利奈唑胺治疗老年人革兰阳性菌感染疗效分析及其对血小板的影响

Efficacy of linezolid on gram-positive bacterial infection in elderly patients and risk factors associated with thrombocytopenia

目的观察利奈唑胺治疗老年患者革兰阳性菌感染的有效性及其对血小板的影响。方法回顾性分析2008年1月至2010年10月我院内科系统收治的≥60岁老年革兰阳性菌感染患者50例，静脉应用利奈唑胺，观察患者症状及体征变化，进行病原体分析，评价其临床疗效并动态观察用药期间血小板变化。结果50例患者利奈唑胺治疗平均疗程（13±2）d，临床有效率74％，其中明确培养有革兰阳性球菌者26例，经治疗后细菌清除18例。利奈唑胺治疗过程中出现血小板减少24例（48％），治疗前后血小板计数均值分别为（239±114）×109／L和（146±87）×109／L，差异有统计学意义（t=3．888，P=0．000）。血小板减少与患者用药前血小板计数及药物疗程有相关性，回归分析显示血小板计数〈200×109／L为风险预测指标（OR=0．244，95％CI：0．068～0．874，P=0．030）；血小板随用药时间有一定的变化趋势，用药7d后明显下降，最低值位于停药1～2d时。结论利奈唑胺治疗老年患者革兰阳性菌感染临床疗效和耐受性好，特别是应用于耐甲氧西林金黄色葡萄球菌等耐药革兰阳性菌院内获得性肺炎时；该药对老年患者肝肾功能影响较小，但可引起血小板减少，血小板减少与用药前患者血小板计数及利奈唑胺平均用药时间有关，可根据其变化规律加强监测，及时处理。

Objective To study the efficacy of linezolid on gram-positive bacterial infection in elderly patients and risk factors associated with thrombocytopenia. Methods A retrospective analysis of 50 elderly patients treated with intravenous linezolid for gram-positive bacterial infection from January 2008 to October 2010 was conducted. Clinical data and bacteriological responses were assessed. Efficacy of linezolid on infection and risk factors associated with thrombocytopenia in elderly patients were analyzed. Results The average duration of treatment was （13±2） d, the efficacy rate was 740/oo and the bacteriological eradication rate was 69% （18/26）. Thromboeytopenia occurred in 24 patients during the treatment, and the average platelet count was significantly reduced compared with pretreatmentE（146±87） 109/L vs. （239±114） 109/L, t=3.888,P=0.000））. Thrombocytopenia was associated with the baseline platelet count and the mean time of linezolid treatment. Based on a Logistic regression analysis, the baseline platelet count 〈 200 × 109/L was identified as the only significant risk factor for linezolid-associated thrombocytopenia in elderly patients （OR = 0. 244,95 CI：0. 068-0. 874, P= 0. 030）. The mean platelet count was decreased significantly after 7 days of treatment, and decreased to the lowest value 1-2 days after the end of therapy. Conclusions Linezolid is effective and safe for the elderly with gram-positive bacterial infection, especially hospital acquired methicillin-resistant staphylococcus aureus infection. Linezolid has little effect on liver andrenal function in elderly patients, but it can cause thrombocytopenia, which is associated with baseline platelet count and the mean time of linezolid treatment. Platelet counts should be monitored during treatment and measures should be taken to prevent hemorrhagic tendencies.