8.A.200.  The LMxysn (LMxysn) Family 

Transmembrane protein LMxysn_1693 of serovar 4h Listeria monocytogenes is associated with bile salt resistance and intestinal colonization (Jin et al. 2022). Listeria monocytogenes (Lm) is a ubiquitous foodborne pathogen consisting of 14 serotypes, of which serovar 4h isolates, belonging to a hybrid sub-lineage, exhibits hypervirulent features. LMxysn_1693 of serovar 4h Lm XYSN, a member of genomic island-7 (GI-7), is predicted to a membrane protein with177 aas and possibly two TMSs, one N-terminal and a second at residues 110 - 130. It is conserved in serovar 4h Lm. Under bile salts stress, Lm XYSN strain lacking LMxysn_1693 (XYSN1693) exhibited a stationary phase growth defect as well as a reduction in biofilm formation and strikingly down-regulated bile-salts-resistance and virulence genes. The LMxysn_1693 protein plays a crucial role in Lm XYSN adhesion and invasion to intestinal epithelial cells, as well as colonization in the ileum of mice. Thus, the LMxysn_1693 gene may encode a component of a putative ABC transport system, synthetically interacts with genes involved in bile resistance, biofilm formation and virulence. It thus contributes to Lm survival within and outside of the host (Jin et al. 2022).

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