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Sharon J. Peacock - One of the best experts on this subject based on the ideXlab platform.
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soil nutrient depletion is associated with the presence of Burkholderia pseudomallei
Applied and Environmental Microbiology, 2016Co-Authors: Viriya Hantrakun, Vanaporn Wuthiekanun, Premjit Amornchai, Sharon J. Peacock, Nicholas P J Day, Patpong Rongkard, Malinee Oyuchua, Cherry LimAbstract:Burkholderia pseudomallei is a soil-dwelling bacterium and the cause of melioidosis, which kills an estimated 89,000 people per year worldwide. Agricultural workers are at high risk of infection due to repeated exposure to the bacterium. Little is known about the soil physicochemical properties associated with the presence or absence of the organism. Here, we evaluated the soil physicochemical properties and presence of B. pseudomallei in 6,100 soil samples collected from 61 rice fields in Thailand. The presence of B. pseudomallei was negatively associated with the proportion of clay, proportion of moisture, level of salinity, percentage of organic matter, presence of cadmium, and nutrient levels (phosphorus, potassium, calcium, magnesium, and iron). The presence of B. pseudomallei was not associated with the level of soil acidity (P = 0.54). In a multivariable logistic regression model, the presence of B. pseudomallei was negatively associated with the percentage of organic matter (odds ratio [OR], 0.06; 95% confidence interval [CI], 0.01 to 0.47; P = 0.007), level of salinity (OR, 0.06; 95% CI, 0.01 to 0.74; P = 0.03), and percentage of soil moisture (OR, 0.81; 95% CI, 0.66 to 1.00; P = 0.05). Our study suggests that B. pseudomallei thrives in rice fields that are nutrient depleted. Some agricultural practices result in a decline in soil nutrients, which may impact the presence and amount of B. pseudomallei bacteria in affected areas. IMPORTANCE Burkholderia pseudomallei is an environmental Gram-negative bacillus and the cause of melioidosis. Humans acquire the disease following skin inoculation, inhalation, or ingestion of the bacterium in the environment. The presence of B. pseudomallei in soil defines geographic regions where humans and livestock are at risk of melioidosis, yet little is known about the soil properties associated with the presence of the organism. We evaluated the soil properties and presence of B. pseudomallei in 61 rice fields in East, Central, and Northeast Thailand. We demonstrated that the organism was more commonly found in soils with lower levels of organic matter and nutrients, including phosphorus, potassium, calcium, magnesium, and iron. We also demonstrated that crop residue burning after harvest, which can reduce soil nutrients, was not uncommon. Some agricultural practices result in a decline in soil nutrients, which may impact the presence and amount of B. pseudomallei bacteria in affected areas.
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predicted global distribution of Burkholderia pseudomallei and burden of melioidosis
Nature microbiology, 2016Co-Authors: Direk Limmathurotsakul, Eric Bertherat, David A. B. Dance, Nicholas P J Day, Nick Golding, Jane P Messina, David M Pigott, Catherine L Moyes, Dionne B Rolim, Sharon J. PeacockAbstract:Burkholderia pseudomallei, a highly pathogenic bacterium that causes melioidosis, is commonly found in soil in Southeast Asia and Northern Australia1,2. Melioidosis can be difficult to diagnose due to its diverse clinical manifestations and the inadequacy of conventional bacterial identification methods3. The bacterium is intrinsically resistant to a wide range of antimicrobials, and treatment with ineffective antimicrobials may result in case fatality rates (CFRs) exceeding 70%4,5. The importation of infected animals has, in the past, spread melioidosis to non-endemic areas6,7. The global distribution of B. pseudomallei and burden of melioidosis, however, remain poorly understood. Here, we map documented human and animal cases, and the presence of environmental B. pseudomallei, and combine this in a formal modelling framework8-10 to estimate the global burden of melioidosis. We estimate there to be 165,000 (95% credible interval 68,000-412,000) human melioidosis cases per year worldwide, of which 89,000 (36,000-227,000) die. Our estimates suggest that melioidosis is severely underreported in the 45 countries in which it is known to be endemic and that melioidosis is likely endemic in a further 34 countries which have never reported the disease. The large numbers of estimated cases and fatalities emphasise that the disease warrants renewed attention from public health officials and policy makers.
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competition between Burkholderia pseudomallei and b thailandensis
BMC Microbiology, 2015Co-Authors: Wikanda Ngamdee, Vanaporn Wuthiekanun, Sarunporn Tandhavanant, Sharon J. Peacock, Chanthiwa Wikraiphat, Onrapak Reamtong, Jeanne Salje, David A Low, Narisara ChantratitaAbstract:Background Burkholderia pseudomallei is a Gram-negative bacterium that causes melioidosis, an often fatal disease in tropical countries. Burkholderia thailandensis is a non-virulent but closely related species. Both species are soil saprophytes but are almost never isolated together.
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microevolution of Burkholderia pseudomallei during an acute infection
Journal of Clinical Microbiology, 2014Co-Authors: Direk Limmathurotsakul, Erin P Price, Vanaporn Wuthiekanun, Premjit Amornchai, Matthew T. G. Holden, Narisara Chantratita, Paul Coupland, Julian Parkhill, Sharon J. PeacockAbstract:We used whole-genome sequencing to evaluate 69 independent colonies of Burkholderia pseudomallei isolated from seven body sites of a patient with acute disseminated melioidosis. Fourteen closely related genotypes were found, providing evidence for the rapid in vivo diversification of B. pseudomallei after inoculation and systemic spread.
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The BpeEF-OprC Efflux Pump Is Responsible for Widespread Trimethoprim Resistance in Clinical and Environmental Burkholderia pseudomallei Isolates
Antimicrobial Agents and Chemotherapy, 2013Co-Authors: Nicole L. Podnecky, Vanaporn Wuthiekanun, Sharon J. Peacock, Herbert P. SchweizerAbstract:Trimethoprim-sulfamethoxazole (co-trimoxazole) is the primary drug used for oral eradication therapy of Burkholderia pseudomallei infections (melioidosis). Here, we demonstrate that trimethoprim resistance is widespread in clinical and environmental isolates from northeast Thailand and northern Australia. This resistance was shown to be due to BpeEF-OprC efflux pump expression. No dihydrofolate reductase target mutations were involved, although frequent insertion of ISBma2 was noted within the putative folA transcriptional terminator. All isolates tested remained susceptible to trimethoprim-sulfamethoxazole, suggesting that resistance to trimethoprim alone in these strains probably does not affect the efficacy of co-trimoxazole therapy.
Nicholas P J Day - One of the best experts on this subject based on the ideXlab platform.
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genetic variation associated with infection and the environment in the accidental pathogen Burkholderia pseudomallei
Communications biology, 2019Co-Authors: Claire Chewapreecha, Vanaporn Wuthiekanun, Matthew T. G. Holden, Alison E Mather, Simon R Harris, Martin Hunt, Chutima Chaichana, Gordon Dougan, Nicholas P J DayAbstract:The environmental bacterium Burkholderia pseudomallei causes melioidosis, an important endemic human disease in tropical and sub-tropical countries. This bacterium occupies broad ecological niches including soil, contaminated water, single-cell microbes, plants and infection in a range of animal species. Here, we performed genome-wide association studies for genetic determinants of environmental and human adaptation using a combined dataset of 1,010 whole genome sequences of B. pseudomallei from Northeast Thailand and Australia, representing two major disease hotspots. With these data, we identified 47 genes from 26 distinct loci associated with clinical or environmental isolates from Thailand and replicated 12 genes in an independent Australian cohort. We next outlined the selective pressures on the genetic loci (dN/dS) and the frequency at which they had been gained or lost throughout their evolutionary history, reflecting the bacterial adaptability to a wide range of ecological niches. Finally, we highlighted loci likely implicated in human disease. Claire Chewapreecha et al. combine 753 newly sequenced Thai Burkholderia pseudomallei isolates with 258 Australian isolates to identify genes associated with either clinical or environmental strains. They find 47 genes, 12 of which replicate in both locations, that may provide clues to the strategy used by this microbe to adapt to survive in wide range of ecological niches, including human hosts.
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thrombocytopenia impairs host defense against Burkholderia pseudomallei melioidosis
The Journal of Infectious Diseases, 2019Co-Authors: Emma Birnie, Direk Limmathurotsakul, Nicholas P J Day, Gavin C K W Koh, Theodora A M Claushuis, Joris J T H Roelofs, Jerry Ware, Baidong HouAbstract:Background Infection with the gram-negative bacillus Burkholderia pseudomallei (melioidosis) is an important cause of pneumosepsis in Southeast Asia and has a mortality of up to 40%. We aimed to assess the role of platelets in the host response against B. pseudomallei infection. Methods Association between platelet counts and mortality was determined in 1160 patients with culture-proven melioidosis. Mice treated with (low- or high-dose) platelet-depleting antibody were inoculated intranasally with B. pseudomallei and killed. Additional studies using functional glycoprotein Ibα-deficient mice were conducted. Results Thrombocytopenia was present in 31% of patients at admission and predicted mortality in melioidosis patients even after adjustment for confounders. In our murine-melioidosis model, platelet counts decreased, and mice treated with a platelet-depleting antibody showed enhanced mortality and higher bacterial loads compared to mice with normal platelet counts. Low platelet counts had a modest impact on early-pulmonary neutrophil influx. Reminiscent of their role in hemostasis, platelet depletion impaired vascular integrity, resulting in early lung bleeding. Glycoprotein Ibα-deficient mice had reduced platelet counts during B. pseudomallei infection together with an impaired local host defense in the lung. Conclusions Thrombocytopenia predicts mortality in melioidosis patients and, during experimental melioidosis, platelets play a protective role in both innate immunity and vascular integrity.
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soil nutrient depletion is associated with the presence of Burkholderia pseudomallei
Applied and Environmental Microbiology, 2016Co-Authors: Viriya Hantrakun, Vanaporn Wuthiekanun, Premjit Amornchai, Sharon J. Peacock, Nicholas P J Day, Patpong Rongkard, Malinee Oyuchua, Cherry LimAbstract:Burkholderia pseudomallei is a soil-dwelling bacterium and the cause of melioidosis, which kills an estimated 89,000 people per year worldwide. Agricultural workers are at high risk of infection due to repeated exposure to the bacterium. Little is known about the soil physicochemical properties associated with the presence or absence of the organism. Here, we evaluated the soil physicochemical properties and presence of B. pseudomallei in 6,100 soil samples collected from 61 rice fields in Thailand. The presence of B. pseudomallei was negatively associated with the proportion of clay, proportion of moisture, level of salinity, percentage of organic matter, presence of cadmium, and nutrient levels (phosphorus, potassium, calcium, magnesium, and iron). The presence of B. pseudomallei was not associated with the level of soil acidity (P = 0.54). In a multivariable logistic regression model, the presence of B. pseudomallei was negatively associated with the percentage of organic matter (odds ratio [OR], 0.06; 95% confidence interval [CI], 0.01 to 0.47; P = 0.007), level of salinity (OR, 0.06; 95% CI, 0.01 to 0.74; P = 0.03), and percentage of soil moisture (OR, 0.81; 95% CI, 0.66 to 1.00; P = 0.05). Our study suggests that B. pseudomallei thrives in rice fields that are nutrient depleted. Some agricultural practices result in a decline in soil nutrients, which may impact the presence and amount of B. pseudomallei bacteria in affected areas. IMPORTANCE Burkholderia pseudomallei is an environmental Gram-negative bacillus and the cause of melioidosis. Humans acquire the disease following skin inoculation, inhalation, or ingestion of the bacterium in the environment. The presence of B. pseudomallei in soil defines geographic regions where humans and livestock are at risk of melioidosis, yet little is known about the soil properties associated with the presence of the organism. We evaluated the soil properties and presence of B. pseudomallei in 61 rice fields in East, Central, and Northeast Thailand. We demonstrated that the organism was more commonly found in soils with lower levels of organic matter and nutrients, including phosphorus, potassium, calcium, magnesium, and iron. We also demonstrated that crop residue burning after harvest, which can reduce soil nutrients, was not uncommon. Some agricultural practices result in a decline in soil nutrients, which may impact the presence and amount of B. pseudomallei bacteria in affected areas.
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predicted global distribution of Burkholderia pseudomallei and burden of melioidosis
Nature microbiology, 2016Co-Authors: Direk Limmathurotsakul, Eric Bertherat, David A. B. Dance, Nicholas P J Day, Nick Golding, Jane P Messina, David M Pigott, Catherine L Moyes, Dionne B Rolim, Sharon J. PeacockAbstract:Burkholderia pseudomallei, a highly pathogenic bacterium that causes melioidosis, is commonly found in soil in Southeast Asia and Northern Australia1,2. Melioidosis can be difficult to diagnose due to its diverse clinical manifestations and the inadequacy of conventional bacterial identification methods3. The bacterium is intrinsically resistant to a wide range of antimicrobials, and treatment with ineffective antimicrobials may result in case fatality rates (CFRs) exceeding 70%4,5. The importation of infected animals has, in the past, spread melioidosis to non-endemic areas6,7. The global distribution of B. pseudomallei and burden of melioidosis, however, remain poorly understood. Here, we map documented human and animal cases, and the presence of environmental B. pseudomallei, and combine this in a formal modelling framework8-10 to estimate the global burden of melioidosis. We estimate there to be 165,000 (95% credible interval 68,000-412,000) human melioidosis cases per year worldwide, of which 89,000 (36,000-227,000) die. Our estimates suggest that melioidosis is severely underreported in the 45 countries in which it is known to be endemic and that melioidosis is likely endemic in a further 34 countries which have never reported the disease. The large numbers of estimated cases and fatalities emphasise that the disease warrants renewed attention from public health officials and policy makers.
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failure of Burkholderia pseudomallei to grow in an automated blood culture system
American Journal of Tropical Medicine and Hygiene, 2014Co-Authors: Nittaya Teerawattanasook, Direk Limmathurotsakul, Nicholas P J Day, Vanaporn WuthiekanunAbstract:We compared the organisms isolated from 30,210 pairs of blood culture bottles by using BacT/Alert system and the conventional system. Overall, 2,575 (8.5%) specimens were culture positive for pathogenic organisms. The sensitivity for detection of pathogenic organisms with the BACT/Alert system (85.6%, 2,203 of 2,575) was significantly higher than that with the conventional method (74.1%, 1,908 of 2,575; P < 0.0001). However, Burkholderia pseudomallei was isolated less often with the BacT/ALERT system (73.5%, 328 of 446) than with the conventional system (90.3%, 403 of 446; P < 0.0001). This finding suggests that use of the conventional culture method in conjunction with the BacT/Alert system may improve the isolation rate for B. pseudomallei in melioidosis-endemic areas.
Vanaporn Wuthiekanun - One of the best experts on this subject based on the ideXlab platform.
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genetic variation associated with infection and the environment in the accidental pathogen Burkholderia pseudomallei
Communications biology, 2019Co-Authors: Claire Chewapreecha, Vanaporn Wuthiekanun, Matthew T. G. Holden, Alison E Mather, Simon R Harris, Martin Hunt, Chutima Chaichana, Gordon Dougan, Nicholas P J DayAbstract:The environmental bacterium Burkholderia pseudomallei causes melioidosis, an important endemic human disease in tropical and sub-tropical countries. This bacterium occupies broad ecological niches including soil, contaminated water, single-cell microbes, plants and infection in a range of animal species. Here, we performed genome-wide association studies for genetic determinants of environmental and human adaptation using a combined dataset of 1,010 whole genome sequences of B. pseudomallei from Northeast Thailand and Australia, representing two major disease hotspots. With these data, we identified 47 genes from 26 distinct loci associated with clinical or environmental isolates from Thailand and replicated 12 genes in an independent Australian cohort. We next outlined the selective pressures on the genetic loci (dN/dS) and the frequency at which they had been gained or lost throughout their evolutionary history, reflecting the bacterial adaptability to a wide range of ecological niches. Finally, we highlighted loci likely implicated in human disease. Claire Chewapreecha et al. combine 753 newly sequenced Thai Burkholderia pseudomallei isolates with 258 Australian isolates to identify genes associated with either clinical or environmental strains. They find 47 genes, 12 of which replicate in both locations, that may provide clues to the strategy used by this microbe to adapt to survive in wide range of ecological niches, including human hosts.
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misidentification of Burkholderia pseudomallei as acinetobacter species in northern thailand
Transactions of The Royal Society of Tropical Medicine and Hygiene, 2019Co-Authors: Rachel C Greer, Vanaporn Wuthiekanun, Premjit Amornchai, Tri Wangrangsimakul, Achara Laongnualpanich, Dance Dab, Direk LimmathurotsakulAbstract:Background Burkholderia pseudomallei is the causative agent of melioidosis, a disease endemic throughout the tropics. Methods A study of reported Acinetobacter spp. bacteraemia was performed at Chiang Rai provincial hospital from 2014 to 2015. Isolates were collected and tested for confirmation. Results A total of 419 putative Acinetobacter spp. isolates from 412 patients were re-identified and 5/419 (1.2%) were identified as B. pseudomallei. Four of the five patients with melioidosis died. An estimated 88/419 (21%) isolates were correctly identified as Acinetobacter spp. Conclusions Misidentification of Acinetobacter spp. as B. pseudomallei or other bacteria is not uncommon and programmes to address these shortfalls are urgently required.
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soil nutrient depletion is associated with the presence of Burkholderia pseudomallei
Applied and Environmental Microbiology, 2016Co-Authors: Viriya Hantrakun, Vanaporn Wuthiekanun, Premjit Amornchai, Sharon J. Peacock, Nicholas P J Day, Patpong Rongkard, Malinee Oyuchua, Cherry LimAbstract:Burkholderia pseudomallei is a soil-dwelling bacterium and the cause of melioidosis, which kills an estimated 89,000 people per year worldwide. Agricultural workers are at high risk of infection due to repeated exposure to the bacterium. Little is known about the soil physicochemical properties associated with the presence or absence of the organism. Here, we evaluated the soil physicochemical properties and presence of B. pseudomallei in 6,100 soil samples collected from 61 rice fields in Thailand. The presence of B. pseudomallei was negatively associated with the proportion of clay, proportion of moisture, level of salinity, percentage of organic matter, presence of cadmium, and nutrient levels (phosphorus, potassium, calcium, magnesium, and iron). The presence of B. pseudomallei was not associated with the level of soil acidity (P = 0.54). In a multivariable logistic regression model, the presence of B. pseudomallei was negatively associated with the percentage of organic matter (odds ratio [OR], 0.06; 95% confidence interval [CI], 0.01 to 0.47; P = 0.007), level of salinity (OR, 0.06; 95% CI, 0.01 to 0.74; P = 0.03), and percentage of soil moisture (OR, 0.81; 95% CI, 0.66 to 1.00; P = 0.05). Our study suggests that B. pseudomallei thrives in rice fields that are nutrient depleted. Some agricultural practices result in a decline in soil nutrients, which may impact the presence and amount of B. pseudomallei bacteria in affected areas. IMPORTANCE Burkholderia pseudomallei is an environmental Gram-negative bacillus and the cause of melioidosis. Humans acquire the disease following skin inoculation, inhalation, or ingestion of the bacterium in the environment. The presence of B. pseudomallei in soil defines geographic regions where humans and livestock are at risk of melioidosis, yet little is known about the soil properties associated with the presence of the organism. We evaluated the soil properties and presence of B. pseudomallei in 61 rice fields in East, Central, and Northeast Thailand. We demonstrated that the organism was more commonly found in soils with lower levels of organic matter and nutrients, including phosphorus, potassium, calcium, magnesium, and iron. We also demonstrated that crop residue burning after harvest, which can reduce soil nutrients, was not uncommon. Some agricultural practices result in a decline in soil nutrients, which may impact the presence and amount of B. pseudomallei bacteria in affected areas.
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competition between Burkholderia pseudomallei and b thailandensis
BMC Microbiology, 2015Co-Authors: Wikanda Ngamdee, Vanaporn Wuthiekanun, Sarunporn Tandhavanant, Sharon J. Peacock, Chanthiwa Wikraiphat, Onrapak Reamtong, Jeanne Salje, David A Low, Narisara ChantratitaAbstract:Background Burkholderia pseudomallei is a Gram-negative bacterium that causes melioidosis, an often fatal disease in tropical countries. Burkholderia thailandensis is a non-virulent but closely related species. Both species are soil saprophytes but are almost never isolated together.
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failure of Burkholderia pseudomallei to grow in an automated blood culture system
American Journal of Tropical Medicine and Hygiene, 2014Co-Authors: Nittaya Teerawattanasook, Direk Limmathurotsakul, Nicholas P J Day, Vanaporn WuthiekanunAbstract:We compared the organisms isolated from 30,210 pairs of blood culture bottles by using BacT/Alert system and the conventional system. Overall, 2,575 (8.5%) specimens were culture positive for pathogenic organisms. The sensitivity for detection of pathogenic organisms with the BACT/Alert system (85.6%, 2,203 of 2,575) was significantly higher than that with the conventional method (74.1%, 1,908 of 2,575; P < 0.0001). However, Burkholderia pseudomallei was isolated less often with the BacT/ALERT system (73.5%, 328 of 446) than with the conventional system (90.3%, 403 of 446; P < 0.0001). This finding suggests that use of the conventional culture method in conjunction with the BacT/Alert system may improve the isolation rate for B. pseudomallei in melioidosis-endemic areas.
Direk Limmathurotsakul - One of the best experts on this subject based on the ideXlab platform.
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thrombocytopenia impairs host defense against Burkholderia pseudomallei melioidosis
The Journal of Infectious Diseases, 2019Co-Authors: Emma Birnie, Direk Limmathurotsakul, Nicholas P J Day, Gavin C K W Koh, Theodora A M Claushuis, Joris J T H Roelofs, Jerry Ware, Baidong HouAbstract:Background Infection with the gram-negative bacillus Burkholderia pseudomallei (melioidosis) is an important cause of pneumosepsis in Southeast Asia and has a mortality of up to 40%. We aimed to assess the role of platelets in the host response against B. pseudomallei infection. Methods Association between platelet counts and mortality was determined in 1160 patients with culture-proven melioidosis. Mice treated with (low- or high-dose) platelet-depleting antibody were inoculated intranasally with B. pseudomallei and killed. Additional studies using functional glycoprotein Ibα-deficient mice were conducted. Results Thrombocytopenia was present in 31% of patients at admission and predicted mortality in melioidosis patients even after adjustment for confounders. In our murine-melioidosis model, platelet counts decreased, and mice treated with a platelet-depleting antibody showed enhanced mortality and higher bacterial loads compared to mice with normal platelet counts. Low platelet counts had a modest impact on early-pulmonary neutrophil influx. Reminiscent of their role in hemostasis, platelet depletion impaired vascular integrity, resulting in early lung bleeding. Glycoprotein Ibα-deficient mice had reduced platelet counts during B. pseudomallei infection together with an impaired local host defense in the lung. Conclusions Thrombocytopenia predicts mortality in melioidosis patients and, during experimental melioidosis, platelets play a protective role in both innate immunity and vascular integrity.
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misidentification of Burkholderia pseudomallei as acinetobacter species in northern thailand
Transactions of The Royal Society of Tropical Medicine and Hygiene, 2019Co-Authors: Rachel C Greer, Vanaporn Wuthiekanun, Premjit Amornchai, Tri Wangrangsimakul, Achara Laongnualpanich, Dance Dab, Direk LimmathurotsakulAbstract:Background Burkholderia pseudomallei is the causative agent of melioidosis, a disease endemic throughout the tropics. Methods A study of reported Acinetobacter spp. bacteraemia was performed at Chiang Rai provincial hospital from 2014 to 2015. Isolates were collected and tested for confirmation. Results A total of 419 putative Acinetobacter spp. isolates from 412 patients were re-identified and 5/419 (1.2%) were identified as B. pseudomallei. Four of the five patients with melioidosis died. An estimated 88/419 (21%) isolates were correctly identified as Acinetobacter spp. Conclusions Misidentification of Acinetobacter spp. as B. pseudomallei or other bacteria is not uncommon and programmes to address these shortfalls are urgently required.
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predicted global distribution of Burkholderia pseudomallei and burden of melioidosis
Nature microbiology, 2016Co-Authors: Direk Limmathurotsakul, Eric Bertherat, David A. B. Dance, Nicholas P J Day, Nick Golding, Jane P Messina, David M Pigott, Catherine L Moyes, Dionne B Rolim, Sharon J. PeacockAbstract:Burkholderia pseudomallei, a highly pathogenic bacterium that causes melioidosis, is commonly found in soil in Southeast Asia and Northern Australia1,2. Melioidosis can be difficult to diagnose due to its diverse clinical manifestations and the inadequacy of conventional bacterial identification methods3. The bacterium is intrinsically resistant to a wide range of antimicrobials, and treatment with ineffective antimicrobials may result in case fatality rates (CFRs) exceeding 70%4,5. The importation of infected animals has, in the past, spread melioidosis to non-endemic areas6,7. The global distribution of B. pseudomallei and burden of melioidosis, however, remain poorly understood. Here, we map documented human and animal cases, and the presence of environmental B. pseudomallei, and combine this in a formal modelling framework8-10 to estimate the global burden of melioidosis. We estimate there to be 165,000 (95% credible interval 68,000-412,000) human melioidosis cases per year worldwide, of which 89,000 (36,000-227,000) die. Our estimates suggest that melioidosis is severely underreported in the 45 countries in which it is known to be endemic and that melioidosis is likely endemic in a further 34 countries which have never reported the disease. The large numbers of estimated cases and fatalities emphasise that the disease warrants renewed attention from public health officials and policy makers.
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failure of Burkholderia pseudomallei to grow in an automated blood culture system
American Journal of Tropical Medicine and Hygiene, 2014Co-Authors: Nittaya Teerawattanasook, Direk Limmathurotsakul, Nicholas P J Day, Vanaporn WuthiekanunAbstract:We compared the organisms isolated from 30,210 pairs of blood culture bottles by using BacT/Alert system and the conventional system. Overall, 2,575 (8.5%) specimens were culture positive for pathogenic organisms. The sensitivity for detection of pathogenic organisms with the BACT/Alert system (85.6%, 2,203 of 2,575) was significantly higher than that with the conventional method (74.1%, 1,908 of 2,575; P < 0.0001). However, Burkholderia pseudomallei was isolated less often with the BacT/ALERT system (73.5%, 328 of 446) than with the conventional system (90.3%, 403 of 446; P < 0.0001). This finding suggests that use of the conventional culture method in conjunction with the BacT/Alert system may improve the isolation rate for B. pseudomallei in melioidosis-endemic areas.
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role of Burkholderia pseudomallei biofilm formation and lipopolysaccharide in relapse of melioidosis
Clinical Microbiology and Infection, 2014Co-Authors: Direk Limmathurotsakul, Vanaporn Wuthiekanun, Narisara Chantratita, Surasakdi Wongratanacheewin, Nicholas P J Day, A Paeyao, Natnaree Saiprom, Natthaporn Takpho, Janjira ThaipadungpanitAbstract:We examined whether quantitative biofilm formation and/or lipopolysaccharide type of Burkholderia pseudomallei was associated with relapsing melioidosis. We devised a 1 : 4 nested case–control study in which both cases and controls were drawn from a cohort of patients with primary melioidosis. Paired isolates from 80 patients with relapse and single isolates from 184 patients without relapse were tested. Relapse was associated with biofilm formation of the primary infecting isolate (conditional OR 2.03; 95% CI 1.27–3.25; p 0.003), but not with lipopolysaccharide type (p 0.74). This finding highlights the importance of biofilm formation in relapsing melioidosis.
David A. B. Dance - One of the best experts on this subject based on the ideXlab platform.
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predicted global distribution of Burkholderia pseudomallei and burden of melioidosis
Nature microbiology, 2016Co-Authors: Direk Limmathurotsakul, Eric Bertherat, David A. B. Dance, Nicholas P J Day, Nick Golding, Jane P Messina, David M Pigott, Catherine L Moyes, Dionne B Rolim, Sharon J. PeacockAbstract:Burkholderia pseudomallei, a highly pathogenic bacterium that causes melioidosis, is commonly found in soil in Southeast Asia and Northern Australia1,2. Melioidosis can be difficult to diagnose due to its diverse clinical manifestations and the inadequacy of conventional bacterial identification methods3. The bacterium is intrinsically resistant to a wide range of antimicrobials, and treatment with ineffective antimicrobials may result in case fatality rates (CFRs) exceeding 70%4,5. The importation of infected animals has, in the past, spread melioidosis to non-endemic areas6,7. The global distribution of B. pseudomallei and burden of melioidosis, however, remain poorly understood. Here, we map documented human and animal cases, and the presence of environmental B. pseudomallei, and combine this in a formal modelling framework8-10 to estimate the global burden of melioidosis. We estimate there to be 165,000 (95% credible interval 68,000-412,000) human melioidosis cases per year worldwide, of which 89,000 (36,000-227,000) die. Our estimates suggest that melioidosis is severely underreported in the 45 countries in which it is known to be endemic and that melioidosis is likely endemic in a further 34 countries which have never reported the disease. The large numbers of estimated cases and fatalities emphasise that the disease warrants renewed attention from public health officials and policy makers.
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trimethoprim sulfamethoxazole resistance in Burkholderia pseudomallei
International Journal of Antimicrobial Agents, 2014Co-Authors: Rattanaphone Phetsouvanh, David A. B. Dance, Paul N. Newton, Viengmone Davong, Sona Soeng, Paul TurnerAbstract:Sir, With the recent publication of the MERTH study [1], trimethoprim/sulfamethoxazole (SXT) monotherapy will be used increasingly in the treatment of melioidosis during the eradication phase, and possibly as the only treatment for some mild infections. It is therefore important to know the prevalence of SXT resistance in Burkholderia pseudomallei. This is difficult to test in vitro, with disc diffusion testing overestimating resistance, and indistinct endpoints in all methods [2]. Even using the Etest method to estimate the minimum inhibitory concentration (MIC), SXT resistance rates as high as 24% in a year have occasionally been reported from Thailand [3]. Recent data from Northern Australia published in this journal [4] are consistent with our own experience in Southeast Asia and suggest that true resistance to SXT in B. pseudomallei is actually very rare. As our own experience indicated a substantially lower prevalence of SXT resistance than the literature suggests, we reviewed routine data from our diagnostic laboratories in Laos (February 2003 to October 2012) and Cambodia (February 2006 to December 2012). Etest (bioMerieux, Basingstoke, UK) was performed according to the manufacturer's instructions on all isolates in Vientiane (Laos) and on all isolates that appeared non-susceptible by disc diffusion testing [Clinical and Laboratory Standards Institute (CLSI) M02-A11 method; zone diameter < 16 mm] in Siem Reap (Cambodia), as previously recommended [3]. The sources of the strains tested are shown in Table 1. Table 1 Source of isolates. Of 769 sequential isolates, 99.2% (615/620) from Laos and 100% (149/149) from Cambodia were classified as susceptible to SXT according to CLSI criteria (trimethoprim MIC ≤ 2 mg/L). Three isolates had a trimethoprim MIC of 3 mg/L and two isolates had a trimethoprim MIC of 4 mg/L. The range of MICs is shown in Fig. 1. Fig. 1 Distribution of trimethoprim/sulfamethoxazole (co-trimoxazole) Etest minimum inhibitory concentrations (MICs) of clinical isolates of Burkholderia pseudomallei from (a) Laos and (b) Cambodia. This confirms that primary resistance of B. pseudomallei to SXT is extremely uncommon and should rarely be a contraindication to SXT monotherapy. These results from Vientiane and Siem Reap closely mirror those of Crowe et al. in Darwin [4]. Although the CLSI currently only recommends broth microdilution testing for B. pseudomallei [5], many years of experience in melioidosis-endemic areas suggests that disc diffusion testing is reliable for all agents except SXT, for which Etest gives acceptable results. We think that the misleading data in the literature are due to the difficulty of interpreting endpoints in testing susceptibility of B. pseudomallei to SXT. We tried to follow the manufacturer's instructions and read the Etest at 80% inhibition, but this is a somewhat subjective endpoint. However, the really important thing that remains to be established is whether SXT MICs can predict the outcome of SXT monotherapy in melioidosis. Funding: The Laos-Oxford-Mahosot Hospital-Wellcome Trust Research Unit and the Cambodia-Oxford Medical Research Unit are funded by the Wellcome Trust of Great Britain. The authors thank all of the laboratory staff in the microbiology laboratories in Cambodia (Angkor Hospital for Children, Siem Reap) and Laos (Mahosot Hospital, Vientiane) who undertook the testing for their assistance. Competing interests: None declared. Ethical approval: Not required.
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systematic review and consensus guidelines for environmental sampling of Burkholderia pseudomallei
PLOS Neglected Tropical Diseases, 2013Co-Authors: Direk Limmathurotsakul, Mark Mayo, Mirjam Kaestli, Vanaporn Wuthiekanun, Apichai Tuanyok, David A. B. Dance, Jeffrey H Warner, David M Wagner, Heiman F L WertheimAbstract:Burkholderia pseudomallei, a Tier 1 Select Agent and the cause of melioidosis, is a Gram-negative bacillus present in the environment in many tropical countries. Defining the global pattern of B. pseudomallei distribution underpins efforts to prevent infection, and is dependent upon robust environmental sampling methodology. Our objective was to review the literature on the detection of environmental B. pseudomallei, update the risk map for melioidosis, and propose international consensus guidelines for soil sampling.An international working party (Detection of Environmental Burkholderia pseudomallei Working Party (DEBWorP)) was formed during the VIth World Melioidosis Congress in 2010. PubMed (January 1912 to December 2011) was searched using the following MeSH terms: pseudomallei or melioidosis. Bibliographies were hand-searched for secondary references. The reported geographical distribution of B. pseudomallei in the environment was mapped and categorized as definite, probable, or possible. The methodology used for detecting environmental B. pseudomallei was extracted and collated. We found that global coverage was patchy, with a lack of studies in many areas where melioidosis is suspected to occur. The sampling strategies and bacterial identification methods used were highly variable, and not all were robust. We developed consensus guidelines with the goals of reducing the probability of false-negative results, and the provision of affordable and 'low-tech' methodology that is applicable in both developed and developing countries.The proposed consensus guidelines provide the basis for the development of an accurate and comprehensive global map of environmental B. pseudomallei.
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workshop on treatment of and postexposure prophylaxis for Burkholderia pseudomallei and b mallei infection 2010
Emerging Infectious Diseases, 2012Co-Authors: Rebecca Lipsitz, David A. B. Dance, Bart J. Currie, Allen C Cheng, Susan Garges, Rosemarie Aurigemma, Prasith Baccam, David D Blaney, Joseph Larsen, Direk LimmathurotsakulAbstract:The US Public Health Emergency Medical Countermeasures Enterprise convened subject matter experts at the 2010 HHS Burkholderia Workshop to develop consensus recommendations for postexposure prophylaxis against and treatment for Burkholderia pseudomallei and B. mallei infections, which cause melioidosis and glanders, respectively. Drugs recommended by consensus of the participants are ceftazidime or meropenem for initial intensive therapy, and trimethoprim/sulfamethoxazole or amoxicillin/clavulanic acid for eradication therapy. For postexposure prophylaxis, recommended drugs are trimethoprim/sulfamethoxazole or co-amoxiclav. To improve the timely diagnosis of melioidosis and glanders, further development and wide distribution of rapid diagnostic assays were also recommended. Standardized animal models and B. pseudomallei strains are needed for further development of therapeutic options. Training for laboratory technicians and physicians would facilitate better diagnosis and treatment options.
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the global distribution of Burkholderia pseudomallei and melioidosis an update
Transactions of The Royal Society of Tropical Medicine and Hygiene, 2008Co-Authors: David A. B. Dance, Bart J. Currie, Allen C ChengAbstract:While Southeast Asia and northern Australia are well recognized as the major endemic regions for melioidosis, recent reports have expanded the endemic zone. Severe weather events and environmental disasters such as the 2004 Asian tsunami have unmasked locations of sporadic cases and have reconfirmed endemicity in Indonesia. The endemic region now includes the majority of the Indian subcontinent, southern China, Hong Kong and Taiwan. Sporadic cases have occurred in Brazil and elsewhere in the Americas and in island communities such as New Caledonia, in the Pacific Ocean, and Mauritius in the Indian Ocean. Some of the factors that are critical to further elucidating the global distribution of Burkholderia pseudomallei and melioidosis include improved access to diagnostic laboratory facilities and formal confirmation of the identity of bacterial isolates from suspected cases.
