Distribution of tetracycline and trimethoprim/sulfamethoxazole resistance genes in aerobic bacteria isolated from cooked meat products in Guangzhou, China

The aim of this study was to investigate the antimicrobial resistance to tetracycline and trimethoprim/sulfamethoxazole and the prevalence of corresponding resistant genes of aerobic bacteria isolated from cooked meat products in Guangzhou. Among the 169 tested isolates, 55 (32.5%) exhibited resistance to tetracycline and 40 (23.7%) were resistant to trimethoprim/sulfamethoxazole. Among tetracycline resistance genes, tetM (14.2%) was found in the highest frequency followed by tetA (10.1%), tetS (5.9%), and tetB (2.9%). Among trimethoprim/sulfamethoxazole resistant genes, sulI (10.6%) was observed in the highest frequency which was twofold higher than sulII (5.3%). Multiple antimicrobial resistance genes were detected in 19 of 169 (11.2%) bacteria. One strain of Citrobacter freundii and one strain of Escherichia coli contained five antimicrobial resistance genes. The presence of resistance genes in isolates from cooked meats indicate that these bacteria may act as a reservoir of antimicrobial resistance genes and could play a role in the dissemination of resistant genes along the food chain.