Antimicrobial determinants of multidrug resistant Escherichia coli serotypes isolated from diarrheic calves

Calf diarrhea is one of the most important devastating enteric problems that threats the bovine industry worldwide. Pathogenic Escherichia coli (E. coli) is considered the most problematic etiology. Therefore this study was conducted to investigate the antibiogram pattern and antibiotics resistance genes of E. coli strains isolated from calf diarrhea. Sixteen (21.33%) E. coli strains were isolated from 75 diarrheic calves and serotyping revealed that O26 and O157 were the most common serotypes (25%) and (18.75%), respectively. The results antibiogram profile indicated that all isolates found to be resistant to multiclass of antimicrobial groups. All isolates exhibit resistance to streptomycin and cefaclor 100%, amoxycilline 81.25%, sulpha/trimethoprim 62.5%, gentamycin 56.25%, cefotaxime 50%. Meanwhile high susceptible to chloramphenicol, enrofloxacin and cefotaxime was recorded. In the same context, blaTEM, tetA, aadA2, sul1 and drfA were the most frequently detected antibiotic resistance genes. In conclusion, our findings revealed that E. coli is considered one of the important bacterial etiology causing diarrhea in newborn calves. In addition to, most of E.coli serotypes express high resistance to multi- groups of antimicrobials in phenotypic and genotypic profile. Our results suggested a relationship between the phenotypic and antimicrobial resistance genes which could contribute the emerging and evolution of antibiotics resistance pattern by E.coli strains that complicated the control of such organism.