血清降钙素原在严重脓毒血症病原诊断中的价值研究

Effect of bloodstream infections caused by different pathogens on serum procalcitonin

目的评价血清降钙素原（PCT）水平是否可以早期区分血流感染的不同病原体。方法回顾性分析广州医科大学第一附属医院重症医学科2011年1月至2013年12月收治的脓毒血症并有血培养阳性的资料完整患者142例,根据血培养阳性结果分成革兰阳性菌组（G＋组）51例、革兰阴性菌组（G-组）75例和真菌组（fungal组）16例。比较三组患者间PCT与白细胞（WBC）计数水平。结果 G-组患者的PCT（65.32±49.23）μg/L明显高于G＋组（5.36±4.37）μg/L和真菌组（1.59±1.22）μg/L,三组间差异有统计学意义。而WBC在三组间比较差异无统计学意义（P=0.62）。为PCT诊断是否由G-菌导致血流感染而描绘ROC曲线,曲线下面积为0.973（95%CI0.953～0.993）。诊断阈值为〈17μg/L。特异度为95%,敏感度为84%。为PCT诊断是否由鲍曼不动杆菌导致血流感染而描绘ROC曲线,曲线下面积为0.965（95%CI0.941～0.990）。诊断阈值为〈42μg/L,特异度为92%,敏感度为85%。为PCT诊断是否由真菌导致血流感染而描绘ROC曲线,曲线下面积为0.965,95%CI0.934～0.996。利用cut-off法得出PCT对于诊断是否真菌导致血流感染的诊断阈值为〈2.1μg/L。特异度为82%,敏感度为95%。结论血清PCT升高水平可以早期鉴别血流感染的病原菌,具有较高的敏感度和特异度。

Objective To evaluate the value of serum procalcitonin（PCT）in differentiating pathogens in bloodstream in fection patients. Methods Data of septic patients with positive blood cultures who received treatment from January 2011 to December 2013 in the ICU of the First Affiliated Hospital of Guangzhou Medical University were analyzed retrospectively.Based on the culture findings,patients were assigned into 3 groups：Gram positive group（G＋group）,Gram negative group（G-group）and fungal group. The levels of serum PCT and the White Blood Cell（WBC）count were compared among the3 groups. Results One hundred and forty two patients were enrolled,including51 cases in the G＋group（35.9%）,75 ca ses in the G-group（52.8%）and 16 cases in the fungal group（11.3%）. The level of serum PCT（65.32 ±49.23）μg/L in G-group was significantly higher than that of the G＋group（5.36 ±4.37）μg/L and that of the fungal group（1.59 ±1.22）μg/L. However,no significant difference in WBC counts was found in 3 groups（P =0.62）. ROC curve was drawn to evaluate the value of the level of serum PCT to distinguish the G-bacteria from the non G bacteria. The area under curve was 0.973（95%CI was0.953-0.993）. The diagnostic threshold was 17 μg/L with the specificity of95% and the sen sitivity of 84%. We also drew a ROC curve to evaluate the value of the level of serum PCT to distinguish the acinetobacter baumannii from other pathogens. The area under curve was 0.965（95%CI was 0.941-0.990）. PCT for cut off 42 μg/L with the specificity of 92% and the sensitivity of 85%. In addition,the ROC curve was drawn to evaluate the value of the level of serum PCT to distinguish fungi from other pathogens. The area under curve was 0.965（95% CI was 0.934-0.996）. PCT for cut off 2.1 μg/L with the specificity of 82% and the sensitivity of 95%. Conclusion PCT can distin guish pathogens in the early stage with high specificity and sensitivity.