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Campbell S, Taylor B, Menouhos D, Hennessy J, Mayo M, Baird R, Currie BJ, Meumann EM. Performance of MALDI-TOF MS, real-time PCR, antigen detection, and automated biochemical testing for the identification of Burkholderia pseudomallei. J Clin Microbiol 2024:e0096124. [PMID: 39235248 DOI: 10.1128/jcm.00961-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2024] [Accepted: 08/17/2024] [Indexed: 09/06/2024] Open
Abstract
Burkholderia pseudomallei is the causative agent of melioidosis, a disease highly endemic to Southeast Asia and northern Australia, though the area of endemicity is expanding. Cases may occur in returning travelers or, rarely, from imported contaminated products. Identification of B. pseudomallei is challenging for laboratories that do not see this organism frequently, and misidentifications by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and automated biochemical testing have been reported. The in vitro diagnostic database for use with the Vitek MS has recently been updated to include B. pseudomallei and we aimed to validate the performance for identification in comparison to automated biochemical testing with the Vitek 2 GN card, quantitative real-time polymerase chain reaction (qPCR) targeting the type III secretion system, and capsular polysaccharide antigen detection using a lateral flow immunoassay (LFA). We tested a "derivation" cohort including geographically diverse B. pseudomallei and a range of closely related Burkholderia species, and a prospective "validation" cohort of B. pseudomallei and B. cepacia complex clinical isolates. MALDI-TOF MS had a sensitivity of 1.0 and specificity of 1.0 for the identification and differentiation of B. pseudomallei from related Burkholderia species when a certainty cutoff of 99.9% was used. In contrast, automated biochemical testing for B. pseudomallei identification had a sensitivity of 0.83 and specificity of 0.88. Both qPCR and LFA correctly identified all B. pseudomallei isolates with no false positives. Due to the high level of accuracy, we have now incorporated MALDI-TOF MS into our laboratory's B. pseudomallei identification workflow.IMPORTANCEBurkholderia pseudomallei causes melioidosis, a disease associated with high morbidity and mortality that disproportionately affects rural areas in Southeast Asia and northern Australia. The known area of endemicity is expanding and now includes the continental United States. Laboratory identification can be challenging which may result in missed or delayed diagnoses and poor patient outcomes. In this study, we compared mass spectrometry using an updated spectral database with multiple other methods for B. pseudomallei identification and found mass spectrometry highly accurate. We have therefore incorporated this fast and cost-effective method into our laboratory's workflow for B. pseudomallei identification.
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Affiliation(s)
- Stuart Campbell
- Department of Infectious Diseases, Division of Medicine, Royal Darwin Hospital, Darwin, Australia
| | - Brooke Taylor
- Microbiology Department, Territory Pathology, Royal Darwin Hospital, Darwin, Australia
| | - Dimitrios Menouhos
- Microbiology Department, Territory Pathology, Royal Darwin Hospital, Darwin, Australia
| | - Jann Hennessy
- Microbiology Department, Territory Pathology, Royal Darwin Hospital, Darwin, Australia
| | - Mark Mayo
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | - Robert Baird
- Department of Infectious Diseases, Division of Medicine, Royal Darwin Hospital, Darwin, Australia
- Microbiology Department, Territory Pathology, Royal Darwin Hospital, Darwin, Australia
| | - Bart J Currie
- Department of Infectious Diseases, Division of Medicine, Royal Darwin Hospital, Darwin, Australia
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | - Ella M Meumann
- Department of Infectious Diseases, Division of Medicine, Royal Darwin Hospital, Darwin, Australia
- Microbiology Department, Territory Pathology, Royal Darwin Hospital, Darwin, Australia
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
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Li C, Shi K, Zhao S, Liu J, Zhai Q, Hou X, Xu J, Wang X, Liu J, Wu X, Fan W. Natural-source payloads used in the conjugated drugs architecture for cancer therapy: Recent advances and future directions. Pharmacol Res 2024; 207:107341. [PMID: 39134188 DOI: 10.1016/j.phrs.2024.107341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Revised: 07/30/2024] [Accepted: 08/02/2024] [Indexed: 08/15/2024]
Abstract
Drug conjugates are obtained from tumor-located vectors connected to cytotoxic agents via linkers, which are designed to deliver hyper-toxic payloads directly to targeted cancer cells. These drug conjugates include antibody-drug conjugates (ADCs), peptide-drug conjugates (PDCs), small molecule-drug conjugates (SMDCs), nucleic acid aptamer-drug conjugates (ApDCs), and virus-like drug conjugate (VDCs), which show great therapeutic value in the clinic. Drug conjugates consist of a targeting carrier, a linker, and a payload. Payloads are key therapy components. Cytotoxic molecules and their derivatives derived from natural products are commonly used in the payload portion of conjugates. The ideal payload should have sufficient toxicity, stability, coupling sites, and the ability to be released under specific conditions to kill tumor cells. Microtubule protein inhibitors, DNA damage agents, and RNA inhibitors are common cytotoxic molecules. Among these conjugates, cytotoxic molecules of natural origin are summarized based on their mechanism of action, conformational relationships, and the discovery of new derivatives. This paper also mentions some cytotoxic molecules that have the potential to be payloads. It also summarizes the latest technologies and novel conjugates developed in recent years to overcome the shortcomings of ADCs, PDCs, SMDCs, ApDCs, and VDCs. In addition, this paper summarizes the clinical trials conducted on conjugates of these cytotoxic molecules over the last five years. It provides a reference for designing and developing safer and more efficient conjugates.
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Affiliation(s)
- Cuiping Li
- Department of Pharmacy, Seventh People's Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 200137, China.
| | - Kourong Shi
- Department of Pharmacy, Seventh People's Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 200137, China.
| | - Siyuan Zhao
- Department of Pharmacy, Seventh People's Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 200137, China.
| | - Juan Liu
- Department of Pharmacy, Seventh People's Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 200137, China.
| | - Qiaoli Zhai
- Department of Pharmacy, Seventh People's Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 200137, China.
| | - Xiaoli Hou
- Department of Pharmacy, Seventh People's Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 200137, China.
| | - Jie Xu
- Department of Pharmacy, Seventh People's Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 200137, China.
| | - Xinyu Wang
- Shanghai Wei Er Lab, Shanghai 201707, China.
| | - Jiahui Liu
- Fujian University of Traditional Chinese Medicine, Fuzhou 350108, China.
| | - Xin Wu
- Fujian University of Traditional Chinese Medicine, Fuzhou 350108, China; Shanghai Wei Er Lab, Shanghai 201707, China.
| | - Wei Fan
- Department of Pharmacy, Seventh People's Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 200137, China.
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Hall CM, Stone NE, Martz M, Hutton SM, Santana-Propper E, Versluis L, Guidry K, Ortiz M, Busch JD, Maness T, Stewart J, Sidwa T, Gee JE, Elrod MG, Petras JK, Ty MC, Gulvik C, Weiner ZP, Salzer JS, Hoffmaster AR, Rivera-Garcia S, Keim P, Kieffer A, Sahl JW, Soltero F, Wagner DM. Burkholderia thailandensis Isolated from the Environment, United States. Emerg Infect Dis 2023; 29:618-621. [PMID: 36823515 PMCID: PMC9973702 DOI: 10.3201/eid2903.221245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
Burkholderia thailandensis, an opportunistic pathogen found in the environment, is a bacterium closely related to B. pseudomallei, the cause of melioidosis. Human B. thailandensis infections are uncommon. We isolated B. thailandensis from water in Texas and Puerto Rico and soil in Mississippi in the United States, demonstrating a potential public health risk.
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Protein Microarray-Guided Development of a Highly Sensitive and Specific Dipstick Assay for Glanders Serodiagnostics. J Clin Microbiol 2023; 61:e0123422. [PMID: 36541753 PMCID: PMC9879090 DOI: 10.1128/jcm.01234-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Burkholderia mallei, the causative agent of glanders, is a clonal descendant of Burkholderia pseudomallei, the causative agent of melioidosis, which has lost its environmental reservoir and has a restricted host range. Despite limitations in terms of sensitivity and specificity, complement fixation is still the official diagnostic test for glanders. Therefore, new tools are needed for diagnostics and to study the B. mallei epidemiology. We recently developed a highly sensitive serodiagnostic microarray test for human melioidosis based on the multiplex detection of B. pseudomallei proteins. In this study, we modified our array tests by using anti-horse IgG conjugate and tested sera from B. mallei-infected horses (n = 30), negative controls (n = 39), and horses infected with other pathogens (n = 14). Our array results show a sensitivity of 96.7% (confidence interval [CI] 85.5 to 99.6%) and a specificity of 100.0% (CI, 95.4 to 100.0%). The reactivity pattern of the positive sera on our array test allowed us to identify a set of 12 highly reactive proteins of interest for glanders diagnosis. The B. mallei variants of the three best protein candidates were selected for the development of a novel dipstick assay. Our point-of-care test detected glanders cases in less than 15 min with a sensitivity of 90.0% (CI, 75.7 to 97.1%) and a specificity of 100.0% (CI, 95.4 to 100.0%). The microarray and dipstick can easily be adopted for the diagnosis of both B. mallei and B. pseudomallei infections in different animals. Future studies will show whether multiplex serological testing has the potential to differentiate between these pathogens.
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Li J, Hu WW, Qu GX, Li XR, Xiang Y, Jiang P, Luo JQ, He WH, Jin YJ, Shi Q. Characterization of a Type VI Secretion System vgrG2 Gene in the Pathogenicity of Burkholderia thailandensis BPM. Front Microbiol 2022; 12:811343. [PMID: 35069514 PMCID: PMC8767068 DOI: 10.3389/fmicb.2021.811343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 12/13/2021] [Indexed: 11/17/2022] Open
Abstract
Burkholderia thailandensis is a clinically underestimated conditional pathogen in the genus Burkholderia, the pathogenicity of the infection caused by B. thailandensis remains poorly understood. According to previous studies, Type-VI secretion system (T6SS) is a protein secreting device widely existing in Gram-negative bacilli. Valine-glycine repeat protein G (VgrG) is not only an important component of T6SS, but also a virulence factor of many Gram-negative bacilli. In one of our previous studies, a unique T6SS vgrG gene (vgrG2 gene) was present in a virulent B. thailandensis strain BPM (BPM), but not in the relatively avirulent B. thailandensis strain E264 (E264). Meanwhile, transcriptome analysis of BPM and E264 showed that the vgrG2 gene was strongly expressed in BPM, but not in E264. Therefore, we identified the function of the vgrG2 gene by constructing the mutant and complemented strains in this study. In vitro, the vgrG2 gene was observed to be involved in the interactions with host cells. The animal model experiment showed that the deletion of vgrG2 gene significantly led to the decrease in the lethality of BPM and impaired its ability to trigger host immune response. In conclusion, our study provides a new perspective for studying the pathogenicity of B. thailandensis and lays the foundation for discovering the potential T6SS effectors.
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Affiliation(s)
- Jin Li
- M.O.E. Key Laboratory of Laboratory Medicine Diagnostics, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Wei-Wei Hu
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Guo-Xin Qu
- Department of Orthopedic Surgery, The First Affiliated Hospital of Hainan Medical University, Hainan, China
| | - Xiao-Rong Li
- M.O.E. Key Laboratory of Laboratory Medicine Diagnostics, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Yi Xiang
- M.O.E. Key Laboratory of Laboratory Medicine Diagnostics, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Peng Jiang
- M.O.E. Key Laboratory of Laboratory Medicine Diagnostics, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Jiang-Qiao Luo
- M.O.E. Key Laboratory of Laboratory Medicine Diagnostics, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Wen-Huan He
- M.O.E. Key Laboratory of Laboratory Medicine Diagnostics, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Yu-Jia Jin
- M.O.E. Key Laboratory of Laboratory Medicine Diagnostics, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Qiong Shi
- M.O.E. Key Laboratory of Laboratory Medicine Diagnostics, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, China
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Wu H, Wang X, Zhou X, Chen S, Mai W, Huang H, You Z, Zhang S, Zhang X, Lu B. Osteomyelitis and Septic Arthritis Due to Burkholderia pseudomallei: A 10-Year Retrospective Melioidosis Study From South China. Front Cell Infect Microbiol 2021; 11:654745. [PMID: 34123870 PMCID: PMC8194086 DOI: 10.3389/fcimb.2021.654745] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 05/04/2021] [Indexed: 01/07/2023] Open
Abstract
Burkholderia pseudomallei is the causative agent of melioidosis, endemic mainly in tropical and subtropical areas. Its clinical manifestation is broad ranging from a localized skin lesion to a life-threatening systemic disease. Osteomyelitis and septic arthritis caused by B. pseudomallei are a rare, fatal illness, whose clinical features have not been illustrated in mainland China. Over 10 years (2010 to 2019), of 334 culture-confirmed melioidosis in Hainan province, China, 44 patients (13.2%) were confirmed to have osteomyelitis and septic arthritis through the combination of clinical features, imaging examination and microbiological culture. Herein, we summarized these 44 patients' clinical manifestations, demographical features, antibiotic treatment, and outcomes. Of them, osteomyelitis and septic arthritis accounted for 25 (56.8%) and 15 (34.1%), respectively, and 4 patients (9.1%) had both. The gender ratio of male/female was approximately 13.7:1; diabetes mellitus was the most common risk factor (38/44, 86.4%); imipenem and trimethoprim/sulfamethoxazole were the most frequently used antibiotics. Most B. pseudomallei strains were isolated from blood samples (41/44, 93.2%). After surgical handling, antibiotic treatment, or both, 9 patients died, with a mortality rate of 20.5%. In summary, in melioidosis endemic areas, for patients with both localized manifestations of joint and bone and a positive B. pseudomallei blood culture, increased awareness is required for melioidotic osteomyelitis and septic arthritis.
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Affiliation(s)
- Hua Wu
- Department of Laboratory Medicine, Affiliated Hainan Hospital of Hainan Medical College, Haikou, China
| | - Xuming Wang
- Department of Laboratory Medicine, Affiliated Hainan Hospital of Hainan Medical College, Haikou, China
| | - Xiaojun Zhou
- Department of Laboratory Medicine, Affiliated Hainan Hospital of Hainan Medical College, Haikou, China
| | - Shaowen Chen
- Department of Laboratory Medicine, Second Affiliated Hospital of Hainan Medical College, Haikou, China
| | - Wenhui Mai
- Department of Laboratory Medicine, Haikou Third People’s Hospital, Haikou, China
| | - Hui Huang
- Department of Laboratory Medicine, Affiliated Haikou Hospital of Xiangya Medical College, Central South University, Haikou, China
| | - Zelin You
- Department of Laboratory Medicine, Ling Shui Li Autonomous County People’s Hospital, Lingshui, China
| | - Suling Zhang
- Department of Laboratory Medicine, Danzhou People’s Hospital, Danzhou, China
| | - Xiuxia Zhang
- Department of Laboratory Medicine, The Second People’s Hospital of Ledong County, Ledong, China
| | - Binghuai Lu
- Laboratory of Clinical Microbiology and Infectious Diseases, Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, National Clinical Research Center of Respiratory Diseases, Beijing, China
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Detection and differentiation of Burkholderia species with pathogenic potential in environmental soil samples. PLoS One 2021; 16:e0245175. [PMID: 33411797 PMCID: PMC7790303 DOI: 10.1371/journal.pone.0245175] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/22/2020] [Indexed: 01/12/2023] Open
Abstract
The Burkholderia pseudomallei phylogenetic cluster includes B. pseudomallei, B. mallei, B. thailandensis, B. oklahomensis, B. humptydooensis and B. singularis. Regarded as the only pathogenic members of this group, B. pseudomallei and B. mallei cause the diseases melioidosis and glanders, respectively. Additionally, variant strains of B. pseudomallei and B. thailandensis exist that include the geographically restricted B. pseudomallei that express a B. mallei-like BimA protein (BPBM), and B. thailandensis that express a B. pseudomallei-like capsular polysaccharide (BTCV). To establish a PCR-based assay for the detection of pathogenic Burkholderia species or their variants, five PCR primers were designed to amplify species-specific sequences within the bimA (Burkholderiaintracellular motility A) gene. Our multiplex PCR assay could distinguish pathogenic B. pseudomallei and BPBM from the non-pathogenic B. thailandensis and the BTCV strains. A second singleplex PCR successfully discriminated the BTCV from B. thailandensis. Apart from B. humptydooensis, specificity testing against other Burkholderia spp., as well as other Gram-negative and Gram-positive bacteria produced a negative result. The detection limit of the multiplex PCR in soil samples artificially spiked with known quantities of B. pseudomallei and B. thailandensis were 5 and 6 CFU/g soil, respectively. Furthermore, comparison between standard bacterial culture and the multiplex PCR to detect B. pseudomallei from 34 soil samples, collected from an endemic area of melioidosis, showed high sensitivity and specificity. This robust, sensitive, and specific PCR assay will be a useful tool for epidemiological study of B. pseudomallei and closely related members with pathogenic potential in soil.
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Amiss AS, Webb JR, Mayo M, Currie BJ, Craik DJ, Henriques ST, Lawrence N. Safer In Vitro Drug Screening Models for Melioidosis Therapy Development. Am J Trop Med Hyg 2020; 103:1846-1851. [PMID: 32975176 DOI: 10.4269/ajtmh.20-0248] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Melioidosis is a neglected tropical disease caused by the Gram-negative soil bacterium Burkholderia pseudomallei. Current antibiotic regimens used to treat melioidosis are prolonged and expensive, and often ineffective because of intrinsic and acquired antimicrobial resistance. Efforts to develop new treatments for melioidosis are limited by the risks associated with handling pathogenic B. pseudomallei, which restricts research to facilities with biosafety level three containment. Closely related nonpathogenic Burkholderia can be investigated under less stringent biosafety level two containment, and we hypothesized that they could be used as model organisms for developing therapies that would also be effective against B. pseudomallei. We used microbroth dilution assays to compare drug susceptibility profiles of three B. pseudomallei strains and five nonpathogenic Burkholderia strains. Burkholderia humptydooensis, Burkholderia thailandensis, and Burkholderia territorii had similar susceptibility profiles to pathogenic B. pseudomallei that support their potential as safer in vitro models for developing new melioidosis therapies.
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Affiliation(s)
- Anna S Amiss
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Jessica R Webb
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Australia
| | - Mark Mayo
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Australia
| | - Bart J Currie
- Northern Territory Medical Program, Department of Infectious Diseases, Royal Darwin Hospital, Darwin, Australia.,Global and Tropical Health Division, Menzies School of Health Research, Darwin, Australia
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Sónia Troeira Henriques
- Queensland University of Technology, School of Biomedical Sciences, Institute of Healthy and Biomedical Innovation, and Translational Research Institute, Brisbane, Queensland, Australia.,Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Nicole Lawrence
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
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Testamenti VA, Surya M, Saepuloh U, Iskandriati D, Tandang MV, Kristina L, Wahyudi AT, Sajuthi D, Santi VD, Patispathika FH, Wahyu M, Nurcahyo A, Pamungkas J. Characterization of Burkholderia pseudomallei from spontaneous melioidosis in a Bornean orangutan. Vet World 2020; 13:2459-2468. [PMID: 33363342 PMCID: PMC7750211 DOI: 10.14202/vetworld.2020.2459-2468] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 10/13/2020] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND AND AIM Melioidosis is a potentially fatal disease affecting humans and a wide range of animal species; it is often underdiagnosed and underreported in veterinary medicine in Indonesia. This study aimed to characterize morphological and molecular features of Burkholderia pseudomallei, the causative agent of melioidosis which caused the death of a Bornean orangutan. MATERIALS AND METHODS Pulmonary abscess samples were cultured on several types of media, including Ashdown agar, Ashdown broth, and MacConkey agar. Type three secretion system orf 2 real-time polymerase chain reaction (PCR) and latex agglutination tests were performed to identify the bacteria. Morphological characteristics were compared to all previously published morphotypes. Subsequently, the bacteria were characterized by multilocus sequence typing (MLST) and Yersinia-like flagellum/Burkholderia thailandensis-like flagellum and chemotaxis PCR. The results of the genotyping were afterward compared to all genotypes from Southeast Asia. RESULTS Multiple morphotypes of B. pseudomallei were perceived during the growth on Ashdown agar. Furthermore, it was identified by MLST that the Type I and Type II morphotypes observed in this study were clones of a single ST, ST54, which is predominantly found in humans and the environment in Malaysia and Thailand, although a very limited number of reports was published in association with animals. Moreover, the E-BURST analysis showed that the ST is grouped together with isolates from Southeast Asian countries, including Malaysia, Thailand, Singapore, and Cambodia. ST54 was predicted to be the founding genotype of several STs from those regions. CONCLUSION B. pseudomallei ST54 that caused the death of a Bornean orangutan has a distant genetic relationship with other STs which were previously reported in Indonesia, implying a vast genetic diversity in Indonesia that has not been discovered yet.
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Affiliation(s)
| | - Maryati Surya
- Primate Research Center, IPB University, Bogor 16128, Indonesia
| | - Uus Saepuloh
- Primate Research Center, IPB University, Bogor 16128, Indonesia
| | - Diah Iskandriati
- Primatology Graduate Study Program, Graduate School of IPB University, Bogor 16128, Indonesia
- Primate Research Center, IPB University, Bogor 16128, Indonesia
| | | | - Lia Kristina
- Borneo Orangutan Survival Foundation, Bogor 16128, Indonesia
| | - Aris Tri Wahyudi
- Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University, Bogor 16680, Indonesia
| | - Dondin Sajuthi
- Primatology Graduate Study Program, Graduate School of IPB University, Bogor 16128, Indonesia
- Primate Research Center, IPB University, Bogor 16128, Indonesia
- Department of Clinics, Reproduction, and Pathology, Faculty of Veterinary Medicine, IPB University, Bogor 16680, Indonesia
| | - Vivi Dwi Santi
- Borneo Orangutan Survival Foundation, Bogor 16128, Indonesia
| | | | - Muhtadin Wahyu
- Borneo Orangutan Survival Foundation, Bogor 16128, Indonesia
| | - Anton Nurcahyo
- Borneo Orangutan Survival Foundation, Bogor 16128, Indonesia
| | - Joko Pamungkas
- Primatology Graduate Study Program, Graduate School of IPB University, Bogor 16128, Indonesia
- Primate Research Center, IPB University, Bogor 16128, Indonesia
- Department of Animal Infectious Diseases and Veterinary Public Health, Faculty of Veterinary Medicine, IPB University, Bogor 16680, Indonesia
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A Phylogeny-Informed Proteomics Approach for Species Identification within the Burkholderia cepacia Complex. J Clin Microbiol 2020; 58:JCM.01741-20. [PMID: 32878952 DOI: 10.1128/jcm.01741-20] [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: 07/06/2020] [Accepted: 08/26/2020] [Indexed: 01/17/2023] Open
Abstract
Ancestral genetic exchange between members of many important bacterial pathogen groups has resulted in phylogenetic relationships better described as networks than as bifurcating trees. In certain cases, these reticulated phylogenies have resulted in phenotypic and molecular overlap that challenges the construction of practical approaches for species identification in the clinical microbiology laboratory. Burkholderia cepacia complex (Bcc), a betaproteobacteria species group responsible for significant morbidity in persons with cystic fibrosis and chronic granulomatous disease, represents one such group where network-structured phylogeny has hampered the development of diagnostic methods for species-level discrimination. Here, we present a phylogeny-informed proteomics approach to facilitate diagnostic classification of pathogen groups with reticulated phylogenies, using Bcc as an example. Starting with a set of more than 800 Bcc and Burkholderia gladioli whole-genome assemblies, we constructed phylogenies with explicit representation of inferred interspecies recombination. Sixteen highly discriminatory peptides were chosen to distinguish B. cepacia, Burkholderia cenocepacia, Burkholderia multivorans, and B. gladioli and multiplexed into a single, rapid liquid chromatography-tandem mass spectrometry multiple reaction monitoring (LC-MS/MS MRM) assay. Testing of a blinded set of isolates containing these four Burkholderia species demonstrated 50/50 correct automatic negative calls (100% accuracy with a 95% confidence interval [CI] of 92.9 to 100%), and 70/70 correct automatic species-level positive identifications (100% accuracy with 95% CI 94.9 to 100%) after accounting for a single initial incorrect identification due to a preanalytic error, correctly identified on retesting. The approach to analysis described here is applicable to other pathogen groups for which development of diagnostic classification methods is complicated by interspecies recombination.
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Ahmad Izaham AR, Scott NE. Open Database Searching Enables the Identification and Comparison of Bacterial Glycoproteomes without Defining Glycan Compositions Prior to Searching. Mol Cell Proteomics 2020. [PMID: 32576591 DOI: 10.1101/2020.04.21.052845] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023] Open
Abstract
Mass spectrometry has become an indispensable tool for the characterization of glycosylation across biological systems. Our ability to generate rich fragmentation of glycopeptides has dramatically improved over the last decade yet our informatic approaches still lag behind. Although glycoproteomic informatics approaches using glycan databases have attracted considerable attention, database independent approaches have not. This has significantly limited high throughput studies of unusual or atypical glycosylation events such as those observed in bacteria. As such, computational approaches to examine bacterial glycosylation and identify chemically diverse glycans are desperately needed. Here we describe the use of wide-tolerance (up to 2000 Da) open searching as a means to rapidly examine bacterial glycoproteomes. We benchmarked this approach using N-linked glycopeptides of Campylobacter fetus subsp. fetus as well as O-linked glycopeptides of Acinetobacter baumannii and Burkholderia cenocepacia revealing glycopeptides modified with a range of glycans can be readily identified without defining the glycan masses before database searching. Using this approach, we demonstrate how wide tolerance searching can be used to compare glycan use across bacterial species by examining the glycoproteomes of eight Burkholderia species (B. pseudomallei; B. multivorans; B. dolosa; B. humptydooensis; B. ubonensis, B. anthina; B. diffusa; B. pseudomultivorans). Finally, we demonstrate how open searching enables the identification of low frequency glycoforms based on shared modified peptides sequences. Combined, these results show that open searching is a robust computational approach for the determination of glycan diversity within bacterial proteomes.
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Affiliation(s)
- Ameera Raudah Ahmad Izaham
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia.
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Ahmad Izaham AR, Scott NE. Open Database Searching Enables the Identification and Comparison of Bacterial Glycoproteomes without Defining Glycan Compositions Prior to Searching. Mol Cell Proteomics 2020; 19:1561-1574. [PMID: 32576591 PMCID: PMC8143609 DOI: 10.1074/mcp.tir120.002100] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/27/2020] [Indexed: 12/23/2022] Open
Abstract
Mass spectrometry has become an indispensable tool for the characterization of glycosylation across biological systems. Our ability to generate rich fragmentation of glycopeptides has dramatically improved over the last decade yet our informatic approaches still lag behind. Although glycoproteomic informatics approaches using glycan databases have attracted considerable attention, database independent approaches have not. This has significantly limited high throughput studies of unusual or atypical glycosylation events such as those observed in bacteria. As such, computational approaches to examine bacterial glycosylation and identify chemically diverse glycans are desperately needed. Here we describe the use of wide-tolerance (up to 2000 Da) open searching as a means to rapidly examine bacterial glycoproteomes. We benchmarked this approach using N-linked glycopeptides of Campylobacter fetus subsp. fetus as well as O-linked glycopeptides of Acinetobacter baumannii and Burkholderia cenocepacia revealing glycopeptides modified with a range of glycans can be readily identified without defining the glycan masses before database searching. Using this approach, we demonstrate how wide tolerance searching can be used to compare glycan use across bacterial species by examining the glycoproteomes of eight Burkholderia species (B. pseudomallei; B. multivorans; B. dolosa; B. humptydooensis; B. ubonensis, B. anthina; B. diffusa; B. pseudomultivorans). Finally, we demonstrate how open searching enables the identification of low frequency glycoforms based on shared modified peptides sequences. Combined, these results show that open searching is a robust computational approach for the determination of glycan diversity within bacterial proteomes.
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Affiliation(s)
- Ameera Raudah Ahmad Izaham
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia.
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13
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Wallner A, King E, Ngonkeu ELM, Moulin L, Béna G. Genomic analyses of Burkholderia cenocepacia reveal multiple species with differential host-adaptation to plants and humans. BMC Genomics 2019; 20:803. [PMID: 31684866 PMCID: PMC6829993 DOI: 10.1186/s12864-019-6186-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 10/15/2019] [Indexed: 12/17/2022] Open
Abstract
Background Burkholderia cenocepacia is a human opportunistic pathogen causing devastating symptoms in patients suffering from immunodeficiency and cystic fibrosis. Out of the 303 B. cenocepacia strains with available genomes, the large majority were isolated from a clinical context. However, several isolates originate from other environmental sources ranging from aerosols to plant endosphere. Plants can represent reservoirs for human infections as some pathogens can survive and sometimes proliferate in the rhizosphere. We therefore investigated if B. cenocepacia had the same potential. Results We selected genome sequences from 31 different strains, representative of the diversity of ecological niches of B. cenocepacia, and conducted comparative genomic analyses in the aim of finding specific niche or host-related genetic determinants. Phylogenetic analyses and whole genome average nucleotide identity suggest that strains, registered as B. cenocepacia, belong to at least two different species. Core-genome analyses show that the clade enriched in environmental isolates lacks multiple key virulence factors, which are conserved in the sister clade where most clinical isolates fall, including the highly virulent ET12 lineage. Similarly, several plant associated genes display an opposite distribution between the two clades. Finally, we suggest that B. cenocepacia underwent a host jump from plants/environment to animals, as supported by the phylogenetic analysis. We eventually propose a name for the new species that lacks several genetic traits involved in human virulence. Conclusion Regardless of the method used, our studies resulted in a disunited perspective of the B. cenocepacia species. Strains currently affiliated to this taxon belong to at least two distinct species, one having lost several determining animal virulence factors.
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Affiliation(s)
- Adrian Wallner
- IRD, CIRAD, University of Montpellier, IPME; 911 avenue Agropolis, BP 64501, 34394, Montpellier, France
| | - Eoghan King
- IRD, CIRAD, University of Montpellier, IPME; 911 avenue Agropolis, BP 64501, 34394, Montpellier, France
| | - Eddy L M Ngonkeu
- Institute of Agronomic Research for Development (IRAD), PO Box 2123, Yaoundé, Cameroon
| | - Lionel Moulin
- IRD, CIRAD, University of Montpellier, IPME; 911 avenue Agropolis, BP 64501, 34394, Montpellier, France
| | - Gilles Béna
- IRD, CIRAD, University of Montpellier, IPME; 911 avenue Agropolis, BP 64501, 34394, Montpellier, France.
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14
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Hall CM, Jaramillo S, Jimenez R, Stone NE, Centner H, Busch JD, Bratsch N, Roe CC, Gee JE, Hoffmaster AR, Rivera-Garcia S, Soltero F, Ryff K, Perez-Padilla J, Keim P, Sahl JW, Wagner DM. Burkholderia pseudomallei, the causative agent of melioidosis, is rare but ecologically established and widely dispersed in the environment in Puerto Rico. PLoS Negl Trop Dis 2019; 13:e0007727. [PMID: 31487287 PMCID: PMC6748447 DOI: 10.1371/journal.pntd.0007727] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/17/2019] [Accepted: 08/23/2019] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Burkholderia pseudomallei is a soil-dwelling bacterium and the causative agent of melioidosis. The global burden and distribution of melioidosis is poorly understood, including in the Caribbean. B. pseudomallei was previously isolated from humans and soil in eastern Puerto Rico but the abundance and distribution of B. pseudomallei in Puerto Rico as a whole has not been thoroughly investigated. METHODOLOGY/PRINCIPAL FINDINGS We collected 600 environmental samples (500 soil and 100 water) from 60 sites around Puerto Rico. We identified B. pseudomallei by isolating it via culturing and/or using PCR to detect its DNA within complex DNA extracts. Only three adjacent soil samples from one site were positive for B. pseudomallei with PCR; we obtained 55 isolates from two of these samples. The 55 B. pseudomallei isolates exhibited fine-scale variation in the core genome and contained four novel genomic islands. Phylogenetic analyses grouped Puerto Rico B. pseudomallei isolates into a monophyletic clade containing other Caribbean isolates, which was nested inside a larger clade containing all isolates from Central/South America. Other Burkholderia species were commonly observed in Puerto Rico; we cultured 129 isolates from multiple soil and water samples collected at numerous sites around Puerto Rico, including representatives of B. anthina, B. cenocepacia, B. cepacia, B. contaminans, B. glumae, B. seminalis, B. stagnalis, B. ubonensis, and several unidentified novel Burkholderia spp. CONCLUSIONS/SIGNIFICANCE B. pseudomallei was only detected in three soil samples collected at one site in north central Puerto Rico with only two of those samples yielding isolates. All previous human and environmental B. pseudomallei isolates were obtained from eastern Puerto Rico. These findings suggest B. pseudomallei is ecologically established and widely dispersed in the environment in Puerto Rico but rare. Phylogeographic patterns suggest the source of B. pseudomallei populations in Puerto Rico and elsewhere in the Caribbean may have been Central or South America.
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Affiliation(s)
- Carina M. Hall
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Sierra Jaramillo
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Rebecca Jimenez
- U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, San Juan, Puerto Rico, United States of America
| | - Nathan E. Stone
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Heather Centner
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Joseph D. Busch
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Nicole Bratsch
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Chandler C. Roe
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Jay E. Gee
- Bacterial Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Alex R. Hoffmaster
- Bacterial Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Sarai Rivera-Garcia
- U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, San Juan, Puerto Rico, United States of America
| | - Fred Soltero
- U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, San Juan, Puerto Rico, United States of America
| | - Kyle Ryff
- Dengue Branch, Centers for Disease Control and Prevention, San Juan, Puerto Rico, United States of America
| | - Janice Perez-Padilla
- Dengue Branch, Centers for Disease Control and Prevention, San Juan, Puerto Rico, United States of America
| | - Paul Keim
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Jason W. Sahl
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - David M. Wagner
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
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15
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An in situ high-throughput screen identifies inhibitors of intracellular Burkholderia pseudomallei with therapeutic efficacy. Proc Natl Acad Sci U S A 2019; 116:18597-18606. [PMID: 31439817 PMCID: PMC6744847 DOI: 10.1073/pnas.1906388116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Burkholderia pseudomallei, the etiologic agent of melioidosis, is an environmental organism that inhabits tropical soils and kills an estimated 90,000 people each year. Caused by an intracellular and often drug-resistant pathogen, melioidosis is notoriously difficult to treat, with mortality rates approaching 50% in some settings despite appropriate diagnosis and clinical management. Using a high-throughput, cell-based phenotypic screen we have discovered 2 antibiotic candidates with improved in vivo efficacy compared to the current standard of care: a fluoroquinolone analog, burkfloxacin, and an FDA-approved antifungal drug, flucytosine. As a widely used antifungal with a well-known safety profile, the potential to repurpose flucytosine for treating melioidosis may represent a rapid route to clinical translation. Burkholderia pseudomallei (Bp) and Burkholderia mallei (Bm) are Tier-1 Select Agents that cause melioidosis and glanders, respectively. These are highly lethal human infections with limited therapeutic options. Intercellular spread is a hallmark of Burkholderia pathogenesis, and its prominent ties to virulence make it an attractive therapeutic target. We developed a high-throughput cell-based phenotypic assay and screened ∼220,000 small molecules for their ability to disrupt intercellular spread by Burkholderia thailandensis, a closely related BSL-2 surrogate. We identified 268 hits, and cross-species validation found 32 hits that also disrupt intercellular spread by Bp and/or Bm. Among these were a fluoroquinolone analog, which we named burkfloxacin (BFX), which potently inhibits growth of intracellular Burkholderia, and flucytosine (5-FC), an FDA-approved antifungal drug. We found that 5-FC blocks the intracellular life cycle at the point of type VI secretion system 5 (T6SS-5)-mediated cell–cell spread. Bacterial conversion of 5-FC to 5-fluorouracil and subsequently to fluorouridine monophosphate is required for potent and selective activity against intracellular Burkholderia. In a murine model of fulminant respiratory melioidosis, treatment with BFX or 5-FC was significantly more effective than ceftazidime, the current antibiotic of choice, for improving survival and decreasing bacterial counts in major organs. Our results demonstrate the utility of cell-based phenotypic screening for Select Agent drug discovery and warrant the advancement of BFX and 5-FC as candidate therapeutics for melioidosis in humans.
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16
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Gee JE, Elrod MG, Gulvik CA, Haselow DT, Waters C, Liu L, Hoffmaster AR. Burkholderia thailandensis Isolated from Infected Wound, Arkansas, USA. Emerg Infect Dis 2019; 24:2091-2094. [PMID: 30334705 PMCID: PMC6199988 DOI: 10.3201/eid2411.180821] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The bacterium Burkholderia thailandensis, a member of the Burkholderia pseudomallei complex, is generally considered nonpathogenic; however, on rare occasions, B. thailandensis infections have been reported. We describe a clinical isolate of B. thailandensis, BtAR2017, recovered from a patient with an infected wound in Arkansas, USA, in 2017.
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17
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Devanga Ragupathi NK, Veeraraghavan B. Accurate identification and epidemiological characterization of Burkholderia cepacia complex: an update. Ann Clin Microbiol Antimicrob 2019; 18:7. [PMID: 30717798 PMCID: PMC6360774 DOI: 10.1186/s12941-019-0306-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Accepted: 01/25/2019] [Indexed: 12/16/2022] Open
Abstract
Bacteria belonging to the Burkholderia cepacia complex (Bcc) are among the most important pathogens isolated from cystic fibrosis (CF) patients and in hospital acquired infections (HAI). Accurate identification of Bcc is questionable by conventional biochemical methods. Clonal typing of Burkholderia is also limited due to the problem with identification. Phenotypic identification methods such as VITEK2, protein signature identification methods like VITEK MS, Bruker Biotyper, and molecular targets such as 16S rRNA, recA, hisA and rpsU were reported with varying level of discrimination to identify Bcc. rpsU and/or 16S rRNA sequencing, VITEK2, VITEK MS and Bruker Biotyper could discriminate between Burkholderia spp. and non-Burkholderia spp. Whereas, Bcc complex level identification can be given by VITEK MS, Bruker Biotyper, and 16S rRNA/rpsU/recA/hisA sequencing. For species level identification within Bcc hisA or recA sequencing are reliable. Identification of Bcc is indispensable in CF patients and HAI to ensure appropriate antimicrobial therapy.
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Affiliation(s)
| | - Balaji Veeraraghavan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, 632004, India.
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18
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Peddayelachagiri BV, Paul S, Gogoi M, Sripathy MH, Batra HV. Evaluation of fimC and bdha based duplex PCR for specific identification and differentiation of Burkholderia pseudomallei from near-neighbor Burkholderia species. Int J Med Microbiol 2017; 308:271-278. [PMID: 29273310 DOI: 10.1016/j.ijmm.2017.11.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 11/18/2017] [Accepted: 11/19/2017] [Indexed: 11/16/2022] Open
Abstract
Assays for the rapid detection and accurate differentiation of Burkholderia pseudomallei from near-neighbor species are urgently needed in melioidosis endemic regions due to the high associated mortality and biowarfare importance of the pathogen. PCR-based methods have revolutionized this field due to the accuracy, sensitivity, and specificity that are achievable in a rapid way. In this study, a compound molecular detection system, consisting of a duplex PCR assay, was developed for the specific identification of Burkholderia pseudomallei and differentiation from other Burkholderia species. For accurate identification of B. pseudomallei, we deciphered and adopted a novel gene termed putative fimbrial chaperone (fimC). d-beta hydroxybutyrate dehydrogenase (bdha), reported previously by our group for sequence-based differentiation of B. pseudomallei from other Burkholderia species, was employed as a genus-specific target. Enforcement of an internal amplification control in the PCR format ruled out possible false negative results in the assay. Thus, the developed PCR assay was highly specific (100%) in its detection features, and a clear detection sensitivity of 10 pg/μl for purified gDNA and 3 × 103 CFU/ml for B. pseudomallei spiked urine was recorded. Successful identification of B. pseudomallei from an experimental mouse model at both the genus and species level revealed the accurate diagnostic efficiency of the duplex PCR method.
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Affiliation(s)
| | - Soumya Paul
- Microbiology Division, Defence Food Research Laboratory, Mysore 570 011, Karnataka, India
| | - Madhurjya Gogoi
- Centre for Biotechnology and Bioinformatics, Dibrugarh University, Dibrugarh 786004, Assam, India
| | - Murali H Sripathy
- Microbiology Division, Defence Food Research Laboratory, Mysore 570 011, Karnataka, India.
| | - Harsh V Batra
- Microbiology Division, Defence Food Research Laboratory, Mysore 570 011, Karnataka, India
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19
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Borlee GI, Plumley BA, Martin KH, Somprasong N, Mangalea MR, Islam MN, Burtnick MN, Brett PJ, Steinmetz I, AuCoin DP, Belisle JT, Crick DC, Schweizer HP, Borlee BR. Genome-scale analysis of the genes that contribute to Burkholderia pseudomallei biofilm formation identifies a crucial exopolysaccharide biosynthesis gene cluster. PLoS Negl Trop Dis 2017; 11:e0005689. [PMID: 28658258 PMCID: PMC5507470 DOI: 10.1371/journal.pntd.0005689] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 07/11/2017] [Accepted: 06/08/2017] [Indexed: 11/19/2022] Open
Abstract
Burkholderia pseudomallei, the causative agent of melioidosis, is an important public health threat due to limited therapeutic options for treatment. Efforts to improve therapeutics for B. pseudomallei infections are dependent on the need to understand the role of B. pseudomallei biofilm formation and its contribution to antibiotic tolerance and persistence as these are bacterial traits that prevent effective therapy. In order to reveal the genes that regulate and/or contribute to B. pseudomallei 1026b biofilm formation, we screened a sequence defined two-allele transposon library and identified 118 transposon insertion mutants that were deficient in biofilm formation. These mutants include transposon insertions in genes predicted to encode flagella, fimbriae, transcriptional regulators, polysaccharides, and hypothetical proteins. Polysaccharides are key constituents of biofilms and B. pseudomallei has the capacity to produce a diversity of polysaccharides, thus there is a critical need to link these biosynthetic genes with the polysaccharides they produce to better understand their biological role during infection. An allelic exchange deletion mutant of the entire B. pseudomallei biofilm-associated exopolysaccharide biosynthetic cluster was decreased in biofilm formation and produced a smooth colony morphology suggestive of the loss of exopolysaccharide production. Conversely, deletion of the previously defined capsule I polysaccharide biosynthesis gene cluster increased biofilm formation. Bioinformatics analyses combined with immunoblot analysis and glycosyl composition studies of the partially purified exopolysaccharide indicate that the biofilm-associated exopolysaccharide is neither cepacian nor the previously described acidic exopolysaccharide. The biofilm-associated exopolysaccharide described here is also specific to the B. pseudomallei complex of bacteria. Since this novel exopolysaccharide biosynthesis cluster is retained in B. mallei, it is predicted to have a role in colonization and infection of the host. These findings will facilitate further advances in understanding the pathogenesis of B. pseudomallei and improve diagnostics and therapeutic treatment strategies.
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Affiliation(s)
- Grace I. Borlee
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Brooke A. Plumley
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Kevin H. Martin
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Nawarat Somprasong
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States of America
| | - Mihnea R. Mangalea
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - M. Nurul Islam
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Mary N. Burtnick
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama, United States of America
| | - Paul J. Brett
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama, United States of America
| | - Ivo Steinmetz
- Institute of Hygiene, Microbiology, and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - David P. AuCoin
- Department of Molecular Microbiology and Immunology, University of Nevada-Reno, School of Medicine Reno, Nevada, United States of America
| | - John T. Belisle
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Dean C. Crick
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Herbert P. Schweizer
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States of America
| | - Bradley R. Borlee
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
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20
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Suttisunhakul V, Pumpuang A, Ekchariyawat P, Wuthiekanun V, Elrod MG, Turner P, Currie BJ, Phetsouvanh R, Dance DAB, Limmathurotsakul D, Peacock SJ, Chantratita N. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for the identification of Burkholderia pseudomallei from Asia and Australia and differentiation between Burkholderia species. PLoS One 2017; 12:e0175294. [PMID: 28384252 PMCID: PMC5383291 DOI: 10.1371/journal.pone.0175294] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 03/23/2017] [Indexed: 11/21/2022] Open
Abstract
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is increasingly used for rapid bacterial identification. Studies of Burkholderia pseudomallei identification have involved small isolate numbers drawn from a restricted geographic region. There is a need to expand the reference database and evaluate B. pseudomallei from a wider geographic distribution that more fully captures the extensive genetic diversity of this species. Here, we describe the evaluation of over 650 isolates. Main spectral profiles (MSP) for 26 isolates of B. pseudomallei (N = 5) and other Burkholderia species (N = 21) were added to the Biotyper database. MALDI-TOF MS was then performed on 581 B. pseudomallei, 19 B. mallei, 6 B. thailandensis and 23 isolates representing a range of other bacterial species. B. pseudomallei originated from northeast and east Thailand (N = 524), Laos (N = 12), Cambodia (N = 14), Hong Kong (N = 4) and Australia (N = 27). All 581 B. pseudomallei were correctly identified, with 100% sensitivity and specificity. Accurate identification required a minimum inoculum of 5 x 107 CFU/ml, and identification could be performed on spiked blood cultures after 24 hours of incubation. Comparison between a dendrogram constructed from MALDI-TOF MS main spectrum profiles and a phylogenetic tree based on recA gene sequencing demonstrated that MALDI-TOF MS distinguished between B. pseudomallei and B. mallei, while the recA tree did not. MALDI-TOF MS is an accurate method for the identification of B. pseudomallei, and discriminates between this and other related Burkholderia species.
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Affiliation(s)
- Vichaya Suttisunhakul
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Apinya Pumpuang
- Department of Clinical Pathology, Faculty of Medicine, Navamindradhiraj University, Bangkok, Thailand
| | - Peeraya Ekchariyawat
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Vanaporn Wuthiekanun
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mindy G. Elrod
- Bacterial Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Zoonotic and Emerging Infectious Diseases, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, United States of America
| | - Paul Turner
- Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Bart J. Currie
- Department of Infectious Diseases, Royal Darwin Hospital, Darwin, Northern Territory, Australia; Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Rattanaphone Phetsouvanh
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic; Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - David A. B. Dance
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic; Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Direk Limmathurotsakul
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sharon J. Peacock
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Narisara Chantratita
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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21
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Tuanyok A, Mayo M, Scholz H, Hall CM, Allender CJ, Kaestli M, Ginther J, Spring-Pearson S, Bollig MC, Stone JK, Settles EW, Busch JD, Sidak-Loftis L, Sahl JW, Thomas A, Kreutzer L, Georgi E, Gee JE, Bowen RA, Ladner JT, Lovett S, Koroleva G, Palacios G, Wagner DM, Currie BJ, Keim P. Burkholderia humptydooensis sp. nov., a New Species Related to Burkholderia thailandensis and the Fifth Member of the Burkholderia pseudomallei Complex. Appl Environ Microbiol 2017; 83:e02802-16. [PMID: 27986727 PMCID: PMC5311406 DOI: 10.1128/aem.02802-16] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 12/02/2016] [Indexed: 11/29/2022] Open
Abstract
During routine screening for Burkholderia pseudomallei from water wells in northern Australia in areas where it is endemic, Gram-negative bacteria (strains MSMB43T, MSMB121, and MSMB122) with a similar morphology and biochemical pattern to B. pseudomallei and B. thailandensis were coisolated with B. pseudomallei on Ashdown's selective agar. To determine the exact taxonomic position of these strains and to distinguish them from B. pseudomallei and B. thailandensis, they were subjected to a series of phenotypic and molecular analyses. Biochemical and fatty acid methyl ester analysis was unable to distinguish B. humptydooensis sp. nov. from closely related species. With matrix-assisted laser desorption ionization-time of flight analysis, all isolates grouped together in a cluster separate from other Burkholderia spp. 16S rRNA and recA sequence analyses demonstrated phylogenetic placement for B. humptydooensis sp. nov. in a novel clade within the B. pseudomallei group. Multilocus sequence typing (MLST) analysis of the three isolates in comparison with MLST data from 3,340 B. pseudomallei strains and related taxa revealed a new sequence type (ST318). Genome-to-genome distance calculations and the average nucleotide identity of all isolates to both B. thailandensis and B. pseudomallei, based on whole-genome sequences, also confirmed B. humptydooensis sp. nov. as a novel Burkholderia species within the B. pseudomallei complex. Molecular analyses clearly demonstrated that strains MSMB43T, MSMB121, and MSMB122 belong to a novel Burkholderia species for which the name Burkholderia humptydooensis sp. nov. is proposed, with the type strain MSMB43T (American Type Culture Collection BAA-2767; Belgian Co-ordinated Collections of Microorganisms LMG 29471; DDBJ accession numbers CP013380 to CP013382).IMPORTANCEBurkholderia pseudomallei is a soil-dwelling bacterium and the causative agent of melioidosis. The genus Burkholderia consists of a diverse group of species, with the closest relatives of B. pseudomallei referred to as the B. pseudomallei complex. A proposed novel species, B. humptydooensis sp. nov., was isolated from a bore water sample from the Northern Territory in Australia. B. humptydooensis sp. nov. is phylogenetically distinct from B. pseudomallei and other members of the B. pseudomallei complex, making it the fifth member of this important group of bacteria.
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Affiliation(s)
- Apichai Tuanyok
- Department of Biological Sciences and The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Mark Mayo
- Menzies School of Health Research, Charles Darwin University, and Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Holger Scholz
- Bundeswehr Institute of Microbiology, Munich, Germany
| | - Carina M Hall
- Department of Biological Sciences and The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Christopher J Allender
- Department of Biological Sciences and The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Mirjam Kaestli
- Menzies School of Health Research, Charles Darwin University, and Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Jennifer Ginther
- Department of Biological Sciences and The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Senanu Spring-Pearson
- Department of Biological Sciences and The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Molly C Bollig
- Department of Biological Sciences and The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Joshua K Stone
- Department of Biological Sciences and The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Erik W Settles
- Department of Biological Sciences and The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Joseph D Busch
- Department of Biological Sciences and The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Lindsay Sidak-Loftis
- Department of Biological Sciences and The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Jason W Sahl
- Department of Biological Sciences and The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Astrid Thomas
- Bundeswehr Institute of Microbiology, Munich, Germany
| | - Lisa Kreutzer
- Bundeswehr Institute of Microbiology, Munich, Germany
| | - Enrico Georgi
- Bundeswehr Institute of Microbiology, Munich, Germany
| | - Jay E Gee
- Bacterial Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Richard A Bowen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Jason T Ladner
- Center for Genome Sciences, USAMRIID, Fort Detrick, Maryland, USA
| | - Sean Lovett
- Center for Genome Sciences, USAMRIID, Fort Detrick, Maryland, USA
| | - Galina Koroleva
- Center for Genome Sciences, USAMRIID, Fort Detrick, Maryland, USA
| | - Gustavo Palacios
- Center for Genome Sciences, USAMRIID, Fort Detrick, Maryland, USA
| | - David M Wagner
- Department of Biological Sciences and The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Bart J Currie
- Menzies School of Health Research, Charles Darwin University, and Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Paul Keim
- Department of Biological Sciences and The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
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Lowe CW, Satterfield BA, Nelson DB, Thiriot JD, Heder MJ, March JK, Drake DS, Lew CS, Bunnell AJ, Moore ES, O'Neill KL, Robison RA. A Quadruplex Real-Time PCR Assay for the Rapid Detection and Differentiation of the Most Relevant Members of the B. pseudomallei Complex: B. mallei, B. pseudomallei, and B. thailandensis. PLoS One 2016; 11:e0164006. [PMID: 27736903 PMCID: PMC5063335 DOI: 10.1371/journal.pone.0164006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 09/19/2016] [Indexed: 11/24/2022] Open
Abstract
The Burkholderia pseudomallei complex classically consisted of B. mallei, B. pseudomallei, and B. thailandensis, but has now expanded to include B. oklahomensis, B. humptydooensis, and three unassigned Burkholderia clades. Methods for detecting and differentiating the B. pseudomallei complex has been the topic of recent research due to phenotypic and genotypic similarities of these species. B. mallei and B. pseudomallei are recognized as CDC Tier 1 select agents, and are the causative agents of glanders and melioidosis, respectively. Although B. thailandensis and B. oklahomensis are generally avirulent, both display similar phenotypic characteristics to that of B. pseudomallei. B. humptydooensis and the Burkholderia clades are genetically similar to the B. pseudomallei complex, and are not associated with disease. Optimal identification of these species remains problematic, and PCR-based methods can resolve issues with B. pseudomallei complex detection and differentiation. Currently, no PCR assay is available that detects the major species of the B. pseudomallei complex. A real-time PCR assay in a multiplex single-tube format was developed to simultaneously detect and differentiate B. mallei, B. pseudomallei, and B. thailandensis, and a common sequence found in B. pseudomallei, B. mallei, B. thailandensis, and B. oklahomensis. A total of 309 Burkholderia isolates and 5 other bacterial species were evaluated. The assay was 100% sensitive and specific, demonstrated sensitivity beyond culture and GC methods for the isolates tested, and is completed in about an hour with a detection limit between 2.6pg and 48.9pg of gDNA. Bioinformatic analyses also showed the assay is likely 100% specific and sensitive for all 84 fully sequenced B. pseudomallei, B. mallei, B. thailandensis, and B. oklahomensis strains currently available in GenBank. For these reasons, this assay could be a rapid and sensitive tool in the detection and differentiation for those species of the B. pseudomallei complex with recognized clinical and practical significance.
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Affiliation(s)
- Chinn-Woan Lowe
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, United States of America
| | - Benjamin A. Satterfield
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, United States of America
| | - Daniel B. Nelson
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, United States of America
| | - Joseph D. Thiriot
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, United States of America
| | - Michael J. Heder
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, United States of America
| | - Jordon K. March
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, United States of America
| | - David S. Drake
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, United States of America
| | - Cynthia S. Lew
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, United States of America
| | - Annette J. Bunnell
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, United States of America
| | - Emily S. Moore
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, United States of America
| | - Kim L. O'Neill
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, United States of America
| | - Richard A. Robison
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, 84602, United States of America
- * E-mail:
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The Effects of Signal Erosion and Core Genome Reduction on the Identification of Diagnostic Markers. mBio 2016; 7:mBio.00846-16. [PMID: 27651357 PMCID: PMC5030356 DOI: 10.1128/mbio.00846-16] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Whole-genome sequence (WGS) data are commonly used to design diagnostic targets for the identification of bacterial pathogens. To do this effectively, genomics databases must be comprehensive to identify the strict core genome that is specific to the target pathogen. As additional genomes are analyzed, the core genome size is reduced and there is erosion of the target-specific regions due to commonality with related species, potentially resulting in the identification of false positives and/or false negatives. A comparative analysis of 1,130 Burkholderia genomes identified unique markers for many named species, including the human pathogens B. pseudomallei and B. mallei. Due to core genome reduction and signature erosion, only 38 targets specific to B. pseudomallei/mallei were identified. By using only public genomes, a larger number of markers were identified, due to undersampling, and this larger number represents the potential for false positives. This analysis has implications for the design of diagnostics for other species where the genomic space of the target and/or closely related species is not well defined.
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Peddayelachagiri BV, Paul S, Nagaraj S, Gogoi M, Sripathy MH, Batra HV. Prevalence and Identification of Burkholderia pseudomallei and Near-Neighbor Species in the Malabar Coastal Region of India. PLoS Negl Trop Dis 2016; 10:e0004956. [PMID: 27632353 PMCID: PMC5025242 DOI: 10.1371/journal.pntd.0004956] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/06/2016] [Indexed: 12/31/2022] Open
Abstract
Accurate identification of pathogens with biowarfare importance requires detection tools that specifically differentiate them from near-neighbor species. Burkholderia pseudomallei, the causative agent of a fatal disease melioidosis, is one such biothreat agent whose differentiation from its near-neighbor species is always a challenge. This is because of its phenotypic similarity with other Burkholderia species which have a wide spread geographical distribution with shared environmental niches. Melioidosis is a major public health concern in endemic regions including Southeast Asia and northern Australia. In India, the disease is still considered to be emerging. Prevalence surveys of this saprophytic bacterium in environment are under-reported in the country. A major challenge in this case is the specific identification and differentiation of B. pseudomallei from the growing list of species of Burkholderia genus. The objectives of this study included examining the prevalence of B. pseudomallei and near-neighbor species in coastal region of South India and development of a novel detection tool for specific identification and differentiation of Burkholderia species. Briefly, we analyzed soil and water samples collected from Malabar coastal region of Kerala, South India for prevalence of B. pseudomallei. The presumptive Burkholderia isolates were identified using recA PCR assay. The recA PCR assay identified 22 of the total 40 presumptive isolates as Burkholderia strains (22.72% and 77.27% B. pseudomallei and non-pseudomallei Burkholderia respectively). In order to identify each isolate screened, we performed recA and 16S rDNA sequencing. This two genes sequencing revealed that the presumptive isolates included B. pseudomallei, non-pseudomallei Burkholderia as well as non-Burkholderia strains. Furthermore, a gene termed D-beta hydroxybutyrate dehydrogenase (bdha) was studied both in silico and in vitro for accurate detection of Burkholderia genus. The optimized bdha based PCR assay when evaluated on the Burkholderia isolates of this study, it was found to be highly specific (100%) in its detection feature and a clear detection sensitivity of 10 pg/μl of purified gDNA was recorded. Nucleotide sequence variations of bdha among interspecies, as per in silico analysis, ranged from 8 to 29% within the target stretch of 730 bp highlighting the potential utility of bdha sequencing method in specific detection of Burkholderia species. Further, sequencing of the 730 bp bdha PCR amplicon of each Burkholderia strain isolated could differentiate the species and the data was comparable with recA sequence data of the strains. All sequencing results obtained were submitted to NCBI database. Bayesian phylogenetic analysis of bdha in comparison with recA and 16S rDNA showed that the bdha gene provided comparable identification of Burkholderia species.
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Affiliation(s)
| | - Soumya Paul
- Microbiology Division, Defence Food Research Laboratory, Karnataka, India
| | - Sowmya Nagaraj
- Microbiology Division, Defence Food Research Laboratory, Karnataka, India
| | - Madhurjya Gogoi
- Centre for Biotechnology and Bioinformatics, Dibrugarh University, Dibrugarh, Assam, India
| | - Murali H. Sripathy
- Microbiology Division, Defence Food Research Laboratory, Karnataka, India
| | - Harsh V. Batra
- Microbiology Division, Defence Food Research Laboratory, Karnataka, India
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25
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Garcia EC, Cotter PA. Burkholderia thailandensis: Growth and Laboratory Maintenance. CURRENT PROTOCOLS IN MICROBIOLOGY 2016; 42:4C.1.1-4C.1.7. [PMID: 27517336 DOI: 10.1002/cpmc.15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Burkholderia thailandensis is a nonpathogenic Gram-negative bacterium found in tropical soils. Closely related to several human pathogens, its ease of genetic manipulation, rapid growth in the laboratory, and low virulence make B. thailandensis a commonly used model organism. This unit describes the fundamental protocols for in vitro growth and maintenance of B. thailandensis in the laboratory. © 2016 by John Wiley & Sons, Inc.
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Affiliation(s)
- Erin C Garcia
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Peggy A Cotter
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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26
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Abstract
The genus Burkholderia comprises metabolically diverse and adaptable Gram-negative bacteria, which thrive in often adversarial environments. A few members of the genus are prominent opportunistic pathogens. These include Burkholderia mallei and Burkholderia pseudomallei of the B. pseudomallei complex, which cause glanders and melioidosis, respectively. Burkholderia cenocepacia, Burkholderia multivorans, and Burkholderia vietnamiensis belong to the Burkholderia cepacia complex and affect mostly cystic fibrosis patients. Infections caused by these bacteria are difficult to treat because of significant antibiotic resistance. The first line of defense against antimicrobials in Burkholderia species is the outer membrane penetration barrier. Most Burkholderia contain a modified lipopolysaccharide that causes intrinsic polymyxin resistance. Contributing to reduced drug penetration are restrictive porin proteins. Efflux pumps of the resistance nodulation cell division family are major players in Burkholderia multidrug resistance. Third and fourth generation β-lactam antibiotics are seminal for treatment of Burkholderia infections, but therapeutic efficacy is compromised by expression of several β-lactamases and ceftazidime target mutations. Altered DNA gyrase and dihydrofolate reductase targets cause fluoroquinolone and trimethoprim resistance, respectively. Although antibiotic resistance hampers therapy of Burkholderia infections, the characterization of resistance mechanisms lags behind other non-enteric Gram-negative pathogens, especially ESKAPE bacteria such as Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa.
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Affiliation(s)
- Katherine A Rhodes
- Department of Molecular Genetics and Microbiology, College of Medicine, Emerging Pathogens Institute and Institute for Therapeutic Innovation, University of Florida, Gainesville, FL, USA; Department of Microbiology Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Herbert P Schweizer
- Department of Molecular Genetics and Microbiology, College of Medicine, Emerging Pathogens Institute and Institute for Therapeutic Innovation, University of Florida, Gainesville, FL, USA.
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27
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Price EP, MacHunter B, Spratt BG, Wagner DM, Currie BJ, Sarovich DS. Improved multilocus sequence typing of Burkholderia pseudomallei and closely related species. J Med Microbiol 2016; 65:992-997. [PMID: 27412128 DOI: 10.1099/jmm.0.000312] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The Burkholderiapseudomallei multilocus sequence typing (MLST) database (http://pubmlst.org/bpseudomallei/) contains the largest global sequence repository for B. pseudomallei and its closest genetic relatives. Using conventional MLST and in silico MLST data derived from publicly available whole-genome sequences, we first defined the phylogenetic relatedness of B. pseudomallei and its nearest neighbours. Based on this analysis, we propose that the recently described B. pseudomallei complex (Bpc) should be expanded to encompass B. pseudomallei, Burkholderiahumptydooensis (proposed), Burkholderiamallei, Burkholderiaoklahomensis, Burkholderiathailandensis and three unassigned Burkholderia Clades A, B and C (represented by type strains BDU 5, BDU 8 and MSMB0265, respectively). Of note, the MLST narK locus is present in all Bpc species but is missing in all other Burkholderia spp., including all Burkholderiacepacia complex species, with the exception of most Burkholderiaubonensis strains, which contain narK but encode genetically distinct sequences. The presence of narK is thus indicative of a Bpc strain. Next, we revisited in silico the performance of the existing MLST primers, which prompted redesign of primers targeting the gmhD, lepA, lipA, narK and ndh loci to encompass genetic diversity among Bpc strains and to address amplification/sequencing issues. We show in silico and in vitro that the redesigned primers yield good-quality amplification and sequencing results for the gmhD, lepA, lipA, narK and ndh loci in Bpc species. These primers provide an alternative for amplification and sequencing of MLST loci in Bpc species in cases when poor-quality amplification or sequencing data are obtained using the original MLST primers.
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Affiliation(s)
- Erin P Price
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Barbara MacHunter
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Brian G Spratt
- Faculty of Medicine, Imperial College London, London, UK
| | - David M Wagner
- Center for Microbial Genetics and Genomics, Northern Arizona University, Flagstaff, AZ, USA
| | - Bart J Currie
- Department of Infectious Diseases and Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Northern Territory, Australia
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Derek S Sarovich
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
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The melioidosis agent Burkholderia pseudomallei and related opportunistic pathogens detected in faecal matter of wildlife and livestock in northern Australia. Epidemiol Infect 2016; 144:1924-32. [PMID: 26935879 DOI: 10.1017/s0950268816000285] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The Darwin region in northern Australia has experienced rapid population growth in recent years, and with it, an increased incidence of melioidosis. Previous studies in Darwin have associated the environmental presence of Burkholderia pseudomallei, the causative agent of melioidosis, with anthropogenic land usage and proximity to animals. In our study, we estimated the occurrence of B. pseudomallei and Burkholderia spp. relatives in faecal matter of wildlife, livestock and domestic animals in the Darwin region. A total of 357 faecal samples were collected and bacteria isolated through culture and direct DNA extraction after enrichment in selective media. Identification of B. pseudomallei, B. ubonensis, and other Burkholderia spp. was carried out using TTS1, Bu550, and recA BUR3-BUR4 quantitative PCR assays, respectively. B. pseudomallei was detected in seven faecal samples from wallabies and a chicken. B. cepacia complex spp. and Pandoraea spp. were cultured from wallaby faecal samples, and B. cenocepacia and B. cepacia were also isolated from livestock animals. Various bacteria isolated in this study represent opportunistic human pathogens, raising the possibility that faecal shedding contributes to the expanding geographical distribution of not just B. pseudomallei but other Burkholderiaceae that can cause human disease.
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Diverse Burkholderia Species Isolated from Soils in the Southern United States with No Evidence of B. pseudomallei. PLoS One 2015; 10:e0143254. [PMID: 26600238 PMCID: PMC4658082 DOI: 10.1371/journal.pone.0143254] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/02/2015] [Indexed: 01/28/2023] Open
Abstract
The global distribution of the soil-dwelling bacterium Burkholderia pseudomallei, causative agent of melioidosis, is poorly understood. We used established culturing methods developed for B. pseudomallei to isolate Burkholderia species from soil collected at 18 sampling sites in three states in the southern United States (Arizona (n = 4), Florida (n = 7), and Louisiana (n = 7)). Using multi-locus sequence typing (MLST) of seven genes, we identified 35 Burkholderia isolates from these soil samples. All species belonged to the B. cepacia complex (Bcc), including B. cenocepacia, B. cepacia, B. contaminans, B. diffusa, B. metallica, B. seminalis, B. vietnamiensis and two unnamed members of the Bcc. The MLST analysis provided a high level of resolution among and within these species. Despite previous clinical cases within the U.S. involving B. pseudomallei and its close phylogenetic relatives, we did not isolate any of these taxa. The Bcc contains a number of opportunistic pathogens that cause infections in cystic fibrosis patients. Interestingly, we found that B. vietnamiensis was present in soil from all three states, suggesting it may be a common component in southern U.S. soils. Most of the Burkholderia isolates collected in this study were from Florida (30/35; 86%), which may be due to the combination of relatively moist, sandy, and acidic soils found there compared to the other two states. We also investigated one MLST gene, recA, for its ability to identify species within Burkholderia. A 365bp fragment of recA recovered nearly the same species-level identification as MLST, thus demonstrating its cost effective utility when conducting environmental surveys for Burkholderia. Although we did not find B. pseudomallei, our findings document that other diverse Burkholderia species are present in soils in the southern United States.
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