血流感染中耐药菌与敏感菌PCT水平的差异研究

Differences of procalcitonin(PCT) between drug-resistant bacteria and drug-sensitive bacteria in bloodstream infections

目的探讨降钙素原(PCT)在血流感染中对大肠埃希菌和产超广谱β-内酰胺酶(ESBLs)的大肠埃希菌、金黄色葡萄球菌和耐甲氧西林金黄色葡萄球菌(MRSA)的鉴别和分类价值。方法采用回顾性研究选择医院2015年1月-12月期间住院患者血培养标本5646例,符合标本1658例,其中血培养阴性组1426例,血培养阳性组232例;排除污染后,血培养阳性组中革兰阴性菌96例,革兰阳性菌82例;用全自动电化学发光仪检测PCT,用全自动细菌分枝杆菌培养监测系统进行血培养,用全自动微生物鉴定仪进行细菌培养和鉴定。结果 PCT鉴别性能的ROC曲线鉴别血培养阳性和阴性的敏感度和特异度分别为78.40%和62.00%;感染革兰阴性菌患者PCT(37.42±13.55)ng/ml显著高于革兰阳性菌患者(11.22±3.56)ng/ml(P<0.05),且当PCT>10.0ng/ml时,革兰阴性菌的数量明显高于革兰阳性菌(P<0.05);ESBLs的大肠埃希菌PCT的均值明显高于大肠埃希菌,MRSA PCT均值明显低于金黄色葡萄球菌(P<0.05)。结论血流感染时PCT的水平有助于快速区分革兰阴性菌和革兰阳性菌;当PCT>10.0ng/ml时,革兰阴性杆菌感染的可能性极高;并且产ESBLs的大肠埃希菌患者的PCT水平高于大肠埃希菌患者,MRSA患者的PCT水平低于金黄色葡萄球菌患者。

OBJECTIVE To explore the values of procalcitonin（PCT）in the identification and classification of Escherichia coli and ESBLs-producing E.coli,Staphylococcus aureus and methicillin-resistant S.aureus（MRSA）in bloodstream infections.METHODS A total of 5646 blood culture specimens who were admitted to Wuhan Central Hospital from Jan.2015 to Dec.2015 were retrospectively analyzed,and 1658 cases were selected,including 1426 cases in negative group and 232 cases in positive group.Among the 178 blood culture in the positive group which had eliminated pollution,96 were detected as gram-negative bacteria and 82 were gram-positive bacteria.The level of PCT was detected by automatic electrochemical luminescence instrument.Blood culture was conducted by an automatic bacteria mycobacterium cultivation monitoring system and the bacterial culture and identification were carried out by an automatic microbe identifying system.RESULTS The sensitivity and specificity of ROC curve of PCT for detecting positive and negative blood culture were 78.40% and 62.00%respectively.The level of PCT in negative group was（37.42±13.55）ng/ml,which was significantly higher than（11.22±3.56）ng/ml in positive group（P〈0.05）.When the level of PCT 10.0 ng/ml,the quantity of gram-negative bacteria was significantly higher than that of gram positive bacteria（P〈0.05）.Meanwhile,the average PCT level of ESBLs-producing E.coli was significantly higher than that of E.coli,and the average PCT level of MRSA was significantly lower than that of S.aureus（P〈0.05）.CONCLUSION By detecting the concentration of PCT,gram-positive bacteria can be quickly distinguished from gram-negative bacteria in bloodstream infections.When the level of PCT 10 ng/ml,the possibility of gram-negative bacteria infection is extremely high.Moreover,the PCT level of the patients with ESBLs-producing E.coli was higher than that of the patients with E.coli.The PCT level of the patients with MRSA was lover than that of the patients with S.aureus.