提高军团菌检出率的实验室研究

A laboratory study on methods for increment of isolating rate of Legionella

目的:军团菌生长缓慢,人工培养条件苛刻,不容易检出。为了提高军团菌检出率,秦皇岛市疾控中心开展了实验室专项研究。方法:定性样品主要来源于集中空调系统的冷却水、冷媒水、冷凝水,采集500 ml,根据ISO11731:1998(E)等标准,运用分离培养这一细菌鉴定的金标准,采用3种方法处理样品,对实验过程进行分析。定量实验的菌株来源于实验过程所获得的,配成0.5麦氏单位后依次10倍稀释,菌液浓度依次成*107、*106、*105、*104、*103cfu/ml。结论:军团菌的分离培养受样品的采集、处理、菌落观察及培养基质量等多种因素影响,在实际工作中至少可以从5个方面提高军团菌的检出率。定量实验证明酸处理既能有效去除杂菌又能保证军团菌的存活,有效提高检出率。

Objective：Legionella is a slowly growth and a harsh artificial culturing conditioned bacterium, it is hard to isolate and detect these bacteria. To increase the isolation rate Legionella, a laboratory study on the method for Legionella isolation was undertaken in Qinhuangdao Municipal Center of Disease Contro and 1Prevention. Methods：Samples isolated were qualitatively ana- lyzed mainly from the cooling water, cold medium water, and condensed water of the central air - conditioning systems. Five hundreds ml of samples were isolated and cultured, base on a gold standard method of ISO11731：1998（ E）, and the samples were pretreated with 3 different procedures, and compounding factors of the laboratory process was analyzed. The strains for quantitative analysis were derived from testing process, and were diluted into a bacterial concentrations of 10^7, 10^6, 10^5, 10^4, and 10^7 cfu/ml. Conclusion： Isolation and culturing of Legionella were influenced by such factors as sample collection, treatment, colony observation and medium quality. To increase the isolation rate of Legionella, at least five aspects of concerns should be taken. Quantitative analysis of Legionella has demonstrated that not only acid treatment could remove the other compound bacteria, but also guarantee the survival of Legionella, therefore, could increase the isolation rate for these bacteria.