Genetic diversity, determinants, and dissemination of Burkholderia pseudomallei lineages implicated in melioidosis in Northeast Thailand.

Melioidosis is an often-fatal neglected tropical disease caused by an environmental bacterium Burkholderia pseudomallei. However, our understanding of the disease-causing bacterial lineages, their dissemination, and adaptive mechanisms remains limited. To address this, we conduct a comprehensive genomic analysis of 1,391 B. pseudomallei isolates collected from nine hospitals in northeast Thailand between 2015 and 2018, and contemporaneous isolates from neighbouring countries, representing the most densely sampled collection to date. Our study identifies three dominant lineages, each with unique gene sets potentially enhancing bacterial fitness in the environment. We find that recombination drives lineage-specific gene flow. Transcriptome analyses of representative clinical isolates from each dominant lineage reveal increased expression of lineage-specific genes under environmental conditions in two out of three lineages. This underscores the potential importance of environmental persistence for these dominant lineages. The study also highlights the influence of environmental factors such as terrain slope, altitude, and river direction on the geographical dispersal of B. pseudomallei. Collectively, our findings suggest that environmental persistence may play a role in facilitating the spread of B. pseudomallei, and as a prerequisite for exposure and infection, thereby providing useful insights for informing melioidosis prevention and control strategies.

Tracking melioidosis in Iran: Utilizing abattoir-based surveillance as a One Health approach.

BACKGROUND: Burkholderia pseudomallei, an environmental saprophyte bacterium, causes melioidosis in humans and animals. It was first discovered in Iran between 1967 and 1976 in small ruminants, equines, environments and humans. No subsequent studies have been conducted to determine the existence and prevalence of this pathogen in the country. OBJECTIVES: The present study aims to monitor the presence of B. pseudomallei in the ruminant population of the Golestan province of Iran, which largely depends on pastures. The ruminants can serve as sentinels to indicate the presence of the bacteria in the environment and its potential impact on human health in the One Health triad. METHODS: Liver and lung abscesses from domestic sheep, cattle and goats in three industrial and three conventional slaughterhouses were sampled and analysed using 23S ribosomal DNA polymerase chain reaction (rDNA PCR) with primers CVMP 23-1 and CVP-23-2 for B. pseudomallei, Burkholderia cepacia and Burkholderia vietnamiensis, as well as B. pseudomallei-specific TTS1 real-time PCR, along with microbiological and biochemical assays. RESULTS: Out of the 97 animals sampled, only 14 (15%) tested positive for 23S rDNA PCR. However, the follow-up evaluation using TTS1 real-time PCR and microbiological and biochemical assays did not confirm the presence of B. pseudomallei in the samples. CONCLUSIONS: Although B. pseudomallei was not detected in the current survey, conducting abattoir-based surveillance of ruminants is a cost-effective One Health approach to monitor pathogenic Burkholderia. Developing standards of clinical and laboratory good practices for Burkholderia infections is crucial for One Health surveillance.

Melioidosis and Activation from Latency: The "Time Bomb" Has Not Occurred.

Burkholderia pseudomallei, the causative agent of melioidosis has long been considered able to exist in a latent form. Seropositivity among U.S. soldiers returning from the Vietnam conflict led to melioidosis being dubbed "the Vietnamese time bomb." Cases assigned to "(re)activation from latency" over 30 years of the Darwin Prospective Melioidosis Study (DPMS) were reviewed and reassessed and additional cases from DPMS years 31-34 were added. Historical reports of melioidosis attributed to activation from latency were reviewed. Some earlier DPMS cases and most historical cases described as activation from latency more accurately reflect undiagnosed chronic melioidosis, often with relapsing-remitting courses, rather than truly latent, asymptomatic infection. Such protracted disease should now be diagnosable much earlier, provided melioidosis is considered and laboratory facilities are available. The longest plausible duration of asymptomatic latency remains 29 years. In conclusion, activation from latency is a rare event in melioidosis, accounting in our analysis for under 3% of DPMS cases, consistent with why the Vietnamese time bomb never eventuated.

Exploring the Relationship between Melioidosis Morbidity Rate and Local Environmental Indicators Using Remotely Sensed Data.

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.

Epidemiology and genetic diversity of Burkholderia pseudomallei from Riau Province, Indonesia.

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.

Understanding The Mimicker: Epidemiological Pattern and Determinant of Melioidosis Mortality in Negeri Sembilan, Malaysia.

BACKGROUND: Melioidosis, a tropical infectious disease caused by Burkholderia pseudomallei, is epidemic in most region in Southeast Asia with high case fatality. However, there is scanty information regarding the disease's epidemiological pattern, demographics, and underlying risk factors. METHOD: This 5-year retrospective study of 185 confirmed cases which were taken from the Negeri Sembilan Melioidosis Registry between 2018 and 2022. We aim to describe the incidence, mortality rate, case fatality, relationship with meteorology, and factors that influence mortality in this central region of Peninsular Malaysia. RESULTS: Incidence rate (IR) of melioidosis in Negeri Sembilan is varied at 1.9 to 5.1 with mean of 3.1 in 100,000 population per year. IR varied between districts in the state from zero to 22.01 in 100,000 population per year. Mortality rate were ranged from 0.17 to 0.74 cases with mean of 0.44 cases in 100,000 population per year. The case fatality rate of this state scattered from 8.70% to 16.67%. There were no significant linear associations between cases and deaths with monthly rainfall and humidity. The mean age of patients was 52.8 years, predominated with age around 41-60 years old. Males (77.8%) predominated, and the majority of cases were Malays (88.9%) and had exposed to soil related activities (74.6%). Mortality from melioidosis was more likely in Bumiputera and non-Malaysians (p<0.05). Patients who had at least one comorbidity were at a higher risk of death from melioidosis (p<0.05). Diabetes mellitus was found in 41.1% of all identified cases, making it a major underlying risk factor for both developing and dying from melioidosis (aOR:19.32, 95%CI:1.91-195.59, p<0.05). Hypertension and mortality status in melioidosis are also significantly correlated (aOR: 7.75, 95% CI: 2.26-26.61, p<0.05). CONCLUSION: The epidemiological patterns of cases reported from Negeri Sembilan are consistent for the most part from previous studies in other states in Malaysia and global with regard to its incidence, case fatality, demographic and predisposing chronic diseases. Diabetes mellitus and hypertension were significantly linked to increased mortality among all determinants.

Genome sequence of two novel virulent clinical strains of Burkholderia pseudomallei isolated from acute melioidosis cases imported to Israel from India and Thailand.

OBJECTIVE: Burkholderia pseudomallei, the etiological cause of melioidosis, is a soil saprophyte endemic in South-East Asia, where it constitutes a public health concern of high-priority. Melioidosis cases are sporadically identified in nonendemic areas, usually associated with travelers or import of goods from endemic regions. Due to extensive intercontinental traveling and the anticipated climate change-associated alterations of the soil bacterial flora, there is an increasing concern for inadvertent establishment of novel endemic areas, which may expand the global burden of melioidosis. Rapid diagnosis, isolation and characterization of B. pseudomallei isolates is therefore of utmost importance particularly in non-endemic locations. DATA DESCRIPTION: We report the genome sequences of two novel clinical isolates (MWH2021 and MST2022) of B. pseudomallei identified in distinct acute cases of melioidosis diagnosed in two individuals arriving to Israel from India and Thailand, respectively. The data includes preliminary genetic analysis of the genomes determining their phylogenetic classification in rapport to the genomes of 131 B. pseudomallei strains documented in the NCBI database. Inspection of the genomic data revealed the presence or absence of loci encoding for several documented virulence determinants involved in the molecular pathogenesis of melioidosis. Virulence analysis in murine models of acute or chronic melioidosis established that both strains belong to the highly virulent class of B. pseudomalleii.

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.

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.

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.

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.

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.

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.

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.

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.