Characteristics and influencing factors of Legionella pneumophila contamination in central air conditioning ventilation system of public places in a district of Shenzhen
Objective To understand the status of Legionella pneumophila contamination and the influencing factors in the central air conditioning ventilation systems of public places in Nanshan District,Shenzhen,and provide the scientific evidence for safeguarding the health of the population.Methods During 2014 and 2023,a total of 254 public places were chosen in the monitoring program,and 661 samples of condensate and chilled water from centralized air-conditioning ventilation systems were collected for the detection of Legionella pneumophila(Lp).Results A total of 85 samples of Legionella pneumophila were detected,accounting for 12.86％,comprising 31 for Legionella pneumophila serogroup 1(Lp1),42 for non-Lp1 serogroups,and 12 showing a mix of Lp1 and non-Lp1.The detection rate in cooling water was 16.97％,while the detection rate in condensate water was 4.57％,with significant difference(P＜0.05).Moreover,the Legionella pneumophila detection rates in water samples varied significantly across different years(P＜0.05),indicating an overall decreasing trend(P＜0.05).The chi-square test results for the detection rate of Legionella pneumophila in cooling water indicated significant differences in the detection rates between different seasons(P＜0.05)and between different types of public places(P＜0.05).The results of the logistic regression analysis revealed that the detection rate was higher in summer samples(OR=3.249,95％CI:1.644-6.419)and also higher in shopping malls(OR=2.069,95％CI:1.114-3.844).Conclusion The potential risk of Legionella pneumophila contamination in the central air conditioning systems in public places is obvious throughout Nanshan district,Shenzhen,and the sampling season,type of public places are the influencing factors for the detection rates of Legionella pneumophila species.It is recommended to strengthen hygienic supervision and monitoring during the summer season,and conduct special inspections for public places such as shopping malls.
Legionella pneumophilaCentral air conditioningCooling waterCondensate water
NETL
NSTL
万方数据
