Study on antimicrobial resistance and genomic characterization of foodborne Listeria monocytogenes strains in Gansu Province
Objective To analyze the drug resistance and genomic characteristics of 25 strains of Listeria monocytogenes isolated from food products sold in Gansu Province and provide a basis for the prevention and control of foodborne diseases caused by L.monocytogenes.Methods The 25 L.monocytogenes isolated from commercial food in Gansu Province from 2021 to 2022 were collected as research subjects.All 25 strains were performed for antimicrobial susceptibility testing to 8 kinds of antibiotics,serum agglutination and sequenced the whole genome.the lineage,CC type,ST type,serotype,drug resistance phenotype and genes,virulence gene,resistance gene,phylogenetic relationship.Results The 25 L.monocytogenes strains were subtypes as lineage Ⅰ and lineage Ⅱ,with lineage Ⅱ being the dominated lineage(84.0％,21/25).The serotype 1/2a was mainly detected(56.0％,14/25).The 25 L.monocytogenes strains were found to belong to 10 CCs,with CC9,CC8 and CC121 the dominant(56.0％,14/25),discovered a new ST type,ST3142.Only one of the 25 L.monocytogenes strains was drug resistant(4.0％,1/25),multiple drug resistant to trimethoprim/sulfamethoxazole,erythromycin,tetracycline and ciprofloxacin.The drug resistance phenotype was consistent with the carrying status of drug resistance genes.All 25 strains of L.monocytogenes carried LIPI-1 and internalin genes,no strains carrying LIPI-3 were found,and only 2 ST87 strains carried LIPI-4.16 strains(64.0％,16/25)carried SSI-1,and 3 ST121 strains carried SSI-2.68.0％(17/25)of the strains had premature stop codons(PMSC)of the inlA gene.The core genome multilocus sequence typing method could clearly distinguish strains of different lineages,serotypes,and CC types.The 25 L.monocytogenes stains were divided into 10 subgroups,which were consistent with their CC type.Conclusion The predominant L.monocytogenes strains in commercial food in Gansu Province exhibited genetic evolutionary diversity,with low resistance rates in both resistance genes and phenotypes,and carried abundant virulence genes.
NETL
NSTL
万方数据
