Genomic Characterization ofListeria monocytogenesIsolated From Ready-to-Eat Meat and Meat Processing Environments in Poland

Listeria monocytogenesis one of the major foodborne pathogens. Isolates of PCR-serogroups IIb (n= 17) and IVb (n= 31) recovered from food (n= 33) and food processing environment (n= 15) in Poland were characterized using whole genome sequencing. Most isolates belonged to Multi-Locus Sequence Type (MLST) ST2 (31.3%) and ST5 (22.9%). Core genome MLST (cgMLST) analysis classified isolates into seven sublineages (SL) and 25 different cgMLST types (CT). Consistent with the MLST results, most sublineages were SL2 and SL5. Eleven isolates harboredaacA4encoding resistance to aminoglycosides, three isolates harboredemrC(n= 3) and onebrcABC(n= 1) encoding tolerance to benzalkonium chloride. Isolates belonging to SL5 CT2323 carried a so far unreportedinlBallele with a deletion of 141 nucleotides encoding the beta-repeat sheet and partially the GW1 domain of InlB. Comparison with publicly available genome sequences fromL. monocytogenesisolated from human listeriosis cases in Poland from 2004 to 2013 revealed five common CTs, suggesting a possible epidemiological link with these strains. The present study contributes to characterize the diversity ofL. monocytogenesin ready-to-eat (RTE) meat and meat processing environments in Poland and unravels previously unnoticed links with clinical cases in Europe.