【摘要】 目的 了解温州市即食食品中单核细胞增生李斯特菌污染水平，分析分离株的耐药性、毒力基因分布及遗传多样性特征。方法 依据GB 4789.30—2016进行菌株分离鉴定，采用微量肉汤稀释法进行药敏试验，基于全基因组测序分析菌株的毒力基因、多位点序列分型（MLST）、核心基因组多位点序列分型（cg MLST）。结果 5类即食食品共1 285份样品中，检出91株单核细胞增生李斯特菌，检出率为7.08%(91/1 285)。中式凉拌菜检出率最高（14.34%,36/251），其次为熟肉制品（9.62%,15/156）。分离株对9种抗菌药物的敏感率为94.51%～100.00%。91株分离株分属两个谱系（Ⅰ和Ⅱ）、15种ST型和14种CC型，血清群以Ⅱa(47.25%,43/91)和Ⅱb(32.97%,30/91)为主，优势型别为CC87/ST87(21.98%,20/91)、CC121/ST121(16.48%,15/91)和CC8/ST8(13.19%,12/91)。所有菌株均携带LIPI-1和LIPI-2相关毒力基因，19.78%(18/91)携带毒力岛LIPI-3,LIPI-4仅存在于CC619/ST3004及CC87/ST87菌株。结论 单核细胞增生李斯特菌在温州市即食食品中存在一定程度流行。菌株耐药率较低，呈现高度遗传多样性，且具有潜在的致病性，需加强高毒力克隆株的风险监测，警惕其引发食源性疾病暴发的风险。更多还原

【Abstract】 Objective To investigate the contamination of Listeria monocytogenes(L. monocytogenes) in ready-to-eat(RTE) foods in Wenzhou City, and characterize the antimicrobial resistance, virulence gene profiles, and genetic diversity of the isolates.Methods L. monocytogenes strains were isolated and identified according to GB 4789. 30—2016. Antimicrobial susceptibility testing was performed using the broth microdilution method. Virulence genes, multilocus sequence typing(MLST), and core genome multilocus sequence typing(cgMLST) were analyzed based on whole-genome sequencing.Results A total of 91 strains of L. monocytogenes were isolated from 1 285 samples across 5 categories of RTE foods, with a detection rate of 7. 08%(91/1 285). Among these, the detection rate of Chinese cold dishes was the highest(14. 34%, 36/251), followed by cooked meat products(9. 62%,15/156). The susceptibility rates of the isolates to each of the nine antimicrobial agents ranged from 94. 51% to 100. 00%. The isolates comprised two lineages （Ⅰ and Ⅱ）, 15 STs, and 14 CCs. The predominant serogroups were Ⅱa(47. 25%,43/91) and Ⅱb(32. 97%,30/91). The CC87/ST87(21. 98%,20/91), CC121/ST121(16. 48%,15/91), and CC8/ST8(13. 19%,12/91) were the dominant sequence types. All isolates carried virulence genes associated with LIPI-1(Listeria Pathogenicity Island 1, LIPI-1) and LIPI-2, 19. 78%(18/91) harbored the LIPI-3, while the LIPI-4 was exclusive to strains of CC619/ST3004 and CC87/ST87.Conclusion L. monocytogenes is prevalent to a certain extent in RTE foods in Wenzhou City. The isolates exhibited low antimicrobial resistance, displayed high genetic diversity, and possessed pathogenic potential. Strengthening surveillance of highly virulent clones is essential for preventing the foodborne disease outbreaks.更多还原