Isolation of Burkholderia pseudomallei from a goat in New Caledonia: implications for animal and human health monitoring and serological tool comparison.

BACKGROUND: Melioidosis is a serious bacterial infection caused by Burkholderia pseudomallei, a gram-negative bacterium commonly found in soil and water. It can affect both humans and animals, and is endemic in regions such as Southeast Asia and Northern Australia. In recent years, there have been reports of an emergence of human melioidosis in other areas, including New Caledonia. RESULTS: During standard laboratory analysis in New Caledonia in 2021, a strain of B. pseudomallei was isolated from a goat. The strain was characterized using both MLST and WGS techniques and was found to cluster with previously described local human strains from the area. In parallel, several serological tests (CFT, ELISA, Luminex (Hcp1, GroEL, BPSS1840), arrays assay and a latex agglutination test) were performed on animals from the farm where the goat originated, and/or from three other neighboring farms. Using two commercial ELISA kits, seropositive animals were found only on the farm where the infected goat originated and tests based on recombinant proteins confirmed the usefulness of the Hcp1 protein for the diagnosis of melioidosis in animals. CONCLUSIONS: Despite the regular reports of human cases, this is the first confirmed case of melioidosis in an animal in New Caledonia. These results confirm the presence of the bacterium in the region and highlight the importance of vigilance for both animal and human health. It is critical that all health partners, including breeders, veterinarians, and biologists, work together to monitor and prevent the spread of the disease.

Melioidosis in Patients with COVID-19 Exposed to Contaminated Tap Water, Thailand, 2021.

In September 2021, a total of 25 patients diagnosed with COVID-19 developed acute melioidosis after (median 7 days) admission to a COVID-19 field hospital in Thailand. Eight nonpotable tap water samples and 6 soil samples were culture-positive for Burkholderia pseudomallei. Genomic analysis suggested contaminated tap water as the likely cause of illness.

Management of unexpected laboratory exposure to Burkholderia pseudomallei.

Burkholderia pseudomallei is a Gram-negative saprophytic bacillus that causes melioidosis. The infection is endemic in South-East of Asia and Northern Australia. B. pseudomallei has been designated as bioterrorism agent and its manipulation should be done in a biological safety level 3 capability. Workers in laboratories may be accidentally exposed to B. pseudomallei before its identification, with a risk of laboratory-acquired melioidosis. We want to describe a case of melioidosis occurred in our hospital and its management at laboratory. The objective of this article is to provide guidance to microbiologists confronted with a suspicious case of B. pseudomallei on the management of the exposition. We report here a couple of microbiological arguments that can usually guide microbiologists towards presumptive identification of B. pseudomallei. This case report shows the importance of MALDI-TOF MS accurate databases to ensure accurate microbial identification and antibiotic prophylaxis adapted to individuals who were exposed. We also want to underline the importance of developing an effective strategy of prevention against any accidental exposure that can occur in a microbiological laboratory.

Burkholderia pseudomallei Bacteria in Ornamental Fish Tanks, Vientiane, Laos, 2023.

In 2019, a melioidosis case in Maryland, USA, was shown to have been acquired from an ornamental fish tank contaminated with Burkholderia pseudomallei bacteria, likely derived from Southeast Asia. We investigated the presence of B. pseudomallei in ornamental fish tanks in the endemic area of Vientiane, Laos.

Are we dealing with melioidosis under the mask of tuberculosis? - A case series.

Melioidosis is prevalent in South-East Asia. India is now become endemic to melioidosis. Melioidosis mimicks Tuberculosis (TB) and is often overlooked clinically. The spectrum of disease ranges from acute pulmonary infection to focal infection and septicemia. We report three cases of melioidosis, which was primarily suspected to be tuberculosis due to similarities in the clinical features. All patients were male and had risk factors such as type 2 diabetes mellitus as well as other risk factors such as chronic obstructive pulmonary disease (COPD), systemic hypertension, glucocorticoid therapy etc. All three patient samples were culture negative as well as negative for tests performed for the detection of tuberculosis. Conventional nested PCR targeting 251bp of 16S-23S spacer region of B. pseudomallei. was performed among individuals suspected to have extrapulmonary Tuberculosis. The presence of 251 bp was considered positive for B. pseudomallei. All three patients were treated with third generation cephalosporin and recovered due to timely diagnosis. Patients suspected for tuberculosis should be screened for B. pseudomallei, especially when AFB smear and MTB GeneXpert are negative. Often clinical samples may be culture negative for B. pseudomallei as patients are treated with antibiotics, therefore it is worthwhile performing PCR for B. pseudomallei to rule in a diagnosis of melioidosis and initiate appropriate antibiotics.

[A multi-resistant bacterium before the era of antibiotics: the agent of melioidosis]. / Une bactérie multirésistante avant l'ère des antibiotiques : l'agent de la mélioïdose.

Melioidosis is an infectious, tropical and emerging disease, due to a bacterium of the hydrotelluric environment, Burkholderia pseudomallei, which is considered as a potential biological weapon because of its exceptional resistance and virulence capacities. Its worldwide spread, outside the original endemic foci of Southeast Asia and Australia, is favoured by global warming and the diabetes mellitus pandemic, which is the main predisposing factor.In humans, melioidosis is an opportunistic infection, following professional (rice farmers, soldiers) or accidental contamination, by inhalation or inoculation. B. pseudomallei is a facultative intracellular bacterium that can overcome host immune defences, induce acute, subacute, or chronic invasive infection, or remain latent for years. The acute infection is polymorphic, bacteraemic in more than 50% of cases, frequently complicated by shock, and revealed by visceral abscesses, most often pulmonary. It is fatal in 20 to 50% of cases, the prognosis depending on the delay before the establishment of effective first-line antibiotic therapy, using ceftazidime or carbapenems, and therefore on the speed of bacteriological diagnosis.B. pseudomallei is a saprophytic bacterium, resident of the rhizosphere where it has developed and accumulated capacities to overcome environmental stresses and competition with organisms living in such ecosystem. These adaptation mechanisms are also the virulence factors that make melioidosis serious, in particular the efflux pumps that are the main support for its multi-resistance to antibiotics.

La mélioïdose est une maladie infectieuse, tropicale et émergente, due à une bactérie de l'environnement hydrotellurique, Burkholderia pseudomallei, qui est considérée comme arme biologique potentielle en raison de ses exceptionnelles capacités de résistance et de virulence. Son extension mondiale, en dehors des foyers endémiques originels d'Asie du Sud-Est et d'Australie, est favorisée par le réchauffement climatique et par la pandémie de diabète de type 2 qui en est le principal facteur prédisposant.Chez l'Homme, la mélioïdose est une infection opportuniste, consécutive à une contamination professionnelle (riziculteurs, militaires) ou accidentelle, par inhalation ou par inoculation. B. pseudomallei est une bactérie intracellulaire facultative qui peut déjouer les défenses immunitaires de l'hôte, induire une infection invasive, aiguë, subaiguë ou chronique, ou rester latente pendant des années. L'infection aiguë est polymorphe, bactériémique dans plus de 50 % des cas, fréquemment compliquée de choc, et révélée par des abcès viscéraux le plus souvent pulmonaires. Elle est mortelle dans 20 à 50 % des cas, le pronostic dépendant du délai avant la mise en place d'une antibiothérapie efficace, utilisant la ceftazidime ou les carbapénèmes, donc de la rapidité du diagnostic bactériologique.B. pseudomallei est une bactérie saprophyte, résidente de la rhizosphère où elle a développé et accumulé des capacités pour supporter les stress environnementaux et la compétition avec les organismes vivant dans cet écosystème. Ces mécanismes d'adaptation sont aussi les facteurs de virulence qui font toute la gravité de la mélioïdose, en particulier les pompes d'efflux qui sont le support principal de sa multirésistance aux antibiotiques.

Newly detected paediatric melioidosis cases in a single referral children's hospital in Ho Chi Minh City indicate the probable underrecognition of melioidosis in South Vietnam.

BACKGROUND: The epidemiology of melioidosis in Vietnam, a disease caused by the soil bacterium Burkholderia pseudomallei, remains unclear. This study aimed to detect paediatric melioidosis in South Vietnam and describe clinical features and the geographic distribution. METHODS: We introduced a simple laboratory algorithm for detecting B. pseudomallei from clinical samples at Children's Hospital 2 in Ho Chi Minh City in July 2015. A retrospective observational study of children <16 y of age with culture-confirmed melioidosis between July 2015 and August 2019 was undertaken. RESULTS: Thirty-five paediatric cases of melioidosis were detected, with cases originating from 13 of 32 provinces and cities in South Vietnam. The number of paediatric melioidosis cases detected from a certain region correlated with the overall number of inpatients originating from the respective geographic area. Suppurative parotitis (n=15 [42.8%]) was the most common clinical presentation, followed by lung infection (n=10 [28.6%]) and septicaemia (n=7 [20%]). Fourteen (40%) children had disseminated disease, including all cases of lung infection, four cases with central nervous system symptoms and four (11.4%) deaths. CONCLUSIONS: The patients' origin indicates a wide distribution of melioidosis in South Vietnam. It seems probable that cases not only in children, but also in adults, remain grossly undiagnosed. Further awareness raising and laboratory capacity strengthening are needed in this part of the country.

Statin Use and Reduced Risk of Pneumonia in Patients with Melioidosis: A Lung-Specific Statin Association.

Rationale: 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) use is associated with a lower risk of incident pneumonia and, less robustly, with nonpulmonary infections. Whether statin use is associated with a lower risk of pneumonia than other clinical presentations of infection with the same pathogen is unknown. Objectives: To assess whether preadmission statin use is associated with a lower risk of pneumonia than nonpneumonia presentations among patients hospitalized with Burkholderia pseudomallei infection (melioidosis). Methods: We performed a secondary analysis of a prospective multicenter cohort study of patients hospitalized with culture-confirmed B. pseudomallei infection (melioidosis). We used Poisson regression with robust standard errors to test for an association between statin use and pneumonia. We then performed several sensitivity analyses that addressed healthy user effect and indication bias. Results: Of 1,372 patients with melioidosis enrolled in the parent cohort, 1,121 were analyzed. Nine hundred eighty (87%) of 1,121 were statin nonusers, and 141 (13%) of 1,121 were statin users. Forty-six (33%) of 141 statin users presented with pneumonia compared with 432 (44%) of 980 statin nonusers. Statin use was associated with a lower risk of pneumonia in unadjusted analysis (relative risk, 0.74; 95% confidence interval, 0.58-0.95; P = 0.02) and, after adjustment for demographic variables, comorbidities, environmental exposures, and symptom duration (relative risk, 0.73; 95% confidence interval, 0.57-0.94; P = 0.02). The results of sensitivity analyses, including active comparator analysis and inverse probability of treatment weighting, were consistent with the primary analysis. Conclusions: In hospitalized patients with melioidosis, preadmission statin use was associated with a lower risk of pneumonia than other clinical presentations of melioidosis, suggesting a lung-specific protective effect of statins.

Burkholderia pseudomallei and melioidosis.

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.

Phylogeographic characterization of Burkholderia pseudomallei isolated from Bangladesh.

BACKGROUND: Burkholderia pseudomallei possesses a diverse set of genes which encode a vast array of biological functions reflecting its clinical, ecological and phenotypic diversity. Strain variation is linked to geographic location as well as pattern of land uses. This soil-dwelling Gram-negative pathogen causes melioidosis, a tropical disease endemic in northern Australia and Southeast Asian regions including Bangladesh. Phylogeographic analyses of B. pseudomallei isolates by molecular typing techniques could be used to examine the diversity of this organism as well as to track melioidosis epidemics. METHODS: In this study, 22 B. pseudomallei isolates, of which 20 clinical and two soil isolates were analyzed, utilizing Real-time PCR assay and multilocus sequence typing (MLST). The sequences were then submitted to PubMLST database for analysis and construction of phylogenetic tree. FINDINGS: A total of 12 different sequence types (STs) that includes four novel STs were identified for the first time. Strains having STs 1005, 1007 and 56 were the most widespread STs frequently isolated in Bangladesh. ST 1005, ST 56, ST 1007 and ST 211 have been detected not only in Bangladesh but are also present in many Southeast Asian countries. SIGNIFICANCE: ST 1005 was detected in both soil and clinical samples of Gazipur. Most prevalent, ST 56 has been previously reported from Myanmar, Thailand, Cambodia and Vietnam, confirming the persistence of the genotype over the entire continent. Further large-scale study is necessary to find out the magnitude of the infection and its different reservoirs in the environment along with phylogeographic association.

Locally Acquired Melioidosis Linked to Environment - Mississippi, 2020-2023.

Melioidosis, caused by Burkholderia pseudomallei, is a rare but potentially fatal bacterial disease endemic to tropical and subtropical regions worldwide. It is typically acquired through contact with contaminated soil or fresh water. Before this investigation, B. pseudomallei was not known to have been isolated from the environment in the continental United States. Here, we report on three patients living in the same Mississippi Gulf Coast county who presented with melioidosis within a 3-year period. They were infected by the same Western Hemisphere B. pseudomallei strain that was discovered in three environmental samples collected from the property of one of the patients. These findings indicate local acquisition of melioidosis from the environment in the Mississippi Gulf Coast region.

Improving the clinical recognition, prognosis, and treatment of melioidosis through epidemiology and clinical findings: The Sabah perspective.

INTRODUCTION: Melioidosis is a deadly endemic disease in northern Australia and Southeast Asia, including Sabah, Malaysia, which is caused by the bacterium Burkholderia pseudomallei. It contributes to high fatality rates, mainly due to misdiagnosis leading to the wrong treatment being administered to the patients. Local epidemiology and data on clinical features could assist clinicians during diagnosis and treatment. However, these details are still scarce, particularly in Sabah. METHODS: A retrospective study of 246 culture-confirmed melioidosis cases in Queen Elizabeth Hospital, Sabah, Malaysia was performed between 2016 and 2018. The epidemiological data and clinical and laboratory findings were extracted and analysed. RESULTS: The annual incidence of culture-confirmed melioidosis cases was estimated to be 4.97 per 100,000 people. The mean age of the patients was 50±15 years. Males and members of the Kadazan-Dusun ethnic group accounted for the majority of the melioidosis cases. The odds ratio analysis indicated that bacteraemic melioidosis in this region was significantly associated with fever (76%), and patients having at least one underlying illness (43%), including diabetes mellitus (32%). Sixty-eight patients (28%) succumbed to melioidosis. Contrary to what is known regarding factors that promote bacteraemic melioidosis, neither patients with fever nor patients with at least one comorbid disease, including diabetes mellitus, were significantly associated with death from melioidosis. There was no statistically significant difference between patients without comorbidities (24, 27%) and those with at least one comorbid disease (26, 25%), including diabetes mellitus (18, 23%). The odds ratios indicate that melioidosis mortality in this region is related to patients showing respiratory organ-associated symptoms (29%), bacteraemia (30%), and septic shock (47%). Burkholderia pseudomallei isolates in this study were highly susceptible to ceftazidime (100%), imipenem (100%), and trimethoprim-sulfamethoxazole (98%). CONCLUSIONS: Information obtained from this study can be used by clinicians to recognise individuals with the highest risk of acquiring melioidosis, estimate an accurate prognosis, and provide effective treatment for melioidosis patients to reduce death from melioidosis.

Clinical Manifestations and Genomic Evaluation of Melioidosis Outbreak among Children after Sporting Event, Australia.

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.

Melioidosis Queensland: An analysis of clinical outcomes and genomic factors.

BACKGROUND: The clinical and genomic epidemiology of melioidosis varies across regions. AIM: To describe the clinical and genetic diversity of B. pseudomallei across Queensland, Australia. METHODS: Whole genome sequencing of clinical isolates stored at the melioidosis reference lab from 1996-2020 was performed and analysed in conjunction with available clinical data. RESULTS: Isolates from 292 patients were analysed. Bacteraemia was present in 71% and pneumonia in 65%. The case-fatality rate was 25%. Novel sequence types (ST) accounted for 51% of all isolates. No association was identified between the variable virulence factors assessed and patient outcome. Over time, the proportion of First Nation's patients declined from 59% to 26%, and the proportion of patients aged >70 years rose from 13% to 38%. CONCLUSION: This study describes a genomically diverse and comparatively distinct collection of B. pseudomallei clinical isolates from across Queensland, Australia. An increasing incidence of melioidosis in elderly patients may be an important factor in the persistently high case-fatality in this region and warrants further investigation and directed intervention.

The public health significance of finding autochthonous melioidosis cases in the continental United States.

Recently, the pathogen that causes melioidosis, Burkholderia pseudomallei, was found in the Gulf Coast region of Mississippi, United States of America, associated with human cases and as bacteria in the soil of affected areas. Therefore, the Centers for Disease Control and Prevention has declared the pathogen as endemic in the continental United States for the first time. This viewpoint discusses some issues that the research, public health communities, and government agencies need to address.

Cutaneous melioidosis: An updated review and primer for the dermatologist.

Melioidosis is an emerging infection with increasing endemic foci and global distribution. It is underrecognized and underdiagnosed because of factors including limited awareness of the disease, nonspecific clinical presentation, lack of diagnostic facilities in some locations, misidentification in laboratories inexperienced with culture, and identification of Burkholderia pseudomallei. Cutaneous findings are reported in approximately 10% to 20% of melioidosis cases and dermatologists may play a significant role in its recognition and management. The most dynamic situation of melioidosis recognition and/or expansion currently is in the United States. Global modeling had predicted that B. pseudomallei were potentially endemic in the southern United States and endemicity with local cases of melioidosis was confirmed in 2022. With the distribution and prevalence of melioidosis increasing globally and with this recent recognition that melioidosis is now endemic in the southern United States, it is important for dermatologists to maintain high clinical suspicion in appropriate patients and be familiar with its diagnosis and treatment. Here we review the available literature on cutaneous melioidosis to evaluate its epidemiology, etiology, pathophysiology and clinical presentation and provide guidance for diagnosis and management in dermatology practice.

Spatiotemporal distribution and geostatistically interpolated mapping of the melioidosis risk in an endemic zone in Thailand.

Melioidosis, a bacterial, infectious disease contracted from contaminated soil or water, is a public health problem identified in tropical regions and endemic several regions of Thailand. Surveillance and prevention are important for determining its distribution patterns and mapping its risk, which have been analysed in the present study. Case reports in Thailand were collected from 1 January 2016 to 31 December 2020. Spatial autocorrelation was analyzed using Moran's I and univariate local Moran's I. Spatial point data of melioidosis incidence were calculated, with riskmapping interpolation performed by Kriging. It was highest in 2016, at 32.37 cases per 100,000 people, and lowest in 2020, at 10.83 cases per 100,000 people. General observations revealed that its incidence decreased slightly from 2016 to 2018 and drastically in 2019 and 2020. The Moran's I values for melioidosis incidence exhibited a random spatial pattern in 2016 and clustered distribution from 2017 to 2020. The risk and variance maps show interval values. These findings may contribute to the monitoring and surveillance of melioidosis outbreaks.

The effect of climate on melioidosis incidence in Townsville, Australia: a dry tropical region.

BACKGROUND: Townsville is in the dry tropics in Northern Australia and an endemic region for melioidosis. Melioidosis is an infectious disease caused by Burkholderia pseudomallei, a soil dwelling organism. The incidence of melioidosis is associated with high levels of rainfall and has been linked to multiple weather variables in other melioidosis endemic regions such as in Darwin. In contrast to Townsville, Darwin is in the wet-dry tropics in Northern Australia and receives 40% more rainfall. We assessed the relationship between melioidosis incidence and weather conditions in Townsville and compared the patterns to the findings in Darwin and other melioidosis endemic regions. METHOD: Performing a time series analysis from 1996 to 2020, we applied a negative binomial regression model to evaluate the link between the incidence of melioidosis in Townsville and various weather variables. Akaike's information criterion was used to assess the most parsimonious model with best predictive performance. Fourier terms and lagged deviance residuals were included to control long term seasonal trends and temporal autocorrelation. RESULTS: Humidity is the strongest predictor for melioidosis incidence in Townsville. Furthermore, the incidence of melioidosis showed a three-times rise in the Townsville region when >200 mm of rain fell within the fortnight. Prolonged rainfall had more impact than a heavy downpour on the overall melioidosis incident rate. There was no statistically significant increase in incidence with cloud cover in the multivariable model. CONCLUSION: Consistent with other reports, melioidosis incidence can be attributed to humidity and rainfall in Townsville. In contrast to Darwin, there was no strong link between melioidosis cases and cloud cover and nor single large rainfall events.

Expanding the Geographic Boundaries of Melioidosis in Queensland, Australia.

Melioidosis is an infectious disease caused by the bacterium Burkholderia pseudomallei. Although this environmental organism is endemic in certain regions of Australia, it is not considered endemic in Southern Queensland, where the last case was reported 21 years ago. We report a climate change-associated outbreak of melioidosis occurring during two La Niña events in a region previously considered nonendemic for B. pseudomallei. During a 15-month period, 14 cases of locally acquired melioidosis were identified. Twelve patients were adults (> 50 years), with diabetes mellitus the most common risk factor in 6 of 12 patients (50%). Eleven patients (79%) had direct exposure to floodwaters or the flooded environment. This study suggests an association between climate change and an increased incidence of melioidosis. In addition, this is the first report of environmental sampling and whole-genome analysis to prove endemicity and local acquisition in this region.