PDF(Pubmed)
Abstract：
Legionella pneumophila is a persistent opportunistic pathogen that poses a significant threat to domestic water systems. Previous studies suggest that copper (Cu) is an effective antimicrobial in water systems. A rapid and sensitive quantification method is desired to optimize the conditions of L. pneumophila treatment by Cu and to better understand the interaction mechanisms between Cu and cells. In this study, we developed a highly sensitive single cell (SC)-ICP-MS method to monitor L. pneumophila cell concentration and track their uptake of Cu. The SC-ICP-MS method showed excellent sensitivity (with a cell concentration detection limit of 1000 cells/mL), accuracy (good agreement with conventional hemocytometry method), and precision (relative standard deviation < 5%) in drinking water matrix. The cupric ions (Cu2+) treatment results indicated that the total L. pneumophila cell concentration, Cu mass per cell, colony-forming unit counting, and Cu concentration in supernatant all exhibited a dose-dependent trend, with 800-1200 µg/L reaching high disinfection rates in drinking water. The investigation of percentages of viable and culturable, viable but nonculturable (VBNC), and lysed cells suggested there always were VBNC present at any Cu concentration. Experimental results of different Cu2+ treatment times further suggested that L. pneumophila cells developed an antimicrobial resistant mechanism with the prolonged Cu exposure. This is the first quantification study on the interactions of Cu and L. pneumophila in drinking water using SC-ICP-MS.
摘要：
嗜肺军团菌是一种持久性机会性病原体，对生活用水系统构成重大威胁。先前的研究表明，铜（Cu）是水系统中的有效抗菌剂。需要一种快速灵敏的定量方法来优化Cu处理嗜肺乳杆菌的条件，并更好地了解Cu与细胞之间的相互作用机制。在这项研究中,我们开发了一种高灵敏度的单细胞（SC）-ICP-MS方法来监测嗜肺乳杆菌细胞浓度并跟踪其对铜的吸收。SC-ICP-MS方法显示出优异的灵敏度（细胞浓度检测极限为1000细胞/mL），准确性（与常规血细胞计数方法吻合良好），饮用水基质的精密度(相对标准偏差<5%)。铜离子(Cu2+)处理结果表明,每个电池的Cu质量，菌落形成单位计数，上清液中的Cu浓度均呈剂量依赖性趋势，800-1200µg/L在饮用水中达到高消毒率。对可行和可培养的百分比的调查，可行但不可培养(VBNC)，和裂解的细胞表明在任何Cu浓度下总是存在VBNC。不同Cu2处理时间的实验结果进一步表明，随着Cu的延长，嗜肺乳杆菌细胞产生了抗菌耐药机制。这是首次使用SC-ICP-MS对饮用水中Cu和嗜肺乳杆菌的相互作用进行定量研究。
