Abstract：
Atypical pathogens are intracellular bacteria causing community-acquired pneumonia (CAP) in a significant minority of patients. Legionella spp., Chlamydia pneumoniae and psittaci, Mycoplasma pneumoniae, and Coxiella burnetii are commonly included in this category. M. pneumoniae is present in 5-8% of CAP, being the second most frequent pathogen after Streptococcus pneumoniae. Legionella pneumophila is found in 3-5% of inpatients. Chlamydia spp. and Coxiella burnetii are present in less than 1% of patients. Legionella longbeachae is relatively frequent in New Zealand and Australia and might also be present in other parts of the world. Uncertainty remains on the prevalence of atypical pathogens, due to limitations in diagnostic means and methodological issues in epidemiological studies. Despite differences between CAP caused by typical and atypical pathogens, the clinical presentation alone does not allow accurate discrimination. Hence, antibiotics active against atypical pathogens (macrolides, tetracyclines and fluoroquinolones) should be included in the empiric antibiotic treatment of all patients with severe CAP. For patients with milder disease, evidence is lacking and recommendations differ between guidelines. Use of clinical prediction rules to identify patients most likely to be infected with atypical pathogens, and strategies of narrowing the antibiotic spectrum according to initial microbiologic investigations, should be the focus of future investigations.
摘要：
非典型病原体是在相当少的患者中引起社区获得性肺炎(CAP)的细胞内细菌。军团菌属。,肺炎衣原体和鹦鹉，肺炎支原体,和伯氏柯西拉通常包括在这一类别中。肺炎支原体存在于5-8%的CAP中，是仅次于肺炎链球菌的第二常见病原体。在3-5％的住院患者中发现了嗜肺军团菌。衣原体属。不到1％的患者存在伯氏柯西氏菌。Longbeachae军团菌在新西兰和澳大利亚相对频繁，也可能出现在世界其他地区。非典型病原体的流行仍然存在不确定性，由于流行病学研究中诊断手段和方法学问题的限制。尽管由典型和非典型病原体引起的CAP之间存在差异，仅凭临床表现无法进行准确的辨别.因此，对非典型病原体有活性的抗生素(大环内酯类，四环素和氟喹诺酮）应包括在所有严重CAP患者的经验性抗生素治疗中。对于患有轻度疾病的患者，缺乏证据,不同指南的建议也不同.使用临床预测规则来识别最有可能感染非典型病原体的患者，以及根据初始微生物调查缩小抗生素谱的策略，应该是未来调查的重点。
