中试循环输水管道系统中建立嗜肺军团菌生物膜

目的模拟医院供水系统,建立代表上海地区自来水特征的新型中试循环输水管道系统,研究军团菌定植供水系统的能力;评估水流的停滞和层流状态对嗜肺军团菌生物膜的影响。方法采用培养技术和共聚焦激光扫描显微镜动态监测嗜肺军团菌进入生物膜达到稳态的过程。结果军团菌黏附和进入生物膜后开始增殖,第5周达到稳态,95.8%的嗜肺军团菌分布在生物膜内;管壁军团菌定植数量在层流状态明显高于停滞状态,平均值为7.8×104CFU/cm2和1.5×103CFU/cm2。结论中试循环输水管道中成功建立嗜肺军团菌生物膜;生物膜在军团菌增殖中起重要作用;水流停滞不会促进军团菌增殖。

Biofilm Formation of Legionella pneumophila in a Pilot-scale Water Re-circulation System

OBJECTIVE To develop a novel pilot-scale water re-circulation system to evaluate the potential of Legionella biofilm colonied in water distribution system and to assess the effect of flow regimes(laminar vs stagnant) on the presence of Legionella within the biofilm.METHODS Culture techniques and confocal laser scanning microscopy were used to monitor the process of Legionella attachment to the surface of re-circulation loops and formation of the biofilm.RESULTS After 5 weeks of adhesion and multiplication of the Legionella pneumophila,a stable ecosystem in the pilot-scale water re-circulation system was established,more than 95.8% Legionella strains contained in the biofilm.Colonization of Legionella in biofilms was significantly higher in the re-circulation loops(7.8×10~4CFU/cm~2),comparing with the dead legs(1.5×10~3CFU/cm~2).CONCLUSIONS L.pneumophila biofilms are successfully established in pilot-scale water systems.The biofilms play an important role in proliferation of Legionella.The results also reveal that stagnation will not promote the growth of Legionella.