早期血清降钙素原与细菌性血流感染病原菌相关性研究

Study on correlation between early serum procalcitonin and bacterial bloodstream infection

目的:探讨早期血清降钙素原(PCT)水平与细菌性血流感染患者病原菌种类之间的相关性;同时,试图找到适宜的PCT临界值,为细菌性血流感染起始抗感染经验治疗方案的制定提供依据,减少不必要的广谱、超强、联合用药。方法:抽取某院2014年5月-2016年3月203例怀疑细菌性血流感染且在血培养前后<12 h行血清降钙素原(PCT)检查的患者,按照革兰阳性菌和革兰阴性菌分组记录患者血清降钙素原(PCT),比较2组PCT水平的差异,用受试工作者曲线(ROC曲线)分析PCT在鉴别革兰阳性菌和革兰阴性菌血流感染的作用。结果:革兰阴性菌血流感染与革兰阳性菌血流感染早期PCT水平存在显著性差异(P<0.05),且革兰阴性菌血流感染早期PCT明显高于阳性菌,中位数分别为3.92 ng·mL-1和0.62 ng·mL-1;2组患者受试工作者曲线(ROC曲线)显示PCT作为鉴别革兰阴性菌和革兰阳性菌血流感染有一定的意义(AUC为0.70,P<0.05);以初次血清PCT1.81 ng·mL-1作为临界值时,对革兰阴性菌所致血流感染阳性预测值敏感性为62.3%,特异性为71.4%。结论:革兰阴性菌血流感染患者早期血清降钙素原(PCT)高于革兰阳性菌;PCT对革兰阴性菌和革兰阳性菌所致细菌性血流感染有一定的鉴别作用;在PCT高于1.81 ng·mL-1时,细菌性血流感染革兰阴性菌可能性较革兰阳性菌大;可结合初次PCT结果做出病原体的初步判断,为选择适宜的起始抗感染治疗方案提供帮助。

OBJECTIVE To investigate correlation between serum procalcitonin（PCT）concentrations in initial stage and bacterial pathogens in patients with bacterial bloodstream infections,and try to identify aproper critical value of PCT to provide references for initial empirical antimicrobial therapy and reduce use of broad-spectrum antibiotics,powerful antibiotics and combination use of antibiotics.METHODS A total of 203 patients were suspected bacterial bloodstream infections,with PCT detected within 12 h before and after blood bacterial culture sampling were selected.PCT values were categorized into two different groups according to G＋and G-bacterial infections.PCT levels were compared between two groups,function of PCT in identifying G＋and G-bacterial infection was analyzed by receiver operating characteristic curve（ROC curve）.RESULTS Significant difference of PCT level was observed in initial stage between G＋and G-bacterial infections（P〈0.05）,and PCT level of Gbacterial infection was higher than that of G＋bacterial infection.Median values of PCT level were 3.92 ng·mL-1 and 0.62 ng·mL-1,respectively.ROC curve showed PCT was significant in identifying G＋or G-bacterial infection（AUC=0.70,P〈0.05）.When using 1.81 ng·mL-1 of initial serum PCT as critical value,sensitivity of positive predictive value was 62.3% for bacterial bloodstream infections caused by G＋bacterial,and the specificity was 71.4%.CONCLUSION PCT level of G-bacterial infection is higher than that of G＋bacterial infection.PCT level has a certain role in identifying G＋and G-bacterial infection.When PCT is higher than1.81 ng·mL-1,possibility of G-bacterial infection is higher than that of G＋bacterial infection,which can help to diagnose type of pathogenic bacteria and provide references for initial empirical antimicrobial therapy.