Identification of an optimized panel of variable number tandem-repeat (VNTR) loci for Listeria monocytogenes typing.

Listeria monocytogenes is an important worldwide foodborne pathogen. For listeriosis outbreak investigations, an optimal multiple-locus variable-number-tandem-repeat analysis typing panel was identified from 4 previously reported schemes. The optimal combination of loci consisted of 9 loci (LMV6, LMV1, LMV2, Lm11, Lm10, LMV7, Lm32, LM-TR6, and Lm23), which produced the same level of differentiation ability Simpson index of 0.9914 as that of all 14 loci combined in the previous 4 reports. This panel provided higher differentiation ability than the individual of the 4 previously reported schemes, suggesting it would be useful for future surveillance and outbreak investigations.