浙江省61株嗜肺军团菌血清1型菌株的SBT序列分型

Sequence-based typing for 61 Legionella pneumophila serogroup 1 isolates in Zhejiang Province

目的了解浙江省空调冷却塔/冷凝水中嗜肺军团菌血清1型(Lp1)菌株的序列分型特征。方法选取2005～2011年间浙江省10个地区空调冷却塔/冷凝水中分离的61株Lp1型嗜肺军团菌菌株,采用欧盟军团菌感染工作组(EWGLI)军团菌序列分型(SBT)方法,PCR扩增7对管家基因,对扩增产物进行测序、比对、递交,以获取等位基因号以及SBT序列型,运用DNAsp 5.0软件对测序结果进行核苷酸多态性分析,采用SplitsTree及eBURST软件对分型结果进行聚类分析。结果 61株Lp1型嗜肺军团菌可分为11种SBT序列型,其中5株(5/61)均为新发现序列型;ST-1型在10个地区(市)的冷却塔/冷凝水中均有分布,该序列型菌株占81.9%(50/61)。7个管家基因的核苷酸多态性(Pi)范围为0.01095(mip)～0.05355(pilE)。聚类分析显示,浙江省Lp1型菌株分属多个克隆系,但主要分属ST-1序列群、ST-154序列群和ST-149三大序列群,另有1株为不属于任何序列群的单体。结论聚类分析表明浙江省空调冷却塔/冷凝水中分离的Lp1型嗜肺军团菌存在遗传多样性,序列群分布与国内部分省份的结果相似,以ST-1序列型为主。

Objective To analyze the sequence characteristics of the serogroup 1 Legionella pneumophila（Lp1） strains isolated from the cooling tower water in Zhejiang province by sequence-based typing（SBT）.Methods 61 strains of Lp1 isolated from cooling tower water in ten cities of Zhejiang Province from 2005 to 2011 were genotyped by SBT method.The nucleotide polymorphism of the sequencing results was analyzed by DnaSP 5.0,and the SBT results were cluster analyzed using SplitsTree and eBURST software.Results All 61 isolates of Lp1 were resolved into 11 STs,and 5 new STs were found in this study.The ST with the largest number of isolates was ST1（n=50）,and these ST-1 strains were found in 10 cities.The nucleotide polymorphism（Pi） of these seven housekeeping genes ranged from 0.01095（mip） to 0.05355（pilE）.The STs of the Lp1 isolates were clustered to four clonal complexes（CC）,and ST-1,ST-149,ST-154 were the three main clonal complexes（CC）.Conclusion Genetic diversity was shown in the serogroup 1 Legionella pneumophila strains isolated from cooling tower water in Zhejiang Province.