Role of toxigenic and invasive bacteria in acute diarrhea of childhood

Abstract

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.

PIP: The etiological agents responsible for pediatric diarrhea in Brazil were investigated in 40 consecutive infants and children admitted with diarrhea (aged 9 days to 10 years), and in each case the illness was of fewer than 15 days duration. Assays for toxigenic and invasive bacteria were performed on stool samples. In 31 of the 40 children, potential etiological agents were identified: in 20 patients (50%) toxigenic E. coli or Klebsiella were found; in 4 patients invasive E. coli or Salmonella were found (10%); and in 7 patients, both toxigenic and invasive organisms were seen. In addition, fecal leukocytes were present in 9 of the 11 patients shown to have invasive pathogens. Heat-labile cholera-like toxin was produced by the organisms in all 27 patients with toxigenic isolates. 3 patients had E. coli which also produced a heat-stable toxin. 20 controls without diarrhea were also assayed and there were no organisms that produced heat-labile toxin or tissue invasion, although there was 1 E.coli that produced only heat-stable toxin and 1 salmonella. Hence, in this population E. coli seems to cause the most acute diarrheas attributed to toxigenic and invasive pathogenic mechanisms.