Some Bacteriological and Molecular Studies on ESCHERICHIA COLI as Causative Agent of Calves Enteritis at Damietta Governorate

The present study carried out to evaluate the presence of diarrheagenic Escherichia as causes of diarrhea in young calves in Damietta governorate during period from November 2015 to March 2016. Bacteriological examination was done on a total of (100) fecal samples collected from young diarrhoeic calves of average age of 2 to 21 days to detect the prevalence of E. coli . The samples were grouped according to the age of the calves into 3 age groups as follows: 1 st age group (2-7 dayes), 2 nd age group (8-14 dayes) and 3 rd group (15-21 dayes). The results revealed isolation of 27 strains of E. coli (27%). Serotyping of the isolated strains according to somatic (O) and flagellar (H) antigens detected the presence of 6 entertoxigenic E. coli (ETEC; 22.22%); 13 enterohemorrhagic E. coli (EHEC; 48.15%); 5 enteropathogenic E. coli (EPEC; 18.52%) and 3 enterinvasive E. coli (EIEC; 11.11%). Application of PCR for the detection of E. coli virulence genes including; two Shiga toxins: (Stx1; 88.89%), (Stx2; 51.85%), produced from Shiga toxin producing E. coli (STEC); intimin (eaeA; 29.63%) and hylA (59.26%) genes was done. Each isolate was found to carry one or more virulence genes. Mixed E. coli infection is strongly associated with the cases of diarrhea due to the presence of several virulence genes in some isolates. Diarrheic calves were found in high prevalence in the 1st age group (43%) whereas was found in prevalence in the 2 nd group (33%) and in 3 rd group (24%) . Antibiogram study revealed that the isolated E. coli strains were highly sensitive to Ciprofloxacin and Cefotaxime, moderately sensitive to Gentamicin and resistance to Nalidixic acid and Erythromycine. The present study suggests the importance of maintain strict hygienic measures to prevent spreading any pathogens to healthy calves.