Prevalence of antimicrobial resistance and phylogroups among E. coli isolates from calves

The study aimed to assess the antimicrobial resistance profile and population structure of E. coli isolates from calves, focusing on possible public health impacts. N=97 E. coli isolates recovered from calf feacal samples were subjected to patho typing, antimicrobial resistance profiling, and phylo grouping. The results showed that 30.2% of the isolates were diarrheagenic patho types, with Shiga toxin-producing E. coli (STEC) being the predominant one (15.6%). The antibiogram revealed high resistance against β-lactam antibiotics, particularly ceftazidime (86.6%), ampicillin (59.8%), and imipenem (50.5%). 54.6% of the isolates exhibited multidrug resistance (MDR), and 39.2% produced extended-spectrum β-lactamase (ESBL). Phylotyping identified six distinct phylogroups, with B1 being the most predominant (69 isolates). The majority of pathotypic E. coli strains belonged to phylo group B1. These findings highlight the substantial AMR burden in E. coli isolates from calves and the need for enhanced surveillance and control measures to mitigate the spread of resistant strains in veterinary and human medicine.