Listeria monocytogenes persistence in food processing environments: Whole Genome Sequencing and in vitro assessment of disinfectants resistance and biofilm forming ability
Listeria monocytogenes (Lm) is the causative agent of listeriosis,
an invasive disease primarily affecting immunocompromised
people, the elderly, children and pregnant women, with
high hospitalization (98.6%) and fatality rates (13.8%) 1. The
disease is most commonly caused by eating contaminated food,
in particular ready-to-eat. The ability of some strains to persist,
even for years, in food processing environments can increase
the risk of food contamination. Persistence can results
from Lm survival after disinfection, thanks to protective biofilm
formation, disinfectants and stresses resistance mechanisms or from the repeated reintroduction from raw materials 2 3. The
identification of recurring highly genetically related isolates
(Whole Genome Sequencing, WGS and core genome MLST,
cgMLST) is necessary to define a strain persistent in a plant 4.
The aim of this study was to evaluate persistence and resistance
to commercial sanitizers commonly used in food processing
environments, in Lm strains isolated within the laboratory activity
of IZSUM (Istituto Zooprofilattico Sperimentale Umbria
e Marche). Our approach was based on both WGS and in vitro
assays