血培养阳性报警时间对凝固酶阴性葡萄球菌血流感染的诊断价值

Value of time to positive in diagnosis of bloodstream infection caused by coagulase-negative Staphylococcus

目的探讨血培养阳性报警时间(TTP)对未成年人,包括新生儿(<28d)和儿童(<16y),凝固酶阴性葡萄球菌(CoNS)血流感染(BSI)及污染的鉴别诊断价值。方法回顾性分析本院2015年1月至2017年9月血培养分离菌为CoNS的160例病例(新生儿45例,儿童115例),将患儿分为感染组和污染组,并对两组的TTP进行比较,绘制受试者工作特征(ROC)曲线,确定TTP对CoNS BSI或污染鉴别诊断的最佳分界值,并评价其诊断效能。结果新生儿感染组与污染组的TTP分别为(17.32±5.96)h和(21.17±5.26)h,差异具有统计学意义(t=2.170,P=0.032),儿童感染组与污染组的TTP分别为(20.72±7.70)h和(26.20±13.20)h,差异也具有统计学意义(t=2.820,P=0.014);根据ROC曲线,TTP>17.67h可作为鉴别新生儿BSI和污染的最佳分界值,曲线下面积(AUC)为0.74,灵敏度为71.00%,特异度为85.10%,TTP>17.35h可作为区分儿童BSI和污染的最佳分界值,AUC为0.67,灵敏度为31.50%,特异度为97.60%。结论 TTP对新生儿CoNS血流感染的鉴别诊断准确度为中等,对儿童诊断效能为较低,但特异度均较高,对于鉴别未成年人CoNS血流感染和污染有一定的价值。

OBJECTIVE To explore the value of time to positive（TTP）in differential diagnosis of coagulase-negative Staphylococcus（CoNS）bloodstream infection（BSI）and contamination in juveniles,including the neonates（less than 28 days）and the children（less than 16 years）.METHODS From Jan 2015 to Sep 2017,a total of 160 patients（45 neonates and 115 children）,the blood specimens of whom the CoNS strains were isolated,were retrospectively analyzed,the enrolled subjects were divided into the infection group and the contamination group,the TTP was compared between the two groups,the receiver operating characteristic（ROC）curve was drawn to determine the optimal threshold value of TTP in differential diagnosis of the CoNS BSI,and the diagnostic efficiency was evaluated.RESULTS The TTP was（17.32±5.96）h in the neonatal infection group,（21.17±5.26）h in the neonatal contamination group,and there was significant difference（t=2.170,P=0.032）;the TTP was（20.72±7.70）h in the children infection group,（26.20±13.20）h in the children contamination group,and there was significant difference（t=2.820,P=0.014）.The ROC curve analysis showed that more than 17.67 hof TTP was the optimal threshold value for the identification of BSI and contamination in the neonates,the area under curve（AUC）was 0.74,the sensitivity was 71.00%,the specificity was 85.10%;more than 17.35 hof TTP was the optimal threshold value for the identification of BSI and contamination in the children,the AUC was 0.67,the sensitivity was 31.50%,and the specificity was 97.60%.CONCLUSIONThe TTP has the medium accuracy in the differential diagnosis of CoNS BSI in the neonates,the diagnostic efficiency is low for the children,however,specificities are both high,and the TTP has certain value in the identification of the CoNS BSI and contamination in the juveniles.