MEDSCAPE观点]：患者是肺炎？需要考虑军团菌！

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[MEDSCAPE观点]：患者是肺炎？需要考虑军团菌！
2016年04月08日 ⁄ 时讯速递, 进展交流 ⁄ 暂无评论
Medscape Pulmonary Medicine > Viewpoints
COMMENTARY
Patient Has Pneumonia? Think Legionellosis
Nicholas Gross, MD, PhD
February 23, 2016
Active Bacterial Core Surveillance for Legionellosis -- United States, 2011-2013
Dooling KL, Toews KA, Hicks LA, et al
MMWR Morb Mortal Wkly Rep. 2015;64:1190-1193
w_home_banner_legionella

Legionellosis: Underestimating the Incidence? 军团菌病：发病率被低估？
Legionellosis is the disease acquired by inhalation of Legionellabacteria. The most common presentation is a severe form of pneumonia, although a milder self-limited infection—Pontiac fever—can occur. A recent Morbidity and Mortality Weekly Report compared the incidence of legionellosis during 2000-2011, when case finding was passive, with data from 2011-2013, when the Active Bacterial Core Surveillance (ABCs) program was in place and confirmed cases met laboratory criteria for legionellosis.

军团菌病是由于吸入军团菌所导致的疾病。最常见的表现为重症肺炎，尽管也可以表现为病情较轻的自限性感染—庞蒂亚克热。近期的Morbidity and Mortality Weekly Report比较了2000-2011年间（此期间病例发现为被动式）及2011-2013年间（此时实施主动细菌核心监测[ABCs]计划，确诊病例符合军团菌病的实验室标准）军团菌病的发病率。

During the earlier period, the crude incidence of legionellosis increased by 249%, from 0.39 to 1.36 cases per 100,000 persons. During the later period, ABCs data confirmed a total of 1426 cases, for an incidence rate of 1.3 cases per 100,000 persons. Therefore, disease rates were similar in both the passive and active surveillance periods. However, inconsistency in the use of the bacteriologic methods and a reliance on less sensitive urine antigen testing to diagnose legionellosis probably resulted in many missing cases, so these data probably underestimate the actual burden of legionellosis.

在早期，军团菌病的粗发病率增加249%，从每100000人0.39例增加至1.36例。在后期，ABCs数据共确诊1426例患者，发病率为每100000人1.3例。因此，被动与主动监测阶段疾病发病率数据相似。然而，由于在细菌学方法方面存在不一致的情况，而且多依赖敏感性较低的尿抗原检测诊断军团菌病，可能遗漏很多病例，因此上述数据可能低估了军团菌病的实际情况。

The ABCs data from 2011 to 2013 also showed that 44% of patients with legionellosis required intensive care, 27% required mechanical ventilation, and 9% died. Disease incidence was highest on the East Coast, especially in New York, Maryland, and Connecticut; Oregon and California had the lowest incidence. Among other demographic features, the incidence was higher among black persons than white persons and among males than females, and it increased progressively with age older 50 years. Underlying conditions that predisposed to legionella infection were current cigarette smoking, immunosuppression, chronic obstructive pulmonary disease (COPD), and diabetes.

2011-2013年的ABCs数据还表明，约44%的军团菌病患者需要入住ICU，27%接受机械通气，9%死亡。东海岸军团菌病的发病率最高，尤其是纽约、马里兰和康涅狄格州；俄勒冈州和加州发病率最低。人口统计学方面，黑人发病率高于白人，男性发病率高于女性，年龄超过50岁后发病率进行性升高。容易发生军团菌感染的基础疾病包括吸烟、免疫功能抑制、COPD和糖尿病。

Viewpoint 观点
Legionellosis has increased in frequency over the decades since its first identification. Its frequency, severity, and high mortality demand greater suspicion on the part of clinicians. Factors that might be considered warnings for the clinician are age (particularly > 70 years) and the presence of comorbid conditions (smoking, COPD, diabetes). The commonly used urine antigen test is limited to detection of the Lp1 antigen which is present in only about 80% of cases; culture is preferred if available. More sensitive tests are required.

自从最初被发现以来，数十年来军团菌病的发病率逐渐升高。军团菌发病率高，病情严重，病死率高，这些特点要求临床医生保持较高的警惕性。对于临床医生而言，需要考虑的高危因素包括年龄（尤其> 70岁），以及基础疾病（吸烟，COPD和糖尿病）。最常使用的尿抗原检测存在局限性，即这种检查方法所能够检测的Lp1抗原仅占病例的80%；如果有条件应首选培养。需要更为敏感的检测方法。

Treatment, which will often be initiated empirically, is based on the newer macrolides, such as azithromycin (1 g initially, followed by 500 mg daily for 7-10 days[1]), or a quinolone, such as levofloxacin (750 mg once daily for 5 days[2]) for patients who are not immunocompromised. Combinations of these agents or the combination of a quinolone with rifampin have been used, but no formal trials of a combination vs monotherapy have been published. Parenteral therapy is preferred to oral therapy. For immunosuppression, a combination given for 21 days has been recommended. Isolation of patients is unnecessary because legionella is not transmitted from person to person.[3]

治疗常常为经验性，没有免疫功能抑制的患者可使用新的大环内酯如阿奇霉素（初始剂量1 g，随后每日500 mg，疗程7-10天）[1]，或喹诺酮如左旋氧氟沙星（750 mg每日一次，疗程5天[2]）。也有人联合使用上述药物，或联合使用喹诺酮和利福平，但尚未发表比较联合用药和单药治疗的临床试验结果。优先选择胃肠外用药。对于免疫功能抑制患者，推荐联合用药21天。患者无需隔离，因为军团菌并不在人群中传播[3]。

References
1. Vergis EN, Indorf A, File TM Jr, et al. Azithromycin vs cefuroxime plus erythromycin for empirical treatment of community-acquired pneumonia in hospitalized patients: a prospective, randomized, multicenter trial. Arch Intern Med. 2000;160:1294-1300.

2. Edelstein PH, Edelstein MA, Lehr KH, Ren J. In-vitro activity of levofloxacin against clinical isolates of Legionellaspp, its pharmacokinetics in guinea pigs, and use in experimental Legionella pneumophila pneumonia. J Antimicrob Chemother. 1996;37:117-126.

3. Yu VL, Sopena Galindo N. Treatment and prevention of Legionella infection. UpToDate. January 21, 2016. http://www.uptodate.com/contents ... egionella-infection Accessed February 3, 2016.

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