Validation of Predicted Virulence Factors in Identified Using Comparative Genomics.

is an intracellular facultative pathogen that causes listeriosis, a foodborne zoonotic infection. There are differences in the pathogenic potential of subtypes and strains. Comparison of the genome sequences among pathogenic strains EGD-e and F2365 with nonpathogenic CLIP1182 and strain HCC23 revealed a set of proteins that were present in pathogenic strains and had no orthologs among the nonpathogenic strains. Among the candidate virulence factors are five proteins: putrescine carbamoyltransferase; InlH/InlC2 family class 1 internalin; phosphotransferase system (PTS) fructose transporter subunit EIIC; putative transketolase; and transcription antiterminator BglG family. To determine if these proteins have a role in adherence and invasion of intestinal epithelial Caco-2 cells and/or contribute to virulence, five mutant strains were constructed. F2365Δ, F2365Δ, and F2365Δ exhibited a significant ( < 0.05) reduction in adhesion to Caco-2 cells compared to parent F2365 strain. The invasion of F2365Δ, F2365Δ, and F2365Δ decreased significantly ( < 0.05) compared with the parent strain. Bacterial loads in mouse liver and spleen infected by F2365 was significantly ( < 0.05) higher than it was for F2365Δ, F2365Δ, F2365Δ, F2365Δ, and F2365Δ strains. This study demonstrates that , , , , and play a role in pathogenicity.