PDF(Pubmed)
Abstract：
Legionella pneumophila can cause a large panel of symptoms besides the classic pneumonia presentation. Here we present a case of fatal nosocomial cellulitis in an immunocompromised patient followed, a year later, by a second case of Legionnaires\' disease in the same ward. While the first case was easily assumed as nosocomial based on the date of symptom onset, the second case required clear typing results to be assigned either as nosocomial and related to the same environmental source as the first case, or community acquired. To untangle this specific question, we applied core-genome multilocus typing (MLST), whole-genome single nucleotide polymorphism and whole-genome MLST methods to a collection of 36 Belgian and 41 international sequence-type 1 (ST1) isolates using both thresholds recommended in the literature and tailored threshold based on local epidemiological data. Based on the thresholds applied to cluster isolates together, the three methods gave different results and no firm conclusion about the nosocomial setting of the second case could been drawn. Our data highlight that despite promising results in the study of outbreaks and for large-scale epidemiological investigations, next-generation sequencing typing methods applied to ST1 outbreak investigation still need standardization regarding both wet-lab protocols and bioinformatics. A deeper evaluation of the L. pneumophila evolutionary clock is also required to increase our understanding of genomic differences between isolates sampled during a clinical infection and in the environment.
摘要：
除了典型的肺炎表现外，嗜肺军团菌还可引起大量症状。在这里，我们介绍了一个在随后的免疫功能低下患者中致命的医院蜂窝织炎的病例，一年后,同一病房的第二例军团病。虽然根据症状出现的日期，第一例很容易被认为是医院感染，第二种情况需要明确的分型结果被分配为医院和与第一种情况相同的环境来源，或社区获得。为了解开这个具体的问题，我们应用核心基因组多位点分型(MLST)，使用文献中推荐的阈值和基于当地流行病学数据的定制阈值,对36个比利时和41个国际序列1型(ST1)分离株进行全基因组单核苷酸多态性和全基因组MLST方法.根据应用于集群隔离的阈值，这三种方法给出了不同的结果，对于第二例病例的医院设置没有得出确切的结论。我们的数据表明，尽管在疫情研究和大规模流行病学调查中取得了有希望的结果，应用于ST1疫情调查的下一代测序分型方法在湿实验室方案和生物信息学方面仍需要标准化.还需要对嗜肺乳杆菌进化时钟进行更深入的评估，以增加我们对在临床感染期间和环境中采样的分离株之间的基因组差异的理解。
