1株ST515型多重耐药单增李斯特菌全基因组测序分析

Whole Genome Sequencing Analysis of a ST515 Strain of Multidrug-resistant Listeria monocytogenes

【目的】了解1株分离自调理肉制品的单增李斯特菌(Listeria monocytogenes,LM)携带耐药基因、毒力基因、可移动元件情况以及遗传进化关系。【方法】以1株从新疆某地的调理肉制品中分离获得的LM菌株LM5567为研究对象,通过VITEK-2 Compact和AST-GP67药敏卡检测LM5567菌株耐药性;经全基因组测序后,对LM5567菌株进行功能注释、分子分型、遗传进化关系和耐药基因、毒力基因及可移动元件携带情况分析。【结果】LM5567菌株对苄青霉素、氨苄西林、苯唑西林、呋喃妥因、复方新诺明、四环素等抗菌药均有耐药性,其基因组全长为2.974 Mb,包含2 941个编码基因。通过GO注释共获得2 144个基因,包含了50种功能特性。多位点序列分型(MLST)分析结果显示,LM5567菌株为ST515型,与分离自不同国家的复合克隆系(clonal complex, CC)CC1菌株具有较近亲缘关系。单核苷酸多态性(SNP)分析表明,LM5567菌株与来自加拿大的菌株02_17924b、02_1103和1株来自波兰的菌株220的突变位点最少,该菌株携带88个毒力基因和6个耐药基因,存在1个转座子Tn6009并携带四环素耐药基因tetM。【结论】食源性LM5567菌株为ST515型多重耐药菌株,基因组携带多种耐药基因、毒力基因和1个转座子,具有发生耐药性转移的潜力,存在通过食物链传播引起人类李斯特菌病的潜在风险。

【Objective】The purpose of this study was to understand the drug resistance gene,virulence gene,mobile element and genetic evolution relationship of a strain of Listeria monocytogenes(LM)isolated from prepared meat products.【Method】The resistance of LM strain LM5567 isolated from prepared meat products in Xinjiang was detected by VITEK-2 Compact and AST-GP67 susceptibility cards.After the whole genome sequencing,the functional annotation,molecular typing,genetic evolution relationship,drug resistance gene,virulence gene and mobile genetic elements of LM5567 strain were analyzed.【Result】LM5567 strain was resistant to benzicillin,ampicillin,oxacillin,furantoin,cotrimoxazole,tetracycline and other antimicrobials.The total length of the genome was 2.974 Mb and contained 2941 coding genes.A total of 2144 genes were obtained by GO annotation,including 50 functional properties.Evolutionary analysis of MLST showed that the LM5567 strain was ST515 and was closely related to CC1 strain isolated from different countries.SNP analysis showed that LM5567 had the fewest mutation sites with Canadian strains 02_17924b and 02_1103,and one strain 220 from Poland.The LM5567 strain carried 88 virulence genes,6 resistance genes and 1 transposon Tn6009,which carring the tetracycline resistance gene tetM.【Conclusion】The food-borne strain LM5567 was a multidrug resistant strain of ST515 type,carrying multiple drug resistance genes,virulence genes and 1 transposon in the genome,which had the potential for drug resistance transfer and a high risk of human listeriosis via the food chain.