冷却塔水环境中军团菌与寄主的相互关系

Legionella are opportunistic pathogens which normally live in water, in soil and within free-living unicellular protozoa and can cause pneumonia known as Legionnaires' disease which is reported frequently all over the world since 1980's. To investigate the occurrence and distribution of Legionella in Guangzhou, a combination of plating isolation, seminested PCR and EnviroAmp PCR reverse hybridization kit was used to isolate and detect the Legionella from man-made water systems where have been proved to be the source of infectious aerosols contaminated with Legionella. The seminested PCR results show that the positive rate of the samples from water-cooling towers was 84% in average, even up to 100% in 3 of 9 sampling sites. The positive rate of tape water was 35%, albeit L.pneumophila ,the most virulent species has not been found. These results demonstrate high Legionella-contaminating degree in Guangzhou man-made water systems, although the positive rate has slight fluctuation along with the sampling time and places. The disadvantage and advantage of each detective method used in this research and seasonal occurrence and distribution of Legionella were also discussed. To investigate the relationship between occurrence of Legionella species and protozoa population, the species of protozoa in 4 cooling tower waters were isolated monthly for a year and identified. The results showed that there are around 11 species of free-living protozoa in the waters. Among them, Oikomonas termo, Cyclidium muscicola, Bodo sp and Trinema lineare are dominant species in all the towers although the numbers in each tower is slightly different. The result of annual variation analysis demonstrate that most number of species was isolated at January, but least number present at June, July and August. The results also indicated that the species number and amount of protozoa in cooling tower waters have a peak in winter and spring. The relationship of population variation between Legionella and protozoa was analyzed and discussed based on the above data.

综合应用分子微生物学检测技术及原生动物学相关技术系统地研究我国城市冷却塔水环境中重要的条件致病菌军团菌及其原生动物寄主的分布、数量及季节性变化，以及军团菌在寄主中的增殖情况，从环境生态的角度探讨军团菌的增殖与寄主的相互关系，为水环境中军团菌的危险性评估和控制提供理论依据，并为进一步的研究打下基础。