Prevalence, species differentiation, and toxigenicity of Aeromonas strains in cases of childhood gastroenteritis and in controls.

In a 1-year period (January to December 1984), Aeromonas strains were isolated from feces of 21 of 561 (3.7%) children with gastroenteritis and from 12 of 576 (2.1%) children without intestinal disturbances (controls). The difference between the two isolation rates was not significant (X2 = 2.2; P greater than 0.05). In five cases of illness other intestinal pathogens were isolated together with Aeromonas in the same stool sample. A total of 39 Aeromonas strains were detected since in some cases aeromonads with different biochemical characteristics were obtained from the same stool sample. Of the 39 Aeromonas isolates, 6 strains (5 from patients) were Aeromonas hydrophila, 5 strains (3 from patients) were Aeromonas sobria, and 26 strains (18 from patients) were Aeromonas caviae; 2 strains isolated from controls did not ferment sucrose and were considered a distinct group of Aeromonas. We found no significant difference between the prevalence of each of these species from patients and the prevalence from controls. We found no significant difference in the prevalence of enterotoxin-producing strains (suckling mouse model), cytotoxin-producing strains (HEp-2 cell model), or hemolysin-producing strains (rabbit erythrocyte model) between patients and controls. In our geographical region there is no evidence that Aeromonas species are primary intestinal pathogens in children.