Abstract: In order to investigate the potential risk of retail chicken products in transmitting antibiotic resistance (AR) encoding genes, sulfamethoxazole/trimethoprim resistant (Sul/Trir) bacteria were isolated from 13 chicken products, including nine chicken meat samples and four giblet samples, purchased from five supermarkets and local markets. The Sul/Trir resistance genes were mapped by Southern blot analysis. Sul/Trir bacteria were detected in all chicken samples. The prevalence of Sul/Trir bacteria ranged from 2.0 × 102 CFU/g to 1.0 × 107 CFU/g, accounting for 1.42%–82.00% of the total cultivable bacteria. Multi-drug resistance was observed for all 297 Sul/Trir isolates, and the positive rates of AR genes including sul1, sul2, tetA, tetB, tetC, tetE, tetG, tetL, tetM and intI were 11.33%, 32.81%, 6.64%, 12.89%, 2.73%, 6.25%, 9.38%, 18.75%, 39.84% and 28.52% respectively. Escherichia sp., Pedobacter sp., Staphylococcus sp., Enterococcus sp., Sphingobacterium sp. and Acinetobacter sp. were identified as hosts for AR genes. The minimum inhibitory concentration (MIC) of Sul for most isolates was higher than 512 μg/mL. Furthermore, a plasmid harboring sul2 gene was found in one Sul/Trir isolate by Southern blot hybridization. In conclusion, retail chicken products can be a potential avenue transmitting antibiotic resistant bacteria and AR genes.

Key words: sulfamethoxazole/trimethoprim resistant bacteria, antibiotic resistance genes, chicken meat, giblets