, and showed evidence of in vivo growth with a bacterial burden of 1.6x10(9) colony forming units (CFU) per gram of spleen 5 days after infection with 200 CFU. The highest bacterial loads were detected in the spleen at all time points, in a range from 2x10(6) to 2x10(9) CFU g(-1). They were still 50-80 times greater than the load of the liver at the time of peak burden. Other investigated organs such as lungs, kidneys, and bone marrow were 10(2)-10(4)-fold less infected than the spleen, with loads ranging from 3x10(2) to 3x10(6) CFU g(-1). The heart and the brain were sites of a delayed infection, with counts in a range from 10(3) to 10(7) times lower than bacterial counts in the spleen. The EPS-specific ELISA proved to be highly sensitive, particularly at the level of those tissues in which colony counting on agar revealed low contamination. In the blood, EPS was detected at concentrations corresponding to bacterial loads ranging from 8x10(3) to 6x10(4) CFU ml(-1). Electron microscopic examination of the spleen revealed figures of phagocytosis, and the presence of large numbers of intact bacteria, which occurred either as single cells or densely packed into vacuoles. Sparse figures suggesting bacterial replication were also observed. In addition, some bacteria could be seen in vacuoles that seemed to have lost their membrane. These observations provide a basis for further investigations on the pathogenesis of the disease.
Collapse
Affiliation(s)
- Y P Gauthier
- Centre de Recherches du Service de Santé des Armées Emile Pardé, Unité de Microbiologie, La Tronche, France.
| | | | | | | | | | | | | |
Collapse
|
40
|
Duque E, Segura A, Mosqueda G, Ramos JL. Global and cognate regulators control the expression of the organic solvent efflux pumps TtgABC and TtgDEF of Pseudomonas putida. Mol Microbiol 2001; 39:1100-6. [PMID: 11251828 DOI: 10.1046/j.1365-2958.2001.02310.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pseudomonas putida DOT-T1E grows on a water-toluene double liquid phase. Toluene tolerance in this microorganism is mainly achieved by at least two efflux pumps that belong to the RND family. The TtgDEF efflux pump is induced by toluene, whereas the other efflux pump, called TtgABC, is expressed at a high level in cells not exposed to toluene and at a lower level in cells grown with toluene. The ttgR gene is adjacent to the ttgABC operon and is transcribed divergently from ttgA. The expression level of ttgR was fourfold higher in cells growing in the presence of toluene than in its absence. In a TtgR-deficient background, expression from the ttgA promoter increased about 20-fold, suggesting that TtgR represses expression from the ttgA promoter. In this mutant, background expression of the ttgR gene was also much higher than in the wild-type background; however, its level of expression increased in the presence of toluene. In a ttgR mutant background, expression from the ttgD promoter followed the same pattern of expression as in the wild type. Analysis of a P. putida pTn5cat mutant that exhibited increased sensitivity to a sudden toluene shock, regardless of whether or not it was previously exposed to low toluene concentrations, revealed that pTn5cat had interrupted an lrp-like gene. The ttgR gene was expressed at very high levels in this mutant, with concomitant repression of expression of the ttgABC operon. The second ttgDEF efflux pump was expressed at low levels in this mutant strain, suggesting that the Lrp-like protein is a global regulatory protein involved in the solvent-tolerant response of this strain.
Collapse
Affiliation(s)
- E Duque
- Consejo Superior de Investigaciones Científicas, Estación Experimental del Zaidín, C/Profesor Albareda 1, E-18008 Granada, Spain
| | | | | | | |
Collapse
|
41
|
Winstanley C, Hart CA. Presence of type III secretion genes in Burkholderia pseudomallei correlates with Ara(-) phenotypes. J Clin Microbiol 2000; 38:883-5. [PMID: 10655407 PMCID: PMC86234 DOI: 10.1128/jcm.38.2.883-885.2000] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Dot blot hybridization and PCR amplification of 14 Ara(+) and 8 Ara(-) Burkholderia pseudomallei strains showed that type III secretion (TTS) genes were present in all the Ara(-) strains but absent from all but one of the Ara(+) strains. The link between TTS genes and an Ara(-) phenotype suggests a role for TTS in virulence.
Collapse
Affiliation(s)
- C Winstanley
- Department of Medical Microbiology and Genito-Urinary Medicine, University of Liverpool, Liverpool L69 3GA, United Kingdom.
| | | |
Collapse
|
42
|
DeShazer D, Brett PJ, Burtnick MN, Woods DE. Molecular characterization of genetic loci required for secretion of exoproducts in Burkholderia pseudomallei. J Bacteriol 1999; 181:4661-4. [PMID: 10419967 PMCID: PMC103600 DOI: 10.1128/jb.181.15.4661-4664.1999] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies have demonstrated that Burkholderia pseudomallei secretes protease, lipase, and phospholipase C (PLC) into the extracellular milieu, but their mechanisms of secretion and roles in pathogenesis have not been elucidated. In this study, we isolated and characterized 29 transposon mutants unable to secrete protease, lipase, and PLC.
Collapse
Affiliation(s)
- D DeShazer
- Genetics and Physiology Branch, Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, USA
| | | | | | | |
Collapse
|