【摘要】 目的 掌握2002—2020年广西3种来源（食源株、病源株及健康人员携带株）单核细胞增生李斯特菌（Listeria monocytogenes,LM）耐药情况和菌株的耐药基因、血清群、基因型及相互之间的分布特征，构建广西LM数据库，应用于LM引起的食源性疾病暴发的识别和调查。方法 采用肉汤稀释法测定LM抗生素敏感性；通过全基因组测序获取LM谱系、血清群、序列分型（ST）、克隆群（CC）及耐药基因分布。结果 317株实验菌株分属3个谱系、5个血清群、32个ST型、22个CC型及1个未分型的ST619，谱系Ⅱ和Ⅱa血清群占比最高，分别为57.41%（182/317）、43.53%（138/317），优势ST型及CC型分别为ST8（17.98%）、ST87（12.62%）、ST9（11.99%）和CC8（17.98%）、CC9（13.88%）、CC87（12.93%）。食源株优势菌株主要分布于谱系Ⅱ、Ⅱa、CC8和Ⅱc、CC9及谱系Ⅰ、Ⅱb、CC87;7株病源株中6株为谱系Ⅰ、Ⅳb;4株健康人员携带株全部为谱系Ⅱ、Ⅱa、CC8。依据CLSI M45-2015及EUCAST-2017判定标准，仅1株菌株对ERY耐药，耐药率为0.32%；依据MIC₉₀值，推断有6株菌（1.89%）极可能对TET耐药。仅9株菌株携带耐药基因，占2.84%，包括tet（M）、dfrG、Msr（D）、Mef（A）、blaA，携带四环素耐药基因tet（M）菌株数最多（7株），2株菌携带3个耐药基因。12株耐药/高MIC值菌株5株来源于餐饮食品，占比41.67%,6株携带耐药基因，其中1株对ERY耐药且TET呈现高MIC值。11株人源株均无耐药、高MIC值及携带耐药基因等情况。结论 广西LM菌株总体以Ⅱa血清群为主，CC8、CC9、CC87为优势CC型，病源株主要为Ⅳb血清群，健康携带株为Ⅱa、CC8，菌株耐药率及耐药基因携带率不高，餐饮食品来源菌株在耐药/高MIC值菌株中占比高，对病人的治疗用药具有重要的指导意义。更多还原

【Abstract】 Objective To understand the drug resistance of Listeria monocytogenes(LM) and the drug resistance genes,serogroups, genotypes, and their distribution characteristics of LM from three sources in Guangxi from 2002 to 2020, and to construct Guangxi LM database for the identification and investigation of foodborne disease outbreaks caused by LM. Methods The antibiotic sensitivity of LM was determined by broth dilution method, and the LM pedigree, serum group, sequence typing(ST), clone group(CC), and drug resistance gene distribution were obtained by whole genome sequencing. Results In total, 317 strains belonged to 3 pedigrees, 5 serogroups, 32 St genotypes, 22 CC genotypes, and 1 untyped ST619. The dominant linage identified was Linage Ⅱ(57.41%, 182/317) and the most frequent serogroup was Ⅱ a(43.53%, 138/317), respectively. The dominant St and CC types were ST8(17.98%), ST87(12.62%), ST9(11.99%), CC8(17.98%), CC9(13.88%),and CC87(12.93%), respectively. The dominant strains of food source strains were mainly distributed in pedigree Ⅱ, Ⅱ a,CC8 and Ⅱ c, CC9 and pedigree Ⅰ, Ⅱ b, CC87. Among the 7 strains from clinical cases, 6 were linageⅠand serogroup Ⅳb. All of the 4 strains from healthy people were identified as linage Ⅱ, serogroupⅡa, and CC8. Only 1 strain was resistant to erythromycin(CLSI M45-2015 and EUCAST 2017). Based on MIC90, 6 strains were found to be probably resistant to tetracycline. Only 9 strains(2.84%) carried antibiotic-resistant genes including tet(M), dfrG, Msr(D), Mef(A), and blaA. The tetracycline-resistant gene tet(M) was the most prevalent(77.8%, 7/9), and 2 strains were found to contain 3 resistance genes. Among 12 strains with high minimal inhibitory concentration(MIC) values, 5(41.67%) were isolated from ready-to-eat food,and 6 contained antibiotic-resistant genes including 1 strain resistant to erythromycin with high MIC of tetracycline. All the11 human isolates showed no antibiotic-resistance, high MIC and antibiotic-resistant genes. Conclusion The dominant serogroup is Ⅱ a in LM isolates in Guangxi. CC8, CC9, and CC87 are the most common clones. Ⅳ b is the main serogroup in human listeriosis strains, while serogroup Ⅱ a and CC8 are more frequently observed in isolates from healthy people. The rates of antibiotic resistance and antibiotic-resistant genes prevalence are not high. The LM isolates from ready-to-eat food accounts for a high percentage of strains with high MIC values, providing important data for medication of infection cases.更多还原