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目的采用基因序列分型方法(sequence-based typing,SBT)研究石家庄市集中空调冷却塔水中军团菌基因特征。方法将石家庄市集中空调冷却塔水中分离出的35株Lp1血清型嗜肺军团菌提取基因组DNA,选取嗜肺军团菌7个管家基因flaA、pilE、asd、mip、mompS、proA、neuA进行PCR扩增,将扩增产物纯化后测序。测序结果上传欧盟军团菌感染工作组(EWGLI)数据库进行比对,得到基因型别(sequence type,ST),对结果进行基因序列分型和系统进化分析。结果 35株Lp1血清型嗜肺军团菌共分为4个ST型,其中1株由于neuA基因不能被扩增而未分型;1株为新的ST型,已获EWGLI分配序号(ST1021);其余为ST1型32株,ST345型1株。结论石家庄市集中空调冷却塔水中嗜肺军团菌分离株的流行以ST1型为主,ST345型和ST1021型为特有型别。SBT分型可以作为研究嗜肺军团菌进化关系的重要手段之一。
Objective To study the genetics of Legionella in water of centralized air-conditioner cooling tower in Shijiazhuang City by sequence-based typing (SBT). Methods The genomic DNA of 35 Lp1 serotypes of Legionella pneumophila isolated from the water of central air-conditioning cooling tower in Shijiazhuang City was extracted. Seven housekeeping gene flaA, pilE, asd, mip, mompS, proA and neuA of Legionella pneumophila were selected for PCR amplification Increase, the amplified product was purified and sequenced. Sequencing results were uploaded to the EU Legionella Infection Working Group (EWGLI) database for comparison, to obtain a sequence type (ST), and the results were genotyped and phylogenetically analyzed. Results 35 strains of Legionella pneumophila with Lp1 serotypes were divided into 4 ST types, of which 1 was not typed because neuA gene could not be amplified; 1 was new ST type and had been assigned EWGLI number (ST1021); The rest were ST1 type 32 strains and ST345 type 1 strain. Conclusion The prevalence of Legionella pneumophila isolates in Shijiazhuang centralized air-conditioner cooling tower is mainly ST1 type, and ST345 type and ST1021 type are endemic type. SBT typing can be used as an important means to study the evolutionary relationship of Legionella pneumophila.