Presence and Antimicrobial Resistance of Escherichia Coli Isolated from Pork at Slaughterhouses in Selected Provinces of the Mekong Delta, Vietnam

Abstract; This study was conducted from August 2023 to August 2024 to evaluate the prevalence, antimicrobial resistance patterns, and distribution of resistance genes in Escherichia coli isolated from pork carcasses at slaughterhouses. A total of 96 pork carcass samples were collected from 16 slaughterhouses located in four provinces of the Mekong Delta, including Hau Giang, Kien Giang, Tra Vinh, and Ben Tre. The overall prevalence of E. coli was 30.21%. Antimicrobial susceptibility testing revealed high resistance rates to sulfamethoxazole/trimethoprim (81.43%), amoxicillin (57.14%), and ampicillin (48.57%). In contrast, resistance rates to amikacin, amoxicillin–clavulanic acid, cefaclor, cefuroxime, enrofloxacin, and ofloxacin were all below 10%. Multidrug resistance was observed in 80% of the isolates, with the most common resistance patterns involving resistance to three (22.86%) or four (21.43%) antibiotics. Notably, 4.29% of the isolates exhibited resistance to seven or eight antibiotics. PCR analysis revealed the presence of several antimicrobial resistance genes, including blaampC (42.86%), blaTEM (21.43%), blaCTX-M (4.29%), tetA (37.14%), qnrA (31.43%), sulII (30.00%), strA (27.14%), and cat1 (4.29%).