Figure 1.

Dendrogram constructed for PFGE analysis using the UPGMA method with BioNumerics v.4.6 software showing the genetic relationships between 92 L. monocytogenes strains. The low-virulence strains are in red. Green lines indicate the division into clusters of strains having 85% similarity. Phenotypic groups were based on results of cellular entry, plaque formation, and the two phospholipase C activities. Genotypic Groups were defined as follows: Group-Ib included the strains with PrfAK220T. Group-Ia included the strains with PrfAΔ174-237. Group-IIIa had the same mutations in the plcA, inlA and inlB genes. Group-Ic showed the K130Q mutation.