摘要目的 了解无锡市不同场所冷却水中军团菌污染状况和菌株分子生物学特性.方法 于2009-2010年对无锡市城区56家场所的冷却水采集平行水样各500 ml,共112份,进行军团菌检测和定量培养,对分离到的菌株进行血清分型、PFGE分型、基因序列分型(SBT),并测定菌株在细胞内的生长能力.结果 56家场所的冷却水水样中,军团菌阳性率为39.3％(22/56),总计分离到29株军团菌,血清型包括LP1、LP3、LP5、LP6,以LP1为主,占65.5％(19/29).29株军团菌PFGE分型得到17个不同带型,其中PFGE带型各异的10株军团菌SBT分型亦不相同.以LP1菌株( ATCC 33152)为参照,WX2011062( LP6)、WX2011067(LP5)细胞内繁殖能力较强[感染当天细胞内菌量分别为(5.5±1.32)×105、(3.9±0.60)×105、(7.8±0.76)×105 CFU/ml,感染第3天细胞内菌量分别为(58.3±1.61)×105、(2700.0±655.74)×105、(3066.7±208.17)×105 CFU/ml].结论 无锡市不同场所冷却水普遍存在军团菌污染,菌型呈现基因多态性,存在巨噬细胞内生长能力较强的菌株.

abstractsObjective To investigate the contamination state of Legionella in cooling water samples from different places in Wuxi city and reveal the molecular biological characteristics of Legionella strains.Methods 112 parallel water samples (500 ml each ) were collected from 56 sites in Wuxi city during year 2009 -2010.The samples were used for Legionella test and quantitative culture.The isolated Legionella strains were used for serotyping,pulsed-field gel electrophoresis ( PFGE),sequence-based typing ( SBT),and intracellular growth were tested.Results The positive proportion of Legionella was 39.3％ (22/56) among all sampling sites.A total of 29 Legionella strains were isolated,and the serotypes include LP1,LP3,LP5 and LP6.LPlserotype was the major one with a proportion of 65.5％ (19/29).29 Legionella strains got 17 PFGE types.There were 10 SBT types among 10 Legionella strains with different PFGE types.Comparing to LP1 strain ( ATCC 33152 ),WX2011062 ( LP6 ) and WX2011067 ( LP5 ) had strong intracellular growth ability in mouse peritoneal macrophages J774 cell line (the amount of intracellular bacteria on day 0 after infection were ( 5.5 ± 1.32 ) × 105,( 3.9 ± 0.60 ) × 105,( 7.8 ± 0.76 ) ×105 CFU/ml,respectively; the amount of intracellular bacteria on day 3 after infection were (58.3 ±1.61)×l05,(2700.0 ± 655.74) × 105,(3066.7 ± 208.17) × 105 CFU/ml,respectively).Conclusion The Legionella contamination existed in cooling water samples from different places in Wuxi city.Legionella strains isolated showed high genetic variation.Some Legionella strains had vigorous intracellular growth ability.