Shiga toxin‐producing Escherichia coli and atypical enteropathogenic Escherichia coli strains isolated from healthy sheep of different populations in São Paulo, Brazil

Aims: Sheep are important carriers of Shiga toxin‐producing Escherichia coli (STEC) in several countries. However, there are a few reports about ovine STEC in American continent. Methods and Results: About 86 E. coli strains previously isolated from 172 healthy sheep from different farms were studied. PCR was used for detection of stx1, stx2, eae, ehxA and saa genes and for the identification of intimin subtypes. Restriction fragment length polymorphism (RFLP)–PCR was performed to investigate the variants of stx1 and stx2, and the flagellar antigen (fliC) genes in nonmotile isolates. Five isolates were eae+ and stx−, and belonged to serotypes O128:H2/β‐intimin (2), O145:H2/γ, O153:H7/β and O178:H7/ε. Eighty‐one STEC isolates were recovered, and the stx genotypes identified were stx1cstx2d‐O118 (46·9%), stx1c (27·2%), stx2d‐O118 (23·4%), and stx1cstx2dOX3a (2·5%). Pulsed‐field gel electrophoresis (PFGE) revealed 27 profiles among 53 STEC and atypical enteropathogenic Escherichia coli (EPEC) isolates. Conclusions: This study demonstrated that healthy sheep in São Paulo, Brazil, can be carriers of potential human pathogenic STEC and atypical EPEC. Significance and Impact of the Study: As some of the STEC serotypes presently found have been involved with haemolytic uraemic syndrome (HUS) in other countries, the important role of sheep as sources of STEC infection in our settings should not be disregarded.