Conclusion
In conclusion, the results of this study display a high level of ESBL-producing and COL-resistance in E. coli of bovine mastitis, blaCTX-M-1 was the most common group, followed by blaCTX-M-9. The major carriers of the blaCTX-M-1 and blaCTX-M-9 were blaCTX-M-28 and blaCTX-M-14 alleles, respectively. The association of ESBL-producing E. coli with mcr-1 is of particular concern. Phylo-group A and phylogroup B1 of E. coli were the predominant, and virulence factors were observed in these isolates. MLST and PFGE fingerprinting enabled us to type and establishes clonal relatedness of ESBL-producing and mcr-1- positive E. coli isolates.