The spectrum of Aeromonas-associated diarrhea in tropical Queensland, Australia.

During a twelve-month period (1 July 91-30 June 92), feces from 912 persons from the Townsville region in the dry tropics of Queensland, Australia were evaluated by culture and 45 (4.9%) immunocompetent patients were found to be carrying Aeromonas in their stools. All patients were index cases and no secondary cases from household or close contact of index cases were identified. Eight patients (9.3%) were from Palm Island, an Aboriginal community, and 37 (4.5%) were from the essentially Caucasian population of Townsville. This is a significant difference in incidence of cases between the two population groups. Infection occurred mainly in two age groups: the under five-year-old (27 cases) and the over 25-year-old age group (17 cases). Except for one patient, all cases of Palm Island Aborigines were children less than five years of age, and 13 of these infants (48%) were less than 1 year old, but none were neonates. Of the 37 Townsville patients, 20 cases (54%) were in the under five-year-old group. Signs and symptoms of Aeromonas-associated diarrhea in patients where Aeromonas was the sole pathogen isolated were diarrhea sometimes with vomiting, absence of fever and of fecal leukocytes and blood in the stools. No cases of Aeromonas-associated diarrhea with dysentery were encountered. After rotavirus (12.3%), Aeromonas was the second most common enteric pathogen detected, but was only marginally more common than Giardia and Salmonella. Of the aeromonad isolations, 50% were Aeromonas hydrophila, 22% were A. sobria, and 28% were A. caviae.(ABSTRACT TRUNCATED AT 250 WORDS)