title: Burkholderia pseudomallei in soil samples from an oceanarium in Hong Kong detected using a sensitive PCR assay.
abstract: Melioidosis, caused by Burkholderia pseudomallei, is an emerging infectious disease with an expanding geographical distribution. Although assessment of the environmental load of B. pseudomallei is important for risk assessment in humans or animals in endemic areas, traditional methods of bacterial culture for isolation have low sensitivities and are labor-intensive. Using a specific polymerase chain reaction (PCR) assay targeting a Tat domain protein in comparison with a bacterial culture method, we examined the prevalence of B. pseudomallei in soil samples from an oceanarium in Hong Kong where captive marine mammals and birds have contracted melioidosis. Among 1420 soil samples collected from various sites in the oceanarium over a 15-month period, B. pseudomallei was detected in nine (0.6%) soil samples using bacterial culture, whereas it was detected in 96 (6.8%) soil samples using the specific PCR assay confirmed by sequencing. The PCR-positive samples were detected during various months, with higher detection rates observed during summer months. Positive PCR detection was significantly correlated with ambient temperature (P<0.0001) and relative humidity (P=0.011) but not with daily rainfall (P=0.241) or a recent typhoon (P=0.787). PCR-positive samples were obtained from all sampling locations, with the highest detection rate in the valley. Our results suggest that B. pseudomallei is prevalent and endemic in the oceanarium. The present PCR assay is more sensitive than the bacterial culture method, and it may be used to help better assess the transmission of melioidosis and to design infection control measures for captive animals in this unique and understudied environment.
authors.affiliation: Department of Microbiology, The University of Hong Kong , Hong Kong, China ; Research Centre of Infection and Immunology, The University of Hong Kong , Hong Kong, China ; State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong , Hong Kong, China ; Carol Yu Center for Infection, The University of Hong Kong , Hong Kong, China.
authors.forename: Susanna Kp
authors.initials: SK
authors.lastname: Lau
authors.affiliation: Ocean Park Corporation, Hong Kong, China.
authors.forename: San-Yuen
authors.initials: SY
authors.lastname: Chan
authors.affiliation: Department of Microbiology, The University of Hong Kong , Hong Kong, China.
authors.forename: Shirly Ot
authors.initials: SO
authors.lastname: Curreem
authors.affiliation: Ocean Park Corporation, Hong Kong, China.
authors.forename: Suk-Wai
authors.initials: SW
authors.lastname: Hui
authors.affiliation: Department of Microbiology, The University of Hong Kong , Hong Kong, China.
authors.forename: Candy Cy
authors.initials: CC
authors.lastname: Lau
authors.affiliation: Ocean Park Corporation, Hong Kong, China.
authors.forename: Paul
authors.initials: P
authors.lastname: Lee
authors.affiliation: Department of Microbiology, The University of Hong Kong , Hong Kong, China.
authors.forename: Chi-Chun
authors.initials: CC
authors.lastname: Ho
authors.affiliation: Ocean Park Corporation, Hong Kong, China.
authors.forename: Paolo
authors.initials: P
authors.lastname: Martelli
authors.affiliation: Department of Microbiology, The University of Hong Kong , Hong Kong, China ; Research Centre of Infection and Immunology, The University of Hong Kong , Hong Kong, China ; State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong , Hong Kong, China ; Carol Yu Center for Infection, The University of Hong Kong , Hong Kong, China.
authors.forename: Patrick Cy
authors.initials: PC
authors.lastname: Woo
keywords: Burkholderia pseudomallei; PCR; culture; melioidosis; oceanarium; soil