Burkholderia pseudomallei is a saprophytic bacterium which is the causative agent of melioidosis, a common cause of fatal bacterial pneumonia and sepsis in the tropics. The incidence of melioidosis is clustered spatially and temporally and is heavily linked to rainfall and extreme weather events. Clinical case clustering has recently been reported in Townsville, Australia, and has implicated Castle Hill, a granite monolith in the city center, as a potential reservoir of infection. Topsoil and water from seasonal groundwater seeps were collected around the base of Castle Hill and analyzed by quantitative real-time PCR targeting the type III secretion system genes for the presence of B. pseudomallei. The organism was identified in 65% (95% confidence interval [CI], 49.5 to 80.4) of soil samples (n = 40) and 92.5% (95% CI, 83.9 to 100) of seasonal groundwater samples (n = 40). Further sampling of water collected from roads and gutters in nearby residential areas after an intense rainfall event found that 88.2% (95% CI, 72.9 to 100) of samples (n = 16) contained viable B. pseudomallei at concentrations up to 113 CFU/ml. Comparison of isolates using multilocus sequence typing demonstrated clinical matches and close associations between environmental isolates and isolates derived from clinical samples from patients in Townsville. This study demonstrated that waterborne B. pseudomallei from groundwater seeps around Castle Hill may facilitate exposure to B. pseudomallei and contribute to the clinical clustering at this site. Access to this type of information will advise the development and implementation of public health measures to reduce the incidence of melioidosis.

Item Type:	Refereed Article
Keywords:	epidemiology, melioidosis, groundwater
Research Division:	Biological Sciences
Research Group:	Microbiology
Research Field:	Infectious Agents
Objective Division:	Health
Objective Group:	Public Health (excl. Specific Population Health)
Objective Field:	Disease Distribution and Transmission (incl. Surveillance and Response)
Author:	Baker, A (Dr Anthony Baker)
ID Code:	99304
Year Published:	2011
Web of Science® Times Cited:	19
Deposited By:	Tasmanian Institute of Agriculture
Deposited On:	2015-03-19
Last Modified:	2017-11-08
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