Spectrum of extraintestinal disease due to Aeromonas species in tropical Queensland, Australia.

During a 12-month period, the clinical spectrum of extraintestinal disease due to Aeromonas species was determined for 56 patients in tropical Queensland (Australia). Forty-six patients acquired their infection in the community, six patients were infected in the hospital, and four patients were colonized. Demographic risk factors included male gender (67%) and Aboriginal ethnic background (35%). The disease ranged from deep-seated infection (four cases) to soft-tissue infection of varying intensity (48 cases). Among patients whose infections were community acquired, 22 required hospitalization and 27 suffered trauma-associated infection. Seventeen patients (63%) in the latter group had lacerations to the hands and feet that were contaminated with surface water or soil. The appearance of the wounds was not pathognomonic, and diagnosis was made by laboratory evaluation. Aeromonas was the sole pathogen in nine patients. Polymicrobial infections were due to Aeromonas and mainly Staphylococcus aureus and/or mixed enteric bacteria. Aeromonas hydrophila was the most common species isolated (71%), followed by Aeromonas sobria (25%). In nine cases, the empirical antibiotic regimen prescribed did not adequately cover infection due to Aeromonas. Infection was seen regularly throughout the year, but a cluster of cases also occurred during the tropical Australian wet season.