Classification of Listeria monocytogenes by PCR-restriction enzyme analysis in the two genes of hlyA and iap.

PCR-restriction enzyme analysis in the two virulence-associated genes was performed. The hlyA gene cording for listeriolysin O and the iap gene cording for an invasion associated factor were amplified with primers SH2 or SI3. The PCR products obtained were cleaved with 32 restriction enzymes, and restriction profiles from 12 strains, 6 each of serotypes 1/2a and 4b, were compared. We obtained two profiles for the hlyA using 4 restriction enzymes and eight profiles for the iap by using AluI, and the results of the profiles did not correlate with the serotypes. The polymorphism in the iap region was of a higher degree than that in the hlyA region, and the PCR-restriction enzyme analysis of the iap gene with primers SI3 and AluI was confirmed as one of the useful epidemiological analysis methods for listerosis outbreaks.