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Updated: Jun 18, 2026

Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes
Published on: September 19, 2013
A Listeria monocytogenes strain is still virulent despite nonfunctional major virulence genes
S M Roche1, O Grépinet, Y Corde
1Institut National de la Recherche Agronomique, UR 1282 Infectiologie Animale et Santé Publique, and IFR 136, Agents transmissibles et Infectiologie, Nouzilly, France. sylvie.roche@tours.inra.fr
Abstract:
The low-virulence Listeria monocytogenes strains have been previously assigned to 4 phenotypic groups. This study aimed to characterize the A23 strain, which exhibits a pulsed-field gel electrophoresis profile specific to low-virulence strains. This strain has the same causal mutations as the group III strains and a supplementary mutation in the mpl gene, leading to the absence of internalin A expression and the presence of inactive internalin B, phosphatidyl-inositol phospholipase C, and phosphatidylcholine phospholipase C. Despite these mutations in major virulence genes, the A23 strain formed plaques in cell monolayers and contaminated 100% of inoculated mice, suggesting that it evolved from group III strains by acquiring new virulence genes.
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