Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.
BMC Infect Dis. 2011 Dec 5;11:335. doi: 10.1186/1471-2334-11-335.
Management of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia remains a challenge. The emergence of MRSA strains with reduced vancomycin susceptibility complicates treatment.
A prospective cohort study (2005-2007) of patients with MRSA bacteremia treated with vancomycin was performed at an academic hospital. Vancomycin minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for stored MRSA isolates. Cox regression analysis was performed to predict 28-day all-cause mortality.
One hundred sixty-three patients with MRSA bacteremia were evaluated. One hundred twelve patients (68.7%) had bacteremia due to MRSA with a vancomycin MIC ≥ 2 ug/mL. Among strains with a vancomycin MIC ≥ 2 ug/mL, 10 isolates (8.9%) were vancomycin-intermediate S. aureus (VISA). Thirty-five patients (21.5%) died within 28 days after the diagnosis of MRSA bacteremia. Higher vancomycin MIC was not associated with mortality in this cohort [adjusted hazard ratio (aHR), 1.57; 95% confidence interval (CI), 0.73-3.37]. Vancomycin tolerance was observed in 4.3% (7/162) of isolates and was not associated with mortality (crude HR, 0.62; 95% CI, 0.08-4.50). Factors independently associated with mortality included higher age (aHR, 1.03; 95% CI 1.00-1.05), cirrhosis (aHR, 3.01; 95% CI, 1.24-7.30), and intensive care unit admission within 48 hours after the diagnosis of bacteremia (aHR, 5.99; 95% CI, 2.86-12.58).
Among patients with MRSA bacteremia treated with vancomycin, reduced vancomycin susceptibility and vancomycin tolerance were not associated with mortality after adjusting for patient factors. Patient factors including severity of illness and underlying co-morbidities were associated with the mortality.
耐甲氧西林金黄色葡萄球菌（MRSA）菌血症的治疗仍然是一个挑战。具有较低万古霉素敏感性的 MRSA 菌株的出现使治疗变得复杂。
对一家学术医院接受万古霉素治疗的 MRSA 菌血症患者进行了一项前瞻性队列研究（2005-2007 年）。对储存的 MRSA 分离株进行了万古霉素最小抑菌浓度（MIC）和最小杀菌浓度（MBC）的测定。采用 Cox 回归分析预测 28 天全因死亡率。
共评估了 163 例 MRSA 菌血症患者。112 例（68.7%）患者的菌血症由万古霉素 MIC≥2μg/ml 的 MRSA 引起。在万古霉素 MIC≥2μg/ml 的菌株中，有 10 株（8.9%）为万古霉素中介金黄色葡萄球菌（VISA）。35 例（21.5%）患者在诊断为 MRSA 菌血症后 28 天内死亡。在本队列中，较高的万古霉素 MIC 与死亡率无关[校正后的危险比（aHR），1.57；95%置信区间（CI），0.73-3.37]。在 162 株分离株中观察到 4.3%（7/162）的万古霉素耐受性，但与死亡率无关（粗 HR，0.62；95%CI，0.08-4.50）。与死亡率独立相关的因素包括年龄较大（aHR，1.03；95%CI，1.00-1.05）、肝硬化（aHR，3.01；95%CI，1.24-7.30）和菌血症诊断后 48 小时内入住重症监护病房（aHR，5.99；95%CI，2.86-12.58）。
在接受万古霉素治疗的 MRSA 菌血症患者中，调整患者因素后，万古霉素敏感性降低和万古霉素耐受性与死亡率无关。患者的严重程度和潜在合并症等因素与死亡率相关。
