Sequence comparison of individual genes in the prfA virulence gene cluster (pVGC), a central virulence gene cluster, from different Listeria species indicated that priming sites within the genes appeared to be specific for Listeria monocytogenes exclusively. Therefore, the pVGC was targeted for polymerase chain reaction (PCR) assays to detect and specifically identify L. monocytogenes. Each gene of the pVGC was specifically amplified in L. monocytogenes but not in other Listeria species.