Bosch Thijs, Euser Sjoerd M, Landman Fabian, Bruin Jacob P, IJzerman Ed P, den Boer Jeroen W, Schouls Leo M
National Institute for Public Health and the Environment, Bilthoven, the Netherlands
Regional Public Health Laboratory Kennemerland, Haarlem, the Netherlands.
J Clin Microbiol. 2015 Oct;53(10):3234-8. doi: 10.1128/JCM.01369-15. Epub 2015 Jul 22.
Legionella is the causative agent for Legionnaires' disease (LD) and is responsible for several large outbreaks in the world. More than 90% of LD cases are caused by Legionella pneumophila, and studies on the origin and transmission routes of this pathogen rely on adequate molecular characterization of isolates. Current typing of L. pneumophila mainly depends on sequence-based typing (SBT). However, studies have shown that in some outbreak situations, SBT does not have sufficient discriminatory power to distinguish between related and nonrelated L. pneumophila isolates. In this study, we used a novel high-resolution typing technique, called whole-genome mapping (WGM), to differentiate between epidemiologically related and nonrelated L. pneumophila isolates. Assessment of the method by various validation experiments showed highly reproducible results, and WGM was able to confirm two well-documented Dutch L. pneumophila outbreaks. Comparison of whole-genome maps of the two outbreaks together with WGMs of epidemiologically nonrelated L. pneumophila isolates showed major differences between the maps, and WGM yielded a higher discriminatory power than SBT. In conclusion, WGM can be a valuable alternative to perform outbreak investigations of L. pneumophila in real time since the turnaround time from culture to comparison of the L. pneumophila maps is less than 24 h.
嗜肺军团菌是军团病(LD)的病原体,在全球引发了多起大规模疫情。超过90%的军团病病例由嗜肺军团菌引起,对该病原体的起源和传播途径的研究依赖于对分离株进行充分的分子特征分析。目前嗜肺军团菌的分型主要依赖基于序列的分型(SBT)。然而,研究表明,在一些疫情情况下,SBT没有足够的鉴别能力来区分相关和不相关的嗜肺军团菌分离株。在本研究中,我们使用了一种名为全基因组图谱(WGM)的新型高分辨率分型技术,来区分流行病学上相关和不相关的嗜肺军团菌分离株。通过各种验证实验对该方法进行评估,结果显示具有高度可重复性,并且WGM能够确认两起有充分记录的荷兰嗜肺军团菌疫情。对这两起疫情的全基因组图谱以及流行病学上不相关的嗜肺军团菌分离株的WGM进行比较,结果显示图谱之间存在重大差异,并且WGM比SBT具有更高的鉴别能力。总之,WGM可以成为实时进行嗜肺军团菌疫情调查的有价值的替代方法,因为从培养到比较嗜肺军团菌图谱的周转时间不到24小时。