Molecular Screening of Certain Virulence Encoding Genes Associated with E. coli Strains Isolated from Diarrheic Calves

Abstract

Calf diarrhea is main causes of mortality among neonatal calves in large-scale cattle operations. The disease syndrome usually associated with severe economic losses. Bacteria represent the common causes of diarrhea in calves. In this study, we are collected one hundred fecal samples from diarrheic mixed-sex neonatal calves aged 1-60 days located at El-Behera Governorate were examined the presence of E. coli by bacteriological tests and further screened for the presence of some virulence encoding genes. Results were showed that 95% were positive for E. coli. The isolates belonged to 9 different serogroups namely O1, O27, O126, O119, O158, O146, O25, O148, and O115. The confirmed isolates were further examining for the existence ofsome virulence encoding genes (stx1, stx2, eaeA, and hlyA). The results appeared that,stx1, stx2, eaeA, and hylA were successfully amplified in 66.6 %,41, 6 %,16.6 %, and 16.6% of the examined isolates, respectively. In conclusion; the comprehensive understanding of the virulence encoding determinants and the subcellular mechanism of E. coli pathogenesis will help develop accurate preventive and curative measures to decrease E. coli induced calf diarrhea in large-scale cattle farms.