Molecular Characteristics Analysis of Foodborne Listeria monocytogenes in Linyi City
Objective:Based on whole genome sequencing,the virulence genes,drug resistance gene carriers and molecular typing characteristics of foodborne Listeria monocytogenes in Linyi city were analyzed.Method:Using sequencing data,27 foodborne single-increase Listeria monocytogenes were analyzed by multi-locus sequence typing,virulence genes and drug resistance genes,and a phylogenetic tree based on cg-SNP was constructed.Result:The 27 isolated strains were divided into 10 ST types,among which ST121 was the dominant type.Among the 27 strains of Listeria monocytogenes,26 strains carried fosfomycin(FosX)resistance genes,accounting for 96.3％,and two strains carried tetracyclines(tetM)and trimethoprim(dfrG)resistance genes,only one strain was not resistant.Two types of virulence were lost in 27 strains,the first was the virulence island LIPI-1 deletion,with a deletion rate of 7.4％.The second was a single deletion of inlF in the virulence island LIPI-2,with a deletion rate of 40.7％.Phylogenetic tree analysis showed that 27 strains were close together and clustered in 3 branches.The vast majority of the strains were isolated from meat products,accounting for 74.1％(20/27).Conclusion:There are a variety of drug resistance genes in foodborne Listeria monocytogenes,and the distribution of virulence genes is dominated by virulence islands(LIPI-1 and LIPI-2),which has potential pathogenicity.It is suggested that the special monitoring work of Listeria monocytogenes in Linyi city should be based on livestock meat products,and should increase the supervision of frozen beverages and their dairy raw materials,raw poultry meat,fruits and vegetables samples,further reducing the risk of foodborne diseases caused by Listeria monocytogenes.
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