Contrasting genetic diversity of listeria pathogenicity islands 3 and 4 harbored by non-pathogenic listeria spp.

Dungan, R.S. (2023) Contrasting genetic diversity of listeria pathogenicity islands 3 and 4 harbored by non-pathogenic listeria spp. Applied and Environmental Microbiology. 89(2):1-16. 2 February 2023.

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Abstract

Listeria monocytogenes causes the severe foodborne disease listeriosis. Several clonal groups of L. monocytogenes possess the pathogenicity islands Listeria pathogenicity island 3 (LIPI-3) and LIPI-4. Here, we investigated the prevalence and genetic diversity of LIPI-3 and LIPI-4 among 63 strains of seven non-pathogenic Listeria species from the natural environment (i.e., wildlife and surface waters). Analysis of the whole genome sequence data suggested that both islands were horizontally acquired but differed considerably in their incidence and genetic diversity. LIPI-3 was identified among half of the Listeria innocua strains in the same genomic location as Listeria monocytogenes (guaA hotspot) in a truncated form with only three strains harboring full-length LIPI-3, and a highly divergent partial LIPI-3 was observed in three Listeria seeligeri strains, outside the guaA hotspot. Premature stop codons (PMSCs) and frameshifts were frequently noted in the LIPI-3 gene encoding listeriolysin S. On the other hand, full-length LIPI-4 without any PMSCs was found in all Listeria innocua strains, in the same genomic location as L. monocytogenes and with ~85% similarity to the L. monocytogenes counterpart. Our study provides intriguing examples of genetic changes that pathogenicity islands may undergo in non-pathogenic bacterial species, potentially in response to environmental pressures that promote either maintenance or degeneration of the islands. Investigations of the roles that LIPI-3 and LIPI-4 play in non-pathogenic Listeria species are warranted to further understand the differential evolution of genetic elements in pathogenic versus non-pathogenic hosts of the same genus.

Item Type:	Article
NWISRL Publication Number:	1755
Subjects:	Research methodology
Depositing User:	Users 11 not found.
Date Deposited:	01 May 2023 19:17
Last Modified:	01 May 2023 19:17
Item ID:	1795
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/1795