广西单核细胞增生李斯特菌的流行率、毒力特征和分子分型研究

Prevalence,virulence profiling,and molecular typing of Listeria monocytogenes isolated in Guangxi

目的比较广西不同种类食品中单核细胞增生李斯特菌(以下简称单增李斯特菌)的流行情况、毒力特征和分子分型特征,更好地了解单增李斯特菌的遗传特点及其传播的潜力。方法对来自2002—2020年的210株单增李斯特菌进行全基因组测序(WGS),分析其序列分型(ST)、克隆群(CC)型及毒力基因。结果2002—2020年广西53.8%单增李斯特菌分离株来源于肉与肉制品,59.0%分离株来自于谱系Ⅱ,优势ST型为ST8和ST9。79.4%菌株携带LIPI-1基因(hly、prfA、plcA、plcB、mpl、actA),83.7%菌株携带LIPI-2基因(inlC、inlF、inlJ、inlK)。17.6%菌株携带LIPI-3基因(llsA、llsB、llsD、llsG、llsH、llsP、llsX、llsY)。结论肉与肉制品是广西单增李斯特菌检出率最高的食品类型,分子分型结果证实了单增李斯特菌种群具有高度的遗传多样性,WGS的高分辨力可用于监测食源性单增李斯特菌病的暴发。毒力基因的分布表明广西单增李斯特菌存在不同程度毒力基因的缺失,应警惕高致病性的菌株引起的食源性暴发事件。

Objective This study aimed to comprehensively analyze the prevalence,virulence characteristics,and molecular typing of Listeria monocytogenes(L.monocytogenes)isolated from various food sources in Guangxi.By investigating the genetic attributes and potential transmission mechanisms of L.monocytogenes,this research contributes to our understanding of this pathogen.Methods A total of 210 L.monocytogenes strains collected from 2002 to 2020 in Guangxi were subjected to whole genome sequencing(WGS)analysis.The study included the determination of sequence types(STs),clonal complexes(CC),and the presence of L.monocytogenes pathogenicity islands(LIPIs).Results Of the L.monocytogenes isolates,53.8%were traced back to meat and meat products from 2002 to 2020 in Guangxi.Among these isolates,59.0%belonged to lineageⅡ.The predominant STs were ST8 and ST9.Virulence gene analysis revealed that 79.4%of isolates carried LIPI-1 genes(hly,prfA,plcA,plcB,mpl,and actA),while 83.7%carried LIPI-2 genes(inlC,inlF,inlJ,and inlK).Furthermore,17.6%of isolates carried LIPI-3 genes(llsA,llsB,llsD,llsG,llsH,llsP,llsX,and llsY).Conclusion Meat and meat products in Guangxi showed the highest prevalence of L.monocytogenes.Molecular typing results demonstrated a high genetic diversity among L.monocytogenes strains.The discriminatory power of WGS makes it a valuable tool for monitoring foodborne listeriosis outbreaks.The distribution of virulence genes indicated that L.monocytogenes of Guangxi had different degree of deletion of virulence genes,underscoring the importance of vigilance regarding highly pathogenic strains that could potentially cause foodborne outbreaks.