Comparative Analysis of Pathogenicity Assays and PCR for Listeria monocytogenes Isolated from Animal, Raw Food and Environmental Sources in Korea

Abstract

Results of PCR with oligonucleotide primers were designed from the assembled panel of four potential virulence genes (two of internalin gene and two of transcriptional regulator gene). Most of the isolates including reference strains were reactive by PCR, whereas the other strains (No.80, 81, and 83) isolated from pork, were non-reactive by PCR. In par-ticular, all pork isolates were PCR-negative for two primers (lmo2672 and 2821) sets tested. However, No.82 was posi-tive for lmo1134 primer, and No.84 was positive for lmo2470 of pork isolates. It was observed that all Listeria mono-cytogenes (L. monocytogenes) penetrate Vero cells, although the invasion efficiency of each strain varied (between 0.5 and 18.9%). When compared in cell assay with PFGE, the results were shown that the mean invasion efficiency for lineage II isolate (2.6%) was significantly lower (ANOVA-test, p < 0.05) than that for lineage I (12.9%) and III isolates (10.3%).