Biochemical characteristics of clinical and environmental isolates of Burkholderia pseudomallei

Faculty of Tropical Medicine, Mahidol University, Rajvithi Road, Bangkok 10400, Thailand and Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford University, Oxford OX3 9DU * Public Health Laboratory, Derriford Hospital, Derriford Road, Plymouth PL6 8DH Laboratory of Hospital Infection, Central Public Health Laboratory, Colindale Avenue, London NW9 5HT Received January 25, 1996 Accepted March 26, 1996 The biochemical characteristics of 213 isolates of Burkholderia pseudomallei from patients with melioidosis and 140 isolates from the soil in central and northeastern Thailand were compared. Whereas the biochemical profiles of all the clinical isolates were similar, all soil isolates from the central area and 25% of isolates from northeastern Thailand comprised a different phenotype. This was characterised by the ability to assimilate L-arabinose (100%), adonitol (100%), 5-keto-gluconate (90%) and D-xylose (84%), but failure to assimilate dulcitol (0%), erythritol (0%) and trehalose (10%). Compared with clinical isolates, these organisms had similar antibiotic susceptibility profiles and were also recognised by a specific polyclonal antibody against B. pseudomallei . As melioidosis is rare in central Thailand, but common in the northeast, this raises the possibility that this biochemical phenotype may be less virulent, or may even represent a different species.