Jones Jeffrey C, Rogers Theodore J, Brookmeyer Peter, Dunne William Michael, Storch Gregory A, Coopersmith Craig M, Fraser Victoria J, Warren David K
Division of Infectious Diseases, Washington University School of Medicine, St. Louis, MO 63110, USA.
Clin Infect Dis. 2007 Sep 1;45(5):541-7. doi: 10.1086/520663. Epub 2007 Jul 13.
Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) can be a precursor to serious infection, and decolonization with topical mupirocin has been studied as a means of preventing clinical infection. Mupirocin resistance in patients with MRSA has been reported, usually in the context of widespread mupirocin use.
Patients admitted to a surgical intensive care unit (SICU) had nasal swab cultures for MRSA performed at admission, weekly, and at discharge in an active surveillance program. Collected MRSA isolates were tested for mupirocin resistance, and molecular analysis was performed. Clinical data on the characteristics and outcomes of the patients who stayed in the SICU for >48 h were collected prospectively.
Of the 302 MRSA isolates available for testing, 13.2% were resistant to mupirocin, with 8.6% having high-level resistance (minimum inhibitory concentration, >or=512 microg/mL) and 4.6% having low-level resistance (minimum inhibitory concentration, 8-256 microg/mL). Patients admitted to the SICU for >48 h who were colonized with mupirocin-resistant MRSA were more likely to have been admitted to our hospital during the previous year (P=.016), were older (P=.009), and had higher in-hospital mortality (16% vs. 33%; P=.027), compared with patients colonized with mupirocin-susceptible MRSA. Molecular analysis of the mupirocin-resistant isolates revealed that 72.5% of isolates contained staphylococcal cassette chromosome mec II. Repetitive sequence polymerase chain reaction typing revealed that high-level mupirocin resistance was present in multiple clonal groups. The rate of mupirocin use hospital-wide during the study period was 6.08 treatment-days per 1000 patient-days.
We documented a high rate of mupirocin resistance in MRSA isolates from SICU patients, despite low levels of in-hospital mupirocin use.
耐甲氧西林金黄色葡萄球菌（MRSA）鼻腔定植可能是严重感染的先兆，外用莫匹罗星去定植已作为预防临床感染的一种方法进行了研究。已报道MRSA患者中存在莫匹罗星耐药，通常是在广泛使用莫匹罗星的情况下。
在一项主动监测计划中，入住外科重症监护病房（SICU）的患者在入院时、每周以及出院时进行鼻腔拭子MRSA培养。对收集的MRSA分离株进行莫匹罗星耐药性检测，并进行分子分析。前瞻性收集在SICU停留超过48小时的患者的特征和结局的临床数据。
在302株可供检测的MRSA分离株中，13.2%对莫匹罗星耐药，其中8.6%具有高水平耐药（最低抑菌浓度，≥512μg/mL），4.6%具有低水平耐药（最低抑菌浓度，8 - 256μg/mL）。与莫匹罗星敏感的MRSA定植患者相比，入住SICU超过48小时且被莫匹罗星耐药的MRSA定植的患者更有可能在前一年入住我院（P = 0.016），年龄更大（P = 0.009），院内死亡率更高（16%对33%；P = 0.027）。对莫匹罗星耐药分离株的分子分析显示，72.5%的分离株含有葡萄球菌盒式染色体mec II。重复序列聚合酶链反应分型显示，多个克隆组中存在高水平莫匹罗星耐药。研究期间全院莫匹罗星的使用频率为每1000患者日6.08个治疗日。
尽管院内莫匹罗星使用水平较低，但我们记录到SICU患者的MRSA分离株中莫匹罗星耐药率很高。
