BioMed Central Page 1 of 6 (page number not for citation purposes) BMC Research Notes Open Access Short Report Survival of Burkholderia pseudomallei in Water Richard A Moore 1 , Apichai Tuanyok 2 and Donald E Woods* 1 Address: 1 Department of Microbiology and Infectious Diseases, Faculty of Medicine, University of Calgary Health Sciences Centre, Calgary, Alberta, T2N 4N1, Canada and 2 Microbial Genetics and Genomics Center, Northern Arizona University, Flagstaff, Arizona, 86011, USA Email: Richard A Moore - rmoore@ucalgary.ca; Apichai Tuanyok - Apichai.Tuanyok@NAU.EDU; Donald E Woods* - woods@ucalgary.ca * Corresponding author Abstract Background: The ability of Burkholderia pseudomallei to survive in water likely contributes to its environmental persistence in endemic regions. To determine the physiological adaptations which allow B. pseudomallei to survive in aqueous environments, we performed microarray analyses of B. pseudomallei cultures transferred from Luria broth (LB) to distilled water. Findings: Increased expression of a gene encoding for a putative membrane protein (BPSL0721) was confirmed using a lux-based transcriptional reporter system, and maximal expression was noted at approximately 6 hrs after shifting cells from LB to water. A BPSL0721 deficient mutant of B. pseudomallei was able to survive in water for at least 90 days indicating that although involved, BPSL0721 was not essential for survival. BPSL2961, a gene encoding a putative phosphatidylglycerol phosphatase (PGP), was also induced when cells were shifted to water. This gene is likely involved in cell membrane biosynthesis. We were unable to construct a PGP mutant suggesting that the gene is not only involved in survival in water but is essential for cell viability. We also examined mutants of polyhydroxybutyrate synthase (phbC), lipopolysaccharide (LPS) oligosaccharide and capsule synthesis, and these mutations did not affect survival in water. LPS mutants lacking outer core were found to lose viability in water by 200 days indicating that an intact LPS core provides an outer membrane architecture which allows prolonged survival in water. Conclusion: The results from these studies suggest that B. pseudomallei survival in water is a complex process that requires an LPS molecule which contains an intact core region. Background Burkholderia pseudomallei is the causative agent of melio- idosis, a disease endemic to southeast Asia, northern Aus- tralia and temperate areas that lie near the equator[1]. The disease is classified by acute, subacute and chronic ill- nesses and often mistaken for malaria, plague, pneumo- nia and miliary tuberculosis [2]. The acute form of the disease is a septicemic illness and is often fatal despite antibiotic treatment. Subacute meliodosis often results in multi-organ involvement, systemic abscess formation and bacteremia [3]. Chronic meliodosis often is detected only after post mortem examination or by activation of other forms of the disease as a result of a traumatic event [4]. Infection most likely occurs as a result of aspiration, inha- lation or by exposure to contaminated soil or water [5,6]. B. pseudomallei is able to survive in soils in endemic areas however recovery is dependent upon moisture content [7]. Previous studies have demonstrated the ability of B. pseudomallei to survive in double distilled water for 3 years Published: 7 May 2008 BMC Research Notes 2008, 1:11 doi:10.1186/1756-0500-1-11 Received: 14 March 2008 Accepted: 7 May 2008 This article is available from: http://www.biomedcentral.com/1756-0500/1/11 © 2008 Moore et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.