Genetic diversity of isolates of foodborne Listeria monocytogenes by RAPD-PCR

In this study, randomly amplified polymorphic DNA-PCR (RAPD-PCR) was employed to investigate the genetic diversity of 308 wild isolates of Listeria monocytogenes. These isolates were taken from 1288 samples isolated from six food sources obtained within the Baoding and Shijiazhuang areas of Hebei province, China. Genetic distant coefficient analysis of the band profiles was carried out using unweighted pair-group method analysis (UPGMA) and cluster analysis. The oligomer RP1 was used as a primer to type 308 isolates of foodborne L. monocytogenes and 228 different RAPD-PCR fingerprinting patterns were obtained. The clustering analysis showed that the 308 isolates of L. monocytogenes could be grouped into six genetic clusters. Among them, Clusters I and II were the dominant species from this region. Also, many differences between genetic clusters from different foods, sampling times, and regions were found. The differences in RAPD-PCR fingerprinting patterns obtained from the six food types sampled indicate that the L. monocytogenes subtypes isolated were genetically diverse.