南方某城市公共场所空调冷却塔水军团菌污染状况调查

Investigation on Legionella Contamination in Cooling Tower Water of Central Air Conditioning System in Public Places of a City in South China

目的了解南方某城市公共场所空调冷却塔水中军团菌污染状况并对影响因素进行分析。方法于2009年7月随机采集该城市22户公共场所集中空调冷却塔水54份,根据《公共场所集中空调通风系统卫生规范》和ISO11731-1998《Water quality-Detection and enumeration of Legionella》检测军团菌,并对集中空调使用及管理情况进行调查。结果 22户公共场所中有19户检出军团菌,阳性率高达86.4%;54份空调冷却塔的水样中有31份检出军团菌,总检出率为57.4%。不同类型场所采集的水样军团菌检出率无统计学意义(P>0.05)。检出的菌株均为嗜肺军团菌,其中Lp1型占35.5%,Lp2～14型占64.5%。不同冷却塔水温、水样菌落总数、空调使用年限、水样消毒与否对军团菌检出率影响均不显著(P>0.05)。结论该城市公共场所空调冷却塔水军团菌污染较为严重,分布较为广泛,对人群健康具有潜在威胁。应定期有效地对冷却塔水及空调系统进行消毒清洗,避免军团菌病的暴发流行。

Objective To know the status of Legionella contamination in cooling tower water of central air conditioning system in the public places of a city in south China and the related factors. Methods Fifty-four water samples from cooling towers of 22 public places were randomly collected for the determination of Legionella according to the Sanitation Criteria for Central Conditioners in Public Buildings and Water Quality-Detection and Enumeration of LegioneUa ISOl1731-1998, and the questionnaire survey was performed for the use, operation and management of the central air conditioning systems. Results Legionella was detected in water samples from 19 public places among the total water samples from 22 public places,the detection rate was as high as 86.4%. There were 31 isolates ofLegioneUapneumophila （Lp） from 54 samples with the total detection rate of 57.4%. No significant difference was seen in the detection rate of LegioneUa in the samples from different public places （P〉0.05）. The isolates were initially classified by serotyping as Lpl and Lp2-14 with percent of 35.5%, 64.5% respectively. The detection rates of Legionella showed no significant differences under the different conditions including water temperature, standard plate- count bacteria,service life of air conditioning systems or disinfection of the samples （P〉O.05）. Conclusion Legionella contamination of cooling tower water in the public places of this city is serious and distributes widely. There is a potential threat to the health of the residents. The hygienic management of central air conditioning system should be enhanced to avoid the outbreak of Legionnaires＇ disease.