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Wongbutdee J, Jittimanee J, Daendee S, Thongsang P, Saengnill W. Exploring the Relationship between Melioidosis Morbidity Rate and Local Environmental Indicators Using Remotely Sensed Data. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2024; 21:614. [PMID: 38791828 PMCID: PMC11121278 DOI: 10.3390/ijerph21050614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 05/09/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024]
Abstract
Melioidosis is an endemic infectious disease caused by Burkholderia pseudomallei bacteria, which contaminates soil and water. To better understand the environmental changes that have contributed to melioidosis outbreaks, this study used spatiotemporal analyses to clarify the distribution pattern of melioidosis and the relationship between melioidosis morbidity rate and local environmental indicators (land surface temperature, normalised difference vegetation index, normalised difference water index) and rainfall. A retrospective study was conducted from January 2013 to December 2022, covering data from 219 sub-districts in Northeast Thailand, with each exhibiting a varying morbidity rate of melioidosis on a monthly basis. Spatial autocorrelation was determined using local Moran's I, and the relationship between the melioidosis morbidity rate and the environmental indicators was evaluated using a geographically weighted Poisson regression. The results revealed clustered spatiotemporal patterns of melioidosis morbidity rate across sub-districts, with hotspots predominantly observed in the northern region. Furthermore, we observed a range of coefficients for the environmental indicators, varying from negative to positive, which provided insights into their relative contributions to melioidosis in each local area and month. These findings highlight the presence of spatial heterogeneity driven by environmental indicators and underscore the importance of public health offices implementing targeted monitoring and surveillance strategies for melioidosis in different locations.
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Affiliation(s)
- Jaruwan Wongbutdee
- Geospatial Health Research Group, College of Medicine and Public Health, Ubon Ratchathani University, Ubonratchathani 34190, Thailand; (J.W.); (J.J.); (S.D.)
| | - Jutharat Jittimanee
- Geospatial Health Research Group, College of Medicine and Public Health, Ubon Ratchathani University, Ubonratchathani 34190, Thailand; (J.W.); (J.J.); (S.D.)
| | - Suwaporn Daendee
- Geospatial Health Research Group, College of Medicine and Public Health, Ubon Ratchathani University, Ubonratchathani 34190, Thailand; (J.W.); (J.J.); (S.D.)
| | - Pongthep Thongsang
- Department of Geology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand;
| | - Wacharapong Saengnill
- Geospatial Health Research Group, College of Medicine and Public Health, Ubon Ratchathani University, Ubonratchathani 34190, Thailand; (J.W.); (J.J.); (S.D.)
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Anggraini D, Siregar FM, Rosdiana D, Kemal RA, Yovi I, Triani ZD, Jasmin N, Dwijelita N, Webb JR, Mayo M, Kaestli M, Currie BJ. Epidemiology and genetic diversity of Burkholderia pseudomallei from Riau Province, Indonesia. PLoS Negl Trop Dis 2024; 18:e0012195. [PMID: 38805481 PMCID: PMC11161056 DOI: 10.1371/journal.pntd.0012195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 06/07/2024] [Accepted: 05/06/2024] [Indexed: 05/30/2024] Open
Abstract
Melioidosis is a bacterial infection caused by Burkholderia pseudomallei, that is common in tropical and subtropical countries including Southeast Asia and Northern Australia. The magnitude of undiagnosed and untreated melioidosis across the country remains unclear. Given its proximity to regions with high infection rates, Riau Province on Sumatera Island is anticipated to have endemic melioidosis. This study reports retrospectively collected data on 68 culture-confirmed melioidosis cases from two hospitals in Riau Province between January 1, 2009, and December 31, 2021, with full clinical data available on 41 cases. We also describe whole genome sequencing and genotypic analysis of six isolates of B. pseudomallei. The mean age of the melioidosis patients was 49.1 (SD 11.5) years, 85% were male and the most common risk factor was diabetes mellitus (78%). Pulmonary infection was the most common presentation (39%), and overall mortality was 41%. Lung as a focal infection (aOR: 6.43; 95% CI: 1.13-36.59, p = 0.036) and bacteremia (aOR: 15.21; 95% CI: 2.59-89.31, p = 0.003) were significantly associated with death. Multilocus sequence typing analysis conducted on six B.pseudomallei genomes identified three sequence types (STs), namely novel ST1794 (n = 3), ST46 (n = 2), and ST289 (n = 1). A phylogenetic tree of Riau B. pseudomallei whole genome sequences with a global dataset of genomes clearly distinguished the genomes of B. pseudomallei in Indonesia from the ancestral Australian clade and classified them within the Asian clade. This study expands the known presence of B. pseudomallei within Indonesia and confirms that Indonesian B. pseudomallei are genetically linked to those in the rest of Southeast Asia. It is anticipated that melioidosis will be found in other locations across Indonesia as laboratory capacities improve and standardized protocols for detecting and confirming suspected cases of melioidosis are more widely implemented.
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Affiliation(s)
- Dewi Anggraini
- Department of Microbiology, Faculty of Medicine, Universitas Riau, Pekanbaru, Indonesia
- Arifin Achmad General Hospital, Riau Province, Pekanbaru, Indonesia
- Eka Hospital Pekanbaru, Pekanbaru, Indonesia
| | - Fajri Marindra Siregar
- Arifin Achmad General Hospital, Riau Province, Pekanbaru, Indonesia
- Department of Biochemistry, Faculty of Medicine, Universitas Riau, Pekanbaru, Indonesia
| | - Dani Rosdiana
- Arifin Achmad General Hospital, Riau Province, Pekanbaru, Indonesia
- Department of Internal Medicine, Faculty of Medicine, Universitas Riau, Pekanbaru, Indonesia
| | - Rahmat Azhari Kemal
- Arifin Achmad General Hospital, Riau Province, Pekanbaru, Indonesia
- Department of Medical Biology, Faculty of Medicine, Universitas Riau, Pekanbaru, Indonesia
| | - Indra Yovi
- Arifin Achmad General Hospital, Riau Province, Pekanbaru, Indonesia
- Eka Hospital Pekanbaru, Pekanbaru, Indonesia
- Department of Pulmonology, Faculty of Medicine, Universitas Riau, Pekanbaru, Indonesia
| | | | - Novira Jasmin
- Department of Microbiology, Faculty of Medicine, Universitas Riau, Pekanbaru, Indonesia
| | - Norsila Dwijelita
- Department of Microbiology, Faculty of Medicine, Universitas Riau, Pekanbaru, Indonesia
| | - Jessica R. Webb
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
- Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Mark Mayo
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Mirjam Kaestli
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Bart J. Currie
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
- Department of Infectious Diseases, Royal Darwin Hospital, Darwin, Northern Territory, Australia
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Meumann EM, Limmathurotsakul D, Dunachie SJ, Wiersinga WJ, Currie BJ. Burkholderia pseudomallei and melioidosis. Nat Rev Microbiol 2024; 22:155-169. [PMID: 37794173 DOI: 10.1038/s41579-023-00972-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2023] [Indexed: 10/06/2023]
Abstract
Burkholderia pseudomallei, the causative agent of melioidosis, is found in soil and water of tropical and subtropical regions globally. Modelled estimates of the global burden predict that melioidosis remains vastly under-reported, and a call has been made for it to be recognized as a neglected tropical disease by the World Health Organization. Severe weather events and environmental disturbance are associated with increased case numbers, and it is anticipated that, in some regions, cases will increase in association with climate change. Genomic epidemiological investigations have confirmed B. pseudomallei endemicity in newly recognized regions, including the southern United States. Melioidosis follows environmental exposure to B. pseudomallei and is associated with comorbidities that affect the immune response, such as diabetes, and with socioeconomic disadvantage. Several vaccine candidates are ready for phase I clinical trials. In this Review, we explore the global burden, epidemiology and pathophysiology of B. pseudomallei as well as current diagnostics, treatment recommendations and preventive measures, highlighting research needs and priorities.
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Affiliation(s)
- Ella M Meumann
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia.
- Department of Infectious Diseases, Division of Medicine, Royal Darwin Hospital, Darwin, Northern Territory, Australia.
| | - Direk Limmathurotsakul
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- NDM Centre for Global Health Research, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Susanna J Dunachie
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- NDM Centre for Global Health Research, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Willem J Wiersinga
- Division of Infectious Diseases, Center for Experimental Molecular Medicine, Amsterdam University Medical Centers, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Bart J Currie
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
- Department of Infectious Diseases, Division of Medicine, Royal Darwin Hospital, Darwin, Northern Territory, Australia
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Phillips ED, Garcia EC. Burkholderia pseudomallei. Trends Microbiol 2024; 32:105-106. [PMID: 37634974 PMCID: PMC10803057 DOI: 10.1016/j.tim.2023.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/13/2023] [Accepted: 07/14/2023] [Indexed: 08/29/2023]
Abstract
Burkholderia pseudomallei is a Gram negative, facultative intracellular bacterium that resides in the rhizosphere of tropical soils. B. pseudomallei causes melioidosis, which is transmitted by cutaneous entry, ingestion, or inhalation of contaminated soil or water. Infection with B. pseudomallei can cause a wide array of clinical symptoms such as pneumonia, bone, joint, skin, genitourinary, and central nervous system infections, as well as parotid abscesses in children. Mammalian virulence is linked to the B. pseudomallei intracellular life cycle, which begins with attachment and internalization by host cells. B. pseudomallei can infect a wide range of eukaryotic cells, including macrophages, monocytes, and neutrophils, as well as nonphagocytic cells. Once internalized, a type 3 secretion system (T3SSBsa) facilitates B. pseudomallei escape from the phagosome, and the bacteria replicate in the cytoplasm. Autotransporter protein BimA mediates actin polymerization, enabling B. pseudomallei to spread, cell to cell, using actin-based motility. This process, coupled with the activity of a type 6 secretion system (T6SS-5), results in host membrane fusion and the formation of multinucleated giant cells. Capsule polysaccharides also contribute to virulence and evasion of host innate immunity. Treatment of B. pseudomallei infections is complicated by the organism’s intrinsic resistance to multiple classes of antimicrobials, largely due to an abundance of efflux pumps and reduced outer membrane permeability. While B. pseudomallei is commonly associated with endemic ‘hotspots’ in southeast Asia and northern Australia, there is increasing evidence that it is likely endemic in a large range of tropical and subtropical areas, including regions in Africa, South America, the Middle East, Central America, and the Caribbean. Soil and climate conditions favorable for B. pseudomallei survival are also found in additional areas worldwide. Consequently, it is important for clinical and public health laboratories located outside of high-endemicity areas to be aware of B. pseudomallei , as well as for improved diagnostic and reporting methods.
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Affiliation(s)
- Erica D Phillips
- University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Erin C Garcia
- University of Kentucky College of Medicine, Lexington, KY 40536, USA.
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Smith S, Marquardt T, Jennison AV, D'Addona A, Stewart J, Yarwood T, Ho J, Binotto E, Harris J, Fahmy M, Esmonde J, Richardson M, Graham RMA, Gair R, Ariotti L, Preston-Thomas A, Rubenach S, O'Sullivan S, Allen D, Ragh T, Grayson S, Manoy S, Warner JM, Meumann EM, Robson JM, Hanson J. Clinical Manifestations and Genomic Evaluation of Melioidosis Outbreak among Children after Sporting Event, Australia. Emerg Infect Dis 2023; 29:2218-2228. [PMID: 37877500 PMCID: PMC10617349 DOI: 10.3201/eid2911.230951] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023] Open
Abstract
Melioidosis, caused by the environmental gram-negative bacterium Burkholderia pseudomallei, usually develops in adults with predisposing conditions and in Australia more commonly occurs during the monsoonal wet season. We report an outbreak of 7 cases of melioidosis in immunocompetent children in Australia. All the children had participated in a single-day sporting event during the dry season in a tropical region of Australia, and all had limited cutaneous disease. All case-patients had an adverse reaction to oral trimethoprim/sulfamethoxazole treatment, necessitating its discontinuation. We describe the clinical features, environmental sampling, genomic epidemiologic investigation, and public health response to the outbreak. Management of this outbreak shows the potential benefits of making melioidosis a notifiable disease. The approach used could also be used as a framework for similar outbreaks in the future.
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Zheng W, Kuang S, Zhong C, Zhou J, Long W, Xiao S, Wu B. Risk Factors for Melioidosis Mortality and Epidemics: A Multicentre, 10-Year Retrospective Cohort Study in Northern Hainan. Infect Dis Ther 2023; 12:951-964. [PMID: 36800150 PMCID: PMC9936936 DOI: 10.1007/s40121-023-00768-3] [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: 11/29/2022] [Accepted: 01/25/2023] [Indexed: 02/18/2023] Open
Abstract
INTRODUCTION Burkholderia pseudomallei is a gram-negative environmental bacterium and aetiological agent of melioidosis, a tropical infectious disease with diverse clinical presentations. We aimed to describe the epidemiological and clinical characteristics of melioidosis in northern Hainan and to determine the meteorological factors affecting its morbidity. METHODS We conducted a retrospective, multicentre, observational cohort study of 90 patients with melioidosis admitted to four general hospitals in northern Hainan from 2010 to 2020. Epidemiological, clinical presentation, laboratory and treatment outcome data were collected and analysed. The monthly incidence of melioidosis and meteorological data, including precipitation, temperature, humidity, air pressure and wind speed, for the same period were collected to analyse the relationship between meteorological factors and the incidence of melioidosis. RESULTS Of the 90 patients included in the study, 79 (87.78%) were male. Patient age ranged from 10 to 81 years old, but most patients, namely, 78 (86.67%), were middle-aged and elderly people aged 41-81 years old. Forty-six patients (51.11%) were farmers. The number of cases increased significantly after 2014, with the highest numbers occurring in 2014 and 2016. The highest number of cases occurred in summer and autumn and were associated with abundant rainfall, and 58 cases (64.44%) occurred from July to December. The patients showed diverse presentations and abnormal laboratory parameters: 69 patients (76.67%) had a history of diabetes mellitus; bacteremia was present in 50 patients (55.56%), sepsis was present in 39 patients (43.33%) and pneumonia in 19 patients (21.11%). An average high-sensitivity C-reactive protein (hs-CRP) level of 149.57 ± 13.65 mg/L and a median procalcitonin (PCT) level of 1.31 (0.39, 6.21) ng/mL were observed. Among all the cases, 21 (23.33%) were identified as acute infections, 51 (56.67%) as subacute infections and 18 (20.00%) as chronic infections. Six patients (6.67%) died of illness; five of these patients were male, and five of these patients were middle-aged and elderly patients. The monthly average precipitation was significantly positively correlated with the monthly average incidence of melioidosis (r = 0.74, P < 0.01). CONCLUSION Male patients, farmers and especially middle-aged and elderly individuals with a history of diabetes mellitus accounted for most of the patients. The majority of cases were concentrated in coastal areas. Most cases of melioidosis occurred during the rainy seasons, and the monthly average precipitation was an independent factor affecting the average monthly incidence of melioidosis.
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Affiliation(s)
- Wanting Zheng
- International School of Public Health and One Health, Heinz Mehlhorn Academician Workstation, Hainan Medical University, Haikou, 571199, China
| | - Shicheng Kuang
- Department of Pharmacy, Hainan Affiliated Hospital of Hainan Medical University, Hainan General Hospital, Haikou, 570311, China
| | - Chengwang Zhong
- International School of Public Health and One Health, Heinz Mehlhorn Academician Workstation, Hainan Medical University, Haikou, 571199, China
| | - Jing Zhou
- International School of Public Health and One Health, Heinz Mehlhorn Academician Workstation, Hainan Medical University, Haikou, 571199, China
| | - Wenfang Long
- International School of Public Health and One Health, Heinz Mehlhorn Academician Workstation, Hainan Medical University, Haikou, 571199, China
| | - Sha Xiao
- International School of Public Health and One Health, Heinz Mehlhorn Academician Workstation, Hainan Medical University, Haikou, 571199, China.
| | - Biao Wu
- Department of Hospital Infection Management and Diseases Control and Prevention, Center for Infection Diseases, Hainan Affiliated Hospital of Hainan Medical University, Hainan General Hospital, Haikou, 570311, China.
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An Investigation of Burkholderia pseudomallei Seroprevalence in Market Pigs Slaughtered at Selected Pig Abattoirs in Uganda. Pathogens 2022; 11:pathogens11111363. [DOI: 10.3390/pathogens11111363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/08/2022] [Accepted: 11/14/2022] [Indexed: 11/17/2022] Open
Abstract
Burkholderia pseudomallei is a Gram-negative bacterium that causes melioidosis, a disease of humans and animals. It is primarily transmitted through direct contact with contaminated soil and surface water. The epidemiology of this pathogen in Africa, including Uganda, is largely unknown. The objectives of this study were to estimate the seroprevalence of B. pseudomallei in pigs slaughtered in central Uganda and to identify potential hotspots for this pathogen in the country. A total of 1035 pig sera were analyzed for serological responses to B. pseudomallei with type A and type B LPS using OPS type A and OPS type B ELISAs. Of the 1035 samples, 75 (7.25%, 95% CI: 5.8–9%) were seropositive to the OPS-A ELISA using a two standard deviations (SD) cutoff and 19 (1.84%, 95% CI: 1.2–2.9%) at 3 SD. For the OPS-B ELISA, 93/1035 (8.99%, 95% CI: 7.4–10.9%) were seropositive at the 2 SD cutoff, and 28/1035 (2.71%, 95% CI: 1.9–3.9%) at the 3 SD cutoff. Pigs slaughtered in central Uganda were exposed to B. pseudomallei, and there is a higher seroprevalence in the rainy months. Public health awareness campaigns about melioidosis may be needed.
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Klimko CP, Shoe JL, Rill NO, Hunter M, Dankmeyer JL, Talyansky Y, Schmidt LK, Orne CE, Fetterer DP, Biryukov SS, Burtnick MN, Brett PJ, DeShazer D, Cote CK. Layered and integrated medical countermeasures against Burkholderia pseudomallei infections in C57BL/6 mice. Front Microbiol 2022; 13:965572. [PMID: 36060756 PMCID: PMC9432870 DOI: 10.3389/fmicb.2022.965572] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Burkholderia pseudomallei, the gram-negative bacterium that causes melioidosis, is notoriously difficult to treat with antibiotics. A significant effort has focused on identifying protective vaccine strategies to prevent melioidosis. However, when used as individual medical countermeasures both antibiotic treatments (therapeutics or post-exposure prophylaxes) and experimental vaccine strategies remain partially protective. Here we demonstrate that when used in combination, current vaccine strategies (recombinant protein subunits AhpC and/or Hcp1 plus capsular polysaccharide conjugated to CRM197 or the live attenuated vaccine strain B. pseudomallei 668 ΔilvI) and co-trimoxazole regimens can result in near uniform protection in a mouse model of melioidosis due to apparent synergy associated with distinct medical countermeasures. Our results demonstrated significant improvement when examining several suboptimal antibiotic regimens (e.g., 7-day antibiotic course started early after infection or 21-day antibiotic course with delayed initiation). Importantly, this combinatorial strategy worked similarly when either protein subunit or live attenuated vaccines were evaluated. Layered and integrated medical countermeasures will provide novel treatment options for melioidosis as well as diseases caused by other pathogens that are refractory to individual strategies, particularly in the case of engineered, emerging, or re-emerging bacterial biothreat agents.
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Affiliation(s)
- Christopher P. Klimko
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
| | - Jennifer L. Shoe
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
| | - Nathaniel O. Rill
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
| | - Melissa Hunter
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
| | - Jennifer L. Dankmeyer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
| | - Yuli Talyansky
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
| | - Lindsey K. Schmidt
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine, Reno, NV, United States
| | - Caitlyn E. Orne
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine, Reno, NV, United States
| | - David P. Fetterer
- Biostatistics Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
| | - Sergei S. Biryukov
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
| | - Mary N. Burtnick
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine, Reno, NV, United States
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Paul J. Brett
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine, Reno, NV, United States
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - David DeShazer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
| | - Christopher K. Cote
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States
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Hodgetts K, Kleinecke M, Woerle C, Kaestli M, Budd R, Webb JR, Ward L, Mayo M, Currie BJ, Meumann EM. Melioidosis in the remote Katherine region of northern Australia. PLoS Negl Trop Dis 2022; 16:e0010486. [PMID: 35696415 PMCID: PMC9232150 DOI: 10.1371/journal.pntd.0010486] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 06/24/2022] [Accepted: 05/10/2022] [Indexed: 11/19/2022] Open
Abstract
Melioidosis is endemic in the remote Katherine region of northern Australia. In a population with high rates of chronic disease, social inequities, and extreme remoteness, the impact of melioidosis is exacerbated by severe weather events and disproportionately affects First Nations Australians. All culture-confirmed melioidosis cases in the Katherine region of the Australian Top End between 1989–2021 were included in the study, and the clinical features and epidemiology were described. The diversity of Burkholderia pseudomallei strains in the region was investigated using genomic sequencing. From 1989–2021 there were 128 patients with melioidosis in the Katherine region. 96/128 (75%) patients were First Nations Australians, 72/128 (56%) were from a very remote region, 68/128 (53%) had diabetes, 57/128 (44%) had a history of hazardous alcohol consumption, and 11/128 (9%) died from melioidosis. There were 9 melioidosis cases attributable to the flooding of the Katherine River in January 1998; 7/9 flood-associated cases had cutaneous melioidosis, five of whom recalled an inoculating event injury sustained wading through flood waters or cleaning up after the flood. The 126 first-episode clinical B. pseudomallei isolates that underwent genomic sequencing belonged to 107 different sequence types and were highly diverse, reflecting the vast geographic area of the study region. In conclusion, melioidosis in the Katherine region disproportionately affects First Nations Australians with risk factors and is exacerbated by severe weather events. Diabetes management, public health intervention for hazardous alcohol consumption, provision of housing to address homelessness, and patient education on melioidosis prevention in First Nations languages should be prioritised. Melioidosis, caused by the environmental bacterium Burkholderia pseudomallei, disproportionately affects Australian First Nations peoples in the Northern Territory of Australia. The Katherine region has some of the highest rates of homelessness in Australia, and social inequity impacts health outcomes for First Nations people whose access to care is further complicated by remoteness. In this study, we describe the clinical features and epidemiology of melioidosis in the Katherine region over a 32-year period. Almost three quarters of melioidosis cases were First Nations Australians, over half lived in a very remote region, and diabetes and hazardous alcohol consumption were common risk factors. Following a severe flooding event in the region in 1998, a spike in cases of melioidosis was seen, the majority presenting as skin and soft tissue infections. The B. pseudomallei isolates in the study were extremely genetically diverse, reflecting the large geographic area of the Katherine region. With predicted climate change-driven increases in severe weather events and subsequent increases in melioidosis cases, public health priorities in the region should include addressing high rates of homelessness and hazardous alcohol consumption, optimisation of diabetes management, and ongoing education in First Nations languages regarding prevention of B. pseudomallei exposure.
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Affiliation(s)
- Kay Hodgetts
- Department of Infectious Diseases, Wellington Regional Hospital, Wellington, New Zealand
- Department of Infectious Diseases, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Mariana Kleinecke
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Celeste Woerle
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Mirjam Kaestli
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Richard Budd
- Katherine District Hospital, Katherine, Northern Territory, Australia
| | - Jessica R. Webb
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
- Department of Microbiology & Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Linda Ward
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Mark Mayo
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Bart J. Currie
- Department of Infectious Diseases, Royal Darwin Hospital, Darwin, Northern Territory, Australia
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Ella M. Meumann
- Department of Infectious Diseases, Royal Darwin Hospital, Darwin, Northern Territory, Australia
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
- * E-mail:
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Savelkoel J, Dance DAB, Currie BJ, Limmathurotsakul D, Wiersinga WJ. A call to action: time to recognise melioidosis as a neglected tropical disease. THE LANCET INFECTIOUS DISEASES 2022; 22:e176-e182. [DOI: 10.1016/s1473-3099(21)00394-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 05/07/2021] [Accepted: 06/28/2021] [Indexed: 10/19/2022]
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Birnie E, Biemond JJ, Wiersinga WJ. Drivers of melioidosis endemicity: epidemiological transition, zoonosis, and climate change. Curr Opin Infect Dis 2022; 35:196-204. [PMID: 35665713 PMCID: PMC10128909 DOI: 10.1097/qco.0000000000000827] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE OF REVIEW Melioidosis, caused by the soil-dwelling bacterium Burkholderia pseudomallei, is a tropical infection associated with high morbidity and mortality. This review summarizes current insights into melioidosis' endemicity, focusing on epidemiological transitions, zoonosis, and climate change. RECENT FINDINGS Estimates of the global burden of melioidosis affirm the significance of hot-spots in Australia and Thailand. However, it also highlights the paucity of systematic data from South Asia, The Americas, and Africa. Globally, the growing incidence of diabetes, chronic renal and (alcoholic) liver diseases further increase the susceptibility of individuals to B. pseudomallei infection. Recent outbreaks in nonendemic regions have further exposed the hazard from the trade of animals and products as potential reservoirs for B. pseudomallei. Lastly, global warming will increase precipitation, severe weather events, soil salinity and anthrosol, all associated with the occurrence of B. pseudomallei. SUMMARY Epidemiological transitions, zoonotic hazards, and climate change are all contributing to the emergence of novel melioidosis-endemic areas. The adoption of the One Health approach involving multidisciplinary collaboration is important in unraveling the real incidence of B. pseudomallei, as well as reducing the spread and associated mortality.
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Affiliation(s)
- Emma Birnie
- Amsterdam UMC location University of Amsterdam, Center for Experimental and Molecular Medicine
- Amsterdam UMC location University of Amsterdam, Division of Infectious Diseases, Meibergdreef 9, Amsterdam, Netherlands
| | - Jason J. Biemond
- Amsterdam UMC location University of Amsterdam, Center for Experimental and Molecular Medicine
| | - W. Joost Wiersinga
- Amsterdam UMC location University of Amsterdam, Center for Experimental and Molecular Medicine
- Amsterdam UMC location University of Amsterdam, Division of Infectious Diseases, Meibergdreef 9, Amsterdam, Netherlands
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12
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Pongmala K, Pierret A, Oliva P, Pando A, Davong V, Rattanavong S, Silvera N, Luangraj M, Boithias L, Xayyathip K, Menjot L, Macouin M, Rochelle-Newall E, Robain H, Vongvixay A, Simpson AJH, Dance DAB, Ribolzi O. Distribution of Burkholderia pseudomallei within a 300-cm deep soil profile: implications for environmental sampling. Sci Rep 2022; 12:8674. [PMID: 35606475 PMCID: PMC9126866 DOI: 10.1038/s41598-022-12795-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 05/12/2022] [Indexed: 01/02/2023] Open
Abstract
The environmental distribution of Burkholderia pseudomallei, the causative agent of melioidosis, remains poorly understood. B. pseudomallei is known to have the ability to occupy a variety of environmental niches, particularly in soil. This paper provides novel information about a putative association of soil biogeochemical heterogeneity and the vertical distribution of B. pseudomallei. We investigated (1) the distribution of B. pseudomallei along a 300-cm deep soil profile together with the variation of a range of soil physico-chemical properties; (2) whether correlations between the distribution of B. pseudomallei and soil physico-chemical properties exist and (3) when they exist, what such correlations indicate with regards to the environmental conditions conducive to the occurrence of B. pseudomallei in soils. Unexpectedly, the highest concentrations of B. pseudomallei were observed between 100 and 200 cm below the soil surface. Our results indicate that unravelling the environmental conditions favorable to B. pseudomallei entails considering many aspects of the actual complexity of soil. Important recommendations regarding environmental sampling for B. pseudomallei can be drawn from this work, in particular that collecting samples down to the water table is of foremost importance, as groundwater persistence appears to be a controlling factor of the occurrence of B. pseudomallei in soil.
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Grist EPM, McKinley TJ, Das S, Tregenza T, Jeffries A, Tregenza N. Estimating cetacean population trends from static acoustic monitoring data using Paired Year Ratio Assessment (PYRA). PLoS One 2022; 17:e0264289. [PMID: 35298473 PMCID: PMC8929582 DOI: 10.1371/journal.pone.0264289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/07/2022] [Indexed: 11/19/2022] Open
Abstract
The cetacean conservationist is often faced with evaluating population trends from abundance data that are either sparse or recorded at different times in different years. The presence of diel or seasonal patterns in the data together with unplanned gaps is often problematic. Such data are typical of those obtained from static acoustic monitoring. We present a simple and transparent non-parametric trend evaluation method, ‘Paired Year Ratio Assessment (PYRA)’ that uses only whole days of data wherever they are present in each of successive pairs of periods of 365 days. We provide a quantitative comparison of the performance of PYRA with traditional generalised additive models (GAMS) and nonparametric randomisation tests that require a greater level of skill and experience for both application and interpretation. We conclude that PYRA is a powerful tool, particularly in the context of identifying population trends which is often the main aim of conservation-targeted acoustic monitoring.
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Affiliation(s)
- Eric P. M. Grist
- Chelonia Ltd., Mousehole, Cornwall, United Kingdom
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom
- * E-mail:
| | | | - Saptarshi Das
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom
- Institute for Data Science and Artificial Intelligence, University of Exeter, Exeter, United Kingdom
| | - Tom Tregenza
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, United Kingdom
| | - Aileen Jeffries
- Harbor Porpoise Project, Anacortes, Washington, United States of America
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Fairhead LJ, Smith S, Sim BZ, Stewart AGA, Stewart JD, Binotto E, Law M, Hanson J. The seasonality of infections in tropical Far North Queensland, Australia: A 21-year retrospective evaluation of the seasonal patterns of six endemic pathogens. PLOS GLOBAL PUBLIC HEALTH 2022; 2:e0000506. [PMID: 36962353 PMCID: PMC10021965 DOI: 10.1371/journal.pgph.0000506] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 04/27/2022] [Indexed: 01/17/2023]
Abstract
An understanding of the seasonality of infections informs public health strategies and assists clinicians in their management of patients with undifferentiated illness. The seasonality of infections is driven by a variety of environmental and human factors; however, the role of individual climatic factors has garnered much attention. This study utilises Poisson regression models to assess the seasonality of six important infections in tropical Australia and their association with climatic factors and severe weather events over a 21-year period. Melioidosis and leptospirosis showed marked wet season predominance, while more cases of rickettsial disease and cryptococcosis were seen in cooler, drier months. Staphylococcus aureus infections were not seasonal, while influenza demonstrated inter-seasonality. The climate did not significantly change during the 21 years of the study period, but the incidence of melioidosis and rickettsial disease increased considerably, highlighting the primacy of other factors-including societal inequality, and the impact of urban expansion-in the incidence of these infections. While anthropogenic climate change poses a threat to the region-and may influence the burden of these infections in the future-this study highlights the fact that, even for seasonal diseases, other factors presently have a greater effect on disease incidence. Public health strategies must also target these broader drivers of infection if they are to be effective.
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Affiliation(s)
- Lee J Fairhead
- Department of Medicine, Cairns Hospital, Cairns, Queensland, Australia
| | - Simon Smith
- Department of Medicine, Cairns Hospital, Cairns, Queensland, Australia
| | - Beatrice Z Sim
- Infectious Diseases Service, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | | | - James D Stewart
- Department of Medicine, Cairns Hospital, Cairns, Queensland, Australia
| | - Enzo Binotto
- Department of Medicine, Cairns Hospital, Cairns, Queensland, Australia
| | - Matthew Law
- The Kirby Institute, University of New South Wales, Sydney, New South Wales, Australia
| | - Josh Hanson
- Department of Medicine, Cairns Hospital, Cairns, Queensland, Australia
- The Kirby Institute, University of New South Wales, Sydney, New South Wales, Australia
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15
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Smith S, Horne P, Rubenach S, Gair R, Stewart J, Fairhead L, Hanson J. Increased Incidence of Melioidosis in Far North Queensland, Queensland, Australia, 1998-2019. Emerg Infect Dis 2021; 27:3119-3123. [PMID: 34808088 PMCID: PMC8632158 DOI: 10.3201/eid2712.211302] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
During January 1998–December 2019, the annual incidence of melioidosis in Far North Queensland, Queensland, Australia, more than doubled. Because climate and prevalence of predisposing medical conditions remained stable during that time, we hypothesize that the increased incidence was caused by urban expansion and increased construction, resulting in greater exposure to Burkholderia pseudomallei.
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FRICKMANN HAGEN, POPPERT SVEN. No hints for abundance of Bacillus anthracis and Burkholderia pseudomallei in 100 environmental samples from Cameroon. Eur J Microbiol Immunol (Bp) 2021; 11:57-61. [PMID: 34478403 PMCID: PMC8614492 DOI: 10.1556/1886.2021.00014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 08/14/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Little is known on the abundance of the pathogens Bacillus anthracis and Burkholderia pseudomallei in environmental samples in Cameroon. Therefore, 100 respective samples were assessed in a proof-of-principle assessment. METHODS DNA residuals from nucleic acid extractions of 100 environmental samples, which were collected between 2011 and 2013 in the Mapé Basin of Cameroon, were screened for B. anthracis and B. pseudomallei by real-time PCR. The samples comprised soil samples with water contact (n = 88), soil samples without water contact (n = 6), plant material with water contact (n = 3), water (n = 2), and soil from a hospital dressing room (n = 1). RESULTS B. anthracis and B. pseudomallei were detected in none of the samples assessed. CONCLUSION The results indicate that at least a quantitatively overwhelming, ubiquitous occurrence of B. anthracis and B. pseudomallei in the environment in Cameroon is highly unlikely. However, the number and choice of the assessed samples limit the interpretability of the results.
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Affiliation(s)
- HAGEN FRICKMANN
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, Hamburg, Germany
- Institute for Medical Microbiology, Virology and Hygiene, University Hospital Rostock, Rostock, Germany
| | - SVEN POPPERT
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- Faculty of Medicine, University Basel, Basel, Switzerland
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17
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Currie BJ, Mayo M, Ward LM, Kaestli M, Meumann EM, Webb JR, Woerle C, Baird RW, Price RN, Marshall CS, Ralph AP, Spencer E, Davies J, Huffam SE, Janson S, Lynar S, Markey P, Krause VL, Anstey NM. The Darwin Prospective Melioidosis Study: a 30-year prospective, observational investigation. THE LANCET. INFECTIOUS DISEASES 2021; 21:1737-1746. [PMID: 34303419 DOI: 10.1016/s1473-3099(21)00022-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 12/14/2020] [Accepted: 01/11/2021] [Indexed: 01/23/2023]
Abstract
BACKGROUND The global distribution of melioidosis is under considerable scrutiny, with both unmasking of endemic disease in African and Pacific nations and evidence of more recent dispersal in the Americas. Because of the high incidence of disease in tropical northern Australia, The Darwin Prospective Melioidosis Study commenced in October, 1989. We present epidemiology, clinical features, outcomes, and bacterial genomics from this 30-year study, highlighting changes in the past decade. METHODS The present study was a prospective analysis of epidemiological, clinical, and laboratory data for all culture-confirmed melioidosis cases from the tropical Northern Territory of Australia from Oct 1, 1989, until Sept 30, 2019. Cases were identified on the basis of culture-confirmed melioidosis, a laboratory-notifiable disease in the Northern Territory of Australia. Patients who were culture-positive were included in the study. Multivariable analysis determined predictors of clinical presentations and outcome. Incidence, survival, and cluster analyses were facilitated by population and rainfall data and genotyping of Burkholderia pseudomallei, including multilocus sequence typing and whole-genome sequencing. FINDINGS There were 1148 individuals with culture-confirmed melioidosis, of whom 133 (12%) died. Median age was 50 years (IQR 38-60), 48 (4%) study participants were children younger than 15 years of age, 721 (63%) were male individuals, and 600 (52%) Indigenous Australians. All but 186 (16%) had clinical risk factors, 513 (45%) had diabetes, and 455 (40%) hazardous alcohol use. Only three (2%) of 133 fatalities had no identified risk. Pneumonia was the most common presentation occurring in 595 (52%) patients. Bacteraemia occurred in 633 (56%) of 1135 patients, septic shock in 240 (21%) patients, and 180 (16%) patients required mechanical ventilation. Cases correlated with rainfall, with 80% of infections occurring during the wet season (November to April). Median annual incidence was 20·5 cases per 100 000 people; the highest annual incidence in Indigenous Australians was 103·6 per 100 000 in 2011-12. Over the 30 years, annual incidences increased, as did the proportion of patients with diabetes, although mortality decreased to 17 (6%) of 278 patients over the past 5 years. Genotyping of B pseudomallei confirmed case clusters linked to environmental sources and defined evolving and new sequence types. INTERPRETATION Melioidosis is an opportunistic infection with a diverse spectrum of clinical presentations and severity. With early diagnosis, specific antimicrobial therapy, and state-of-the-art intensive care, mortality can be reduced to less than 10%. However, mortality remains much higher in the many endemic regions where health resources remain scarce. Genotyping of B pseudomallei informs evolving local and global epidemiology. FUNDING The Australian National Health and Medical Research Council.
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Affiliation(s)
- Bart J Currie
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia; Infectious Diseases Department, Royal Darwin Hospital and Northern Territory Medical Programme, Darwin, NT, Australia.
| | - Mark Mayo
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Linda M Ward
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Mirjam Kaestli
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Ella M Meumann
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia; Infectious Diseases Department, Royal Darwin Hospital and Northern Territory Medical Programme, Darwin, NT, Australia
| | - Jessica R Webb
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Celeste Woerle
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Robert W Baird
- Infectious Diseases Department, Royal Darwin Hospital and Northern Territory Medical Programme, Darwin, NT, Australia; Pathology Department, Royal Darwin Hospital and Northern Territory Medical Programme, Darwin, NT, Australia
| | - Ric N Price
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia; Infectious Diseases Department, Royal Darwin Hospital and Northern Territory Medical Programme, Darwin, NT, Australia
| | - Catherine S Marshall
- Infectious Diseases Department, Royal Darwin Hospital and Northern Territory Medical Programme, Darwin, NT, Australia
| | - Anna P Ralph
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia; Infectious Diseases Department, Royal Darwin Hospital and Northern Territory Medical Programme, Darwin, NT, Australia
| | - Emma Spencer
- Infectious Diseases Department, Royal Darwin Hospital and Northern Territory Medical Programme, Darwin, NT, Australia
| | - Jane Davies
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia; Infectious Diseases Department, Royal Darwin Hospital and Northern Territory Medical Programme, Darwin, NT, Australia
| | - Sarah E Huffam
- Infectious Diseases Department, Royal Darwin Hospital and Northern Territory Medical Programme, Darwin, NT, Australia
| | - Sonja Janson
- Infectious Diseases Department, Royal Darwin Hospital and Northern Territory Medical Programme, Darwin, NT, Australia
| | - Sarah Lynar
- Infectious Diseases Department, Royal Darwin Hospital and Northern Territory Medical Programme, Darwin, NT, Australia
| | - Peter Markey
- Centre for Disease Control, Top End Health Services, Northern Territory Department of Health, Darwin, NT, Australia
| | - Vicki L Krause
- Centre for Disease Control, Top End Health Services, Northern Territory Department of Health, Darwin, NT, Australia
| | - Nicholas M Anstey
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia; Infectious Diseases Department, Royal Darwin Hospital and Northern Territory Medical Programme, Darwin, NT, Australia
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Meumann EM, Kaestli M, Mayo M, Ward L, Rachlin A, Webb JR, Kleinecke M, Price EP, Currie BJ. Emergence of Burkholderia pseudomallei Sequence Type 562, Northern Australia. Emerg Infect Dis 2021; 27:1057-1067. [PMID: 33754984 PMCID: PMC8007296 DOI: 10.3201/eid2704.202716] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Since 2005, the range of Burkholderia pseudomallei sequence type 562 (ST562) has expanded in northern Australia. During 2005–2019, ST562 caused melioidosis in 61 humans and 3 animals. Cases initially occurred in suburbs surrounding a creek before spreading across urban Darwin, Australia and a nearby island community. In urban Darwin, ST562 caused 12% (53/440) of melioidosis cases, a proportion that increased during the study period. We analyzed 2 clusters of cases with epidemiologic links and used genomic analysis to identify previously unassociated cases. We found that ST562 isolates from Hainan Province, China, and Pingtung County, Taiwan, were distantly related to ST562 strains from Australia. Temporal genomic analysis suggested a single ST562 introduction into the Darwin region in ≈1988. The origin and transmission mode of ST562 into Australia remain uncertain.
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Hall NL, Barnes S, Canuto C, Nona F, Redmond AM. Climate change and infectious diseases in Australia's Torres Strait Islands. Aust N Z J Public Health 2021; 45:122-128. [PMID: 33522674 DOI: 10.1111/1753-6405.13073] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/01/2020] [Accepted: 12/01/2020] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVE This research seeks to identify climate-sensitive infectious diseases of concern with a present and future likelihood of increased occurrence in the geographically vulnerable Torres Strait Islands, Australia. The objective is to contribute evidence to the need for adequate climate change responses. METHODS Case data of infectious diseases with proven, potential and speculative climate sensitivity were compiled. RESULTS Five climate-sensitive diseases in the Torres Strait and Cape York region were identified as of concern: tuberculosis, dengue, Ross River virus, melioidosis and nontuberculous mycobacterial infection. The region constitutes 0.52% of Queensland's population but has a disproportionately high proportion of the state's cases: 20.4% of melioidosis, 2.4% of tuberculosis and 2.1% of dengue. CONCLUSIONS The Indigenous Torres Strait Islander peoples intend to remain living on their traditional country long-term, yet climate change brings risks of both direct and indirect human health impacts. Implications for public health: Climate-sensitive infections pose a disproportionate burden and ongoing risk to Torres Strait Islander peoples. Addressing the causes of climate change is the responsibility of various agencies in parallel with direct action to minimise or prevent infections. All efforts should privilege Torres Strait Islander peoples' voices to self-determine response actions.
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Affiliation(s)
- Nina L Hall
- School of Public Health, The University of Queensland
| | - Samuel Barnes
- School of Public Health, The University of Queensland
| | - Condy Canuto
- School of Public Health, The University of Queensland
| | - Francis Nona
- School of Public Health, The University of Queensland
| | - Andrew M Redmond
- Faculty of Medicine, The University of Queensland.,Infectious Diseases Unit, Royal Brisbane and Women's Hospital, Queensland
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A Persisting Nontropical Focus of Burkholderia pseudomallei with Limited Genome Evolution over Five Decades. mSystems 2020; 5:5/6/e00726-20. [PMID: 33172968 PMCID: PMC7657595 DOI: 10.1128/msystems.00726-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Burkholderia pseudomallei is predominantly a tropical pathogen uncommonly found in the environment of temperate climatic regions. It is unclear if introduction into temperate regions is sporadic and temporary or if B. pseudomallei can persist in such environments. B. pseudomallei was identified in the environment of southwest Western Australia with melioidosis cases between 1966 and 1991. We report a new cluster with 23 animal fatalities in the same region from 2017, with B. pseudomallei again being recovered from the environment. Comparison of the isolates from the first and second clusters using genomics revealed a single sequence type, high clonality, and limited recombination, even though the time of recovery of the isolates spanned 51 years. This is a major contrast to the extensive genomic diversity seen in the tropics. Our data support the suggestion that B. pseudomallei has the ability to persist in nontropical environments, potentially in a latent state, and has the ability to activate following favorable conditions (rainfall) and then infect animals and humans. Burkholderia pseudomallei is the causative agent of the high-mortality disease melioidosis. Although melioidosis is classified as a tropical disease, rare autochthonous cases have been reported from temperate climatic regions, with uncertainty as to whether B. pseudomallei is persistent in the local environment and whether specific genetic mechanisms facilitate the survival of B. pseudomallei outside the tropics. Sporadic cases of melioidosis occurred in a valley region (latitude 31.6°S) in southwest Western Australia, Australia, between 1966 and 1992. We report a new melioidosis cluster in the same region following high rainfall in January 2017. More than 20 animals died, and B. pseudomallei was isolated from four alpacas, a parrot, and three environmental samples taken from the farm where the alpacas resided. Epidemiological data and genomics revealed that two locations on the farm were the probable sources of the alpaca infections. We determined that B. pseudomallei isolates from the 2017 cluster belonged to sequence type 284 (ST-284), as did all isolates recovered from 1966 to 1992. Genomic analysis confirmed that the ST-284 isolates were clonal and contained conserved genomic islands and limited evidence of recombination. We identified protein-coding regions unique to these isolates that might influence the persistence of B. pseudomallei in this temperate region. We demonstrate the environmental persistence of B. pseudomallei in a temperate region for over 50 years, with limited genetic changes suggesting a latent state and with activation, potential aerosolization, and local dispersal following unusually high rainfall. IMPORTANCEBurkholderia pseudomallei is predominantly a tropical pathogen uncommonly found in the environment of temperate climatic regions. It is unclear if introduction into temperate regions is sporadic and temporary or if B. pseudomallei can persist in such environments. B. pseudomallei was identified in the environment of southwest Western Australia with melioidosis cases between 1966 and 1991. We report a new cluster with 23 animal fatalities in the same region from 2017, with B. pseudomallei again being recovered from the environment. Comparison of the isolates from the first and second clusters using genomics revealed a single sequence type, high clonality, and limited recombination, even though the time of recovery of the isolates spanned 51 years. This is a major contrast to the extensive genomic diversity seen in the tropics. Our data support the suggestion that B. pseudomallei has the ability to persist in nontropical environments, potentially in a latent state, and has the ability to activate following favorable conditions (rainfall) and then infect animals and humans.
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21
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Norris MH, Tran HTT, Walker MA, Bluhm AP, Zincke D, Trung TT, Thi NV, Thi NP, Schweizer HP, Unger F, Blackburn JK, Hang NTT. Distribution of Serological Response to Burkholderia pseudomallei in Swine from Three Provinces of Vietnam. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17145203. [PMID: 32708490 PMCID: PMC7399857 DOI: 10.3390/ijerph17145203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/09/2020] [Accepted: 07/16/2020] [Indexed: 01/18/2023]
Abstract
(1) Background: Burkholderia pseudomallei is an environmentally mediated saprophytic pathogen that can cause severe disease in humans. It is well known that B. pseudomallei survives in tropical moist soil environments worldwide, but melioidosis is gaining recognition as a public and veterinary health issue in Vietnam. The contribution of animals to human disease is unknown, necessitating further investigation. (2) Methods: Swine sera were collected from two populations, one grazing and one commercially farmed, from three provinces in Vietnam. ELISAs utilizing B. pseudomallei capsular polysaccharide (CPS), outer polysaccharide (OPS), and Hcp1 protein were used to screen serum samples. Positive samples were mapped to the commune level. Seroprevalence calculations and pig population estimates were used to approximate number of swine exposures per commune. (3) Results: Grazing pigs from Hoa Binh had significantly higher seropositivity levels (11.4%, 95% CI: 9.7–13.1) compared to farmed pigs from Ha Tinh and Nghe An (4%, 95% CI: 3.3–4.7). Average swine seropositivity rates were ~6.3% (95% CI: 5–7.9), higher than previously identified in Vietnam (~0.88%). (4) Conclusions: Initial serological sampling identified a significant number of seropositive and potential melioidosis infections occurring in swine in Vietnam. This work is a critical step in understanding the role swine may play in the epidemiology of human melioidosis in Vietnam.
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Affiliation(s)
- Michael H. Norris
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
- Correspondence:
| | - Hang Thi Thu Tran
- National Institute of Veterinary Research, Hanoi 10000, Vietnam; (H.T.T.T.); (N.V.T.); (N.P.T.); (N.T.T.H.)
| | - Morgan A. Walker
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
| | - Andrew P. Bluhm
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
| | - Diansy Zincke
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
| | - Trinh Thanh Trung
- VNU-Institute of Microbiology and Biotechnology, Vietnam National University, Hanoi 10000, Vietnam;
| | - Nga Vu Thi
- National Institute of Veterinary Research, Hanoi 10000, Vietnam; (H.T.T.T.); (N.V.T.); (N.P.T.); (N.T.T.H.)
| | - Ngoc Pham Thi
- National Institute of Veterinary Research, Hanoi 10000, Vietnam; (H.T.T.T.); (N.V.T.); (N.P.T.); (N.T.T.H.)
| | - Herbert P. Schweizer
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32611, USA
| | - Fred Unger
- International Livestock Research Institute, Hanoi 10000, Vietnam;
| | - Jason K. Blackburn
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
| | - Nguyen Thi Thu Hang
- National Institute of Veterinary Research, Hanoi 10000, Vietnam; (H.T.T.T.); (N.V.T.); (N.P.T.); (N.T.T.H.)
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Polymicrobial community-acquired Acinetobacter baumannii and Burkholderia pseudomallei bacteremia: opportunistic infections with similar risk factors in northern Australia. IDCases 2020; 21:e00833. [PMID: 32509526 PMCID: PMC7264049 DOI: 10.1016/j.idcr.2020.e00833] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 05/19/2020] [Accepted: 05/19/2020] [Indexed: 11/25/2022] Open
Abstract
We report the case of a 61-year-old man from northern Australia with concurrent community-onset Acinetobacter baumannii complex and Burkholderia pseudomallei bacteremia presenting as severe tropical pneumonia requiring intensive care unit support. The pneumonia was complicated by L3/4 discitis and vertebral osteomyelitis presumed to be due to melioidosis. His risk factors included chronic lung disease and immunosuppression with etanercept. This case of concurrent infection highlights the similar risk factors, presentation and epidemiology of both infections, emphasises the importance of accurate microbiologic identification and reinforces the current Australian empiric antimicrobial treatment recommendations for severe tropical pneumonia.
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Whole-genome sequencing of Burkholderia pseudomallei from an urban melioidosis hot spot reveals a fine-scale population structure and localised spatial clustering in the environment. Sci Rep 2020; 10:5443. [PMID: 32214186 PMCID: PMC7096523 DOI: 10.1038/s41598-020-62300-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 12/17/2019] [Indexed: 11/12/2022] Open
Abstract
Melioidosis is a severe disease caused by the environmental bacterium Burkholderia pseudomallei that affects both humans and animals throughout northern Australia, Southeast Asia and increasingly globally. While there is a considerable degree of genetic diversity amongst isolates, B. pseudomallei has a robust global biogeographic structure and genetic populations are spatially clustered in the environment. We examined the distribution and local spread of B. pseudomallei in Darwin, Northern Territory, Australia, which has the highest recorded urban incidence of melioidosis globally. We sampled soil and land runoff throughout the city centre and performed whole-genome sequencing (WGS) on B. pseudomallei isolates. By combining phylogenetic analyses, Bayesian clustering and spatial hot spot analysis our results demonstrate that some sequence types (STs) are widespread in the urban Darwin environment, while others are highly spatially clustered over a small geographic scale. This clustering matches the spatial distribution of clinical cases for one ST. Results also demonstrate a greater overall isolate diversity recovered from drains compared to park soils, further supporting the role drains may play in dispersal of B. pseudomallei STs in the environment. Collectively, knowledge gained from this study will allow for better understanding of B. pseudomallei phylogeography and melioidosis source attribution, particularly on a local level.
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Hempenstall AJ, Smith S, Stanton D, Hanson J. Melioidosis in the Torres Strait Islands, Australia: Exquisite Interplay between Pathogen, Host, and Environment. Am J Trop Med Hyg 2020; 100:517-521. [PMID: 30675834 DOI: 10.4269/ajtmh.18-0806] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Burkholderia pseudomallei, a bacterium that lives in the soil of the tropics, causes the disease melioidosis. This retrospective study investigated the temporospatial epidemiology of the 49 laboratory-confirmed melioidosis cases in the Torres Straits Islands of tropical Australia between 1997 and 2017. An identifiable risk factor for the disease was present in 43/49 (88%) cases and in 35/36 (97%) cases with complete clinical data. The mean incidence of melioidosis varied across the region, from 0/100,000 persons/year in the Eastern Island Cluster to 116.1/100,000 persons/year in the Near Western Island Cluster. An environmental suitability score for the growth of B. pseudomallei-constructed using the rainfall, vegetation, and soil type on each island-correlated with disease incidence (Spearman's rho 0.51; P = 0.035). Melioidosis is an opportunistic disease that occurs in patients with specific risk factors, but its incidence is also strongly influenced by environmental factors that favor the growth of the causative organism.
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Affiliation(s)
| | - Simon Smith
- James Cook University, Cairns, Australia.,Department of Medicine, Cairns Hospital, Cairns, Australia
| | | | - Josh Hanson
- Department of Medicine, Cairns Hospital, Cairns, Australia.,The Kirby Institute, Sydney, Australia
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Erythritol as a single carbon source improves cultural isolation of Burkholderia pseudomallei from rice paddy soils. PLoS Negl Trop Dis 2019; 13:e0007821. [PMID: 31634353 PMCID: PMC6822774 DOI: 10.1371/journal.pntd.0007821] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 10/31/2019] [Accepted: 10/01/2019] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Isolation of the soil bacterium Burkholderia pseudomallei from tropical environments is important to generate a global risk map for man and animals to acquire the infectious disease melioidosis. There is increasing evidence, that the currently recommended soil culture protocol using threonine-basal salt solution with colistin (TBSS-C50) for enrichment of B. pseudomallei and Ashdown agar for subsequent subculture lacks sensitivity. We therefore investigated, if the otherwise rarely encountered erythritol catabolism of B. pseudomallei might be exploited to improve isolation of this bacterium from soil. METHODOLOGY/PRINCIPAL FINDINGS Based on TBSS-C50, we designed a new colistin-containing medium with erythritol as the single carbon source (EM). This medium was validated in various culture protocols by analyzing 80 soil samples from 16 different rice fields in Vietnam. B. pseudomallei enrichment was determined in all culture supernatants by a specific quantitative PCR (qPCR) targeting the type three secretion system 1. 51 out of 80 (63.8%) soil samples gave a positive qPCR signal in at least one of the culture conditions. We observed a significantly higher enrichment shown by lower median cycle threshold values for B. pseudomallei in a two-step culture with TBSS-C50 for 48 h followed by EM for 96h compared to single cultures in TBSS-C50 for either 48h or 144h (p<0.0001, respectively). Accordingly, B. pseudomallei could be isolated on Ashdown agar in 58.8% (30/51) of samples after subcultures from our novel two-step enrichment culture compared to only 9.8% (5/51) after standard enrichment with TBSS-C50 for 48h (p<0.0001) or 25.5% (13/51; p<0.01) after TBSS-C50 for 144h. CONCLUSIONS/SIGNIFICANCE In the present study, we show that specific exploitation of B. pseudomallei metabolic capabilities in enrichment protocols leads to a significantly improved isolation rate of this pathogen from soil compared to established standard procedures. Our new culture method might help to facilitate the creation of environmental risk maps for melioidosis in the future.
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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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Bulterys PL, Bulterys MA, Phommasone K, Luangraj M, Mayxay M, Kloprogge S, Miliya T, Vongsouvath M, Newton PN, Phetsouvanh R, French CT, Miller JF, Turner P, Dance DAB. Climatic drivers of melioidosis in Laos and Cambodia: a 16-year case series analysis. Lancet Planet Health 2018; 2:e334-e343. [PMID: 30082048 PMCID: PMC6076299 DOI: 10.1016/s2542-5196(18)30172-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 07/02/2018] [Accepted: 07/19/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Burkholderia pseudomallei is the cause of melioidosis, a serious and difficult to treat infection that is endemic throughout the tropics. Melioidosis incidence is highly seasonal. We aimed to identify the climatic drivers of infection and to shed light on modes of transmission and potential preventive strategies. METHODS We examined the records of patients diagnosed with melioidosis at the Microbiology Laboratory of Mahosot Hospital in Vientiane, Laos, between October, 1999, and August, 2015, and all patients with culture-confirmed melioidosis presenting to the Angkor Hospital for Children in Siem Reap, Cambodia, between February, 2009, and December, 2013. We also examined local temperature, humidity, precipitation, visibility, and wind data for the corresponding time periods. We estimated the B pseudomallei incubation period by examining profile likelihoods for hypothetical exposure-to-presentation delays. FINDINGS 870 patients were diagnosed with melioidosis in Laos and 173 patients were diagnosed with melioidosis in Cambodia during the study periods. Melioidosis cases were significantly associated with humidity (p<0·0001), low visibility (p<0·0001), and maximum wind speeds (p<0·0001) in Laos, and humidity (p=0·010), rainy days (p=0·015), and maximum wind speed (p=0·0070) in Cambodia. Compared with adults, children were at significantly higher odds of infection during highly humid months (odds ratio 2·79, 95% CI 1·83-4·26). Lung and disseminated infections were more common during windy months. The maximum likelihood estimate of the incubation period was 1 week (95% CI 0-2). INTERPRETATION The results of this study demonstrate a significant seasonal burden of melioidosis among adults and children in Laos and Cambodia. Our findings highlight the risks of infection during highly humid and windy conditions, and suggest a need for increased awareness among at-risk individuals, such as children. FUNDING Wellcome Trust.
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Affiliation(s)
- Philip L Bulterys
- UCLA-Caltech Medical Scientist Training Program, David Geffen School of Medicine, Los Angeles, CA, USA; Molecular Biology Institute, Los Angeles, CA, USA; Department of Microbiology, Immunology, and Molecular Genetics, Los Angeles, CA, USA.
| | | | - Koukeo Phommasone
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Vientiane, Laos
| | - Manophab Luangraj
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Vientiane, Laos
| | - Mayfong Mayxay
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Vientiane, Laos; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Faculty of Postgraduate Studies, University of Health Sciences, Ministry of Health, Vientiane, Laos
| | - Sabine Kloprogge
- Cambodia Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | - Thyl Miliya
- Cambodia Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | | | - Paul N Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Vientiane, Laos; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Rattanaphone Phetsouvanh
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Vientiane, Laos; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Christopher T French
- Department of Microbiology, Immunology, and Molecular Genetics, Los Angeles, CA, USA; California NanoSystems Institute UCLA, Los Angeles, CA, USA
| | - Jeff F Miller
- Molecular Biology Institute, Los Angeles, CA, USA; Department of Microbiology, Immunology, and Molecular Genetics, Los Angeles, CA, USA; California NanoSystems Institute UCLA, Los Angeles, CA, USA
| | - Paul Turner
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Cambodia Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | - David A B Dance
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Vientiane, Laos; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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Soil characteristics influencing the spatial distribution of melioidosis in Far North Queensland, Australia. Epidemiol Infect 2018; 146:1602-1607. [PMID: 29970213 DOI: 10.1017/s0950268818001188] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The environmental bacterium, Burkholderia pseudomallei, is responsible for the potentially fatal disease melioidosis. Factors responsible for the temporospatial distribution of cases are incompletely understood, although a combination of rainfall, groundwater levels and the physicochemical properties of soil are important. The distribution of culture-positive cases of melioidosis from 1996 to 2016 in Far North Queensland, Australia, was investigated to determine the association with different soil types and landforms in Cairns, the region's largest city. Cases were clustered on alluvial fan landforms of strongly bleached gradational textured and yellow massive gradational textured soils indicating these soils are more suitable for B. pseudomallei and risk of melioidosis infection is higher in these areas, cases were less frequent on other soil types on alluvial fan landforms (despite comparable population density) and beach ridges. This indicates that the combination of these soils might be more suitable for B. pseudomallei, increasing the risk of disease in these locations. Sociodemographic characterisics of the population in cluster locations were considered. Knowledge of local soil characteristics may help predict cases of melioidosis and inform public health strategies to prevent the disease. Because melioidosis case clusters were identified, testing for the presence of B. pseudomallei across the study area is a useful target of future research.
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Duangurai T, Indrawattana N, Pumirat P. Burkholderia pseudomallei Adaptation for Survival in Stressful Conditions. BIOMED RESEARCH INTERNATIONAL 2018; 2018:3039106. [PMID: 29992136 PMCID: PMC5994319 DOI: 10.1155/2018/3039106] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/09/2018] [Accepted: 04/05/2018] [Indexed: 12/19/2022]
Abstract
Burkholderia pseudomallei is a Gram-negative bacterium that causes melioidosis, which can be fatal in humans. Melioidosis is prevalent in the tropical regions of Southeast Asia and Northern Australia. Ecological data have shown that this bacterium can survive as a free-living organism in environmental niches, such as soil and water, as well as a parasite living in host organisms, such as ameba, plants, fungi, and animals. This review provides an overview of the survival and adaptation of B. pseudomallei to stressful conditions induced by hostile environmental factors, such as salinity, oxidation, and iron levels. The adaptation of B. pseudomallei in host cells is also reviewed. The adaptive survival mechanisms of this pathogen mainly involve modulation of gene and protein expression, which could cause alterations in the bacteria's cell membrane, metabolism, and virulence. Understanding the adaptations of this organism to environmental factors provides important insights into the survival and pathogenesis of B. pseudomallei, which may lead to the development of novel strategies for the control, prevention, and treatment of melioidosis in the future.
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Affiliation(s)
- Taksaon Duangurai
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
- Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
| | - Nitaya Indrawattana
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Pornpan Pumirat
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
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Virulence of the Melioidosis Pathogen Burkholderia pseudomallei Requires the Oxidoreductase Membrane Protein DsbB. Infect Immun 2018; 86:IAI.00938-17. [PMID: 29440370 PMCID: PMC5913862 DOI: 10.1128/iai.00938-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 02/04/2018] [Indexed: 12/26/2022] Open
Abstract
The naturally antibiotic-resistant bacterium Burkholderia pseudomallei is the causative agent of melioidosis, a disease with stubbornly high mortality and a complex, protracted treatment regimen. The worldwide incidence of melioidosis is likely grossly underreported, though it is known to be highly endemic in northern Australia and Southeast Asia. Bacterial disulfide bond (DSB) proteins catalyze the oxidative folding and isomerization of disulfide bonds in substrate proteins. In the present study, we demonstrate that B. pseudomallei membrane protein disulfide bond protein B (BpsDsbB) forms a functional redox relay with the previously characterized virulence mediator B. pseudomallei disulfide bond protein A (BpsDsbA). Genomic analysis of diverse B. pseudomallei clinical isolates demonstrated that dsbB is a highly conserved core gene. Critically, we show that DsbB is required for virulence in B. pseudomallei. A panel of B. pseudomalleidsbB deletion strains (K96243, 576, MSHR2511, MSHR0305b, and MSHR5858) were phenotypically diverse according to the results of in vitro assays that assess hallmarks of virulence. Irrespective of their in vitro virulence phenotypes, two deletion strains were attenuated in a BALB/c mouse model of infection. A crystal structure of a DsbB-derived peptide complexed with BpsDsbA provides the first molecular characterization of their interaction. This work contributes to our broader understanding of DSB redox biology and will support the design of antimicrobial drugs active against this important family of bacterial virulence targets.
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Melioidosis: An Australian Perspective. Trop Med Infect Dis 2018; 3:tropicalmed3010027. [PMID: 30274424 PMCID: PMC6136632 DOI: 10.3390/tropicalmed3010027] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 02/21/2018] [Accepted: 02/22/2018] [Indexed: 12/16/2022] Open
Abstract
Burkholderia pseudomallei is endemic in northern Australia, with cases of melioidosis most commonly occurring during the wet season in individuals with diabetes, hazardous alcohol use, and chronic kidney disease. Pneumonia is the most common presentation and the majority of patients are bacteraemic—however, infection may involve almost any organ, with the skin and soft tissues, genitourinary system, visceral organs, and bone and joints affected most commonly. Central nervous system involvement is rarer, but has a high attributable mortality. Increased awareness of the disease amongst healthcare providers, ready access to appropriate antibiotic therapy and high-quality intensive care services has resulted in a sharp decline in the case fatality rate over the last 20 years. Further improvement in clinical outcomes will require a greater understanding of the disease′s pathophysiology, its optimal management, and more effective strategies for its prevention.
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Majoni SW, Hughes JT, Heron B, Currie BJ. Trimethoprim+Sulfamethoxazole Reduces Rates of Melioidosis in High-Risk Hemodialysis Patients. Kidney Int Rep 2018; 3:160-167. [PMID: 29340327 PMCID: PMC5762962 DOI: 10.1016/j.ekir.2017.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 09/12/2017] [Accepted: 09/12/2017] [Indexed: 12/27/2022] Open
Abstract
INTRODUCTION Melioidosis causes sepsis and death in the Top End of Northern Australia during the monsoonal wet season. Dialysis-dependent adults suffer higher melioidosis rates compared to low rates among renal transplant patients who routinely receive trimethoprim+sulfamethoxazole prophylaxis. METHODS We performed a prospective interventional study to determine the efficacy and safety of daily trimethoprim+sulfamethoxazole prophylaxis in hemodialysis patients during the wet season, from 1 November 2014 to 30 April 2015. Hemodialysis (for ≥ 3 months) patients ≥ 18 years of age were offered treatment. A total of 269 patients on hemodialysis were eligible. Eight of the 269 patients (3%) were excluded from the analysis for being on melioidosis treatment. In all, 169 of 261 patients (64.8%) received the prophylaxis, and 92 of 261 patients (35.2%) did not, because of allergy history (n = 10), remoteness and logistical reasons (n = 60), poor dialysis attendance (n = 11), and refusal (n = 11). We monitored for clinical side effects 3 times weekly and neutropenia, thrombocytopenia, and liver function monthly throughout treatment and for 2 months posttreatment. RESULTS In all, 169 of 261 patients (64.8%) received the prophylaxis. There was no age (years) difference by group (prophylaxis vs. nonprophylaxis, 54.7 [11.3] vs. 54.3 [11.2] [P = 0.751]). Sixteen of 261 patients (6%) had melioidosis. The event frequency was 0% (0/169, prophylaxis, vs. 17.4% [16/92, nonprophylaxis], P < 0.001). Higher thrombocytopenia and neutropenia rates were noted in the prophylaxis group. These did not warrant treatment stoppage. There was no difference in liver function. Three patients (1.8%) withdrew from the treatment because of side effects. CONCLUSION Daily dosing was effective and safe. Posthemodialysis dosing in the subsequent seasons was effective and safer. We recommend this approach in melioidosis-prevalent regions.
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Affiliation(s)
- Sandawana William Majoni
- Department of Nephrology, Division of Medicine, Royal Darwin Hospital, Casuarina, Darwin, Northern Territory, Australia
- Northern Territory Medical Program, Flinders University School of Medicine, Tiwi, Darwin, Northern Territory, Australia
- Wellbeing and Preventable Chronic Disease Division, Menzies School of Health Research, Charles Darwin University, Casuarina, Northern Territory, Australia
| | - Jaquelyne T. Hughes
- Department of Nephrology, Division of Medicine, Royal Darwin Hospital, Casuarina, Darwin, Northern Territory, Australia
- Wellbeing and Preventable Chronic Disease Division, Menzies School of Health Research, Charles Darwin University, Casuarina, Northern Territory, Australia
| | - Bianca Heron
- Department of Nephrology, Division of Medicine, Royal Darwin Hospital, Casuarina, Darwin, Northern Territory, Australia
| | - Bart J. Currie
- Northern Territory Medical Program, Flinders University School of Medicine, Tiwi, Darwin, Northern Territory, Australia
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Casuarina, Northern Territory, Australia
- Infectious Disease Department, Division of Medicine, Royal Darwin Hospital, Tiwi, Darwin, Northern Territory, Australia
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Stewart JD, Smith S, Hanson J. Melioidosis in Far North Queensland is not correlated with severe weather events. Med J Aust 2017; 207:394. [DOI: 10.5694/mja16.01332] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 01/06/2017] [Indexed: 11/17/2022]
Affiliation(s)
| | | | - Josh Hanson
- Cairns Hospital, Cairns, QLD
- Menzies School of Health Research, Darwin, NT
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Abstract
PURPOSE OF REVIEW Melioidosis epidemiology is susceptible to climate change through direct and indirect effects on human encounter with the causative agent, Burkholderia pseudomallei. This review describes the current depth of knowledge and recent advances in the understanding of this relationship and applies it to observations of melioidosis in Western Australia. RECENT FINDINGS High maximum rainfall and dense cloud cover have been shown to predict environmental presence of B. pseudomallei and cases of melioidosis, probably through correspondingly high moisture levels in B. pseudomallei-receptive soils. Increased melioidosis cases have been observed following storms in Taiwan and cyclones in the Australian Northern Territory and strengthen the association between melioidosis and extreme weather events. Indirect weather effects contribute to bacterial exposure through mechanisms such as increasing B. pseudomallei output from water seeps after heavy rain or localised flooding. Climate and weather have been directly implicated in dissemination of B. pseudomallei and cases of melioidosis in several notable events in Western Australia. Over a 10-year surveillance period, the cases that lay in the path of a tropical cyclone co-located with cyclone systems that repeatedly crossed the Western Australian coast. Cyclone-associated cases were caused by different B. pseudomallei MLST genotypes, arguing against airborne dissemination from a common source. SUMMARY Predicted increases in temperature, changes in global precipitation patterns and an increased incidence of extreme weather events are expected to change melioidosis epidemiology. Further studies of the physical geographic drivers of melioidosis will deepen understanding of the impact of climate on melioidosis.
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Affiliation(s)
- Adam J. Merritt
- Department of Microbiology, PathWest Laboratory Medicine Western Australia, PP Building, QEII Medical Centre, Hospital Avenue, Nedlands, WA 6009 Australia
- School of Biomedical Sciences, Faculty of Health and Medical Sciences, The University of Western Australia (M504), 35 Stirling Highway, Crawley, WA 6009 Australia
| | - Timothy J. J. Inglis
- Department of Microbiology, PathWest Laboratory Medicine Western Australia, PP Building, QEII Medical Centre, Hospital Avenue, Nedlands, WA 6009 Australia
- School of Biomedical Sciences, Faculty of Health and Medical Sciences, The University of Western Australia (M504), 35 Stirling Highway, Crawley, WA 6009 Australia
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Stewart JD, Smith S, Binotto E, McBride WJ, Currie BJ, Hanson J. The epidemiology and clinical features of melioidosis in Far North Queensland: Implications for patient management. PLoS Negl Trop Dis 2017; 11:e0005411. [PMID: 28264029 PMCID: PMC5363997 DOI: 10.1371/journal.pntd.0005411] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 03/23/2017] [Accepted: 02/14/2017] [Indexed: 01/19/2023] Open
Abstract
Background The epidemiology, clinical presentation and management of melioidosis vary around the world. It is essential to define the disease’s local features to optimise its management. Principal findings Between 1998 and 2016 there were 197 cases of culture confirmed melioidosis in Far North Queensland; 154 (78%) presented in the December-April wet season. 145 (74%) patients were bacteraemic, 58 (29%) were admitted to the Intensive Care Unit and 27 (14%) died; nine (33%) of these deaths occurred within 48 hours of presentation. Pneumonia was the most frequent clinical finding, present in 101 (61%) of the 166 with available imaging. A recognised risk factor for melioidosis (diabetes, hazardous alcohol use, chronic renal disease, chronic lung disease, immunosuppression or malignancy) was present in 148 (91%) of 162 patients with complete comorbidity data. Despite representing only 9% of the region’s population, Aboriginal and Torres Strait Island (ATSI) people comprised 59% of the cases. ATSI patients were younger than non-ATSI patients (median (interquartile range): 46 (38–56) years versus 59 (43–69) years (p<0.001) and had a higher case-fatality rate (22/117 (19%) versus 5/80 (6.3%) (p = 0.01)). In the 155 patients surviving the initial intensive intravenous phase of treatment, eleven (7.1%) had disease recurrence, despite the fact that nine (82%) of these patients had received prolonged intravenous therapy. Recurrence was usually due to inadequate source control or poor adherence to oral eradication therapy. The case fatality rate declined from 12/44 (27%) in the first five years of the study to 7/76 (9%) in the last five (p = 0.009), reflecting national improvements in sepsis management. Conclusions Melioidosis in Far North Queensland is a seasonal, opportunistic infection of patients with specific comorbidities. The ATSI population bear the greatest burden of disease. Although the case-fatality rate is declining, deaths frequently occur early after hospitalisation, reinforcing the importance of prompt, targeted therapy in high-risk patients. Burkholderia pseudomallei is endemic to the tropics and is responsible for the disease melioidosis. Exposure rarely evolves to significant disease in the absence of specific comorbidities. Conversely, in susceptible hosts, the disease can be rapidly fatal if unrecognised. Patients require an extended course of intravenous and oral antibiotic therapy to treat the disease and to prevent its recurrence. This retrospective, case series describes the epidemiology, presentation and outcomes of 197 cases of melioidosis in Far North Queensland (FNQ), Australia. The study confirms that melioidosis is predominantly a seasonal, opportunistic infection occurring among patients with specific comorbidities that include diabetes mellitus, hazardous alcohol use, chronic kidney disease, chronic lung disease, malignancy and immunosuppressive therapy. Melioidosis is more common in the local Aboriginal and Torres Strait Islander (ATSI) population, which has a higher prevalence of these comorbidities. Although overall case-fatality rates are declining, they are higher in the ATSI population, reflecting ongoing socioeconomic disadvantage. Disease recurrence is more likely in patients with inadequate source control and suboptimal adherence, factors that are not necessarily mitigated by extending the duration of intravenous therapy.
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Affiliation(s)
- James D. Stewart
- Department of Medicine, Cairns Hospital, Cairns, Queensland, Australia
| | - Simon Smith
- Department of Medicine, Cairns Hospital, Cairns, Queensland, Australia
- James Cook University Clinical School, Cairns Hospital, Cairns, Queensland, Australia
| | - Enzo Binotto
- Department of Medicine, Cairns Hospital, Cairns, Queensland, Australia
| | - William J. McBride
- James Cook University Clinical School, Cairns Hospital, Cairns, Queensland, Australia
| | - Bart J. Currie
- Infectious Diseases Department, Royal Darwin Hospital, Darwin, Northern Territory, Australia
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Josh Hanson
- Department of Medicine, Cairns Hospital, Cairns, Queensland, Australia
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
- The Kirby Institute, University of New South Wales, Sydney, New South Wales, Australia
- * E-mail:
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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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