Objective To investigate Legionella pollution in cooling water of central air conditioning system in public places of Wenzhou.
Methods A total of 126 water samples of cooling towers were collected from 30 public places (hospitals, hotels, and supermarkets) of Wenzhou in 2010 and 2011. Isolated pathogen cultivation and fluorescent quantitative polymerase chain reaction (PCR) were used to detect Legionella organisms in the water samples.
Results In 2010 and 2011, the positive rates of Legionella were 62.50% and 33.93%, respectively. Of the 56 strains isolated, 33 were identified as Legionella pneumophila Lp1-15, of which 19.64% was Lp6 (11/56) and 17.86% was Lp1 (10/56) and both were predominant serological types and principally derived from hospitals. According to the results of fluorescent quantitative PCR detection, positive 16S rRNA genes were found in 56 Legionella isolates, of which 35 isolates showed mip gene positive, accounting for 62.50%.
Conclusion Legionella pollution is commonly found in the cooling water of central air conditioning systems in Wenzhou public places, and Lp6 and Lp1 are predominant serological types.
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