【摘要】 目的 通过构建嗜肺军团菌全基因组系统发育树，探究菌群进化关系，为揭示江门市嗜肺军团菌的暴发流行规律和遗传进化特征提供科学依据。方法 对2019—2022年江门市13间淋浴场所分离培养的51株嗜肺军团菌进行血清分型和测序，将菌株序列上传到美国国立生物技术信息中心（National Center for Biotechnology Information,NCBI）数据库获得分型信息。采用单核苷酸多态性（single nucleotide polymorphisms,SNP）分析构建系统发育树，解析菌株间的系统发育关系。对血清型1型的菌株进行16S rRNA基因分析，并与国内外菌株进行遗传关系比较。结果 51株嗜肺军团菌鉴定出7种血清型，其中1型（LP1）为优势血清型，共检出15株（29.41%）；同时获得12种NCBI分型，其中LPE509型为优势分型，共19株（37.25%）；单个淋浴场所可检出1～3种NCBI分型，存在多株嗜肺军团菌污染的现象。SNP系统发育树显示，51株嗜肺军团菌可分为18个分支（9个大支和9个独株小支），NCBI分型与进化树分支呈现一致性聚类。系统发育树分析表明，同一污染源具有长期持续存在的特征，并且存在跨地区传播的现象。16S rRNA基因种系发生结果显示，15株LP1属于同一个主分支，具有较高的同源性，5株NCBI国内外参考菌株分别来源于中国（广州）、美国、日本、法国，各自形成独立分支，与本地分离株显示出明显的遗传差异。结论 江门市存在嗜肺军团菌污染，污染源呈现长期持续存在和跨地区传播的特征，建议卫生执法部门加强对公共淋浴场所的监管力度，相关机构应强化对淋浴水中嗜肺军团菌的监测，可有效预防和控制军团菌病的发生与传播。更多还原

【Abstract】 Objective To construct a whole-genome phylogenetic tree of Legionella pneumophila to explore the evolutionary relationships among strains,providing evidence to better understand the epidemic patterns and genetic evolution of Legionella pneumophila in Jiangmen City.Methods A total of 51 strains of Legionella pneumophila were isolated and cultured from 13 shower facilities in Jiangmen City from 2019 to 2022.Serotyping and sequencing were conducted,and the sequences of the strains were uploaded to the National Center for Biotechnology Information(NCBI) database to obtain typing information.A phylogenetic tree was constructed using single nucleotide polymorphism(SNP) analysis to elucidate the phylogenetic relationships among the strains.Additionally,16S rRNA gene analysis was performed on the strains of serotype 1,and their genetic relationships were compared with both domestic and international reference strains.Results Among the 51 strains of Legionella pneumophila,seven serotypes were identified,with serotype 1(LP1) being the dominant type,comprising15 strains(29.41%,15/51).Twelve NCBI sequence types(STs) were identified,with LPE509 as the dominant type,accounting for 19 strains(37.25%).Each shower facility exhibited contamination with 1 to 3 different NCBI types,indicating multiple strains of Legionella pneumophila.The SNP phylogenetic tree divided the 51strains into 18 branches(nine major branches and nine unique minor branches),with consistent clustering observed between NCBI types and phylogenetic tree branches.The analysis indicated that the same contamination source exhibited characteristics of long-term persistence and inter-regional transmission.The 16S rRNA gene phylogeny revealed that the 15 LP1 strains belonged to the same main branch with high homology,while five reference strains from NCBI,sourced from China(Guangzhou),the USA,Japan,and France,formed distinct branches,demonstrating significant genetic differences from the local isolates.Conclusions Legionella pneumophila contamination exists in Jiangmen City,characterized by long-term persistence and inter-regional transmission of contamination sources.It is recommended that health enforcement agencies strengthen the regulation of public shower facilities,and relevant institutions enhance monitoring of Legionella pneumophila in shower water to effectively prevent and control the occurrence and spread of legionellosis.更多还原