Abstract：
Legionella pneumophila (L. pneumophila) is one of the main pathogens, causing pneumonia and respiratory tract infections, especially in patients with ventilator-associated pneumonia (VAP). This study aimed to approve the hypothesis that the serogroup distribution of L. pneumophila isolates from patients is correlated with Legionella strains in the environment. A total of 280 bronchoalveolar lavage (BAL) samples from VAP patients admitted to the intensive care unit (ICU) as well as 116 water samples from different sources in four hospitals in Tehran, Iran, were evaluated for the presence of L. pneumophila infection by culture, nested polymerase chain reaction (PCR), real-time PCR, and sequencing for genetic diversity. The molecular and culture methods found 24 (8.6%) and 5 (1.8%) samples to be positive for L. pneumophila in VAP patients, while they found 23 (19.8%) and 8 (6.9%) positive samples in water resources, respectively. The sequencing results indicated that all positive clinical samples and 14 (60.8%) environmental samples were belonged to L. pneumophila serogroup 1. Smoking, age, length of ICU stay, and duration of ventilator use had strong relationship with L. pneumophila infectivity. In conclusion, this is the first report from Iran to determine minor differences in the serogroup distribution of environmental and clinical strains. However, further studies are needed to confirm this relationship in different regions of Iran.
摘要：
嗜肺军团菌（L.肺炎)是主要的病原体之一，引起肺炎和呼吸道感染,尤其是呼吸机相关性肺炎（VAP）患者。这项研究旨在批准以下假设：来自患者的嗜肺乳杆菌分离株的血清群分布与环境中的军团菌菌株相关。共有280个支气管肺泡灌洗（BAL）样本，来自VAP患者的重症监护病房（ICU）以及来自德黑兰四家医院的不同来源的116个水样，伊朗,通过培养评估嗜肺乳杆菌感染的存在，巢式聚合酶链反应（PCR），实时PCR，和遗传多样性测序。分子和培养方法在VAP患者中发现24（8.6％）和5（1.8％）个样本对肺炎杆菌呈阳性，虽然他们在水资源中发现了23份(19.8%)和8份(6.9%)阳性样本，分别。测序结果表明，所有阳性临床样本和14份（60.8%）环境样本均属于1型肺炎杆菌血清群。吸烟,年龄,ICU住院时间,呼吸机的使用时间与嗜肺乳杆菌的传染性有很强的关系。总之,这是伊朗首次报告确定环境和临床菌株血清群分布的微小差异.然而,需要进一步的研究来证实伊朗不同地区的这种关系。
