肺炎支原体实验室诊断方法的临床价值评估

Clinical evaluation of laboratory diagnosis of Mycoplasma pneumoniae

目的对肺炎支原体(MP)实验室诊断方法进行比较,评估其临床应用价值。方法前瞻性研究。采集2016年12月至2017年1月中国医科大学附属盛京医院临床诊断为MP感染的患儿咽拭子及双份血清;采集2017年3月至5月北京市朝阳区3~5岁健康儿童的咽拭子样本。采用被动凝集法(PA)检测双份血清,以双份血清特异性抗体滴度的4倍升高或降低为金标准,绘制受试者工作特征曲线(ROC),对检测MP感染的实验室方法进行比较和评估。结果1.入组临床诊断MP感染患儿93例,其中男42例(45.2%),女51例(54.8%),平均年龄5.5岁,检出确诊MP感染60例(64.5%)。健康儿童349例,男198例,女151例,平均年龄4.3岁,咽拭子样本培养阳性率0.6%(2例),荧光定量PCR(qPCR)检测阳性18.9%(66例)。2.培养特异性最高(100.0%),敏感性最低(65.0%)。PA和酶联免疫吸附试验(ELISA)检测急性期单份血清,敏感性分别为71.7%、86.5%,绘制ROC曲线提示,目前临床采用诊断界值MP特异性抗体IgM≥1∶160并非最佳诊断界值。分子生物学诊断方法敏感性最高,分别为RNA恒温扩增实时荧光检测(SAT)85.0%,qPCR 93.0%;但特异性较低,分别为SAT 75.7%,qPCR 63.6%。3.同时检测患儿咽拭子MP核酸(SAT、PCR)和患儿急性期单份血清(ELISA、PA),敏感性提升至95.0%~100.0%,特异性63.6%~75.7%。结论分子生物学诊断MP感染敏感性高,其存在无症状感染或感染后携带,MP检测阳性,是否需要治疗需结合临床。检测病程1周左右的急性期单份血清敏感性高,对MP感染诊断有参考价值,但确诊需结合临床;采用急性期单份血清学检测方法结合SAT较单独应用检测MP感染的敏感性及准确性高。

Objective To compare the laboratory diagnostic methods of Mycoplasma pneumonia(MP)and evaluate its clinical value.Methods A prospective study.Throat swabs and double sera of children with MP infection were collected from December 2016 to January 2017 in Shengjing Hospital Affiliated to China Medical University;throat swab samples of healthy children aged 3 to 5 in Chaoyang District,Beijing were collected from March to May 2017.Passive agglutination(PA)was used to detect the double serum.Taking the 4-fold increase or decrease of the specific antibody titer of the double serum as the gold standard,the receiver operating characteristic curve(ROC)was drawn,and the laboratory methods for detecting MP infection were compared and evaluated.Results(1)A total of 93 children with MP infection were clinically diagnosed,including 42 males(45.2%)and 51 females(54.8%),with an average age of 5.5 years.Sixty cases(64.5%)of MP infection were diagnosed.There were 349 healthy children,198 males and 151 females,with an average age of 4.3 years.The positive rate of throat swab culture was 0.6%(2 cases),and the positive rate of fluorescent quantitative PCR(qPCR)was 18.9%(66 cases).(2)The culture specificity was the highest(100.0%)and the sensitivity was the lowest(65.0%).PA and enzyme linked immunosorbent assay(ELISA)were used to detect a single serum in the acute phase,the sensitivity was 71.7%and 86.5%respectively.ROC curve suggested that the current clinical diagnostic threshold MP specific antibody IgM≥1∶160 was not the best diagnostic threshold.Molecular biological diagnostic methods were the most sensitive,RNA simultaneous and testing(SAT)was 85.0%and qPCR was 93.0%;while the specificity was low,75.7%(SAT)and 63.6%(qPCR),respectively.(3)At the same time,MP nucleic acid(SAT,PCR)of throat swabs and a single serum(ELISA,PA)of children in acute phase were detected,the sensitivity was increased to 95.0%-100.0%,and the specificity was 63.6%-75.7%.Conclusions Molecular biology is highly sensitive in diagnosing MP infection.It has asymptomatic infection or is carried after infection.Whether it needs treatment needs to be combined with clinical practice,when MP detection is positive.The detection of a single serum in the acute phase with a course of about 1 week has high sensitivity and is of reference value for the diagnosis of MP infection,but the diagnosis needs to be combined with clinical practice.The sensitivity and accuracy of detecting MP infection by single serological test combined with SAT in acute phase are higher than that by single application.