AUTHOR=Anast Justin M. , Bobik Thomas A. , Schmitz-Esser Stephan 

TITLE=The Cobalamin-Dependent Gene Cluster of Listeria monocytogenes: Implications for Virulence, Stress Response, and Food Safety

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.601816

DOI=10.3389/fmicb.2020.601816

ISSN=1664-302X

ABSTRACT=<p>Several genes of the <italic>eut</italic>, <italic>pdu</italic>, and <italic>cob/cbi</italic> operons are responsible for the metabolism of ethanolamine (EA) and 1,2-propanediol (PD) and are essential during the pathogenic lifecycles of various enteric pathogens. Studies concerning EA and PD metabolism have primarily focused on bacterial genera from the family <italic>Enterobacteriaceae</italic>, especially the genus <italic>Salmonella</italic>. <italic>Listeria monocytogenes</italic> is a member of the <italic>Firmicutes</italic> phylum and is the causative agent of the rare but highly fatal foodborne disease listeriosis. The <italic>eut</italic>, <italic>pdu</italic>, and <italic>cob/cbi</italic> operons are organized as a single large locus collectively referred to as the cobalamin-dependent gene cluster (CDGC). The CDGC is well conserved in <italic>L. monocytogenes</italic>; however, functional characterization of the genes in this cluster and how they may contribute to <italic>Listeria</italic> virulence and stress tolerance in food production environments is highly limited. Previous work suggests that the degradation pathway of PD is essential for <italic>L. monocytogenes</italic> establishment in the gastrointestinal tract. In contrast, EA metabolism may be more important during intracellular replication. Other studies indicate that the CDGC is utilized when <italic>L. monocytogenes</italic> is exposed to food and food production relevant stress conditions. Perhaps most noteworthy, <italic>L. monocytogenes</italic> exhibits attenuated growth at cold temperatures when a key EA utilization pathway gene was deleted. This review aims to summarize the current knowledge of these pathways in <italic>L. monocytogenes</italic> and their significance in virulence and stress tolerance, especially considering recent developments.</p>