儿科患儿双份血培养实践与效果评价

Assessment of two - site blood cultures practice in pediatric patients

目的评价儿科患者双份血培养对血培养阳性率的影响。方法回顾性分析2013年1月至2015年2月首都医科大学附属北京儿童医院感染内科1 985例住院患儿血培养采集方式、采样前抗生素应用与血培养阳性情况，按照血培养采集方式分3个阶段，血培养单瓶阶段：患儿单送1瓶需氧瓶血培养；血培养双瓶过渡阶段：自相同的皮肤穿刺点抽取2份血液标本同时送检进行需氧瓶培养；双份血培养阶段：自不同的皮肤穿刺点各抽取1份血液标本同时送检进行需氧瓶培养，抽取2份血培养的间隔时间应尽量〈5 min。3个阶段的阳性率比较采用Pearson χ2检验，3个阶段阳性率的变化趋势采用Cochran－Armitage趋势检验。所有检验分析以双侧P〈0.05为差异有统计学意义。结果3个阶段血培养采集之前80%以上患儿都用过抗生素。真阳性率方面，各阶段差异无统计学意义（χ2＝1.343，P〉0.05），各阶段真阳性率变化趋势差异无统计学意义（P〉0.05）。假阳性菌株常见的是凝固酶阴性葡萄球菌。假阳性率方面，血培养单瓶阶段高于双份血培养阶段，差异有统计学意义（χ2＝6.051，P〈0.05）。结论对于儿童（不包括新生儿）双份血培养可以降低血培养假阳性率，起到鉴别血培养污染的作用。

Objective To evaluate the effect of two-site blood cultures on detection rate in pediatric patients.Methods The data were retrospectively analyzed of 1 985 hospitalized children with blood cultures from January 2013 to February 2015 in Department of Infectious Diseases, Beijing Children′s Hospital, Capital Medical University, including blood culture collection, the administration of antibiotics prior to obtaining blood cultures and positive condition of blood culture.It was divided into 3 stages according to blood culture collection.Blood culture of a single bottle referred to the blood culture in an aerobic bottle.Double bottles transition stage referred to two blood samples taken from the same skin puncture point and the aerobic bottle culture was carried out at the same time.Two-site blood cultures referred to two blood samples taken from the different skin puncture point and the aerobic bottle culture was carried out at the same time.The interval time between the two blood cultures should be less than 5 minutes.The positive rates of three stages were analyzed by Pearson χ2 test.The change tendency of positive rates in three stages were analyzed by Cochran-Armitage test.Bilateral P〈0.05 was considered as statistically significant difference in all test analysis.Results More than 80% of the children in the three stages were given antibiotics.There was no significant difference in the true positive rate （χ2=1.343, P〉0.05）. There was no significant difference in the change tendency of positive rates （P〉0.05）. False- positive strains were common for coagulase-negative staphylococci.In terms of false positive rate, blood culture of single bottle was higher than two-site blood culture （χ2=6.051, P〈0.05）.Conclusion For children （non-neonates）, two-site blood cultures can reduce the false positive rate of blood culture and play a role in distinguishing between true positives and false positives in blood culture.