Genomic insights into persistence of Listeria species in the food processing environment

Lydia Palaiodimou, Séamus Fanning, Edward M. Fox*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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Listeria species may colonise and persist in food processing facilities for prolonged periods of time, despite hygiene interventions in place. To understand the genetic factors contributing to persistence of Listeria strains, this study undertook a comparative analysis of 7 persistent and 6 presumed non‐persistent strains, isolated from a single food processing environment, to identify genetic markers correlating to promoting persistence of Listeria strains, through whole genome sequence analysis.

Methods and Results
A diverse pool of genetic markers relevant to hygiene tolerance were identified, including disinfectant resistance markers qacH, emrC, and the efflux cassette bcrABC. Both persistent and presumed non‐persistent cohorts encoded a range of stress resistance markers, including heavy metal resistance, oxidative and pH stress, although trends were associated with each cohort (e.g. qacH and cadA1C resistance was more frequently found in persistent isolates). Persistent isolates were more likely to contain mutations associated with attenuated virulence, including a truncated InlA. Plasmids and transposons were widespread between cohorts.

Results suggest no single genetic marker identified was universally responsible for a strains ability to persist. Persistent strains were more likely to harbour mutation associated with hypovirulence.

Significance and Impact of The Study
This study provides additional insights into the distribution of genetic elements relevant to persistence across Listeria species, as well as strain virulence potential.
Original languageEnglish
Number of pages13
JournalJournal of Applied Microbiology
Early online date3 Apr 2021
Publication statusE-pub ahead of print - 3 Apr 2021


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