2020-2021年辽宁省食源性单核细胞增生李斯特菌毒力基因分布

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

目的分析2020—2021年辽宁省食源性单核细胞增生李斯特菌(Lm)毒力基因分布特征及分子血清分型情况。方法采用普通PCR方法对Lm的19个毒力基因包括毒力岛Ⅰ在内的6个位点(prfA、plcA、plcB、hlyA、mpl和actA)和毒力岛Ⅱ内化素家族蛋白基因的10个位点(inlA、inlB、inlC、inlD、inlE、inlF、inlG、inlH/C2、inlI、inlJ),以及3个毒力基因相关位点(iap、fbpA、hpt)进行检测。同时应用多重PCR对所有菌株进行5种(1/2a、1/2b、1/2c、4b和3a)血清型分型检测。结果在辽宁省食源性分离到的91株Lm中,36株Lm的19种毒力基因全部检出,其检出率高达39.6%。55株Lm菌株出现2种及2种以上毒力基因的不同缺失。inlG和inlF基因缺失率较高,分别为41.8%(38/91)和52.7%(48/91)。依据毒力基因携带情况,可分为13个基因型,其中携带19种毒力基因的Ⅰ型为辽宁省的优势基因型别。辽宁省Lm被分成4组分子血清型,1/2a(3a)血清型占比为59.3%(54/91),1/2b(3b)占比为34.1%(31/91),1/2c(3c)占比为3.3%(3/91),4b(4d、4e)占比为3.3%(3/91),3株4b血清型均分离自肉及肉制品。结论辽宁省食源性Lm的毒力基因携带率高,毒力基因缺失具有多样性且存在样品种类上的差异。

Objective To analyze the distribution characteristics of virulence genes and drug resistance of foodborne Listeria monocytogenes(Lm)in Liaoning Province,2020—2021.Methods The 19 virulence genes of Lm including 6 loci(prfA,plcA,plcB,hlyA,mpl and actA)and 10 loci of virulence islandⅡ(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.Results Among 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 typeⅠwith 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.Conclusion The virulence gene carrying rate of foodborne Lm in Liaoning Province is high,and the virulence gene deletion has diversity and sample differences.