Role of toxigenic and invasive bacteria in acute diarrhea of childhood.

The cause of pediatric diarrhea in Brazil was investigated with use of assays for toxigenic and invasive bacteria. Potential etiologic agents were identified in 31 of 40 consecutive children with diarrhea: toxigenic Escherichia coli or klebsiella in 20 patients (50 per cent); invasive Esch, coli or salmonella in four (10 per cent), and both toxigenic and invasive organisms in seven (18 per cent). Fecal leukocytes were present in nine of the 11 patients (82 per cent) with invasive pathogens. All 27 patients with toxigenic isolates had organisms that produced heat-labile cholera-like toxin; three patients had Esch. coli that also produced a heat-stable toxin. Among 20 controls without diarrhea there were no organisms that produced heat-labile toxin or tissue invasion, but there was one Esch. coli that produced only heat-stable toxin and one salmonella. In this pediatric population Esch. coli appears to cause most acute diarrheas due to toxigenic and invasive pathogenic mechanisms.