Infection Control Program, Department of Infectious Diseases and Microbiology, Royal Prince Alfred Hospital, Sydney, Australia.
Clin Infect Dis. 2011 Jun 15;52(12):1422-30. doi: 10.1093/cid/cir233.
The clinical importance of low-level mupirocin resistance and genotypic chlorhexidine resistance remains unclear. We aimed to determine whether resistance to these agents increases the risk of persistent methicillin-resistant Staphylococcus aureus (MRSA) carriage after their use for topical decolonization therapy.
A nested case-control study was conducted of MRSA carriers who received decolonization therapy from 2001 through 2008. Cases, patients who remained colonized, were matched by year to controls, those in whom MRSA was eradicated (follow-up, 2 years). Baseline MRSA isolates were tested for mupirocin resistance by Etest and chlorhexidine resistance by qacA/B polymerase chain reaction. MRSA carriers with high-level mupirocin resistance were excluded. The effect of the primary exposure of interest, low-level mupirocin and genotypic chlorhexidine resistance, was evaluated with multivariate conditional logistic regression analysis.
The 75 case patients and 75 control patients were similar except that those persistently colonized were older (P = .007) with longer lengths of hospital stay (P = .001). After multivariate analysis, carriage of combined low-level mupirocin and genotypic chlorhexidine resistance before decolonization independently predicted persistent MRSA carriage (odds ratio [OR], 3.4 [95% confidence interval {CI}, 1.5-7.8]). Other risk factors were older age (OR, 1.04 [95% CI, 1.02-1.1]), previous hospitalization (OR, 2.4 [95% CI, 1.1-5.7]), presence of a skin wound (OR, 5.7 [95% CI, 1.8-17.6]), recent antibiotic use (OR, 3.1 [95% CI, 1.3-7.2]), and central venous catheterization (OR, 5.7 [95% CI, 1.4-23.9]).
Combined low-level mupirocin and genotypic chlorhexidine resistance significantly increases the risk of persistent MRSA carriage after decolonization therapy. Institutions with widespread use of these agents should monitor for resistance and loss of clinical effectiveness.
低水平莫匹罗星耐药和基因型洗必泰耐药的临床重要性仍不清楚。我们旨在确定这些药物耐药性是否会增加其用于局部去定植治疗后持续耐甲氧西林金黄色葡萄球菌（MRSA）定植的风险。
对 2001 年至 2008 年间接受去定植治疗的 MRSA 携带者进行了巢式病例对照研究。病例为持续定植的患者，按年份与对照组相匹配，即 MRSA 根除的患者（随访 2 年）。基线 MRSA 分离株用 Etest 检测莫匹罗星耐药性，用 qacA/B 聚合酶链反应检测洗必泰耐药性。排除高水平莫匹罗星耐药的 MRSA 携带者。用多变量条件逻辑回归分析评估主要暴露因素（低水平莫匹罗星和基因型洗必泰耐药）的作用。
75 例病例患者和 75 例对照患者除了持续性定植的患者年龄较大（P=0.007）和住院时间较长（P=0.001）外，无明显差异。多变量分析后，去定植前携带低水平莫匹罗星和基因型洗必泰耐药的联合耐药独立预测 MRSA 持续携带（比值比[OR]，3.4[95%置信区间{CI}，1.5-7.8]）。其他危险因素为年龄较大（OR，1.04[95%CI，1.02-1.1]）、既往住院（OR，2.4[95%CI，1.1-5.7]）、皮肤伤口（OR，5.7[95%CI，1.8-17.6]）、近期使用抗生素（OR，3.1[95%CI，1.3-7.2]）和中心静脉置管（OR，5.7[95%CI，1.4-23.9]）。
低水平莫匹罗星和基因型洗必泰耐药的联合耐药显著增加了去定植治疗后持续 MRSA 定植的风险。广泛使用这些药物的机构应监测耐药性和临床疗效的丧失。
