Detection of virulence genes and multidrug resistance in Escherichia coli isolated from buffaloes

Objectives This study aimed to determine the prevalence, virulence genes, and antimicrobial resistance (AMR) profiles of E. coli isolated from buffalo feces. Methods A simple random sampling implemented for the collection of 430 feces from buffaloes. The samples were analyzed through conventional bacteriological and molecular techniques to isolate and identify E. coli . Phenotypic antimicrobial resistance of 14 antibiotics using the disc diffusion method and analyzed various AMR genes in the isolated E. coli . Results Out of 430 buffalo fecal samples, 298 isolates were confirmed as E. coli through PCR which is 69.3%, with significantly ( p < 0.05) higher in diarrheic animals (90.4%) compared to healthy ones (63.4%). Calves under one year exhibited the highest prevalence (75.5%). Shiga toxin genes, with stx1 detected in 29.19% and stx2 in 8.72% of the isolates. Antibiotic susceptibility testing showed widespread resistance to tetracycline (88.30%), amoxicillin (86.24%), ampicillin (76.34%), and gentamicin (68.60%). PCR screening confirmed tetA (86.24%), strA (69.12%), sul1 (54.69%), and aac(3)-IV (65.10%). Among ESBL genes, blaTEM was detected at higher rate (91.27%), while blaSHV (11.40%) and blaOXA (3.69%) were less frequent. Conclusions The high prevalence of multidrug resistance and virulence factors in E. coli from buffalo feces highlights the potential role as a reservoir of zoonotic and drug-resistant bacteria.