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Characterisation of Listeria monocytogenes food-associated isolates to assess environmental fitness and virulence potential


Gray, JA and Chandry, PS and Kaur, M and Kocharunchitt, C and Bowman, JP and Fox, EM, Characterisation of Listeria monocytogenes food-associated isolates to assess environmental fitness and virulence potential, International Journal of Food Microbiology, 350 Article 109247. ISSN 0168-1605 (2021) [Refereed Article]


Copyright Statement

Copyright 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license

DOI: doi:10.1016/j.ijfoodmicro.2021.109247


The ability of Listeria monocytogenes isolates to survive within the food production environment (FPE), as well as virulence, varies greatly between strains. There are specific genetic determinants that have been identified which can strongly influence a strains ability to survive in the FPE and/or within human hosts. In this study, we assessed the FPE fitness and virulence potential, including efficacy of selected hygiene or treatment intervention, against 52 L. monocytogenes strains isolated from various food and food environment sources. Phenotypic tests were performed to determine the minimum inhibitory concentration of cadmium chloride and benzalkonium chloride and the sensitivities to five clinically relevant antibiotics. A genomic analysis was also performed to identify resistance genes correlating to the observed phenotypic resistance profiles, along with genetic determinants of interest which may elude to the FPE fitness and virulence potential. A transposon element containing a novel cadmium resistance gene, cadA7, a Tn916 variant insert in the hypervariable Listeriagenomic island 1 region and an LGI2 variant were identified. Resistance to cadmium and disinfectants was prevalent among isolates in this study, although no resistance to clinically important antimicrobials was observed. Potential hypervirulent strains containing full length inlA, LIPI-1 and LIPI-3 were also identified in this study. Cumulatively, the results of this study show a vast array of FPE survival and pathogenicity potential among food production-associated isolates, which may be of concern for food processing operators and clinicians regarding L. monocytogenes strains colonising and persisting within the FPE, and subsequently contaminating food products then causing disease in at risk population groups.

Item Details

Item Type:Refereed Article
Keywords:disinfectant, cadmium, pathogenicity, antimicrobial, plasmid, transposon, Listeria monocytogenes, food production, disinfectant
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Food sciences
Research Field:Food packaging, preservation and processing
Objective Division:Health
Objective Group:Public health (excl. specific population health)
Objective Field:Food safety
UTAS Author:Gray, JA (Mr Jamie Gray)
UTAS Author:Kocharunchitt, C (Dr Jay Kocharunchitt)
UTAS Author:Bowman, JP (Associate Professor John Bowman)
ID Code:145086
Year Published:2021
Web of Science® Times Cited:10
Deposited By:TIA - Research Institute
Deposited On:2021-06-30
Last Modified:2021-11-24
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