Department of Intensive Care Medicine, Chi Mei Medical Center, Yong Kang, Tainan, Taiwan.
Int J Antimicrob Agents. 2011 Jun;37(6):550-3. doi: 10.1016/j.ijantimicag.2011.01.018. Epub 2011 Apr 9.
The aim of this study was to determine the rifampicin (RIF) resistance rate of meticillin-resistant Staphylococcus aureus (MRSA) amongst patients with MRSA bacteraemia who have or have not been exposed to RIF-containing antituberculous (anti-TB) treatment. From 2000 to 2008, patients with MRSA bacteraemia and previous exposure to RIF-containing anti-TB therapy were selected. Patients matched for sex, age and time of culture of MRSA bacteraemia but without exposure to anti-TB therapy were selected as a control group. A total of 139 patients, comprising 49 with RIF exposure and 90 without RIF exposure, were analysed. The RIF resistance rate was higher in patients with previous RIF exposure (61.2% vs. 20.0%; P<0.001). The minimum inhibitory concentration of RIF that inhibited 50% of MRSA isolates (MIC(50)) for the study group was also higher (128 mg/L vs. 0.015 mg/L; P<0.001). The mortality rate was higher in the study group (59.2% vs. 41.1%; P=0.041). MRSA isolates recovered from patients with current usage of a RIF-containing anti-TB regimen were more likely to be resistant to RIF (87.5% vs. 36%; P=0.001), with higher MIC(50) values (256 mg/L vs. 1mg/L; P=0.002), and resulted in a higher mortality rate than isolates from patients with remote usage of an anti-TB regimen (79.2% vs. 40%; P=0.005). Multivariate analysis showed that current anti-TB drug usage was the only risk factor for RIF resistance [odds ratio (OR)=7.457, 95% confidence interval (CI) 1.581-35.167] and mortality (OR=7.201, 95% CI 1.583-32.766). Given the high rate of RIF resistance in patients with prior anti-TB treatment, RIF susceptibility testing should be performed before considering combination treatment of RIF in MRSA infection.
本研究旨在确定耐甲氧西林金黄色葡萄球菌（MRSA）菌血症患者中，既往使用含利福平（RIF）抗结核（anti-TB）治疗与未使用 RIF 治疗患者的 RIF 耐药率。研究纳入了 2000 年至 2008 年间，MRSA 菌血症且有 RIF 暴露史的患者。选择与 RIF 暴露组性别、年龄和 MRSA 菌血症培养时间相匹配，但无抗结核治疗史的患者作为对照组。共分析了 139 例患者，其中 49 例有 RIF 暴露史，90 例无 RIF 暴露史。RIF 暴露组 RIF 耐药率更高（61.2% vs. 20.0%；P<0.001）。研究组 RIF 最低抑菌浓度（MIC(50)）也更高（128mg/L vs. 0.015mg/L；P<0.001）。研究组死亡率更高（59.2% vs. 41.1%；P=0.041）。当前使用含 RIF 抗结核方案的患者中分离的 MRSA 株更可能对 RIF 耐药（87.5% vs. 36%；P=0.001），MIC(50)值更高（256mg/L vs. 1mg/L；P=0.002），死亡率高于既往使用抗结核方案的患者（79.2% vs. 40%；P=0.005）。多变量分析显示，当前抗结核药物的使用是 RIF 耐药（比值比[OR]=7.457，95%置信区间[CI]1.581-35.167）和死亡（OR=7.201，95%CI 1.583-32.766）的唯一危险因素。鉴于既往抗结核治疗患者中 RIF 耐药率较高，在考虑 RIF 联合治疗 MRSA 感染之前，应进行 RIF 药敏试验。
