实时定量PCR与传统微生物培养法诊断呼吸机相关性肺炎病原体的性能比较

Validity analysis between real-time quantitative molecular-based method and conventional culture in the diagnosis of ventilator-associated pneumonia

目的基于分子的实时定量PCR方法与常规微生物培养法诊断呼吸机相关性肺炎(VAP)病原体的性能比较。方法通过气管内抽吸物(EAT)与支气管肺泡灌洗(BAL)两种方法采集了我院112例机械通气>48 h的疑似VAP患者的样本,使用常规微生物培养方法与实时定量PCR法对两种样本均进行微生物分析。结果共收集了112份BAL样本,101份ETA样本,主要分离的细菌是金黄色葡萄球菌,铜绿假单胞菌和流感嗜血杆菌。将分子生物学方法与常规培养方法进行比较,以常规培养方法作为标准,BAL样本灵敏度为89.5%,特异性为96.7%,ETA样本的灵敏度为73.8%,特异性为95.9%。结论采用基于分子的实时定量PCR法在诊断VAP时,与常规微生物培养法结果没有差异,对VAP中常见的病原体具有很高的特异性和良好的灵敏度。

Objective To compare the performance of real-time quantitative molecular-based method with conventional culture in the diagnosis of patients with suspected ventilator-associated pneumonia(VAP). Methods Endotracheal aspirate(ETA) and bronchoalveolar lavage(BAL) were performed at 112 patients with suspected VAP who were ventilated for at least 48 h. Both samples were analyzed by conventional culture and molecular analysis. Results A total of 112 BAL samples and 101 ETA samples were collected. The main isolated bacteria were Staphylococcus aureus, Pseudomonas aeruginosa and Haemophilus influenzae. The sensitivity and specificity of ETA were 89.5% and 96.7%, respectively, and the sensitivity and specificity of BAL samples were 73.8% and 95.9%, respectively, while taking conventional culture as standard. Conclusion Real-time quantitative PCR based on molecular method shows no difference with conventional microbial culture in the diagnosis of VAP, which has highly specificity and sensitivity for common pathogens involved in VAP.