Abstract:To investigate the pork contamination by Listeria monocytogenes, its susceptibility to antimicrobial agents and serotypes, all strains were isolated by the GB 4789.30-2010 method; L. monocytogenes serotypes were identified by PCR; and antibiotic resistant profile of the isolates was examined using disc diffusion assay. A total of 273 pork samples were examined, out of which 52 samples (19.02%) were positive for L. monocytogenes and 78 strains were detected. And 33 (42.31%), 24 (30.71%), 16 (20.51%), 2 (2.56%), 3 (3.85%) of the isolates were identified as serotypes 1/2a (or 3a), 1/2b (or 3b or 7), 1/2c (or 3c), 4a (or4c)and 4b (or 4d or 4e), respectively. With disc diffusion assay, all strains were susceptible to the antibiotics, including ampicillin, ampicillin-sulbactam, imipenem, ciprofloxacin, levofloxacin, and vancomycin. However, the percentages of tetracycline resistances were higher. 11.54% isolates were resistant to penicillin, gentamicin, erythromycin. The conjugative transposon Tn916 is the important determinants of the resistance in spreading of the L. monocytogenes.
