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

Abstract

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. From a total of 80 meat samples comprising of mutton, pork, beef and chicken, organisms belonging to the family Enterobacteriaceae were isolated by standard procedures and identified by API 20E system. Antibiotics susceptibilities testing (AST) against selected classes of antimicrobial agents and plasmid extraction was carried out by disc diffusion and alkaline lysis methods respectively. 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 the organisms to amoxycillin/clavulanic acid was 91 (82.7%), streptomycin 85 (75.7%) and perfloxacin 74 (67.2%) while ofloxacin had the highest susceptibility 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. aerogenes and Proteus mirabilis. All the isolates with plasmids were multidrug resistant and were isolated from chicken except a strain of E. coli from pork which harboured a single plasmid copy suggesting these meat as reservoirs for antibiotic resistant bacteria. Our findings revealed high level of meat contamination with antibiotic resistant Enterobacteriaceae harbouring resistant plasmids. An integrated surveillance system and safety practice must be ensured among the processors and retailers.