Antibiotic Resistance and Pathogenicity of Escherichia coli Isolated from Cattle Raised in Households in the Mekong Delta, Vietnam

Of 127 cattle feces samples collected in the Mekong Delta from March to June 2023, 121 samples were positive for E. coli (95.28%).In those surveyed households, there was no statistically significant difference in the prevalence of E. coli in cattle of different ages, dairy or beef.The antimicrobial susceptibility test indicated that those E. coli strains were susceptible to ceftazidime (87.27%), cefuroxime (89.09%), amikacin, and doxycycline (90.91%).However, E. coli strains were remarkably resistant to ampicillin (81.82%), streptomycin and tetracycline (74.55%), colistin and chloramphenicol (70.91%), amoxicillin/clav.acid(65.45%).Moreover, 63.64% of examined E. coli strains were resistant to one to twelve antibiotics, and the resistant pattern of Am + Ac + Co + Sm + Te + Cl accounted for the highest rate (16.36%).By PCR method, the presence of genes encoding antibiotic resistance was determined, in which the tetA gene had the highest presence (69.09%), and the lowest was the blaTEM gene (18.18%).Most E. coli (34.55%) strains harbored two to four antibiotic resistance genes, and the phenotypes of cat1 + sulII and sulII + tetA were the most common (5.45%).Using the PCR method to determine the presence of virulence genes, it was recorded that the tsh gene had the highest presence rate (54.55%), and the lowest was the fyuA gene (12.73%).Those E. coli strains (23.63%) could carry two to four virulence genes, and the most common pattern was astA + tsh (9.09%).Thus, the prevalence of pathogenic and antibiotic-resistant E. coli in cattle was critical to protect animal and human health.