Prevalence of Antibiotics Resistant Listeria monocytogenes Strains in Nigerian Ready-to-eat Foods.

The Listerial flora and Listeria monocytogenes bio-load associated with 411 ready-to-eat (RTE) foods sold at several locations in southern Nigeria was evaluated using phenotypic procedures which included serial dilution and pour plate techniques. Selected L. monocytogenes strains phenotypically identified from the RTE foods were further identified using virulence gene markers and 16srRNA amplification procedures. All the 90 L. monocytogenes strains cultured from the RTE foods were subjected to antibiogram analysis using disc diffusion. Some of the antibiotics employed included; Ceftazidine, cefuroxime, gentamicin, ofloxacin, augumentin, tetracycline and erythromycin. L. monocytogenes L. ivanovii, L. grayi, L.welshimeri, L. seeligeri and L. innocua were detected in the RTE foods. Haemolysin (hlyA) gene, Internalin gene (inlA) and invasive gene (iap) were detected in all L. monocytogenes isolates. L. monocytogenes LMEW70 with accession number KY053295 was 93% similar to L. monocytogenes L1846. All the L. monocytogenes isolates were resistant to amoxicillin, cloxacillin, augumentin and ceftazidime.