Molecular Identification of Virulence Factors of E. coli in Three Strains of ETEC, EHEC and EPEC in Calves and Lambs with Diarrhea in Shiraz

Pathogenic E.coli (ETEC, EHEC and EPEC) cause diarrhea in new born calves and lambs are important especially due to mortality rate and high economic losses. In this study 200 rectal swab samples were collected from 1-30 day-old calves and lambs with diarrhea during 2013-2014 in Shiraz. The samples were inoculated on Mac Conkey, EMB and Minca agar media. The presence of various virulence genes of ETEC (k99, F41 fimbria and Sta), EHEC (Stx1, Stx2 and eae) and EPEC (bfpb and eae) was investigated using multiplex PCR. The PCR test results showed that out of 133 E. coli isolates, 12.03% and 3% possessed all three virulence genes of ETEC and EHEC, respectively. The sequencing of K99 gene showed 97-100% homology between the isolates. The variety of ETEC, EPEC and EHEC prevalence has been reported in the world. These variations could be due to managing factors, calves age, colostrum intake and dam vaccination.