Antibiotic resistance and plasmid analysis of Enterobacteriaceae isolated from retail meat in Lagos Nigeria

BACKGROUND: The presence of antibiotic resistant microorganisms in food is of great concern globally. This research was carried out to detect and characterize plasmid carriage and profiles among members of Enterobacteriaceae from different meat types in Nigeria. METHOD: From a total of 80 meat samples comprising of mutton,pork, beef and chicken, organisms belonging to the family Enterobacteriaceae wereisolated by standard procedures and identified by API 20E system. Antibiotics susceptibilities testing (AST) againstselected classes of antimicrobial agents and plasmid extraction was carried outby disc diffusion and alkaline lysis methods respectively. RESULTS: One-hundred and ten Enterobacteriaceae were isolated,species identification revealed isolates belonging to 7 genera comprising of Escherichia, Enterobacter, Klebsiella,Citrobacter, Proteus, Salmonella and Serratia. Overall resistance of theorganisms to amoxycillin/clavulanic acid was 91 (82.7%), streptomycin 85(75.7%) and perfloxacin 74 (67.2%) while ofloxacin had the highestsusceptibility rate (91.8%). Plasmids profiling revealed ranges of plasmids from1 to 3 copies with estimated sizes range of 700bp to 1.1kb among E. coli, K. pneumoniae, E. aerogenesand Proteus mirabilis. All theisolates with plasmids were multidrug resistant and were isolated from chicken excepta strain of E. coli from pork whichharboured a single plasmid copy suggesting these meat as reservoirs forantibiotic resistant bacteria. CONCLUSION: Our findings revealed high level of meat contamination with antibioticresistant Enterobacteriaceae harbouring resistant plasmids. An integratedsurveillance system and safety practice must be ensured among the processorsand retailers.