Atypical Listeria innocua strains possess an intact LIPI-3
Clayton, Evelyn M.
Daly, Karen M.
Guinane, Caitriona M.
Cotter, Paul D.
Ross, R. Paul
BioMed Central Ltd.
Background: Listeria monocytogenes is a food-borne pathogen which is the causative agent of listeriosis and can be divided into three evolutionary lineages I, II and III. While all strains possess the well established virulence factors associated with the Listeria pathogenicity island I (LIPI-1), lineage I strains also possess an additional pathogenicity island designated LIPI-3 which encodes listeriolysin S (LLS), a post-translationally modified cytolytic peptide. Up until now, this pathogenicity island has been identified exclusively in a subset of lineage I isolates of the pathogen Listeria monocytogenes. Results: In total 64 L. innocua strains were screened for the presence of LIPI-3. Here we report the identification of an intact LIPI-3 in 11 isolates of L. innocua and the remnants of the cluster in several others. Significantly, we can reveal that placing the L. innocua lls genes under the control of a constitutive promoter results in a haemolytic phenotype, confirming that the cluster is capable of encoding a functional haemolysin. Conclusions: Although the presence of the LIPI-3 gene cluster is confined to lineage I isolates of L. monocytogenes, a corresponding gene cluster or its remnants have been identified in many L. innocua strains.
Genus Listeria , Monocytogenes , Virulence , Evolution , Pathogenesis , Genomics , Genes
CLAYTON, E. M., DALY, K. M., GUINANE, C. M., HILL, C., COTTER, P. D. & ROSS, P. R. 2014. Atypical Listeria innocua strains possess an intact LIPI-3. BMC Microbiology, 14:58, 1-9. http://dx.doi.org/10.1186/1471-2180-14-58
© Clayton et al.; licensee BioMed Central Ltd. 2014. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.