Etiologic profile of acute diarrhea in children in São Paulo

Abstract

OBJECTIVE: To evaluate the etiologic profile of acute diarrhea in socioeconomically deprived children assisted at a regional pediatric emergency care service. METHODS: During two years all children with acute diarrhea assisted at a previously established day and week time schedule were included in the study. Other selective criteria were: a) age less than 5 years; b) nonuse of antibiotics in the previous month; and c) no travel outside the city in the previous month. Stool examination was used for the detection of the following microorganisms: a) rotavirus (immunofluorescence and counterimmunoelectrophoresis); b) bacteria - culture in MacConkey agar, SS agar, Columbia agar, bright green, serotyping, detection of toxins - INV, LT,ST,SLT I, SLT II, Sereny test, detection of virulence factors- EAF, eae, BFP; and c) protozoa (Hoffman and Faust). In the same period, a control group without diarrhea was also evaluated for the same fecal pathogens. RESULTS: Between March 1994 and June 1996, 154 children with acute diarrhea (AD) and 42 control children (WAD), that is, without acute diarrhea, were selected. In the AD group, intestinal pathogens were detected in 112 (72.8%) cases, and in 9 (21.5%) cases in the WAD group. The association of two or more intestinal pathogens occurred in 47 (30.5%) cases in the AD group, and in 3 (7.1%) cases in the WAD group. The pathogens identified in the AD cases were: Rotavirus: 32 (20.8%), bacteria: 53 (34.4%), both: 25 (16.2%), and 2 (1.4%) with Giardia lamblia (in one case associated with Rotavirus and in another one associated with bacteria). In the WAD group, only bacteria were detected in 8 (19.1%) cases, and bacteria associated with Giardia lamblia in 1 (2.4%) case. Altogether, there were 105 bacteria isolated in the AD group: 90 were Escherichia coli (EPEC 27, DAEC 24, ETEC 21, EAEC 18), 12 were Shigella sp, 2 were Salmonella sp, and one was Yersinia sp. Children with mixed infections (viral and bacterial) had increased incidence of severe vomiting, dehydration and hospitalization. CONCLUSIONS: Bacteria were the most frequent pathogens detected in acute diarrhea cases, among which Escherichia coli was highly predominant. The majority of Escherichia coli strains belong to non-EPEC varieties, strains that are not routinely evaluated in clinical laboratories of pathology. Rotavirus was found in a great number of diarrhea cases, often associated with bacteria. Protozoa showed reduced importance.