Francis John S, Doherty Meg C, Lopatin Uri, Johnston Cecilia P, Sinha Gita, Ross Tracy, Cai Mian, Hansel Nadia N, Perl Trish, Ticehurst John R, Carroll Karen, Thomas David L, Nuermberger Eric, Bartlett John G
Division of Infectious Diseases, Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
Clin Infect Dis. 2005 Jan 1;40(1):100-7. doi: 10.1086/427148. Epub 2004 Dec 7.
Recent worldwide reports of community-onset skin abscesses, outbreaks of furunculosis, and severe pneumonia associated with methicillin-resistant Staphylococcus aureus (MRSA) carrying Panton-Valentine leukocidin (PVL) genes and the staphylococcal cassette chromosome mec (SCCmec) type IV indicate that MRSA infections are evolving into a community-related problem. The majority of cases reported to date involve skin and soft-tissue infections, with severe pneumonia representing a relatively rare phenomenon. During a 2-month period in the winter of 2003-2004, four healthy adults presented to 1 of 2 Baltimore hospitals with severe necrotizing MRSA pneumonia in the absence of typical risk factors for MRSA infection.
Patients' MRSA isolates were characterized by strain typing with use of pulsed-field gel electrophoresis and SCCmec typing with use of a multiplex polymerase chain reaction (PCR) assay and detection of PVL genes by PCR.
All 4 patients' MRSA isolates carried the PVL genes and the SCCmec type IV element and belonged to the USA300 pulsed-field type. These 3 findings are among the typical characteristics of community-onset MRSA strains. In addition, 2 of our patients had concomitant influenza A diagnosed, which likely contributed to the severity of their presentation.
To our knowledge, these patients represent the first reported North American adults with severe community-onset MRSA pneumonia caused by strains carrying the PVL genes.
近期全球范围内有关社区获得性皮肤脓肿、疖病暴发以及与携带杀白细胞素（PVL）基因和葡萄球菌盒式染色体mec（SCCmec）IV型的耐甲氧西林金黄色葡萄球菌（MRSA）相关的严重肺炎的报告表明，MRSA感染正演变为一个与社区相关的问题。迄今为止报告的大多数病例涉及皮肤和软组织感染，严重肺炎是一种相对罕见的现象。在2003 - 2004年冬季的两个月期间，4名健康成年人在巴尔的摩的2家医院中的1家就诊，患有严重坏死性MRSA肺炎，且不存在MRSA感染的典型危险因素。
通过脉冲场凝胶电泳进行菌株分型、利用多重聚合酶链反应（PCR）检测SCCmec分型以及通过PCR检测PVL基因，对患者的MRSA分离株进行特征分析。
所有4名患者的MRSA分离株均携带PVL基因和SCCmec IV型元件，且属于USA300脉冲场型。这3项发现是社区获得性MRSA菌株的典型特征。此外，我们的2名患者同时被诊断出患有甲型流感，这可能导致了他们病情的严重程度。
据我们所知，这些患者是首批报告的由携带PVL基因的菌株引起严重社区获得性MRSA肺炎 的北美成年人。
