Breiman R F, Butler J C
Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
Semin Respir Infect. 1998 Jun;13(2):84-9.
Legionnaires' disease is a modern environmental infectious disease. It stems from the capacity of the causative agent, Legionella, to multiply within amoebae in warm water and the use, during the 20th century, of devices that maintain water at warm temperatures and produce aerosols. When contaminated with Legionella, aerosols consisting of respirable droplets place the bacteria in juxtaposition with alveolar macrophages, which, as with amoebae, they may parasitize, resulting in illness in susceptible persons. The disease is much more common than previously appreciated with at least 13,000 cases estimated to occur per year in the United States, based on prospective studies. Two highly specific tests, urinary antigen detection and sputum culture, are available for diagnosis during illness. With 60% to 80% sensitivity, urinary antigen tests rapidly detect antigens of Legionella pneumophila serogroup 1, which are responsible for 70% of the cases of legionnaires' disease; results can be available within a few hours. Culture of sputum is 50% to 60% sensitive, but several days are required for growth, and many patients do not produce sputum. Serologic testing, although useful for epidemiologic studies when convalescent-phase antibody titers can be compared with acute-phase titers, is not helpful for clinical decision making because of the low positive predictive value of commercially available acute-phase serologic tests. Erythromycins, intravenous azithromycin, and levofloxacin are currently approved by the US Food and Drug Administration for treatment of legionnaires' disease. However, clarithromycin and several other fluoroquinolones are active against Legionella and may also provide effective therapy. Recent recommendations from the Centers for Disease Control and Prevention's Hospital Infection Control Practices Advisory Committee should be helpful in reducing nosocomial legionnaires' disease. Recommendations are in place or are being developed to minimize the risk of disease in a variety of other settings.
军团病是一种现代环境感染性疾病。它源于病原体嗜肺军团菌在温水中的变形虫内繁殖的能力，以及20世纪期间使用的将水保持在温暖温度并产生气溶胶的装置。当被嗜肺军团菌污染时，由可吸入飞沫组成的气溶胶会使细菌与肺泡巨噬细胞并列，它们可能像寄生在变形虫中一样寄生在肺泡巨噬细胞中，从而导致易感人群患病。根据前瞻性研究，这种疾病比以前认为的更为常见，在美国估计每年至少有13000例病例。在患病期间，有两种高度特异性的检测方法，即尿抗原检测和痰培养，可用于诊断。尿抗原检测的灵敏度为60%至80%，可快速检测嗜肺军团菌血清型1的抗原，该血清型导致70%的军团病病例；结果可在几小时内获得。痰培养的灵敏度为50%至60%，但生长需要几天时间，而且许多患者不咳痰。血清学检测虽然在将恢复期抗体滴度与急性期滴度进行比较时对流行病学研究有用，但由于市售急性期血清学检测的阳性预测值较低，对临床决策没有帮助。红霉素、静脉注射阿奇霉素和左氧氟沙星目前已被美国食品药品监督管理局批准用于治疗军团病。然而，克拉霉素和其他几种氟喹诺酮类药物对嗜肺军团菌有活性，也可能提供有效的治疗。疾病控制与预防中心医院感染控制实践咨询委员会最近的建议应有助于减少医院内军团病的发生。已经有或正在制定相关建议，以尽量减少在各种其他环境中患病的风险。
