Aeromonas intestinal infections in the United States.

To evaluate the clinical and epidemiologic aspects of aeromonas enteritis, we studied the cases of 34 persons nationwide from whom Aeromonas hydrophila had been isolated in large numbers from stool in 1984. Compared with 68 control subjects, these patients were more likely to have drunk untreated water, usually from private wells (odds ratio = 20.9; p less than 0.01). Eighteen of the isolates belonged to a single DNA-relatedness group of the eight described for Aeromonas species, but no clear correlation between illnesses in patients and any tested genotypic or phenotypic characteristic of recovered organisms was found. Gastrointestinal complaints tended to be chronic in infected adults and acute and severe in children. Nine patients had become ill after taking antimicrobial agents to which recovered Aeromonas species were resistant; 5 persons took antimicrobials to which their Aeromonas strains were susceptible and had alleviation or resolution of their gastrointestinal symptoms. These findings indicate that at least some Aeromonas strains are enteropathogenic for the normal host and that these organisms are acquired by drinking untreated water.