Title

Associations between multiple Listeria monocytogenes isolates genomic characteristics and their growth rates at refrigeration temperature.

ORCID

0000-0003-4340-127X

Department

Biological Sciences

Year of Study

3

Full-time or Part-time Study

Full-time

Level

Postgraduate

Presentation Type

Oral Presentation

Supervisor

Michael Callanan

Supervisor

Maire Begley

Abstract

Introduction: The capabilities of Listeria monocytogenes to proliferate at refrigeration temperature remains a significant food safety concern and a public health issue. The research aims to gain a better understanding of the variance of L. monocytogenes in the ability to proliferate at a refrigerated temperature and their genetic profile linkage.

Methods: A total of 150 L. monocytogenes isolates from various foods, food production environments, and clinical sources available at the Listeria collection, Teagasc Food Research Centre, Moorepark, Co Cork were assessed for their ability to grow at 4 and 7 ℃.

Results: A large variation in growth ability profiles at low temperature was observed and overall clinical isolates exhibited a significantly higher growth rate (p ≤ 0.05) at 7℃ than the other isolates. Analysis of variance (ANOVA) tests on ability growth at cold temperature amongst Clonal Complex (CC) groups revealed that CC18 isolates were significantly ( p ≤0.05) more tolerant of cold at 4℃ than CC121 and CC5 types while CC101, CC18, CC8, CC37 and CC14 were higher cold tolerance amongst other CC types at 7℃. Euclidian distance and Ward method based hierarchical clustering determined that 33.33% of the isolates exhibited fast growth. Scoary, pan-genome-wide association analysis identified six candidate genes that are associated with fast growth in cold conditions.

Conclusion: Heterogeneous cold stress growth profile was observed across the 150 strains studied. CC18 isolates exhibited the fastest growth among the other CC type. This study highlight that differences in growth rates at cold temperature across isolates can be inferred based on CC type and gene-based phylogenetic cluster. Further work is needed to characterise the Scoary selected genes.

Keywords:

Listeria monocytogenes, cold stress, stress genes, genotyping, pan-genome, predictive microbiology, food safety.

Start Date

14-6-2022 9:45 AM

End Date

14-6-2022 10:00 AM

Comments

Oral Session 1 - Technological Advancements in Food and Health Research

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Jun 14th, 9:45 AM Jun 14th, 10:00 AM

Associations between multiple Listeria monocytogenes isolates genomic characteristics and their growth rates at refrigeration temperature.

Introduction: The capabilities of Listeria monocytogenes to proliferate at refrigeration temperature remains a significant food safety concern and a public health issue. The research aims to gain a better understanding of the variance of L. monocytogenes in the ability to proliferate at a refrigerated temperature and their genetic profile linkage.

Methods: A total of 150 L. monocytogenes isolates from various foods, food production environments, and clinical sources available at the Listeria collection, Teagasc Food Research Centre, Moorepark, Co Cork were assessed for their ability to grow at 4 and 7 ℃.

Results: A large variation in growth ability profiles at low temperature was observed and overall clinical isolates exhibited a significantly higher growth rate (p ≤ 0.05) at 7℃ than the other isolates. Analysis of variance (ANOVA) tests on ability growth at cold temperature amongst Clonal Complex (CC) groups revealed that CC18 isolates were significantly ( p ≤0.05) more tolerant of cold at 4℃ than CC121 and CC5 types while CC101, CC18, CC8, CC37 and CC14 were higher cold tolerance amongst other CC types at 7℃. Euclidian distance and Ward method based hierarchical clustering determined that 33.33% of the isolates exhibited fast growth. Scoary, pan-genome-wide association analysis identified six candidate genes that are associated with fast growth in cold conditions.

Conclusion: Heterogeneous cold stress growth profile was observed across the 150 strains studied. CC18 isolates exhibited the fastest growth among the other CC type. This study highlight that differences in growth rates at cold temperature across isolates can be inferred based on CC type and gene-based phylogenetic cluster. Further work is needed to characterise the Scoary selected genes.