title: Sensitive and specific molecular detection of Burkholderia pseudomallei, the causative agent of melioidosis, in the soil of tropical northern Australia.
abstract: Burkholderia pseudomallei, the cause of the severe disease melioidosis in humans and animals, is a gram-negative saprophyte living in soil and water of areas of endemicity such as tropical northern Australia and Southeast Asia. Infection occurs mainly by contact with wet contaminated soil. The environmental distribution of B. pseudomallei in northern Australia is still unclear. We developed and evaluated a direct soil B. pseudomallei DNA detection method based on the recently published real-time PCR targeting the B. pseudomallei type III secretion system. The method was evaluated by inoculating different soil types with B. pseudomallei dilution series and by comparing B. pseudomallei detection rate with culture-based detection rate for 104 randomly collected soil samples from the Darwin rural area in northern Australia. We found that direct soil B. pseudomallei DNA detection not only was substantially faster than culture but also proved to be more sensitive with no evident false-positive results. This assay provides a new tool to detect B. pseudomallei in soil samples in a fast and highly sensitive and specific manner and is applicable for large-scale B. pseudomallei environmental screening studies or in outbreak situations. Furthermore, analysis of the 104 collected soil samples revealed a significant association between B. pseudomallei-positive sites and the presence of animals at these locations and also with moist, reddish brown-to-reddish gray soils.
authors.affiliation: Tropical and Emerging Infectious Diseases Division, Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, Northern Territory 0811, Australia.
authors.forename: Mirjam
authors.initials: M
authors.lastname: Kaestli
authors.forename: Mark
authors.initials: M
authors.lastname: Mayo
authors.forename: Glenda
authors.initials: G
authors.lastname: Harrington
authors.forename: Felicity
authors.initials: F
authors.lastname: Watt
authors.forename: Jason
authors.initials: J
authors.lastname: Hill
authors.forename: Daniel
authors.initials: D
authors.lastname: Gal
authors.forename: Bart J
authors.initials: BJ
authors.lastname: Currie
mesh_terms: D001315:Australia / Q000453:epidemiology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015373:Bacterial Typing Techniques; D016957:Burkholderia pseudomallei / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D006801:Humans; D008554:Melioidosis / Q000382:microbiology*; D021381:Protein Transport / Q000235:genetics; D012680:Sensitivity and Specificity; D012988:Soil Microbiology
chemical_list: D001426:Bacterial Proteins