2008-2019年福建省泉州市公共场所中央空调冷却塔水军团菌污染状况及毒力基因携带情况

Legionella and its carriage of virulence genes detected in air condition cooling towers at public places in Quanzhou,Fujian,2008–2019

目的了解2008—2019年福建省泉州市公共场所中央空调冷却塔水军团菌污染状况,分析分离菌株毒力基因携带情况,为军团菌防控提供数据支撑。方法用荧光定量PCR法和分离培养法对泉州市12个县(区)31家公共场所冷却塔水进行军团菌分离、鉴定、分型和核酸检测。运用PCR方法检测分离菌株的7个毒力基因(iraA、cpxR、cpxA、dotA、rpoB、icmC、icmD)。结果2008—2019年共采集空调冷却塔水样569份,分离到军团菌159株,分离率为27.94%。其中嗜肺军团菌136株,分离率为23.90%。嗜肺军团菌血清型有LP1、3、5、6、8、10型,其中LP1型49株,占30.82%,为优势血清型。此外,还有长滩军团菌、菲利军团菌、杜莫夫军团菌等。2种检测方法的符合率为88.40%,荧光定量PCR法检出率明显高于分离培养法,差异有统计学意义(χ^(2)=313.532,P<0.05)。136株嗜肺军团菌中7个毒力基因全部阳性,82.61%的其他非嗜肺军团菌全部阴性。结论泉州市公共场所中央空调冷却水军团菌污染较严重,分离的嗜肺军团菌菌株均携带毒力基因。应加强公共场所空调冷却水塔的清洗和消毒,持续监测外环境中军团菌,防控军团菌病的发生。

Objective To understand the contamination of Legionella in air condition cooling towers at public places in Quanzhou,Fujian province,from 2008 to 2019,and identify its carriage of virulence genes and pathogenicity and provide evidence for the prevention and control of Legionellosis.Methods The isolation,identification,genotyping and nucleic acid testing of Legionella from water samples collected from the air condition cooling towers at 31 public places in 12 counties of Quanzhou from 2008 to 2019 were conducted.PCR assay was used to detect 7 virulence genes of the isolated strains,including iraA,cpxR,cpxA,dotA,rpoB,icmC,icmD.Results A total of 569 water samples were collected from the air condition cooling towers during 2008–2019,in which 159 Legionella strains were isolated(27.94%).The majority of the Legionella strains were L.pneumophila(136,23.90%),and the remaining included L.longbeachae,L.philliflora and L.dumoffii.The serotypes of L.pneumophila were 1,3,5,6,8 and 10,and serotype 1 was the predominant one(49,30.82%).The consistent rate of the two methods was 88.40%,but the positive rate of quantitative real-time PCR was significantly higher than that of isolation.The difference was significant(χ^(2)=313.532,P<0.05).All the 136 L.pneumophila strains carried 7 virulence genes,while the virulence genes detection results of 82.61%of the non-L.pneumophila strains were negative.Conclusion Serious contamination of Legionella was found in the air condition cooling towers at public places in Quanzhou,and L.pneumophila was predominant and carried virulence genes.Timely cleaning and disinfection of air condition cooling towers are necessary to prevent the infection of Legionella.