Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
Chest. 2010 Jul;138(1):130-6. doi: 10.1378/chest.09-1562. Epub 2010 Feb 19.
Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has been documented to cause community-acquired pneumonias (CAP), notable for necrotizing features. The frequency of occurrence, risk factors, and optimal treatment of CA-MRSA CAP are unclear.
This was a retrospective analysis of patients admitted to Northwestern Memorial Hospital from January 2005 to April 2007 with initial clinical presentation of pneumonia and respiratory or blood culture positive for CA-MRSA. Definition of CA-MRSA was based on sensitivity to trimethoprim/sulfamethoxazole and clindamycin.
Fifteen patients with CA-MRSA CAP were identified during the 28-month period. Only one of the 14 patients tested had evidence of preceding influenza, and no seasonal pattern was seen. Seven patients were never admitted to the ICU. Eight of 14 with chest CT scans had evidence of lung necrosis. Nine of 15 had evidence of pleural effusions early in their hospital course, and five of nine required at least one pleural drainage procedure. Seven of 15 were immunocompromised (three HIV, one acute lymphocytic leukemia [ALL], one high-dose steroids, and two immunoglobulin deficiency) with an additional three patients with diabetes. Mortality was only 13% (two of 15); both deaths occurred in patients with severe immunocompromise (ALL post chemotherapy and AIDS). Fourteen of 15 patients were treated with antimicrobials that inhibit exotoxin production (clindamycin or linezolid).
CA-MRSA pneumonia is not necessarily a post-influenza infection. Despite necrotizing features in many, the mortality of CA-MRSA pneumonia in our series is lower than previously reported, and patients do not routinely require ICU care. Treatment with antibiotics that inhibit exotoxin production and/or nontoxigenic strains may explain this improved outcome.
已证实社区获得性耐甲氧西林金黄色葡萄球菌（CA-MRSA）可引起社区获得性肺炎（CAP），其特征为坏死性。CA-MRSA CAP 的发生频率、危险因素和最佳治疗方法尚不清楚。
这是对 2005 年 1 月至 2007 年 4 月期间因初始临床表现为肺炎且呼吸道或血液培养 CA-MRSA 阳性而入住西北纪念医院的患者进行的回顾性分析。CA-MRSA 的定义基于对复方磺胺甲噁唑/甲氧苄啶和克林霉素的敏感性。
在 28 个月期间发现了 15 例 CA-MRSA CAP 患者。在接受检测的 14 例患者中，仅有 1 例有流感前期证据，且未发现季节性模式。7 例患者从未入住 ICU。14 例胸部 CT 扫描中有 8 例有肺坏死证据。15 例中有 9 例在入院早期即有胸腔积液证据，其中 5 例需要至少 1 次胸腔引流术。15 例中有 7 例免疫功能低下（3 例 HIV、1 例急性淋巴细胞白血病[ALL]、1 例大剂量类固醇和 2 例免疫球蛋白缺乏），另外 3 例有糖尿病。死亡率仅为 13%（15 例中有 2 例）；两名死亡患者均为严重免疫功能低下者（化疗后 ALL 和 AIDS）。15 例中有 14 例接受了抑制外毒素产生的抗生素治疗（克林霉素或利奈唑胺）。
CA-MRSA 肺炎不一定是流感后感染。尽管许多患者具有坏死性特征，但本系列 CA-MRSA 肺炎的死亡率低于以往报道，患者通常不需要 ICU 护理。使用抑制外毒素产生和/或非致病毒株的抗生素治疗可能解释了这种改善的结果。
