Distribution of virulence genes of foodborne Listeria monocytogenes in Liaoning Province, 2020—2021

Abstract

ObjectiveTo analyze the distribution characteristics of virulence genes and drug resistance of foodborne Listeria monocytogenes （Lm） in Liaoning Province， 2020—2021.MethodsThe 19 virulence genes of Lm including 6 loci （prfA， plcA， plcB， hlyA， mpl and actA） and 10 loci of virulence island Ⅱ （inlA， inlB， inlC， inlD， inlE， inlF， inlG， inlH/C2， inlI and inlJ）， and the other 3 virulence related loci （iap， fbpA， hpt） were detected by PCR.ResultsAmong 91 Lm strains， the detection rate of 19 virulence genes was 39.6%. All 19 virulence genes of 36 Lm strains were detected， and 55 Lm strains showed different deletions of two or more virulence genes. inlG and inlF were the most seriously deficient， with a deletion rate of 41.8%（38/91） and 52.7%（48/91）. According to the virulence gene deletion， 91 strains could be divided into 13 genotypes， and the dominant virulence genotype was type Ⅰ with all 19 virulence genes. The 91 Lm strains were divided into four PCR serotypes， namely， 1/2a （3a）， 1/2b （3b）， 1/2c （3c） and 4b （4d， 4e）， with the proportions of each serum 59.3% （54/91）， 34.1%（31/91）， 3.3% （3/91） and 3.3% （3/91）， respectively. The 3 strains of serotype 4b were all from meat and meat products.ConclusionThe virulence gene carrying rate of foodborne Lm in Liaoning Province is high， and the virulence gene deletion has diversity and sample differences.

Keywords

• listeria monocytogenes
• virulence genes
• pathogenicity island
• foodborne pathogen
• liaoning province