Katsiaflaka Anna, Pournaras Spyros, Kristo Ioulia, Mouchtouri Varvara A, Kyritsi Maria, Velonakis Emmanuel, Vatopoulos Alkiviadis C, Hadjichristodoulou Christos
Department of Hygiene and Epidemiology, Faculty of Medicine, University of Thessaly, Larissa, Greece.
Department of Microbiology, Faculty of Medicine, National and Kapodistrian University of Athens, Athens, Greece.
Appl Environ Microbiol. 2016 Sep 30;82(20):6102-6108. doi: 10.1128/AEM.01672-16. Print 2016 Oct 15.
The aim of this study is to explore the dispersion, clonality, and virulence of Legionella pneumophila serogroups 2 to 14 in the Greek environment. Eighty L. pneumophila serogroup 2 to 14 strains isolated from water distribution systems of hotels, hospitals, athletic venues, and ferries in Greece were tested by monoclonal antibodies (MAbs) for serogroup discrimination and molecularly by amplified fragment length polymorphism (AFLP) for genetic diversity. Fifty-six of 80 strains were also typed by the sequence-based typing (SBT) method. Αll strains were further analyzed for detection of two pathogenicity loci: Legionella vir homologue (lvh) and repeats in structural toxin (rtxA). Thirty-seven strains (46.2%) belonged to serogroup 6, 26 strains (32.5%) to serogroup 3, and 7 (8.8%) to other serogroups (4, 5, 8, and 10). Ten strains (12.5%) were nontypeable (NT) into the known serogroups. Thirty-nine different AFLP types were found among the 80 L. pneumophila serogroup 2 to 14 strains, and 24 different SBT types were found among the 56 strains tested. Among the 80 strains, the lvh locus was present in 75 (93.8%), the rtxA locus was found in 76 (95%), and both loci were found in 73 (91.3%) strains. This study showed that there is genetic variability of L. pneumophila serogroups 2 to 14 in the Greek environment as well as a high percentage of the pathogenicity loci. Ιntroducing an effective diagnostic test for L. pneumophila serogroups 2 to 14 in urine and promoting the examination of respiratory specimens from patients hospitalized for pneumonia in Greek hospitals are essential.
In this study, the dispersion, clonality, and virulence of environmental isolates of Legionella pneumophila serogroups 2 to 14 (Lp2-14) in Greece were investigated. Genetic variability of Lp2-14 in the Greek environment was identified together with the presence of the pathogenicity loci in a high percentage of the isolates. Despite the high prevalence of Lp2-14 in the Greek environment, no clinical cases were reported, which may be due to underdiagnosis of the disease. Almost all the legionellosis cases are diagnosed in Greece by using the urine antigen test, which is specific for Lp1. There is an urgent need to improve the clinical diagnosis of legionellosis by introducing an effective diagnostic test for Lp2-14 in urine and by promoting the PCR examination of respiratory specimens from patients with compatible clinical symptoms.
本研究的目的是探索嗜肺军团菌血清型2至14在希腊环境中的分布、克隆性和毒力。从希腊的酒店、医院、体育场馆和渡轮的供水系统中分离出80株嗜肺军团菌血清型2至14菌株，通过单克隆抗体（MAb）进行血清型鉴别，并通过扩增片段长度多态性（AFLP）进行分子分析以检测遗传多样性。80株菌株中的56株还通过基于序列的分型（SBT）方法进行分型。对所有菌株进一步分析以检测两个致病位点：军团菌毒力同源物（lvh）和结构毒素重复序列（rtxA）。37株（46.2%）属于血清型6，26株（32.5%）属于血清型3，7株（8.8%）属于其他血清型（4、5、8和10）。10株（12.5%）无法分型到已知血清型中。在80株嗜肺军团菌血清型2至14菌株中发现了39种不同的AFLP类型，在测试的56株菌株中发现了24种不同的SBT类型。在80株菌株中，75株（93.8%）存在lvh位点，76株（95%）发现有rtxA位点，73株（91.3%）菌株同时存在这两个位点。本研究表明，嗜肺军团菌血清型2至14在希腊环境中存在遗传变异性，并且致病位点的比例很高。引入针对嗜肺军团菌血清型2至14的有效尿液诊断测试，并促进对希腊医院因肺炎住院患者的呼吸道标本进行检查至关重要。
在本研究中，调查了希腊嗜肺军团菌血清型2至14（Lp2 - 14）环境分离株的分布、克隆性和毒力。确定了Lp2 - 14在希腊环境中的遗传变异性以及高比例分离株中致病位点的存在。尽管Lp2 - 14在希腊环境中普遍存在，但未报告临床病例，这可能是由于该疾病诊断不足。在希腊，几乎所有军团菌病病例都是通过尿液抗原检测诊断的，该检测对Lp1具有特异性。迫切需要通过引入针对Lp2 - 14的有效尿液诊断测试以及促进对具有相容临床症状患者的呼吸道标本进行PCR检查来改善军团菌病的临床诊断。
