Potential influence of food value chain level of regulation on prevalence and patterns of antimicrobial resistance: case of tilapia (Oreochromis niloticus).

The current study was designed to evaluate the potential impact of the level of regulation on the prevalence and patterns of antimicrobial agent resistance in bacteria isolated from fish. The study sites included two large lakes and both semi-regulated and unregulated fish value chains. A total of 328 bacterial isolates belonging to 11 genera were evaluated for antimicrobial susceptibility testing using disk diffusion method. The bacteria species were tested against 12 different antibiotics (trimethoprim-sulfamethoxazole, tetracycline, ampicillin, cefotaxime, chloramphenicol, nalidixic acid, amoxicillin, meropenem, ciprofloxacin, nitrofurantoin, cefuroxime and kanamycin). Data analysis was done to assess the heterogeneity in proportion of resistant bacterial species within and between the two value chains using a random-effects model proposed by DerSimonian and Laird. Statistical heterogeneity within and between groups were estimated using the Cochran Chi-square test and the Cochrane-I2. Overall proportion of bacterial species resistant to antimicrobial agents in semi-regulated and unregulated value chains ranged from 0.00 to 0.88 and 0.09 to 0.95, respectively. Shigella spp. had the highest proportion of bacteria that were resistant against most of the antimicrobial agents used. The bacterial species were highly resistant to ampicillin and amoxicillin and the highest multi-drug resistance capacity was observed in Shigella spp. (18.3%, n = 328), Vibrio spp. (18.3%) and L. monocytogenes (12.2%). We observed strong heterogeneity within and between the two value chains regarding proportion of resistant bacterial species. Sun dried fish in both value chains had significantly high proportion of resistant bacterial species. Comparing the two value chains, unregulated value chain had significantly higher proportion of bacterial species that were resistant. In order to mitigate the risk of transmitting antimicrobial resistant bacteria to consumers along the fish value chain, good manufacturing practices coupled with identification and management of possible sources of contamination are recommended for fish and potentially other foods distributed along the less regulated value chains. Importance In order to mitigate the risk of transmitting antimicrobial resistant bacteria to consumers along the fish value chain, good manufacturing practices coupled with identification and management of possible sources of contamination are recommended for fish and potentially other foods distributed along the less regulated value chains.