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Zhang N, Ye F, Wang Y, Liu R, Huang Z, Chen C, Liu L, Kang X, Dong S, Rajaofera MJN, Zhu C, Zhang L, Zhou Y, Xiong Y, Xia Q. Role of type VI secretion system protein TssJ-3 in virulence and intracellular survival of Burkholderia pseudomallei. Biochem Biophys Res Commun 2023; 682:397-406. [PMID: 37852065 DOI: 10.1016/j.bbrc.2023.09.091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/26/2023] [Accepted: 09/29/2023] [Indexed: 10/20/2023]
Abstract
TssJ-3 is an outer-membrane lipoprotein and is one of the key components of the type VI secretion system in Burkholderia pseudomallei. TssJ translocates effector proteins to target cells to induce innate immune response in the host. However, the tssJ gene has not been identified in B. pseudomallei and its function in this bacterium has not yet been characterized. tssJ-3 knockout and tssJ-3-complemented B. pseudomallei strains were constructed to determine the effects of tssJ-3 on bacterial growth, biofilm formation, flagellum synthesis, motility, host cell infection, and gene expression in B. pseudomallei. We found that the ΔtssJ-3 mutant strain of B. pseudomallei showed significantly suppressed biofilm formation, flagellum synthesis, bacterial growth, motility, and bacterial invasion into host cells (A549 cells). Furthermore, the ΔtssJ-3 mutation downregulated multiple key genes, including biofilm and flagellum-related genes in B. pseudomallei and induced interleukin-8 gene expression in host cells. These results suggest that tssJ-3, an important gene controlling TssJ-3 protein expression, has regulatory effects on biofilm formation and flagellum synthesis in B. pseudomallei. In addition, B. pseudomallei-derived tssJ-3 contributes to cell infiltration and intracellular replication. This study provides a molecular basis of tssJ-3 for developing therapeutic strategies against B. pseudomallei infections.
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Affiliation(s)
- Nan Zhang
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Fengqin Ye
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Yanshuang Wang
- The Second Affiliated Hospital of Hainan Medical University, China
| | - Rui Liu
- The Second Affiliated Hospital of Hainan Medical University, China
| | - Zhenyan Huang
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Chuizhe Chen
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Lin Liu
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Xun Kang
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Sufang Dong
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Mamy Jayne Nelly Rajaofera
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Chuanlong Zhu
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China
| | - Liyuan Zhang
- The Second Affiliated Hospital of Hainan Medical University, China
| | - Yanling Zhou
- Department of Pediatrics, The Fourth People's Hospital of Haikou City, China.
| | - Yu Xiong
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China.
| | - Qianfeng Xia
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199, China.
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Waag DM, Chance TB, Trevino SR, Rossi FD, Fetterer DP, Amemiya K, Dankmeyer JL, Ingavale SS, Tobery SA, Zeng X, Kern SJ, Worsham PL, Cote CK, Welkos SL. Comparison of three non-human primate aerosol models for glanders, caused by Burkholderia mallei. Microb Pathog 2021; 155:104919. [PMID: 33915206 DOI: 10.1016/j.micpath.2021.104919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 01/15/2023]
Abstract
Burkholderia mallei is a gram-negative obligate animal pathogen that causes glanders, a highly contagious and potentially fatal disease of solipeds including horses, mules, and donkeys. Humans are also susceptible, and exposure can result in a wide range of clinical forms, i.e., subclinical infection, chronic forms with remission and exacerbation, or acute and potentially lethal septicemia and/or pneumonia. Due to intrinsic antibiotic resistance and the ability of the organisms to survive intracellularly, current treatment regimens are protracted and complicated; and no vaccine is available. As a consequence of these issues, and since B. mallei is infectious by the aerosol route, B. mallei is regarded as a major potential biothreat agent. To develop optimal medical countermeasures and diagnostic tests, well characterized animal models of human glanders are needed. The goal of this study was to perform a head-to-head comparison of models employing three commonly used nonhuman primate (NHP) species, the African green monkey (AGM), Rhesus macaque, and the Cynomolgus macaque. The natural history of infection and in vitro clinical, histopathological, immunochemical, and bacteriological parameters were examined. The AGMs were the most susceptible NHP to B. mallei; five of six expired within 14 days. Although none of the Rhesus or Cynomolgus macaques succumbed, the Rhesus monkeys exhibited abnormal signs and clinical findings associated with B. mallei infection; and the latter may be useful for modeling chronic B. mallei infection. Based on the disease progression observations, gross and histochemical pathology, and humoral and cellular immune response findings, the AGM appears to be the optimal model of acute, lethal glanders infection. AGM models of infection by B. pseudomallei, the etiologic agent of melioidosis, have been characterized recently. Thus, the selection of the AGM species provides the research community with a single NHP model for investigations on acute, severe, inhalational melioidosis and glanders.
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Affiliation(s)
- David M Waag
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, USA
| | - Taylor B Chance
- Pathology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, USA
| | - Sylvia R Trevino
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, USA
| | - Franco D Rossi
- Applied and Advanced Technology-Aerobiology, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, USA
| | - David P Fetterer
- Biostatistics Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, USA
| | - Kei Amemiya
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, USA
| | - Jennifer L Dankmeyer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, USA
| | - Susham S Ingavale
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, USA
| | - Steven A Tobery
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, USA
| | - Xiankun Zeng
- Pathology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, USA
| | - Steven J Kern
- Biostatistics Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, USA
| | - Patricia L Worsham
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, USA
| | - Christopher K Cote
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, USA.
| | - Susan L Welkos
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD, USA.
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Wang G, Zarodkiewicz P, Valvano MA. Current Advances in Burkholderia Vaccines Development. Cells 2020; 9:E2671. [PMID: 33322641 PMCID: PMC7762980 DOI: 10.3390/cells9122671] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/01/2020] [Accepted: 12/09/2020] [Indexed: 12/18/2022] Open
Abstract
The genus Burkholderia includes a wide range of Gram-negative bacterial species some of which are pathogenic to humans and other vertebrates. The most pathogenic species are Burkholderia mallei, Burkholderia pseudomallei, and the members of the Burkholderia cepacia complex (Bcc). B. mallei and B. pseudomallei, the cause of glanders and melioidosis, respectively, are considered potential bioweapons. The Bcc comprises a subset of Burkholderia species associated with respiratory infections in people with chronic granulomatous disease and cystic fibrosis. Antimicrobial treatment of Burkholderia infections is difficult due to the intrinsic multidrug antibiotic resistance of these bacteria; prophylactic vaccines provide an attractive alternative to counteract these infections. Although commercial vaccines against Burkholderia infections are still unavailable, substantial progress has been made over recent years in the development of vaccines against B. pseudomallei and B. mallei. This review critically discusses the current advances in vaccine development against B. mallei, B. pseudomallei, and the Bcc.
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Affiliation(s)
| | | | - Miguel A. Valvano
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast BT9 7BL, UK; (G.W.); (P.Z.)
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Amemiya K, Dankmeyer JL, Biryukov SS, Treviño SR, Klimko CP, Mou SM, Fetterer DP, Garnes PG, Cote CK, Worsham PL, DeShazer D. Deletion of Two Genes in Burkholderia pseudomallei MSHR668 That Target Essential Amino Acids Protect Acutely Infected BALB/c Mice and Promote Long Term Survival. Vaccines (Basel) 2019; 7:vaccines7040196. [PMID: 31779073 PMCID: PMC6963190 DOI: 10.3390/vaccines7040196] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/31/2019] [Accepted: 11/15/2019] [Indexed: 12/25/2022] Open
Abstract
Melioidosis is an emerging disease that is caused by the facultative intracellular pathogen Burkholderia pseudomallei. It is intrinsically resistant to many antibiotics and host risk factors play a major role in susceptibility to infection. Currently, there is no human or animal vaccine against melioidosis. In this study, multiple B. pseudomallei MSHR668 deletion mutants were evaluated as live attenuated vaccines in the sensitive BALB/c mouse model of melioidosis. The most efficacious vaccines after an intraperitoneal challenge with 50-fold over the 50% median lethal dose (MLD50) with B. pseudomallei K96243 were 668 ΔhisF and 668 ΔilvI. Both vaccines completely protected mice in the acute phase of infection and showed significant protection (50% survivors) during the chronic phase of infection. The spleens of the survivors that were examined were sterile. Splenocytes from mice vaccinated with 668 ΔhisF and 668 ΔilvI expressed higher amounts of IFN-γ after stimulation with B. pseudomallei antigens than splenocytes from mice vaccinated with less protective candidates. Finally, we demonstrate that 668 ΔhisF is nonlethal in immunocompromised NOD/SCID mice. Our results show that 668 ΔhisF and 668 ΔilvI provide protective cell-mediated immune responses in the acute phase of infection and promote long term survival in the sensitive BALB/c mouse model of melioidosis.
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Affiliation(s)
- Kei Amemiya
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - Jennifer L. Dankmeyer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - Sergei S. Biryukov
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - Sylvia R. Treviño
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - Christopher P. Klimko
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - Sherry M. Mou
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - David P. Fetterer
- Biostatistical Services, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (D.P.F.); (P.G.G.)
| | - Preston G. Garnes
- Biostatistical Services, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (D.P.F.); (P.G.G.)
| | - Christopher K. Cote
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - Patricia L. Worsham
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - David DeShazer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
- Correspondence: ; Tel.: +1-301-619-4919
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5
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Norris MH, Khan MSR, Chirakul S, Schweizer HP, Tuanyok A. Outer Membrane Vesicle Vaccines from Biosafe Surrogates Prevent Acute Lethal Glanders in Mice. Vaccines (Basel) 2018; 6:E5. [PMID: 29320408 PMCID: PMC5874646 DOI: 10.3390/vaccines6010005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 01/04/2018] [Accepted: 01/06/2018] [Indexed: 01/13/2023] Open
Abstract
Burkholderia mallei is a host-adapted Gram-negative mammalian pathogen that causes the severe disease glanders. Glanders can manifest as a rapid acute progression or a chronic debilitating syndrome primarily affecting solipeds and humans in close association with infected animals. In USA, B. mallei is classified as one of the most important bacterial biothreat agents. Presently, there is no licensed glanders vaccine available for humans or animals. In this work, outer membrane vesicles (OMVs) were isolated from three attenuated biosafe bacterial strains, Burkholderia pseudomallei Bp82, B. thailandensis E555, and B. thailandensis TxDOH and used to vaccinate mice. B. thailandensis OMVs induced significantly higher antibody responses that were investigated. B. mallei specific serum antibody responses were of higher magnitude in mice vaccinated with B. thailandensis OMVs compared to levels in mice vaccinated with B. pseudomallei OMVs. OMVs derived from biosafe strains protected mice from acute lethal glanders with vesicles from the two B. thailandensis strains affording significant protection (>90%) up to 35 days post-infection with some up to 60 days. Organ loads from 35-day survivors indicated bacteria colonization of the lungs, liver, and spleen while those from 60 days had high CFUs in the spleens. The highest antibody producing vaccine (B. thailandensis E555 OMVs) also protected C57BL/6 mice from acute inhalational glanders with evidence of full protection.
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Affiliation(s)
- Michael H Norris
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine; University of Florida, Gainesville, FL 32608, USA.
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA.
| | - Mohammad S R Khan
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine; University of Florida, Gainesville, FL 32608, USA.
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA.
| | - Sunisa Chirakul
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine; University of Florida, Gainesville, FL 32608, USA.
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA.
| | - Herbert P Schweizer
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA.
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32603, USA.
| | - Apichai Tuanyok
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine; University of Florida, Gainesville, FL 32608, USA.
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA.
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A Burkholderia pseudomallei Outer Membrane Vesicle Vaccine Provides Cross Protection against Inhalational Glanders in Mice and Non-Human Primates. Vaccines (Basel) 2017; 5:vaccines5040049. [PMID: 29232837 PMCID: PMC5748615 DOI: 10.3390/vaccines5040049] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 12/05/2017] [Accepted: 12/06/2017] [Indexed: 01/28/2023] Open
Abstract
Burkholderia mallei is a Gram-negative, non-motile, facultative intracellular bacillus and the causative agent of glanders, a highly contagious zoonotic disease. B. mallei is naturally resistant to multiple antibiotics and there is concern for its potential use as a bioweapon, making the development of a vaccine against B. mallei of critical importance. We have previously demonstrated that immunization with multivalent outer membrane vesicles (OMV) derived from B. pseudomallei provide significant protection against pneumonic melioidosis. Given that many virulence determinants are highly conserved between the two species, we sought to determine if the B. pseudomallei OMV vaccine could cross-protect against B. mallei. We immunized C57Bl/6 mice and rhesus macaques with B. pseudomallei OMVs and subsequently challenged animals with aerosolized B. mallei. Immunization with B. pseudomallei OMVs significantly protected mice against B. mallei and the protection observed was comparable to that achieved with a live attenuated vaccine. OMV immunization induced the production of B.mallei-specific serum IgG and a mixed Th1/Th17 CD4 and CD8 T cell response in mice. Additionally, immunization of rhesus macaques with B. pseudomallei OMVs provided protection against glanders and induced B.mallei-specific serum IgG in non-human primates. These results demonstrate the ability of the multivalent OMV vaccine platform to elicit cross-protection against closely-related intracellular pathogens and to induce robust humoral and cellular immune responses against shared protective antigens.
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Antibodies against In Vivo-Expressed Antigens Are Sufficient To Protect against Lethal Aerosol Infection with Burkholderia mallei and Burkholderia pseudomallei. Infect Immun 2017; 85:IAI.00102-17. [PMID: 28507073 DOI: 10.1128/iai.00102-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 05/08/2017] [Indexed: 12/22/2022] Open
Abstract
Burkholderia mallei, a facultative intracellular bacterium and tier 1 biothreat, causes the fatal zoonotic disease glanders. The organism possesses multiple genes encoding autotransporter proteins, which represent important virulence factors and targets for developing countermeasures in pathogenic Gram-negative bacteria. In the present study, we investigated one of these autotransporters, BatA, and demonstrate that it displays lipolytic activity, aids in intracellular survival, is expressed in vivo, elicits production of antibodies during infection, and contributes to pathogenicity in a mouse aerosol challenge model. A mutation in the batA gene of wild-type strain ATCC 23344 was found to be particularly attenuating, as BALB/c mice infected with the equivalent of 80 median lethal doses cleared the organism. This finding prompted us to test the hypothesis that vaccination with the batA mutant strain elicits protective immunity against subsequent infection with wild-type bacteria. We discovered that not only does vaccination provide high levels of protection against lethal aerosol challenge with B. mallei ATCC 23344, it also protects against infection with multiple isolates of the closely related organism and causative agent of melioidosis, Burkholderia pseudomallei Passive-transfer experiments also revealed that the protective immunity afforded by vaccination with the batA mutant strain is predominantly mediated by IgG antibodies binding to antigens expressed exclusively in vivo Collectively, our data demonstrate that BatA is a target for developing medical countermeasures and that vaccination with a mutant lacking expression of the protein provides a platform to gain insights regarding mechanisms of protective immunity against B. mallei and B. pseudomallei, including antigen discovery.
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Abstract
Purpose of review Burkholderia pseudomallei's and Burkholderia mallei's high rate of infectivity, limited treatment options, and potential use as biological warfare agents underscore the need for development of effective vaccines against these bacteria. Research efforts focused on vaccines against these bacteria are in pre-clinical stages, with no approved formulations currently on the market. Recent findings Several live attenuated and subunit vaccine formulations have been evaluated in animal studies, with no reports of significant long term survival after lethal challenge. Summary This review encompasses the most current vaccine strategies to prevent B. pseudomallei and B. mallei infections while providing insight for successful vaccines moving forward.
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Naureen A, Saqib M, Muhammad G, Hussain MH, Asi MN. Comparative Evaluation of Rose Bengal Plate Agglutination Test, Mallein Test, and Some Conventional Serological Tests for Diagnosis of Equine Glanders. J Vet Diagn Invest 2016; 19:362-7. [PMID: 17609344 DOI: 10.1177/104063870701900404] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The Rose Bengal plate agglutination test (RBT) was evaluated for the diagnosis of equine glanders, and its diagnostic efficiency was compared with that of mallein and other serological tests, including indirect hemagglutination test (IHAT), complement fixation test (CFT), and modified counter immunoelectrophoresis test (mCIET). Sera from 70 naturally infected culture-positive, 96 potentially exposed cohorts, and 110 healthy equines were tested. All tests but mCIET showed 100% specificity when testing the sera from glanders-negative equines. The calculated sensitivities of RBT, IHAT, CFT, mCIET, and mallein test when testing culture-positive equines were 90.0, 97.1, 91.4, 81.4, and 75.7%, respectively. The RBT was significantly ( P < 0.05) more sensitive than the mallein test and mCIET. The positive and negative predictive values of each test (RBT, IHAT, CFT, mallein test, and mCIET) were as follows: 100 and 94, 100 and 98.2, 100 and 96.7, 100 and 86.6, and 90.5 and 88.6, respectively. On comparing glandered and nonglandered animals, the highest agreement (0.987) was found between RBT and CFT followed by RBT and IHAT (0.940), RBT and mallein test (0.871), and RBT and mCIET (0.852). Because the RBT is simpler and rapid to perform, the inclusion of the test as a supplementary test for the diagnosis of glanders in field conditions is recommended.
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Affiliation(s)
- Abeera Naureen
- Department of Clinical Medicine and Surgery, University of Agriculture, Faisalabad, 38040 Pakistan.
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Burkholderia mallei CLH001 Attenuated Vaccine Strain Is Immunogenic and Protects against Acute Respiratory Glanders. Infect Immun 2016; 84:2345-54. [PMID: 27271739 DOI: 10.1128/iai.00328-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 05/26/2016] [Indexed: 11/20/2022] Open
Abstract
Burkholderia mallei is the causative agent of glanders, an incapacitating disease with high mortality rates in respiratory cases. Its endemicity and ineffective treatment options emphasize its public health threat and highlight the need for a vaccine. Live attenuated vaccines are considered the most viable vaccine strategy for Burkholderia, but single-gene-deletion mutants have not provided complete protection. In this study, we constructed the select-agent-excluded B. mallei ΔtonB Δhcp1 (CLH001) vaccine strain and investigated its ability to protect against acute respiratory glanders. Here we show that CLH001 is attenuated, safe, and effective at protecting against lethal B. mallei challenge. Intranasal administration of CLH001 to BALB/c and NOD SCID gamma (NSG) mice resulted in complete survival without detectable colonization or abnormal organ histopathology. Additionally, BALB/c mice intranasally immunized with CLH001 in a prime/boost regimen were fully protected against lethal challenge with the B. mallei lux (CSM001) wild-type strain.
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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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Bozue JA, Chaudhury S, Amemiya K, Chua J, Cote CK, Toothman RG, Dankmeyer JL, Klimko CP, Wilhelmsen CL, Raymond JW, Zavaljevski N, Reifman J, Wallqvist A. Phenotypic Characterization of a Novel Virulence-Factor Deletion Strain of Burkholderia mallei That Provides Partial Protection against Inhalational Glanders in Mice. Front Cell Infect Microbiol 2016; 6:21. [PMID: 26955620 PMCID: PMC4767903 DOI: 10.3389/fcimb.2016.00021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 02/01/2016] [Indexed: 01/29/2023] Open
Abstract
Burkholderia mallei (Bm) is a highly infectious intracellular pathogen classified as a category B biological agent by the Centers for Disease Control and Prevention. After respiratory exposure, Bm establishes itself within host macrophages before spreading into major organ systems, which can lead to chronic infection, sepsis, and death. Previously, we combined computational prediction of host-pathogen interactions with yeast two-hybrid experiments and identified novel virulence factor genes in Bm, including BMAA0553, BMAA0728 (tssN), and BMAA1865. In the present study, we used recombinant allelic exchange to construct deletion mutants of BMAA0553 and tssN (ΔBMAA0553 and ΔTssN, respectively) and showed that both deletions completely abrogated virulence at doses of >100 times the LD50 of the wild-type Bm strain. Analysis of ΔBMAA0553- and ΔTssN-infected mice showed starkly reduced bacterial dissemination relative to wild-type Bm, and subsequent in vitro experiments characterized pathogenic phenotypes with respect to intracellular growth, macrophage uptake and phagosomal escape, actin-based motility, and multinucleated giant cell formation. Based on observed in vitro and in vivo phenotypes, we explored the use of ΔTssN as a candidate live-attenuated vaccine. Mice immunized with aerosolized ΔTssN showed a 21-day survival rate of 67% after a high-dose aerosol challenge with the wild-type Bm ATCC 23344 strain, compared to a 0% survival rate for unvaccinated mice. However, analysis of histopathology and bacterial burden showed that while the surviving vaccinated mice were protected from acute infection, Bm was still able to establish a chronic infection. Vaccinated mice showed a modest IgG response, suggesting a limited potential of ΔTssN as a vaccine candidate, but also showed prolonged elevation of pro-inflammatory cytokines, underscoring the role of cellular and innate immunity in mitigating acute infection in inhalational glanders.
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Affiliation(s)
- Joel A Bozue
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases Fort Detrick, MD, USA
| | - Sidhartha Chaudhury
- Telemedicine and Advanced Technology Research Center, Biotechnology HPC Software Applications Institute, United States Army Medical Research and Materiel Command Fort Detrick, MD, USA
| | - Kei Amemiya
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases Fort Detrick, MD, USA
| | - Jennifer Chua
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases Fort Detrick, MD, USA
| | - Christopher K Cote
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases Fort Detrick, MD, USA
| | - Ronald G Toothman
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases Fort Detrick, MD, USA
| | - Jennifer L Dankmeyer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases Fort Detrick, MD, USA
| | - Christopher P Klimko
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases Fort Detrick, MD, USA
| | - Catherine L Wilhelmsen
- Pathology Division, United States Army of Medical Research Institute of Infectious Diseases Fort Detrick, MD, USA
| | - Jolynn W Raymond
- Pathology Division, United States Army of Medical Research Institute of Infectious Diseases Fort Detrick, MD, USA
| | - Nela Zavaljevski
- Telemedicine and Advanced Technology Research Center, Biotechnology HPC Software Applications Institute, United States Army Medical Research and Materiel Command Fort Detrick, MD, USA
| | - Jaques Reifman
- Telemedicine and Advanced Technology Research Center, Biotechnology HPC Software Applications Institute, United States Army Medical Research and Materiel Command Fort Detrick, MD, USA
| | - Anders Wallqvist
- Telemedicine and Advanced Technology Research Center, Biotechnology HPC Software Applications Institute, United States Army Medical Research and Materiel Command Fort Detrick, MD, USA
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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.
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Yingst SL, Facemire P, Chuvala L, Norwood D, Wolcott M, Huzella L. Pathological findings and diagnostic implications of a rhesus macaque (Macacca mulatta) model of aerosol exposure to Burkholderia mallei (glanders). J Med Microbiol 2015; 64:646-653. [PMID: 25850696 DOI: 10.1099/jmm.0.000065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Burkholderia mallei is a Gram-negative bacillus that causes a pneumonic disease known as glanders in equids and humans, and a lymphatic infection known as farcy, primarily in equids. With the potential to infect humans by the respiratory route, aerosol exposure can result in severe, occasionally fatal, pneumonia. Today, glanders infections in humans are rare, likely due to less frequent contact with infected equids than in the past. Acutely ill humans often have non-specific clinical signs and in order to diagnose cases, especially in scenarios of multiple cases in an unexpected setting, rapid diagnostics for B. mallei may be critical. The pathogenesis of acute glanders in the rhesus macaque (Macaca mulatta) was studied as an initial effort to improve diagnostic methods. In the study described here, the diagnostic techniques of PCR, culture and histopathology were compared. The results indicated that PCR may provide rapid, non-invasive diagnosis of glanders in some cases. As expected, PCR results were positive in lung tissue in 11/12 acutely infected rhesus macaques, but more importantly in terms of diagnostic algorithm development, PCR results were frequently positive in non-invasive samples such as broncho-alveolar lavage or nasal swabs (7/12) and occasionally in blood (3/12). However, conventional bacterial culture failed to recover bacteria in many of these samples. The study showed that the clinical presentation of aerosol-exposed rhesus macaques is similar to descriptions of human glanders and that PCR has potential for rapid diagnosis of outbreaks, if not individual cases.
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Affiliation(s)
- Samuel L Yingst
- US Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, USA
| | - Paul Facemire
- US Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, USA
| | | | - David Norwood
- US Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, USA
| | - Mark Wolcott
- US Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, USA
| | - Louis Huzella
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD, USA.,US Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, USA
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Pegoraro G, Eaton BP, Ulrich RL, Lane DJ, Ojeda JF, Bavari S, DeShazer D, Panchal RG. A high-content imaging assay for the quantification of the Burkholderia pseudomallei induced multinucleated giant cell (MNGC) phenotype in murine macrophages. BMC Microbiol 2014; 14:98. [PMID: 24750902 PMCID: PMC4077104 DOI: 10.1186/1471-2180-14-98] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/11/2014] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Burkholderia pseudomallei (Bp), a Gram-negative, motile, facultative intracellular bacterium is the causative agent of melioidosis in humans and animals. The Bp genome encodes a repertoire of virulence factors, including the cluster 3 type III secretion system (T3SS-3), the cluster 1 type VI secretion system (T6SS-1), and the intracellular motility protein BimA, that enable the pathogen to invade both phagocytic and non-phagocytic cells. A unique hallmark of Bp infection both in vitro and in vivo is its ability to induce cell-to-cell fusion of macrophages to form multinucleated giant cells (MNGCs), which to date are semi-quantitatively reported following visual inspection. RESULTS In this study we report the development of an automated high-content image acquisition and analysis assay to quantitate the Bp induced MNGC phenotype. Validation of the assay was performed using T6SS-1 (∆hcp1) and T3SS-3 (∆bsaZ) mutants of Bp that have been previously reported to exhibit defects in their ability to induce MNGCs. Finally, screening of a focused small molecule library identified several Histone Deacetylase (HDAC) inhibitors that inhibited Bp-induced MNGC formation of macrophages. CONCLUSIONS We have successfully developed an automated HCI assay to quantitate MNGCs induced by Bp in macrophages. This assay was then used to characterize the phenotype of the Bp mutants for their ability to induce MNGC formation and identify small molecules that interfere with this process. Successful application of chemical genetics and functional reverse genetics siRNA approaches in the MNGC assay will help gain a better understanding of the molecular targets and cellular mechanisms responsible for the MNGC phenotype induced by Bp, by other bacteria such as Mycobacterium tuberculosis, or by exogenously added cytokines.
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Affiliation(s)
- Gianluca Pegoraro
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702-5011, USA
- Perkin Elmer, Waltham, MA 02451, USA
- Present Address: Center for Cancer Research, National Cancer Institute/NIH, Bethesda, MD 20892, USA
| | - Brett P Eaton
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702-5011, USA
| | - Ricky L Ulrich
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702-5011, USA
| | - Douglas J Lane
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702-5011, USA
| | - Jenifer F Ojeda
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702-5011, USA
| | - Sina Bavari
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702-5011, USA
| | - David DeShazer
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702-5011, USA
| | - Rekha G Panchal
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702-5011, USA
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Verma AK, . MS, . N, . RT, . KD, . SVS. Glanders-A Re-emerging Zoonotic Disease: A Review. ACTA ACUST UNITED AC 2013. [DOI: 10.3923/jbs.2014.38.51] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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17
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Lafontaine ER, Zimmerman SM, Shaffer TL, Michel F, Gao X, Hogan RJ. Use of a safe, reproducible, and rapid aerosol delivery method to study infection by Burkholderia pseudomallei and Burkholderia mallei in mice. PLoS One 2013; 8:e76804. [PMID: 24098563 PMCID: PMC3788738 DOI: 10.1371/journal.pone.0076804] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 08/26/2013] [Indexed: 11/24/2022] Open
Abstract
Burkholderia pseudomallei, the etiologic agent of melioidosis, is a saprophytic bacterium readily isolated from wet soils of countries bordering the equator. Burkholderia mallei is a host-adapted clone of B. pseudomallei that does not persist outside of its equine reservoir and causes the zoonosis glanders, which is endemic in Asia, Africa, the Middle East and South America. Infection by these organisms typically occurs via percutaneous inoculation or inhalation of aerosols, and the most common manifestation is severe pneumonia leading to fatal bacteremia. Glanders and melioidosis are difficult to diagnose and require prolonged antibiotic therapy with low success rates. There are no vaccines available to protect against either Burkholderia species, and there is concern regarding their use as biological warfare agents given that B. mallei has previously been utilized in this manner. Hence, experiments were performed to establish a mouse model of aerosol infection to study the organisms and develop countermeasures. Using a hand-held aerosolizer, BALB/c mice were inoculated intratracheally with strains B. pseudomallei 1026b and B. mallei ATCC23344 and growth of the agents in the lungs, as well as dissemination to the spleen, were examined. Mice infected with 102, 103 and 104 organisms were unable to control growth of B. mallei in the lungs and bacteria rapidly disseminated to the spleen. Though similar results were observed in mice inoculated with 103 and 104B. pseudomallei cells, animals infected with 102 organisms controlled bacterial replication in the lungs, dissemination to the spleen, and the extent of bacteremia. Analysis of sera from mice surviving acute infection revealed that animals produced antibodies against antigens known to be targets of the immune response in humans. Taken together, these data show that small volume aerosol inoculation of mice results in acute disease, dose-dependent chronic infection, and immune responses that correlate with those seen in human infections.
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Affiliation(s)
- Eric R. Lafontaine
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Shawn M. Zimmerman
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Teresa L. Shaffer
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America
| | - Frank Michel
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia, Athens, Georgia, United States of America
| | - Xiudan Gao
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia, Athens, Georgia, United States of America
| | - Robert J. Hogan
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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Stundick MV, Albrecht MT, Houchens CR, Smith AP, Dreier TM, Larsen JC. Animal models for Francisella tularensis and Burkholderia species: scientific and regulatory gaps toward approval of antibiotics under the FDA Animal Rule. Vet Pathol 2013; 50:877-92. [PMID: 23628693 DOI: 10.1177/0300985813486812] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The development and regulatory approval of medical countermeasures (MCMs) for the treatment and prevention of bacterial threat agent infections will require the evaluation of products in animal models. To obtain regulatory approval, these models must accurately recapitulate aspects of human disease, including, but not necessarily limited to, route of exposure, time to disease onset, pathology, immune response, and mortality. This article focuses on the state of animal model development for 3 agents for which models are largely immature: Francisella tularensis, Burkholderia mallei, and Burkholderia pseudomallei. An overview of available models and a description of scientific and regulatory gaps are provided.
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Affiliation(s)
- M V Stundick
- US Department of Health and Human Services, Office of the Assistant Secretary for Preparedness and Response, Biomedical Advanced Research and Development Authority, 375 E. St, SW- 12th Floor, Washington, DC 20024, USA.
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Silva EB, Dow SW. Development of Burkholderia mallei and pseudomallei vaccines. Front Cell Infect Microbiol 2013; 3:10. [PMID: 23508691 PMCID: PMC3598006 DOI: 10.3389/fcimb.2013.00010] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 02/20/2013] [Indexed: 12/16/2022] Open
Abstract
Burkholderia mallei and Burkholderia pseudomallei are Gram-negative bacteria that cause glanders and melioidosis, respectively. Inhalational infection with either organism can result in severe and rapidly fatal pneumonia. Inoculation by the oral and cutaneous routes can also produce infection. Chronic infection may develop after recovery from acute infection with both agents, and control of infection with antibiotics requires prolonged treatment. Symptoms for both meliodosis and glanders are non-specific, making diagnosis difficult. B. pseudomallei can be located in the environment, but in the host, B. mallei and B. psedomallei are intracellular organisms, and infection results in similar immune responses to both agents. Effective early innate immune responses are critical to controlling the early phase of the infection. Innate immune signaling molecules such as TLR, NOD, MyD88, and pro-inflammatory cytokines such as IFN-γ and TNF-α play key roles in regulating control of infection. Neutrophils and monocytes are critical cells in the early infection for both microorganisms. Both monocytes and macrophages are necessary for limiting dissemination of B. pseudomallei. In contrast, the role of adaptive immune responses in controlling Burkholderia infection is less well understood. However, T cell responses are critical for vaccine protection from Burkholderia infection. At present, effective vaccines for prevention of glanders or meliodosis have not been developed, although recently development of Burkholderia vaccines has received renewed attention. This review will summarize current and past approaches to develop B. mallei and B. pseudomalllei vaccines, with emphasis on immune mechanisms of protection and the challenges facing the field. At present, immunization with live attenuated bacteria provides the most effective and durable immunity, and it is important therefore to understand the immune correlates of protection induced by live attenuated vaccines. Subunit vaccines have typically provided less robust immunity, but are safer to administer to a wider variety of people, including immune compromised individuals because they do not reactivate or cause disease. The challenges facing B. mallei and B. pseudomalllei vaccine development include identification of broadly protective antigens, design of efficient vaccine delivery and adjuvant systems, and a better understanding of the correlates of protection from both acute and chronic infection.
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Affiliation(s)
- Ediane B Silva
- Department of Microbiology, Immunology, and Pathology, Regional Center of Excellence in Emerging Diseases and Bioterrorism, Colorado State University Ft. Collins, CO, USA
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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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22
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Burtnick MN, Heiss C, Roberts RA, Schweizer HP, Azadi P, Brett PJ. Development of capsular polysaccharide-based glycoconjugates for immunization against melioidosis and glanders. Front Cell Infect Microbiol 2012; 2:108. [PMID: 22912938 PMCID: PMC3419357 DOI: 10.3389/fcimb.2012.00108] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 07/28/2012] [Indexed: 11/13/2022] Open
Abstract
Burkholderia pseudomallei and Burkholderia mallei, the etiologic agents of melioidosis and glanders, respectively, cause severe disease in humans and animals and are considered potential agents of biological warfare and terrorism. Diagnosis and treatment of infections caused by these pathogens can be challenging and, in the absence of chemotherapeutic intervention, acute disease is frequently fatal. At present, there are no human or veterinary vaccines available for immunization against these emerging/re-emerging infectious diseases. One of the long term objectives of our research, therefore, is to identify and characterize protective antigens expressed by B. pseudomallei and B. mallei and use them to develop efficacious vaccine candidates. Previous studies have demonstrated that the 6-deoxy-heptan capsular polysaccharide (CPS) expressed by these bacterial pathogens is both a virulence determinant and a protective antigen. Consequently, this carbohydrate moiety has become an important component of the various subunit vaccines that we are currently developing in our laboratory. In the present study, we describe a reliable method for isolating CPS antigens from O-polysaccharide (OPS) deficient strains of B. pseudomallei; including a derivative of the select agent excluded strain Bp82. Utilizing these purified CPS samples, we also describe a simple procedure for covalently linking these T-cell independent antigens to carrier proteins. In addition, we demonstrate that high titer IgG responses can be raised against the CPS component of such constructs. Collectively, these approaches provide a tangible starting point for the development of novel CPS-based glycoconjugates for immunization against melioidosis and glanders.
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Affiliation(s)
- Mary N Burtnick
- Department of Microbiology and Immunology, University of South Alabama Mobile, AL, USA
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Fisher NA, Ribot WJ, Applefeld W, DeShazer D. The Madagascar hissing cockroach as a novel surrogate host for Burkholderia pseudomallei, B. mallei and B. thailandensis. BMC Microbiol 2012; 12:117. [PMID: 22892068 PMCID: PMC3431275 DOI: 10.1186/1471-2180-12-117] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 06/07/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Burkholderia pseudomallei and Burkholderia mallei are gram-negative pathogens responsible for the diseases melioidosis and glanders, respectively. Both species cause disease in humans and animals and have been designated as category B select agents by the Centers for Disease Control and Prevention (CDC). Burkholderia thailandensis is a closely related bacterium that is generally considered avirulent for humans. While it can cause disease in rodents, the B. thailandensis 50% lethal dose (LD50) is typically ≥ 104-fold higher than the B. pseudomallei and B. mallei LD50 in mammalian models of infection. Here we describe an alternative to mammalian hosts in the study of virulence and host-pathogen interactions of these Burkholderia species. RESULTS Madagascar hissing cockroaches (MH cockroaches) possess a number of qualities that make them desirable for use as a surrogate host, including ease of breeding, ease of handling, a competent innate immune system, and the ability to survive at 37°C. MH cockroaches were highly susceptible to infection with B. pseudomallei, B. mallei and B. thailandensis and the LD50 was <10 colony-forming units (cfu) for all three species. In comparison, the LD50 for Escherichia coli in MH cockroaches was >105 cfu. B. pseudomallei, B. mallei, and B. thailandensis cluster 1 type VI secretion system (T6SS-1) mutants were all attenuated in MH cockroaches, which is consistent with previous virulence studies conducted in rodents. B. pseudomallei mutants deficient in the other five T6SS gene clusters, T6SS-2 through T6SS-6, were virulent in both MH cockroaches and hamsters. Hemocytes obtained from MH cockroaches infected with B. pseudomallei harbored numerous intracellular bacteria, suggesting that this facultative intracellular pathogen can survive and replicate inside of MH cockroach phagocytic cells. The hemolymph extracted from these MH cockroaches also contained multinuclear giant cells (MNGCs) with intracellular B. pseudomallei, which indicates that infected hemocytes can fuse while flowing through the insect's open circulatory system in vivo. CONCLUSIONS The results demonstrate that MH cockroaches are an attractive alternative to mammals to study host-pathogen interactions and may allow the identification of new Burkholderia virulence determinants. The importance of T6SS-1 as a virulence factor in MH cockroaches and rodents suggests that the primary role of this secretion system is to target evasion of the innate immune system.
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Affiliation(s)
- Nathan A Fisher
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, USA
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Characterization of the Burkholderia pseudomallei K96243 capsular polysaccharide I coding region. Infect Immun 2012; 80:1209-21. [PMID: 22252864 DOI: 10.1128/iai.05805-11] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Burkholderia pseudomallei is the causative agent of melioidosis, a disease endemic to regions of Southeast Asia and Northern Australia. Both humans and a range of other animal species are susceptible to melioidosis, and the production of a group 3 polysaccharide capsule in B. pseudomallei is essential for virulence. B. pseudomallei capsular polysaccharide (CPS) I comprises unbranched manno-heptopyranose residues and is encoded by a 34.5-kb locus on chromosome 1. Despite the importance of this locus, the role of all of the genes within this region is unclear. We inactivated 18 of these genes and analyzed their phenotype using Western blotting and immunofluorescence staining. Furthermore, by combining this approach with bioinformatic analysis, we were able to develop a model for CPS I biosynthesis and export. We report that inactivating gmhA, wcbJ, and wcbN in B. pseudomallei K96243 retains the immunogenic integrity of the polysaccharide despite causing attenuation in the BALB/c murine infection model. Mice immunized with the B. pseudomallei K96243 mutants lacking a functional copy of either gmhA or wcbJ were afforded significant levels of protection against a wild-type B. pseudomallei K96243 challenge.
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Norris MH, Propst KL, Kang Y, Dow SW, Schweizer HP, Hoang TT. The Burkholderia pseudomallei Δasd mutant exhibits attenuated intracellular infectivity and imparts protection against acute inhalation melioidosis in mice. Infect Immun 2011; 79:4010-8. [PMID: 21807903 PMCID: PMC3187240 DOI: 10.1128/iai.05044-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 07/26/2011] [Indexed: 11/20/2022] Open
Abstract
Burkholderia pseudomallei, the cause of serious and life-threatening diseases in humans, is of national biodefense concern because of its potential use as a bioterrorism agent. This microbe is listed as a select agent by the CDC; therefore, development of vaccines is of significant importance. Here, we further investigated the growth characteristics of a recently created B. pseudomallei 1026b Δasd mutant in vitro, in a cell model, and in an animal model of infection. The mutant was typified by an inability to grow in the absence of exogenous diaminopimelate (DAP); upon single-copy complementation with a wild-type copy of the asd gene, growth was restored to wild-type levels. Further characterization of the B. pseudomallei Δasd mutant revealed a marked decrease in RAW264.7 murine macrophage cytotoxicity compared to the wild type and the complemented Δasd mutant. RAW264.7 cells infected by the Δasd mutant did not exhibit signs of cytopathology or multinucleated giant cell (MNGC) formation, which were observed in wild-type B. pseudomallei cell infections. The Δasd mutant was found to be avirulent in BALB/c mice, and mice vaccinated with the mutant were protected against acute inhalation melioidosis. Thus, the B. pseudomallei Δasd mutant may be a promising live attenuated vaccine strain and a biosafe strain for consideration of exclusion from the select agent list.
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Affiliation(s)
- Michael H. Norris
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Manoa, Hawaii 96822
| | - Katie L. Propst
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | | | - Steven W. Dow
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - Herbert P. Schweizer
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - Tung T. Hoang
- Department of Microbiology
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Manoa, Hawaii 96822
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Burtnick MN, Brett PJ, Harding SV, Ngugi SA, Ribot WJ, Chantratita N, Scorpio A, Milne TS, Dean RE, Fritz DL, Peacock SJ, Prior JL, Atkins TP, DeShazer D. The cluster 1 type VI secretion system is a major virulence determinant in Burkholderia pseudomallei. Infect Immun 2011; 79:1512-25. [PMID: 21300775 PMCID: PMC3067527 DOI: 10.1128/iai.01218-10] [Citation(s) in RCA: 209] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Revised: 12/11/2010] [Accepted: 01/27/2011] [Indexed: 11/20/2022] Open
Abstract
The Burkholderia pseudomallei K96243 genome encodes six type VI secretion systems (T6SSs), but little is known about the role of these systems in the biology of B. pseudomallei. In this study, we purified recombinant Hcp proteins from each T6SS and tested them as vaccine candidates in the BALB/c mouse model of melioidosis. Recombinant Hcp2 protected 80% of mice against a lethal challenge with K96243, while recombinant Hcp1, Hcp3, and Hcp6 protected 50% of mice against challenge. Hcp6 was the only Hcp constitutively produced by B. pseudomallei in vitro; however, it was not exported to the extracellular milieu. Hcp1, on the other hand, was produced and exported in vitro when the VirAG two-component regulatory system was overexpressed in trans. We also constructed six hcp deletion mutants (Δhcp1 through Δhcp6) and tested them for virulence in the Syrian hamster model of infection. The 50% lethal doses (LD(50)s) for the Δhcp2 through Δhcp6 mutants were indistinguishable from K96243 (<10 bacteria), but the LD(50) for the Δhcp1 mutant was >10(3) bacteria. The hcp1 deletion mutant also exhibited a growth defect in RAW 264.7 macrophages and was unable to form multinucleated giant cells in this cell line. Unlike K96243, the Δhcp1 mutant was only weakly cytotoxic to RAW 264.7 macrophages 18 h after infection. The results suggest that the cluster 1 T6SS is essential for virulence and plays an important role in the intracellular lifestyle of B. pseudomallei.
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Affiliation(s)
- Mary N. Burtnick
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, United Kingdom, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, Department of Microbiology and Immunology and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland 21702, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Paul J. Brett
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, United Kingdom, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, Department of Microbiology and Immunology and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland 21702, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Sarah V. Harding
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, United Kingdom, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, Department of Microbiology and Immunology and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland 21702, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Sarah A. Ngugi
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, United Kingdom, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, Department of Microbiology and Immunology and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland 21702, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Wilson J. Ribot
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, United Kingdom, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, Department of Microbiology and Immunology and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland 21702, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Narisara Chantratita
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, United Kingdom, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, Department of Microbiology and Immunology and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland 21702, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Angelo Scorpio
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, United Kingdom, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, Department of Microbiology and Immunology and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland 21702, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Timothy S. Milne
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, United Kingdom, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, Department of Microbiology and Immunology and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland 21702, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Rachel E. Dean
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, United Kingdom, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, Department of Microbiology and Immunology and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland 21702, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - David L. Fritz
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, United Kingdom, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, Department of Microbiology and Immunology and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland 21702, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Sharon J. Peacock
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, United Kingdom, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, Department of Microbiology and Immunology and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland 21702, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Joanne L. Prior
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, United Kingdom, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, Department of Microbiology and Immunology and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland 21702, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Timothy P. Atkins
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, United Kingdom, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, Department of Microbiology and Immunology and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland 21702, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - David DeShazer
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, United Kingdom, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702, Department of Microbiology and Immunology and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, National Biodefense Analysis and Countermeasures Center, Frederick, Maryland 21702, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
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De Groot AS, Ardito M, Moise L, Gustafson EA, Spero D, Tejada G, Martin W. Immunogenic Consensus Sequence T helper Epitopes for a Pan- Burkholderia Biodefense Vaccine. Immunome Res 2011; 7. [PMID: 25346775 PMCID: PMC4206550 DOI: 10.4172/1745-7580.1000043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Background Biodefense vaccines against Category B bioterror agents Burkholderia pseudomallei (BPM) and Burkholderia mallei (BM) are needed, as they are both easily accessible to terrorists and have strong weaponization potential. Burkholderia cepaciae (BC), a related pathogen, causes chronic lung infections in cystic fibrosis patients. Since BPM, BM and BC are all intracellular bacteria, they are excellent targets for T cell-based vaccines. However, the sheer volume of available genomic data requires the aid of immunoinformatics for vaccine design. Using EpiMatrix, ClustiMer and EpiAssembler, a set of immunoinformatic vaccine design tools, we screened the 31 available Burkholderia genomes and performed initial tests of our selections that are candidates for an epitope-based multi-pathogen vaccine against Burkholderia species. Results Immunoinformatics analysis of 31 Burkholderia genomes yielded 350,004 9-mer candidate vaccine peptides of which 133,469 had perfect conservation across the 10 BM genomes, 175,722 had perfect conservation across the 11 BPM genomes and 40,813 had perfect conservation across the 10 BC genomes. Further screening with EpiMatrix yielded 54,010 high-scoring Class II epitopes; these were assembled into 2,880 longer highly conserved ‘immunogenic consensus sequence’ T helper epitopes. 100% of the peptides bound to at least one HLA class II allele in vitro, 92.7% bound to at least two alleles, 82.9% to three, and 75.6% of the binding results were consistent with the immunoinformatics analysis. Conclusions Our results show it is possible to rapidly identify promiscuous T helper epitopes conserved across multiple Burkholderia species and test their binding to HLA ligands in vitro. The next step in our process will be to test the epitopes ex vivo using peripheral leukocytes from BC, BPM infected humans and for immunogenicity in human HLA transgenic mice. We expect that this approach will lead to development of a licensable, pan-Burkholderia biodefense vaccine.
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Affiliation(s)
- Anne S De Groot
- EpiVax 146 Clifford St, Providence, RI 02903, USA ; Institute for Immunology and Informatics, University of Rhode Island, 80 Washington St., Providence, RI 02903, USA
| | | | - Leonard Moise
- EpiVax 146 Clifford St, Providence, RI 02903, USA ; Institute for Immunology and Informatics, University of Rhode Island, 80 Washington St., Providence, RI 02903, USA
| | - Eric A Gustafson
- Institute for Immunology and Informatics, University of Rhode Island, 80 Washington St., Providence, RI 02903, USA
| | - Denice Spero
- Institute for Immunology and Informatics, University of Rhode Island, 80 Washington St., Providence, RI 02903, USA
| | - Gloria Tejada
- Institute for Immunology and Informatics, University of Rhode Island, 80 Washington St., Providence, RI 02903, USA
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28
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Galyov EE, Brett PJ, DeShazer D. Molecular insights into Burkholderia pseudomallei and Burkholderia mallei pathogenesis. Annu Rev Microbiol 2010; 64:495-517. [PMID: 20528691 DOI: 10.1146/annurev.micro.112408.134030] [Citation(s) in RCA: 197] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Burkholderia pseudomallei and Burkholderia mallei are closely related gram-negative bacteria that can cause serious diseases in humans and animals. This review summarizes the current and rapidly expanding knowledge on the specific virulence factors employed by these pathogens and their roles in the pathogenesis of melioidosis and glanders. In particular, the contributions of recently identified virulence factors are described in the context of the intracellular lifestyle of these pathogens. Throughout this review, unique and shared virulence features of B. pseudomallei and B. mallei are discussed.
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Affiliation(s)
- Edouard E Galyov
- Department of Infection, Immunity and Inflammation, MSB, University of Leicester, Leicester LE1 9HN, United Kingdom.
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29
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Burtnick MN, DeShazer D, Nair V, Gherardini FC, Brett PJ. Burkholderia mallei cluster 1 type VI secretion mutants exhibit growth and actin polymerization defects in RAW 264.7 murine macrophages. Infect Immun 2010; 78:88-99. [PMID: 19884331 PMCID: PMC2798217 DOI: 10.1128/iai.00985-09] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Revised: 10/06/2009] [Accepted: 10/26/2009] [Indexed: 01/09/2023] Open
Abstract
Burkholderia mallei is a facultative intracellular pathogen that causes severe disease in animals and humans. Recent studies have shown that the cluster 1 type VI secretion system (T6SS-1) expressed by this organism is essential for survival in a hamster model of glanders. To better understand the role of T6SS-1 in the pathogenesis of disease, studies were initiated to examine the interactions of B. mallei tssE mutants with RAW 264.7 murine macrophages. Results obtained by utilizing modified gentamicin protection assays indicated that although the tssE mutants were able to survive within RAW 264.7 cells, significant growth defects were observed in comparison to controls. In addition, analysis of infected monolayers by differential interference contrast and fluorescence microscopy demonstrated that the tssE mutants lacked the ability to induce multinucleated giant cell formation. Via the use of fluorescence microscopy, tssE mutants were shown to undergo escape from lysosome-associated membrane protein 1-positive vacuoles. Curiously, however, following entry into the cytosol, the mutants exhibited actin polymerization defects resulting in inefficient intra- and intercellular spread characteristics. Importantly, all mutant phenotypes observed in this study could be restored by complementation. Based upon these findings, it appears that T6SS-1 plays a critical role in growth and actin-based motility following uptake of B. mallei by RAW 264.7 cells.
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Affiliation(s)
- Mary N. Burtnick
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702, Research Technologies Section, RTB, Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana 59840
| | - David DeShazer
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702, Research Technologies Section, RTB, Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana 59840
| | - Vinod Nair
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702, Research Technologies Section, RTB, Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana 59840
| | - Frank C. Gherardini
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702, Research Technologies Section, RTB, Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana 59840
| | - Paul J. Brett
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama 36688, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702, Research Technologies Section, RTB, Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana 59840
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Goodyear A, Jones A, Troyer R, Bielefeldt-Ohmann H, Dow S. Critical protective role for MCP-1 in pneumonic Burkholderia mallei infection. THE JOURNAL OF IMMUNOLOGY 2009; 184:1445-54. [PMID: 20042590 DOI: 10.4049/jimmunol.0900411] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Burkholderia mallei is a gram-negative bacterial pathogen of domestic equidae and humans that can cause severe, rapidly life-threatening pneumonic infections. Little is known regarding the role of chemokines and early cellular immune responses in protective immunity to pulmonary infection with B. mallei. Although the role of MCP-1 in gram-positive bacterial infections has been previously investigated, the role of MCP-1 in immunity to acute pneumonia caused by gram-negative bacteria, such as B. mallei, has not been assessed. In a mouse model of pneumonic B. mallei infection, we found that both MCP-1(-/-) mice and CCR2(-/-) mice were extremely susceptible to pulmonary infection with B. mallei, compared with wild-type (WT) C57Bl/6 mice. Bacterial burden and organ lesions were significantly increased in CCR2(-/-) mice, compared with WT animals, following B. mallei challenge. Monocyte and dendritic cell recruitment into the lungs of CCR2(-/-) mice was significantly reduced in comparison with that in WT mice following B. mallei infection, whereas neutrophil recruitment was actually increased. Depletion of monocytes and macrophages prior to infection also greatly raised the susceptibility of WT mice to infection. Production of IL-12 and IFN-gamma in the lungs after B. mallei infection was significantly impaired in both MCP-1(-/-) and CCR2(-/-) mice, whereas treatment of CCR2(-/-) mice with rIFN-gamma restored protection against lethal challenge with B. mallei. Thus, we conclude that MCP-1 plays a key role in regulating cellular immunity and IFN-gamma production following pneumonic infection with B. mallei and therefore may also figure importantly in other gram-negative pneumonias.
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Affiliation(s)
- Andrew Goodyear
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Ft. Collins, CO 80523, USA
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Role for the Burkholderia pseudomallei capsular polysaccharide encoded by the wcb operon in acute disseminated melioidosis. Infect Immun 2009; 77:5252-61. [PMID: 19752033 DOI: 10.1128/iai.00824-09] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The capsular polysaccharide of Burkholderia pseudomallei is an essential virulence determinant that is required for protection from host serum cidal activity and opsonophagocytosis. In this study, the immune response directed against a B. pseudomallei capsule mutant (JW270) was investigated in an acute respiratory murine model. JW270 was significantly attenuated in this model ( approximately 2 logs) to levels resembling those of avirulent Burkholderia thailandensis. At lethal doses, JW270 colonized the lung, liver, and spleen at levels similar to the wild-type strain levels and was found to trigger reduced pathology in the liver and spleen. Several cytokine responses were altered in these tissues, and importantly, the levels of gamma interferon were reduced in the livers and spleens of JW270-infected mice but not in the lungs. These results suggest that the capsular polysaccharide of B. pseudomallei is a critical virulence determinant in respiratory tract infections and that it is an important antigen for generating the Th1 immune response commonly observed in systemic melioidosis. Furthermore, the data suggest that host recognition of B. pseudomallei capsular polysaccharide in the lungs may not be as important to the disease outcome as the innate immune response in the peripheral organs.
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Comparison of the in vitro and in vivo susceptibilities of Burkholderia mallei to Ceftazidime and Levofloxacin. BMC Microbiol 2009; 9:88. [PMID: 19426516 PMCID: PMC2686712 DOI: 10.1186/1471-2180-9-88] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 05/09/2009] [Indexed: 11/29/2022] Open
Abstract
Background Burkholderia mallei is a zoonotic Gram negative bacterium which primarily infects solipeds but can cause lethal disease in humans if left untreated. The effect of two antibiotics with different modes of action on Burkholderia mallei strain ATCC23344 was investigated by using in vitro and in vivo studies. Results Determination of minimal inhibitory concentrations (MICs) in vitro was done by the agar diffusion method and the dilution method. The MICs of levofloxacin and ceftazidime were in the similar range, 2.5 and 5.0 μg/ml, respectively. Intracellular susceptibility of the bacterium to these two antibiotics in J774A.1 mouse macrophages in vitro was also investigated. Macrophages treated with antibiotics demonstrated uptake of the drugs and reduced bacterial loads in vitro. The efficacy of ceftazidime and levofloxacin were studied in BALB/c mice as post-exposure treatment following intranasal B. mallei infection. Intranasal infection with 5 × 105 CFUs of B. mallei resulted in 90% death in non-treated control mice. Antibiotic treatments 10 days post-infection proved to be effective in vivo with all antibiotic treated mice surviving to day 34 post-infection. The antibiotics did not result in complete clearance of the bacterial infection and presence of the bacteria was found in lungs and spleens of the survivors, although bacterial burden recovered from levofloxacin treated animals appeared reduced compared to ceftazidime. Conclusion Both antibiotics demonstrated utility for the treatment of glanders, including the ability for intracellular penetration and clearance of organisms in vitro.
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Burkholderia mallei tssM encodes a putative deubiquitinase that is secreted and expressed inside infected RAW 264.7 murine macrophages. Infect Immun 2009; 77:1636-48. [PMID: 19168747 DOI: 10.1128/iai.01339-08] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Burkholderia mallei, a category B biothreat agent, is a facultative intracellular pathogen that causes the zoonotic disease glanders. The B. mallei VirAG two-component regulatory system activates the transcription of approximately 60 genes, including a large virulence gene cluster encoding a type VI secretion system (T6SS). The B. mallei tssM gene encodes a putative ubiquitin-specific protease that is physically linked to, and transcriptionally coregulated with, the T6SS gene cluster. Mass spectrometry and immunoblot analysis demonstrated that TssM was secreted in a virAG-dependent manner in vitro. Surprisingly, the T6SS was found to be dispensable for the secretion of TssM. The C-terminal half of TssM, which contains Cys and His box motifs conserved in eukaryotic deubiquitinases, was purified and biochemically characterized. Recombinant TssM hydrolyzed multiple ubiquitinated substrates and the cysteine at position 102 was critical for enzymatic activity. The tssM gene was expressed within 1 h after uptake of B. mallei into RAW 264.7 murine macrophages, suggesting that the TssM deubiquitinase is produced in this intracellular niche. Although the physiological substrate(s) is currently unknown, the TssM deubiquitinase may provide B. mallei a selective advantage in the intracellular environment during infection.
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Bondi SK, Goldberg JB. Strategies toward vaccines against Burkholderia mallei and Burkholderia pseudomallei. Expert Rev Vaccines 2008; 7:1357-65. [PMID: 18980539 DOI: 10.1586/14760584.7.9.1357] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Burkholderia mallei and Burkholderia pseudomallei are Gram-negative, rod-shaped bacteria, and are the causative agents of the diseases glanders and melioidosis, respectively. These bacteria have been recognized as important pathogens for over 100 years, yet a relative dearth of available information exists regarding their virulence determinants and immunopathology. Infection with either of these bacteria presents with nonspecific symptoms and can be either acute or chronic, impeding rapid diagnosis. The lack of a vaccine for either bacterium also makes them potential candidates for bioweaponization. Together with their high rate of infectivity via aerosols and resistance to many common antibiotics, both bacteria have been classified as category B priority pathogens by the US NIH and US CDC, which has spurred a dramatic increase in interest in these microorganisms. Attempts have been made to develop vaccines for these infections, which would not only benefit military personnel, a group most likely to be targeted in an intentional release, but also individuals who may come in contact with glanders-infected animals or live in areas where melioidosis is endemic. This review highlights some recent attempts of vaccine development for these infections and the strategies used to improve the efficacy of vaccine approaches.
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Affiliation(s)
- Sara K Bondi
- Department of Microbiology, University of Virginia, VA 22908-0734, USA
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35
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Barrett AR, Kang Y, Inamasu KS, Son MS, Vukovich JM, Hoang TT. Genetic tools for allelic replacement in Burkholderia species. Appl Environ Microbiol 2008; 74:4498-508. [PMID: 18502918 PMCID: PMC2493169 DOI: 10.1128/aem.00531-08] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Accepted: 05/13/2008] [Indexed: 11/20/2022] Open
Abstract
Allelic replacement in the Burkholderia genus has been problematic due to the lack of appropriate counter-selectable and selectable markers. The counter-selectable marker sacB, commonly used in gram-negative bacteria, is nonselective on sucrose in many Burkholderia species. In addition, the use of antibiotic resistance markers of clinical importance for the selection of desirable genetic traits is prohibited in the United States for two potential bioterrorism agents, Burkholderia mallei and Burkholderia pseudomallei. Here, we engineered a mutated counter-selectable marker based on the B. pseudomallei PheS (the alpha-subunit of phenylalanyl tRNA synthase) protein and tested its effectiveness in three different Burkholderia species. The mutant PheS protein effectively killed 100% of the bacteria in the presence of 0.1% p-chlorophenylalanine. We assembled the mutant pheS on several allelic replacement vectors, in addition to constructing selectable markers based on tellurite (Tel(r)) and trimethoprim (Tp(r)) resistance that are excisable by flanking unique FLP recombination target (FRT) sequences. As a proof of concept, we utilized one of these gene replacement vectors (pBAKA) and the Tel(r)-FRT cassette to produce a chromosomal mutation in the Burkholderia thailandensis betBA operon, which codes for betaine aldehyde dehydrogenase and choline dehydrogenase. Chromosomal resistance markers could be excised by the introduction of pFLP-AB5 (Tp(r)), which is one of two constructed flp-containing plasmids, pFLP-AB4 (Tel(r)) and pFLP-AB5 (Tp(r)). These flp-containing plasmids harbor the mutant pheS gene and allow self curing on media that contain p-chlorophenylalanine after Flp-FRT excision. The characterization of the Delta betBA::Tel(r)-FRT and Delta betBA::FRT mutants indicated a defect in growth with choline as a sole carbon source, while these mutants grew as well as the wild type with succinate and glucose as alternative carbon sources.
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Affiliation(s)
- Ashley R Barrett
- Department of Microbiology, College of Natural Sciences, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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Bandara AB, DeShazer D, Inzana TJ, Sriranganathan N, Schurig GG, Boyle SM. A disruption of ctpA encoding carboxy-terminal protease attenuates Burkholderia mallei and induces partial protection in CD1 mice. Microb Pathog 2008; 45:207-16. [PMID: 18614331 DOI: 10.1016/j.micpath.2008.05.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 05/09/2008] [Accepted: 05/23/2008] [Indexed: 10/22/2022]
Abstract
Burkholderia mallei is the etiologic agent of glanders in solipeds (horses, mules and donkeys), and incidentally in carnivores and humans. Little is known about the molecular mechanisms of B. mallei pathogenesis. The putative carboxy-terminal processing protease (CtpA) of B. mallei is a member of a novel family of endoproteases involved in the maturation of proteins destined for the cell envelope. All species and isolates of Burkholderia carry a highly conserved copy of ctpA. We studied the involvement of CtpA on growth, cell morphology, persistence, and pathogenicity of B. mallei. A sucrose-resistant strain of B. mallei was constructed by deleting a major portion of the sacB gene of the wild type strain ATCC 23344 by gene replacement, and designated as strain 23344DeltasacB. A portion of the ctpA gene (encoding CtpA) of strain 23344DeltasacB was deleted by gene replacement to generate strain 23344DeltasacBDeltactpA. In contrast to the wild type ATCC 23344 or the sacB mutant 23344DeltasacB, the ctpA mutant 23344DeltasacBDeltactpA displayed altered cell morphologies with partially or fully disintegrated cell envelopes. Furthermore, relative to the wild type, the ctpA mutant displayed slower growth in vitro and less ability to survive in J774.2 murine macrophages. The expression of mRNA of adtA, the gene downstream of ctpA was similar among the three strains suggesting that disruption of ctpA did not induce any polar effects. As with the wild type or the sacB mutant, the ctpA mutant exhibited a dose-dependent lethality when inoculated intraperitoneally into CD1 mice. The CD1 mice inoculated with a non-lethal dose of the ctpA mutant produced specific serum immunoglobulins IgG1 and IgG2a and were partially protected against challenge with wild type B. mallei ATCC 23344. These findings suggest that CtpA regulates in vitro growth, cell morphology and intracellular survival of B. mallei, and a ctpA mutant protects CD1 mice against glanders.
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Affiliation(s)
- Aloka B Bandara
- Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0342, USA.
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Whitlock GC, Estes DM, Torres AG. Glanders: off to the races with Burkholderia mallei. FEMS Microbiol Lett 2008; 277:115-22. [PMID: 18031330 DOI: 10.1111/j.1574-6968.2007.00949.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Burkholderia mallei, the etiologic agent of the disease known as glanders, is primarily a disease affecting horses and is transmitted to humans by direct contact with infected animals. The use of B. mallei as a biological weapon has been reported and currently, there is no vaccine available for either humans or animals. Despite the history and highly infective nature of B. mallei, as well as its potential use as a bio-weapon, B. mallei research to understand the pathogenesis and the host responses to infection remains limited. Therefore, this minireview will focus on current efforts to elucidate B. mallei virulence, the associated host immune responses elicited during infection and discuss the feasibility of vaccine development.
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Affiliation(s)
- Gregory C Whitlock
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555-1070, USA
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Comparative genomics and an insect model rapidly identify novel virulence genes of Burkholderia mallei. J Bacteriol 2008; 190:2306-13. [PMID: 18223084 DOI: 10.1128/jb.01735-07] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia pseudomallei and its host-adapted deletion clone Burkholderia mallei cause the potentially fatal human diseases melioidosis and glanders, respectively. The antibiotic resistance profile and ability to infect via aerosol of these organisms and the absence of protective vaccines have led to their classification as major biothreats and select agents. Although documented infections by these bacteria date back over 100 years, relatively little is known about their virulence and pathogenicity mechanisms. We used in silico genomic subtraction to generate their virulome, a set of 650 putative virulence-related genes shared by B. pseudomallei and B. mallei but not present in five closely related nonpathogenic Burkholderia species. Although most of these genes are clustered in putative operons, the number of targets for mutant construction and verification of reduced virulence in animal models is formidable. Therefore, Galleria mellonella (wax moth) larvae were evaluated as a surrogate host; we found that B. pseudomallei and B. mallei, but not other phylogenetically related bacteria, were highly pathogenic for this insect. More importantly, four previously characterized B. mallei mutants with reduced virulence in hamsters or mice had similarly reduced virulence in G. mellonella larvae. Site-specific inactivation of selected genes in the computationally derived virulome identified three new potential virulence genes, each of which was required for rapid and efficient killing of larvae. Thus, this approach may provide a means to quickly identify high-probability virulence genes in B. pseudomallei, B. mallei, and other pathogens.
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Schell MA, Ulrich RL, Ribot WJ, Brueggemann EE, Hines HB, Chen D, Lipscomb L, Kim HS, Mrázek J, Nierman WC, Deshazer D. Type VI secretion is a major virulence determinant in Burkholderia mallei. Mol Microbiol 2007; 64:1466-85. [PMID: 17555434 DOI: 10.1111/j.1365-2958.2007.05734.x] [Citation(s) in RCA: 268] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Burkholderia mallei is a host-adapted pathogen and a category B biothreat agent. Although the B. mallei VirAG two-component regulatory system is required for virulence in hamsters, the virulence genes it regulates are unknown. Here we show with expression profiling that overexpression of virAG resulted in transcriptional activation of approximately 60 genes, including some involved in capsule production, actin-based intracellular motility, and type VI secretion (T6S). The 15 genes encoding the major sugar component of the homopolymeric capsule were up-expressed > 2.5-fold, but capsule was still produced in the absence of virAG. Actin tail formation required virAG as well as bimB, bimC and bimE, three previously uncharacterized genes that were activated four- to 15-fold when VirAG was overproduced. Surprisingly, actin polymerization was found to be dispensable for virulence in hamsters. In contrast, genes encoding a T6S system were up-expressed as much as 30-fold and mutations in this T6S gene cluster resulted in strains that were avirulent in hamsters. SDS-PAGE and mass spectrometry demonstrated that BMAA0742 was secreted by the T6S system when virAG was overexpressed. Purified His-tagged BMAA0742 was recognized by glanders antiserum from a horse, a human and mice, indicating that this Hcp-family protein is produced in vivo during infection.
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Affiliation(s)
- Mark A Schell
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
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Burkholderia Hep_Hag autotransporter (BuHA) proteins elicit a strong antibody response during experimental glanders but not human melioidosis. BMC Microbiol 2007; 7:19. [PMID: 17362501 PMCID: PMC1847439 DOI: 10.1186/1471-2180-7-19] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Accepted: 03/15/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The bacterial biothreat agents Burkholderia mallei and Burkholderia pseudomallei are the cause of glanders and melioidosis, respectively. Genomic and epidemiological studies have shown that B. mallei is a recently emerged, host restricted clone of B. pseudomallei. RESULTS Using bacteriophage-mediated immunoscreening we identified genes expressed in vivo during experimental equine glanders infection. A family of immunodominant antigens were identified that share protein domain architectures with hemagglutinins and invasins. These have been designated Burkholderia Hep_Hag autotransporter (BuHA) proteins. A total of 110/207 positive clones (53%) of a B. mallei expression library screened with sera from two infected horses belonged to this family. This contrasted with 6/189 positive clones (3%) of a B. pseudomallei expression library screened with serum from 21 patients with culture-proven melioidosis. CONCLUSION Members of the BuHA proteins are found in other Gram-negative bacteria and have been shown to have important roles related to virulence. Compared with other bacterial species, the genomes of both B. mallei and B. pseudomallei contain a relative abundance of this family of proteins. The domain structures of these proteins suggest that they function as multimeric surface proteins that modulate interactions of the cell with the host and environment. Their effect on the cellular immune response to B. mallei and their potential as diagnostics for glanders requires further study.
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Wagner TK, Mulks MH. A subset of Actinobacillus pleuropneumoniae in vivo induced promoters respond to branched-chain amino acid limitation. ACTA ACUST UNITED AC 2007; 48:192-204. [PMID: 16995880 DOI: 10.1111/j.1574-695x.2006.00147.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Actinobacillus pleuropneumoniae is the causative agent of a necrotizing hemorrhagic pleuropneumonia in swine. In this study, we investigate the possibility that the limitation of branched-chain amino acids is a stimulus that A. pleuropneumoniae will encounter during infection and will respond to by up-regulation of genes involved in branched-chain amino acid biosynthesis and virulence. Actinobacillus pleuropneumoniae genetic loci that are specifically induced during infection were screened in vitro for expression in response to limitation of branched-chain amino acids. Of 32 in vivo induced promoter clones screened in vitro, eight were induced on chemically defined medium without isoleucine, leucine and valine as compared to complete chemically defined medium. We identify the genomic context of each clone and discuss its relevance to branched-chain amino acid limitation and virulence. We conclude that limitation of branched-chain amino acids is a cue for expression of a subset in vivo induced genes, including not only genes involved in the biosynthesis of branched-chain amino acids, but also other genes that are induced during infection of the natural host. These results suggest that limitation of branched-chain amino acids may be one of an array of environmental cues responsible for the induction of virulence-associated genes in A. pleuropneumoniae.
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Affiliation(s)
- Trevor K Wagner
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
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Romero CM, DeShazer D, Feldblyum T, Ravel J, Woods D, Kim HS, Yu Y, Ronning CM, Nierman WC. Genome sequence alterations detected upon passage of Burkholderia mallei ATCC 23344 in culture and in mammalian hosts. BMC Genomics 2006; 7:228. [PMID: 16953889 PMCID: PMC1574311 DOI: 10.1186/1471-2164-7-228] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2006] [Accepted: 09/05/2006] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND More than 12,000 simple sequence repeats (SSRs) have been identified in the genome of Burkholderia mallei ATCC 23344. As a demonstrated mechanism of phase variation in other pathogenic bacteria, these may function as mutable loci leading to altered protein expression or structure variation. To determine if such alterations are occurring in vivo, the genomes of various single-colony passaged B. mallei ATCC 23344 isolates, one from each source, were sequenced from culture, a mouse, a horse, and two isolates from a single human patient, and the sequence compared to the published B. mallei ATCC 23344 genome sequence. RESULTS Forty-nine insertions and deletions (indels) were detected at SSRs in the five passaged strains, a majority of which (67.3%) were located within noncoding areas, suggesting that such regions are more tolerant of sequence alterations. Expression profiling of the two human passaged isolates compared to the strain before passage revealed alterations in the mRNA levels of multiple genes when grown in culture. CONCLUSION These data support the notion that genome variability upon passage is a feature of B. mallei ATCC23344, and that within a host B. mallei generates a diverse population of clones that accumulate genome sequence variation at SSR and other loci.
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Affiliation(s)
- Claudia M Romero
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - David DeShazer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702, USA
| | - Tamara Feldblyum
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - Jacques Ravel
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - Donald Woods
- Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Centre, Calgary, Alberta T2N 4N1, Canada
| | - H Stanley Kim
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - Yan Yu
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - Catherine M Ronning
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - William C Nierman
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
- The George Washington University School of Medicine, Departmentof Biochemistry and Molecular Biology, 2300 Eye Street NW, Washington, DC 20037, USA
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Ribot WJ, Ulrich RL. The animal pathogen-like type III secretion system is required for the intracellular survival of Burkholderia mallei within J774.2 macrophages. Infect Immun 2006; 74:4349-53. [PMID: 16790809 PMCID: PMC1489733 DOI: 10.1128/iai.01939-05] [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: 11/28/2005] [Revised: 01/19/2006] [Accepted: 03/30/2006] [Indexed: 11/20/2022] Open
Abstract
Burkholderia mallei is a highly infectious gram-negative pathogen and is the causative agent of human and animal glanders. By generating polar mutations (disruption of bsaQ and bsaZ) in the B. mallei ATCC 23344 animal pathogen-like type III secretion system (TTS), we demonstrate that this bacterial protein delivery system is required for intracellular growth of B. mallei in J774.2 cells, formation of macrophage membrane protrusions, actin polymerization, and phagosomal escape. These findings suggest that TTS plays a role in the intracellular trafficking of B. mallei and may facilitate cell-to-cell spread via actin-based motility.
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Affiliation(s)
- Wilson J Ribot
- Bacteriology Division, USAMRIID, 1425 Porter St., Fort Detrick, Frederick, MD 21702, USA
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Treviño SR, Permenter AR, England MJ, Parthasarathy N, Gibbs PH, Waag DM, Chanh TC. Monoclonal antibodies passively protect BALB/c mice against Burkholderia mallei aerosol challenge. Infect Immun 2006; 74:1958-61. [PMID: 16495574 PMCID: PMC1418687 DOI: 10.1128/iai.74.3.1958-1961.2006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glanders is a debilitating disease with no vaccine available. Murine monoclonal antibodies were produced against Burkholderia mallei, the etiologic agent of glanders, and were shown to be effective in passively protecting mice against a lethal aerosol challenge. The antibodies appeared to target lipopolysaccharide. Humoral antibodies may be important for immune protection against B. mallei infection.
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Affiliation(s)
- Sylvia R Treviño
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases, 1425 Porter St., Fort Detrick, Frederick, MD 21702-5001, USA
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Scholz HC, Joseph M, Tomaso H, Al Dahouk S, Witte A, Kinne J, Hagen RM, Wernery R, Wernery U, Neubauer H. Detection of the reemerging agent Burkholderia mallei in a recent outbreak of glanders in the United Arab Emirates by a newly developed fliP-based polymerase chain reaction assay. Diagn Microbiol Infect Dis 2006; 54:241-7. [PMID: 16466896 DOI: 10.1016/j.diagmicrobio.2005.09.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2005] [Accepted: 09/30/2005] [Indexed: 11/25/2022]
Abstract
A polymerase chain reaction (PCR) assay targeting the flagellin P (fliP)-I S407A genomic region of Burkholderia mallei was developed for the specific detection of this organism in pure cultures and clinical samples from a recent outbreak of equine glanders. Primers deduced from the known fliP-IS407A sequence of B. mallei American Type Culture Collection (ATCC) 23344(T) allowed the specific amplification of a 989-bp fragment from each of the 20 B. mallei strains investigated, whereas other closely related organisms tested negative. The detection limit of the assay was 10 fg for purified DNA of B. mallei ATCC 23344(T). B. mallei DNA was also amplified from various tissues of horses with a generalized B. mallei infection. The developed PCR assay can be used as a simple and rapid tool for the specific and sensitive detection of B. mallei in clinical samples.
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Affiliation(s)
- Holger C Scholz
- Bundeswehr Institute of Microbiology, D-80937 Munich, Germany.
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