Division of Infectious Diseases, Henry Ford Health System, Detroit, Michigan, USA.
J Clin Microbiol. 2012 May;50(5):1640-4. doi: 10.1128/JCM.06701-11. Epub 2012 Feb 15.
Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial pneumonia. To characterize pathogen-derived and host-related factors in intensive care unit (ICU) patients with MRSA pneumonia, we evaluated the Improving Medicine through Pathway Assessment of Critical Therapy in Hospital-Acquired Pneumonia (IMPACT-HAP) database. We performed multivariate regression analyses of 28-day mortality and clinical response using univariate analysis variables at a P level of <0.25. In isolates from 251 patients, the most common molecular characteristics were USA100 (55.0%) and USA300 (23.9%), SCCmec types II (64.1%) and IV (33.1%), and agr I (36.7%) and II (61.8%). Panton-Valentine leukocidin (PVL) was present in 21.9%, and vancomycin heteroresistance was present in 15.9%. Mortality occurred in 37.1% of patients; factors in the univariate analysis were age, APACHE II score, AIDS, cardiac disease, vascular disease, diabetes, SCCmec type II, PVL negativity, and higher vancomycin MIC (all P values were <0.05). In multivariate analysis, independent predictors were APACHE II score (odds ratio [OR], 1.090; 95% confidence interval [CI], 1.041 to 1.141; P < 0.001) and age (OR, 1.024; 95% CI, 1.003 to 1.046; P = 0.02). Clinical failure occurred in 36.8% of 201 evaluable patients; the only independent predictor was APACHE II score (OR, 1.082; 95% CI, 1.031 to 1.136; P = 0.002). In summary, APACHE II score (mortality, clinical failure) and age (mortality) were the only independent predictors, which is consistent with severity of illness in ICU patients with MRSA pneumonia. Interestingly, our univariate findings suggest that both pathogen and host factors influence outcomes. As the epidemiology of MRSA pneumonia continues to evolve, both pathogen- and host-related factors should be considered when describing epidemiological trends and outcomes of therapeutic interventions.
耐甲氧西林金黄色葡萄球菌（MRSA）是医院获得性肺炎的主要病因。为了明确重症监护病房（ICU）中耐甲氧西林金黄色葡萄球菌肺炎患者的病原体衍生和宿主相关因素，我们评估了通过途径评估关键治疗在医院获得性肺炎中的改善药物（IMPACT-HAP）数据库。我们使用单变量分析中 P 值<0.25 的变量进行了 28 天死亡率和临床反应的多变量回归分析。在 251 名患者的分离物中，最常见的分子特征是 USA100（55.0%）和 USA300（23.9%），SCCmec 类型 II（64.1%）和 IV（33.1%），agr I（36.7%）和 II（61.8%）。Panton-Valentine 白细胞毒素（PVL）阳性率为 21.9%，万古霉素异质性耐药率为 15.9%。37.1%的患者死亡；单变量分析中的因素包括年龄、APACHE II 评分、艾滋病、心脏病、血管疾病、糖尿病、SCCmec 类型 II、PVL 阴性和万古霉素 MIC 较高（所有 P 值均<0.05）。在多变量分析中，独立预测因子为 APACHE II 评分（比值比[OR]，1.090；95%置信区间[CI]，1.041 至 1.141；P<0.001）和年龄（OR，1.024；95%CI，1.003 至 1.046；P=0.02）。在 201 名可评估患者中，36.8%的患者临床治疗失败；唯一的独立预测因子是 APACHE II 评分（OR，1.082；95%CI，1.031 至 1.136；P=0.002）。总之，APACHE II 评分（死亡率、临床失败）和年龄（死亡率）是唯一的独立预测因子，这与 ICU 中耐甲氧西林金黄色葡萄球菌肺炎患者的疾病严重程度一致。有趣的是，我们的单变量结果表明，病原体和宿主因素都影响结果。随着耐甲氧西林金黄色葡萄球菌肺炎的流行病学不断演变，在描述流行病学趋势和治疗干预结果时，应同时考虑病原体和宿主相关因素。
