What is community-associated methicillin-resistant Staphylococcus aureus?
What is community-associated methicillin-resistant Staphylococcus aureus?
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DOI：
10.1086/533502
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发表时间：
2008-05-01
影响因子：
6.4
通讯作者：
Daum, Robert S.
中科院分区：
文献类型：
--
作者：
David, Michael Z.;Glikman, Daniel;Daum, Robert S.
背景社区相关耐甲氧西林金黄色葡萄球菌（CA-MRSA）感染被定义为缺乏医疗暴露特定风险因素的患者的MRSA感染。我们试图确定是否存在这些危险因素仍然预测MRSA菌株的表型或基因型特征。从2004年7月至2005年6月，在芝加哥大学医院前瞻性收集所有临床MRSA分离株。对患者进行访谈和/或审查其病历。对分离株进行基因分型和药敏试验。患者和分离株的数据按照8个经常引用的CA-MRSA鉴定标准进行分层，并进行一致性比较。在616例回收MRSA分离株的独特患者中，404例（65.6%）具有医疗暴露的风险因素。在从这些患者中回收的404株分离株中，克林霉素敏感率为41.1%，47.0%携带葡萄球菌盒式染色体mec（SCCmec）IV型，145（35.9%）携带Panton-Valentine杀白细胞素基因（PVL+），（40.1%）经多位点序列分型（MLST）鉴定为序列型（ST）8，所有这些都是CA-MRSA菌株的共同特征。与医疗环境的关联现在对于区分由于多重耐药MRSA分离株感染的患者与被CA-MRSA分离株感染的患者几乎没有预测价值，CA-MRSA分离株即克林霉素敏感、PVL+、ST 8和/或含有SCCmec IV型的分离株。通过缺乏医疗暴露的风险因素来定义CA-MRSA，大大低估了流行性CA-MRSA疾病的负担。
Background. A community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection has been defined as an MRSA infection in a patient who lacks specific risk factors for healthcare exposure. We sought to determine whether the absence or presence of these risk factors still predicts the phenotypic or genotypic characteristics of MRSA strains.Methods. All clinical MRSA isolates were prospectively collected at the University of Chicago Hospitals from July 2004 through June 2005. Patients were interviewed and/or their medical records were reviewed. Isolates underwent genotyping and susceptibility testing. Data on patients and isolates were stratified in accordance with 8 frequently cited criteria for the identification of CA-MRSA and compared for concordance.Results. Among 616 unique patients from whom MRSA isolates were recovered, 404 (65.6%) had risk factors for healthcare exposure. Of the 404 isolates recovered from these patients, 166 (41.1%) were clindamycin susceptible, 190 (47.0%) carried staphylococcal cassette chromosome mec (SCCmec) type IV, 145 (35.9%) carried the Panton-Valentine leukocidin genes (PVL+), and 162 (40.1%) were identified as sequence type (ST) 8 by multilocus sequence typing (MLST), all of which are characteristics commonly attributed to CA-MRSA strains.Conclusions. Association with the healthcare environment now has little predictive value for distinguishing patients with infection due to multidrug resistant MRSA isolates from those infected by CA-MRSA isolates, that is, isolates that are clindamycin-susceptible, PVL+, ST8, and/or contain SCCmec type IV. Defining CA-MRSA by the absence of risk factors for healthcare exposure greatly underestimates the burden of epidemic CA-MRSA disease.