ARS | Publication request: Listeria monocytogenes subgroups IIIA, IIIB and IIIC delineate genetically distinct populations with varied pathogenic potential

Submitted to: Journal of Clinical Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 12, 2006
Publication Date: November 1, 2006
Citation: Liu, D., Lawrence, M.L., Wiedman, M., Gorski, L.A., Mandrell, R.E., Ainsworth, J., Austin, F.W. 2006. Listeria monocytogenes subgroups IIIA, IIIB and IIIC delineate genetically distinct populations with varied pathogenic potential. Journal of Clinical Microbiology.44:4229-4233

Interpretive Summary: This study characterized a subgroup of Listeria monocytogenes strains for virulence. Lineage III strains are consist of several serogroup 4 strains that are not usually associated with human illness. The authors speculate from the evidence that some of these strains form a novel subspecies within L. monocytogenes.

Technical Abstract: Listeria monocytogenes lineage III strains belonging to subgroups IIIA (n=8), IIIB (n=5) and IIIC (n=6) were examined along with other known serotype strains (n=11) by PCR and Southern hybridization using several recently described species-, virulence- and serotype-specific primers and probes. The virulence of seven representative lineage III strains was then evaluated in mice via intraperitoneal route. The results suggest that subgroup IIIA consists of typical rhamnose-positive avirulent serotype 4a and virulent serotype 4c strains, subgroup IIIC of atypical rhamnose-negative virulent serotype 4c strains and subgroup IIIB of atypical rhamnose-negative virulent non-4a and non-4c strains, some of which may be related to serotype 7. It is possible that subgroup IIIB (including serotype 7) may represent a novel subspecies within L. monocytogenes.