聚合酶链反应方法检测诱导排痰标本对卡氏肺孢子虫肺炎的诊断价值

The diagnostic value of polymerase chain reaction for the detection of Pneumocystis carinii DNA from induced sputum samples

目的 评价聚合酶链反应方法检测诱导排痰标本中卡氏肺孢子虫DNA对卡氏肺孢子虫肺炎 (PCP)的诊断意义。方法 分别用姬姆萨和六胺银 (GMS)两种染色方法和mt rRNA PCR方法检测痰液中的卡氏肺孢子虫。结果 化学染色法检测 1 6例临床拟诊PCP的患者痰标本 ,结果 8例阳性 ,2 0例非PCP患者痰标本均为阴性 ,化学染色方法的敏感性和特异性分别为 50 %和 1 0 0 %。PCR方法检测 1 6例临床拟诊PCP患者痰液中卡氏肺孢子虫 ,1 4例阳性 ,2 0例非PCP患者痰标本均为阴性 ,mt rRNA PCR方法的敏感性和特异性分别为 88%和 1 0 0 %。结论 姬姆萨和GMS两种细胞化学染色方法联合检测痰标本卡氏肺孢子虫 ,特异性高 ,但敏感性偏低。mt rRNA PCR检测痰标本中卡氏肺孢子虫DNA方法敏感性高于化学染色法且特异性高 。

Objectives To evaluate the diagnostic value of PCR for detection of Pneumocystis carinii DNA from induced sputum samples Methods P carinii cysts or trophozoites were detected in induced sputa by Giemsa stain or Gomori Methenamine silver(GMS) stain A fragment of the Pneumocystis carinii mitochondrial large subunit rRNA gene was amplified from sputum samples using a one step PCR method with mt rRNA primers Results In this study, sputum samples from 16 patients with a clinical diagnosis of Pneumocystis carinii pneumonia(PCP) and 20 patients with other respiratory infections were first tested by cytochemical staining Pneumocystis carinii was detected in 8 and 0 sputum samples from the two groups, respectively The sensitivity and specificity of cytochemical stain were 50% and 100% With the one step mt rRNA PCR method, Pneumocystis carinii DNA was detected in 14 and 0 sputum samples from 16 PCP patients and 20 non PCP patients The sensitivity and specificity of mt rRNA PCR was 88% and 100%,respetively Conclusions The specificity of both Giemsa and GMS staining of induced sputum samples is high and the methods are simple, but the sensitivity is low The sensitivity of PCR for P carinii DNA from induced sputum samples is significantly higher than cytochemical stains, and the method is highly specific when used in the clinical diagnosis of PCP