广州市公共场所中央空调冷却塔水中军团菌mip基因分型

Mip genotyping of Legionella isolated from central air-conditioning cooling towers in Guangzhou public places

【目的】研究广州市公共场所中央空调冷却塔水中军团菌的基因特征和优势型别。【方法】采用军团菌巨噬细胞感染力增强因子(Macrophage infectivity potentiator,mip)基因分型方法。提取广州市2008-2010年分离的140株(119株嗜肺,21株非嗜肺)军团菌基因组DNA,针对mip基因进行PCR扩增并测序,将核苷酸序列上传至欧洲军团菌感染工作组(EWGLI)数据库进行比对,得到mip型别,并构建系统发育进化树。【结果】140株军团菌均可扩增出700 bp左右的目的条带。119株嗜肺军团菌分为10个mip型别,L.pneumophila-phil-1为优势型别,占52.9%(63/119);21株非嗜肺军团菌分为6个mip型别,L.feeleii-D3131为优势型别,占47.6%(10/21)。【结论】广州市公共场所中央空调冷却塔水中军团菌具有多样性,mip分型技术可用于军团菌的快速基因分型。

[Objective] To analyze the genetic characteristics and dominant types of Legionella isolated from central air-conditioning cooling towers in public places in Guangzhou from 2008 to 2010. [Methods] Genomic DNA was extracted from 140 strains of Legionella （119 strains of pneumophila and 21 strains of non-pneumophila）. Subsequently, the rnip （macrophage in fectivity potentiator） gene was PCR amplified, purified and sequenced. Those nucleotide se- quences were blasted in the European Working Group for Legionella Infections （EWGLI） Da- tabase for the mip typing. Phylogenetic trees were constructed with the Neighbor-Joining （NJ） method using MEGA 5.0. [Results] Approximately 700 bp fragments of the rnip gene was ob- tained from 140 Legionella strains. The 119 L. peumophila were found to be in 10 rnip types, with L. pneumophila-phil-1 as the dominant accounting for 52.9% （63/119）. The 21 non-L, penumophila from the isolates were found to be in 6 mip types, with L. feeleii-D3131 as the dominant accounting for 47.6% （10/21）. [Conclusion] Great diversity was observed among Le- gionella strains in central air-conditioning cooling towers of Guangzhou public places, while the mip typing techniques used in this study could be used for fast genotyping of Legionella.