A case of human melioidosis originating in south-west Western Australia

To report the first human case of autochthonous melioidosis in temperate Australia (latitude 31 degrees 10'S) and to describe the extent of the presence of the causative agent, Pseudomonas pseudomallei, in southwest Western Australia.

A 45-year-old man living on a hobby farm was admitted to hospital for investigation of lung lesions, weight loss and low grade fevers. P. pseudomallei was cultured from material from an aspiration biopsy of a mediastinal mass.

The patient was successfully treated with a regimen of ceftazidime and trimethoprim-sulfamethoxazole. A review of epidemiological data showed that, since 1967, P. pseudomallei has been cultured from animals and soil in a region 50-250 km north-west of Perth, Western Australia, and that pockets of endemicity are found in the districts of Toodyay (where our patient's farm was), Chittering, Ballidu, Gidgegannup, Badgingarra, and Wongan Hills.

The persistence of the bacterium in animals and soil in south-west Western Australia demonstrates abundantly that P. pseudomallei can exist opportunely beyond its traditional tropical habitat. It is likely that there will be further clinical cases of melioidosis originating in this region, and that the boundaries of endemicity in Australia will expand further.