耐甲氧西林金黄色葡萄球菌血流感染的临床特征及易感因素分析

Clinical characteristics and risk factors of bloodstream infection caused by methicillin-resistant Staphylococcus aureus

目的:了解耐甲氧西林金黄色葡萄球菌(MRSA)血流感染患者的临床特征,探究其易感因素。方法:回顾分析空军总医院MRSA及甲氧西林敏感的金黄色葡萄球菌(MSSA)血流感染患者,比较两组患者临床资料,归纳总结MRSA血流感染的临床特征及其易感因素。结果:MRSA血流感染原发灶多为导管相关性感染,而MSSA感染多来源于皮肤软组织。细菌分离阳性前MRSA组患者住院时间长于MSSA组(P<0.05),总住院时间和细菌分离阳性后住院时间,差异无统计学意义(P>0.05)。MRSA组病死率、TTP(血培养阳性报警时间)、合并休克及多脏器功能衰竭的发生率均高于MSSA组(P<0.05)。多因素分析显示年龄>65岁、TTP是MRSA感染的独立危险因素,皮肤病是MSSA感染的独立危险因素。ROC曲线表明TTP>19.41 h可作为区分MRSA及MSSA的切点,曲线下面积为0.811。结论:MRSA感染并发症重,住院时间的延长导致MRSA感染风险增加。TTP>19.41 h可作为MRSA血流感染的早期预警指标,预测MRSA血流感染的准确度为中等。

Objective To explore the clinical characteristics and risk factors of bloodstream infections caused by methicillin-resistant Staphylococcus aureus. Methods The clinical features,laboratory manifestations,diagnosis and treatment of patients with MRSA and MSSA bloodstream infection in the Air Force Hospital of PLA were analyzed retrospectively. Results The primary infection site of MRSA group was mainly catheter related infection, while it was mainly skin and soft tissue in MSSA group. Before infection,the hospital stay of MRSA group was longer than MSSA group（P〈0.05）.There was no significant difference between the two groups in the total length of hospital stay and the days after bacterial separation（P〉0.05）. Compared with the MSSA group,the mortality rate, the incidence of combined shock and multiple organ failure were higher than that of MSSA group（P〈0.05）. The time to blood culture positivity（TTP）of MRSA was longer than MSSA group（P〈0.01）.Multivariate analysis showed that patients with age over 65 years old and TTP were independent risk factors for MRSA infection（P〈0.05）. While skin disorder was the protective factor of MRSA, which was the independent risk factor of MSSA bloodstream infection. ROC curve showed that TTP 19.41 h was the optimal cutoff to distinguish MRSA and MSSA, with area under the ROC curve（AUC）of 0.811. Conclusion The complications of MRSA infection were severe. Prolonged hospital stay contributes to increasing risk of MRSA infection. TTP which is more than 19.41 h can be used as an early warning indicator of MRSA and the accuracy is moderate.