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Abstract :
[en] Escherichia coli producing the attaching-effacing (AE) lesion are called enteropathogenic E. coli (EPEC) and are responsible for diarrhoea in animals and humans. EPEC are subdivided into typical (t) EPEC producing the “Bundle Forming Pili” type 4 fimbriae and isolated from humans, and atypical (a) EPEC not producing the BFP and isolated from humans and animals, including diarrheic young calves and healthy adult cattle. tEPEC and several aEPEC belong to specific serotypes, but different aEPEC can also belong to classical Shigatoxigenic E. coli (STEC) O serotypes (O26, O103, O111, O121, O145, O157, O165) and derive from STEC after loss of genes encoding the Shiga toxins. In 2014 several hundreds of EPEC from healthy cattle at two slaughterhouses in Wallonia, but the prevalence of the classical STEC O serotypes was low and all were negative for the recently described O80 EPEC serotype. The aim of this study was to identify 6 other unconventional O serotypes (O123/186, O146, O156, O177, O182, O183) recently identified by PCR in different bovine aEPEC and STEC by one of us, amongst 312 EPEC isolated at slaughterhouse that previously tested negative, applying two triplex PCRs either for the O146_O182_O183 or for the O123/186_O156_O177 serotypes. So far the first triplex PCR identified 1 O146-positive and 8 O182-positive EPEC. The second triplex PCR identified 30 O156. The further steps of this study are: (i) the identification of still other unconventional serogroups among EPEC (ii) the identification of their H antigen-encoding genes; (iii) the comparison of these bovine EPEC between themselves, with EPEC from diarrheic calves and with STEC from cattle and humans belonging to the same serotypes.
