Melioidosis Caused by Burkholderia pseudomallei in Drinking Water, Thailand, 2012

Direk Limmathurotsakul

, Gumphol Wongsuvan, David Aanensen, Sujittra Ngamwilai, Natnaree Saiprom, Patpong Rongkard, Janjira Thaipadungpanit, Manas Kanoksil, Narisara Chantratita, Nicholas P.J. Day, and Sharon J. Peacock

Author affiliations: Mahidol University, Bangkok, Thailand (D. Limmathurotsakul, G. Wongsuvan, S. Ngamwilai, N. Saiprom, P. Rongkard, J. Thaipadungpanit, N. Chantratits, N.P.J. Day, S.J. Peacock); Imperial College London, London, UK (D. Aanensen);Sappasithiprasong Hospital, Ubon Ratchathani, Thailand (M. Kanoksil); Churchill Hospital, Oxford, UK (N.P.J. Day);Addenbrooke’s Hospital, Cambridge, UK (S.J. Peacock)

Abstract

We identified 10 patients in Thailand with culture-confirmed melioidosis who hadBurkholderia pseudomallei isolated from their drinking water. The multilocus sequence type ofB. pseudomallei from clinical specimens and water samples were identical for 2 patients. This finding suggests that drinking water is a preventable source of B. pseudomallei infection.

Burkholderia pseudomallei is a Tier 1 select agent and the cause of naturally acquired melioidosis in Southeast Asia, northern Australia, the Indian subcontinent, and areas of South America (1). The organism is present in soil and surface water, and most melioidosis cases are believed to result from bacterial inoculation or inhalation (1). Ingestion has been increasingly suspected to be an alternative route of infection. B. pseudomallei isolated from a community water supply in Australia was genetically identical to that causing disease in clusters (2,3), although no direct evidence was available to show that affected cases had consumed contaminated water. The pattern of infection after ingestion in an experimental model includes multiple organ dissemination and hepatosplenic abscesses, which are common features of human melioidosis and supportive evidence for ingestion as a route of human infection (4).

Our previous study in Ubon Ratchathani Province in northeastern Thailand investigated the activities of daily living associated with acquisition of melioidosis (5). Households of participants who resided ≤100 km of Sappasithiprasong Hospital in Ubon Ratchathani were visited, and water samples were collected from all sources of drinking water and from tap water (5). Culture of these samples for B. pseudomallei provided borderline statistical evidence to suggest that consuming water containing B. pseudomallei was associated with melioidosis (conditional odds ratio 2.2, 95% CI 0.8–5.8, p = 0.08) (5). We performed a study to further evaluate the role of ingestion as a route of infection, and we identified the genotypes of B. pseudomallei isolated from patients and the water supplies consumed by them.