PREVALENCE AND CLINICAL MANIFESTATIONS OF SHIGA TOXIN-PRODUCING ESCHERICHIA-COLI INFECTIONS IN AUSTRIAN CHILDREN

The prevalence and clinical manifestations of infections associated wi th Shiga toxin-producing Escherichia coli (STEC) among Austrian childr en were assessed. Stool samples from 280 pediatric patients were analy zed by enzyme immunoassay (EIA) for the presence of free fecal Shiga t oxin (Stx) 1 and 2, and by culture on sorbitol MacConkey agar. Specime ns testing positive by the EIA were subjected to a cytotoxicity assay, polymerase chain reaction analysis, and a colony hybridization test, Direct culture on MacConkey agar demonstrated the presence of three Es cherichia coli O157:H7-positive stools, These were also positive by EI A and by the DNA-based methods, An additional six samples were positiv e by EIA, and in four of these, non-O157 STEC of serotypes O111H(-), O 146:H-, and O113:H53 could be isolated. Analysis of stools for a varie ty of enteric pathogens demonstrated that STEC was the third most comm on bacterial pathogen, The clinical manifestations of STEC infections were difficult to distinguish from those of infections caused by other enteric pathogens, as most patients presented with watery diarrhea, T he median age of children with STEC infections was 27.6 months (range, 7 months to 5.75 years); children with Salmonella or Campylobacter in fections were younger on average, while those with Rotavirus infection s were older, This study demonstrated that although Escherichia coli O 157:H7 could be identified with the same sensitivity by both EIA or ag ar-based methods, the identification of non-O157 STEC strains was enha nced by the use of EIA followed by colony hybridization. Analysis of o vernight cultures from 53 STEC isolates revealed that all strains prod ucing Stx1, Stx2, or Stx2c reacted in the EIA. However, culture supern atants from Stx2e-producing Escherichia coli O101 were negative in the EIA. Despite this disadvantage, the EIA is easy to perform and time e fficient and can be recommended as a screening test for non-O157 STEC in children with diarrhea.