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Genome‐wide‐analyses of Listeria monocytogenes from food‐processing plants reveal clonal diversity and date the emergence of persisting sequence types
Author(s) -
Knudsen Gitte M.,
Nielsen Jesper Boye,
Marvig Rasmus L.,
Ng Yin,
Worning Peder,
Westh Henrik,
Gram Lone
Publication year - 2017
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/1758-2229.12552
Subject(s) - biology , listeria monocytogenes , genome , whole genome sequencing , genetics , locus (genetics) , multilocus sequence typing , phylogenetic tree , reference genome , genomics , outbreak , evolutionary biology , gene , genotype , virology , bacteria
Summary Whole genome sequencing is increasing used in epidemiology, e.g. for tracing outbreaks of food‐borne diseases. This requires in‐depth understanding of pathogen emergence, persistence and genomic diversity along the food production chain including in food processing plants. We sequenced the genomes of 80 isolates of Listeria monocytogenes sampled from Danish food processing plants over a time‐period of 20 years, and analysed the sequences together with 10 public available reference genomes to advance our understanding of interplant and intraplant genomic diversity of L. monocytogenes . Except for three persisting sequence types (ST) based on Multi Locus Sequence Typing being ST7, ST8 and ST121, long‐term persistence of clonal groups was limited, and new clones were introduced continuously, potentially from raw materials. No particular gene could be linked to the persistence phenotype. Using time‐based phylogenetic analyses of the persistent STs, we estimate the L. monocytogenes evolutionary rate to be 0.18–0.35 single nucleotide polymorphisms/year, suggesting that the persistent STs emerged approximately 100 years ago, which correlates with the onset of industrialization and globalization of the food market.