Whole-Genome Sequencing Characterization of Virulence Profiles of Listeria monocytogenes Food and Human Isolates and In Vitro Adhesion/Invasion Assessment
none13sìListeria monocytogenes (Lm) is the causative agent of human listeriosis. Lm strains have
different virulence potential. For this reason, we preliminarily characterised via Whole-Genome
Sequencing (WGS) some Lm strains for their key genomic features and virulence-associated determinants,
assigning the clonal complex (CC). Moreover, the ability of the same strains to adhere to and
invade human colon carcinoma cell line Caco-2, evaluating the possible correspondence with their
genetic virulence profile, was also assessed. The clinical strains typed belonged to clonal complex
(CC)1, CC31, and CC101 and showed a very low invasiveness. The Lm strains isolated from food
were assigned to CC1, CC7, CC9, and CC121. All CC1 carried the hypervirulence pathogenicity
island LIPI-3 in addition to LIPI-1. Premature stop codons in the inlA gene were found only in Lm of
food origin belonging to CC9 and CC121. The presence of LIPI2_inlII was observed in all the CCs
except CC1. The CC7 strain, belonging to an epidemic cluster, also carried the internalin genes inlG
and inlL and showed the highest level of invasion. In contrast, the human CC31 strain lacked the
lapB and vip genes and presented the lowest level of invasiveness. In Lm, the genetic determinants
of hypo- or hypervirulence are not necessarily predictive of a cell adhesion and/or invasion ability
in vitro. Moreover, since listeriosis results from the interplay between host and virulence features of
the pathogen, even hypovirulent clones are able to cause infection in immunocompromised people.openGiuditta Fiorella Schiavano * , Collins Njie Ateba , Annalisa Petruzzelli , Veronica Mele ,
Giulia Amagliani , Fabrizia Guidi , Mauro De Santi , Francesco Pomilio , Giuliana Blasi ,
Antonietta Gattuso , Stefania Di Lullo , Elena Rocchegiani, Giorgio BrandiSchiavano, GIUDITTA FIORELLA; Njie Ateba, Collins; Petruzzelli, Annalisa; Mele, Veronica; Amagliani, Giulia; Guidi, Fabrizia; DE SANTI, Mauro; Pomilio, Francesco; Blasi, Giuliana; Gattuso, Antonietta; Di Lullo, Stefania; Rocchegiani, Elena; Brandi, Giorgi