Resumo

Diarrheal diseases remain as an important public health concern. Diarrhoeagenic Escherichia coli (DEC) is among the most important bacterial enteric pathogens, particularly EPEC in developing countries. Recent studies have also shown a clear declining in the incidence of EPEC strains in these countries. The aim of this study was evaluated the etiologic profile of acute diarrhoea in socioeconomically deprived children assisted at a regional paediatric emergency care service for three decades in São Paulo, Brazil. During two years of the 1980's, 1990's and 2000's, stool samples were collected from children. Cases consisted of children with acute diarrhoea, and controls of children without diarrhoea, the exclusion criteria were diarrhoea after 14 days and antibiotics until 15 days before collection. Stools of both groups were processed exactly the same way, logistically and methodologically. Faeces from cases and controls were collected upon the ER assistance and preserved in Cary-Blair medium until culture. The bacteria studied were DEC, Salmonella, Shigella, Y. enterocolitica and Campylobacter sp. The viral agents were surveyed rotavirus. In 1980's the major enteropathogens were Rotavirus (56%), Campylobacter sp (14%), typical EPEC (7%), Shigella (4%), and Salmonella (4%) while in 1990's the prevalence was 36%, 6%, 9%, 6,5 %, and 0,7%, respectively. EAEC in the latter study was investigated and was found in 5% of children with diarrhoea. Now, we are conducting a new study in the same hospital with the same socio-economic population. It is possible realize that the major enteropathogen was atypical EPEC (24%) while EAEC in 8 %. Rotavirus and Campylobacter sp, important pathogens in 1980's, the prevalence in the recently study were 18% and 3% respectively. All enteropathogens were associated with diarrhoea (p < 0.01). The availability of several epidemiologic studies suggests that the relative importance of different pathogens associated with diarrhea is changing in Brazil. In the 1980s, the major cause of diarrhea in infants was EPEC (ETEC, Shigella, and Salmonella were more common in older children. Now, EAEC and a-EPEC may be the most prevalent pathogens. Rotavirus has been decreasing, but is still a important enteropathogen. However, this hypothesis needs to be taken with caution because, in contrast to studies conducted 20 years ago, today, it is possible to identify the etiologic agent in most patients