206株中国环境分离嗜肺军团菌1型菌株基因序列分型研究

Sequence based typing of Legionella pneumophila serotype 1 isolated from natural environment in China,2008-2012

目的对中国不同自然环境来源分离的嗜肺军团菌血清1型菌株进行分子分型和种群结构分析。方法应用7个基因（fla A、pil E、asd、mip、momp S、pro A、neu A）序列分型方法（Sequence based typing,SBT）对不同环境来源的206株嗜肺军团菌血清1型菌株进行分型研究,通过查询嗜肺军团菌SBT数据库（http：//www.ewgli.org）和用Bio Numerics软件构建最小生成树揭示菌株的分子分型和种群结构特征。结果 206株菌分成54个ST型（IOD=0.7205）。其中49株温泉水分离株分成25个ST型（IOD=0.9498）,各位点Nei指数0.7721~0.8563;130株冷却塔水分离株分成31个ST型（IOD=0.6453）,各位点Nei指数为0.4227~0.4970;27株管道水分离株分成3个ST型（IOD=0.1453）,各位点Nei指数为0.1425~0.1453。ST1型含108株菌,占52.4%,是优势带型。54个ST型形成5个克隆群。通过中国菌株和其他20个国家的菌株综合分析,共计1199株菌分成304个ST型,形成21个序列群。其中ST-1型为全球优势型别,其余型别和序列群呈地区性分布特征。结论中国环境分离的嗜肺军团菌1型菌株具有高度复杂的基因多态性和种群结构,其中ST1是我国也是全球环境菌株的优势型别。

Objective To understand the genotype and population structure of Legionella pneumophila serogroup 1isolates from natural environment in China. Methods Sequence-based typing（ fla A,pile,asd,mip,momp S,pro A,neu A） w as conducted to analyze 206 strains of L. pneumophila serogroup 1 isolated from different environments in China. Results Fifty-four STs w ere obtained w ith an index of discrimination（ IOD） of 0. 7205. The 49 hot spring isolates w ere classified into 25 STs（ IOD = 0. 9498）,the 130 cooling tow er isolates w ere classified into 31 STs（IOD = 0. 6453）,and the 27 potable water isolates were classified into 3 STs（IOD = 0. 1453）. For seven SBT loci,Nei’s index w ere 0. 7721- 0. 8563,0. 4227- 0. 4970,and 0. 1425- 0. 1453 for hot spring,cooling tow er,and potable w ater isolates respectively. Fifty-four STs w ere predicted to form five complexes. The comparison betw een the strains isolated in China and the strains isolated in other countries revealed that similar clones（ ST1 complex） exist in these countries. Conclusion In China,the STs of L. pneumophila serogroup 1 had highly complex gene polymorphism and population structure,and ST1 w as the most predominant sequence type of environmental L. pneumophila serogroup 1isolates obth in China and in the w orld.