Ontario Agency for Health Protection and Promotion, Canada.
Med Mycol. 2012 Apr;50(3):324-7. doi: 10.3109/13693786.2011.598878. Epub 2011 Aug 23.
We compared the FXG™: RESP (Asp +) real-time PCR assay (Myconostica Ltd) with two microscopic staining methods (direct immunofluorescence [IFA] and calcofluor white) for the detection of Pneumocystis jirovecii in 411 respiratory specimens submitted for P. jirovecii examination. We considered the specimen to be microscopically positive if the organism could be visualized through the use of either IFA or calcofluor white. A second, published real-time PCR assay targeting the cdc2 gene of P. jirovecii was used to adjudicate those specimens that were microscopically negative but Myconostica PCR positive. The Myconostica PCR positive samples were deemed to be true positives if they were concordant with microscopically positive results or if they were positive by the second PCR assay. As a result, the Myconostica PCR assay was found to be more sensitive than the two microscopy methods in detecting P. jirovecii (10.5% true positivity rate by PCR, 8.0% by immunofluorescence, and 7.1% by calcofluor white). The Myconostica PCR assay showed 93.5% sensitivity, 95.1% specificity, 70.5% positive predictive value, and 99.1% negative predictive value. Its high negative predictive value suggests a role of the Myconostica PCR assay in ruling out Pneumocystis pneumonia.
我们比较了 FXG™：RESP（Asp+）实时 PCR 检测法（Myconostica Ltd）与两种显微镜染色方法（直接免疫荧光[IFA]和钙荧光白），以检测 411 份提交用于检测肺孢子菌的呼吸道标本中的肺孢子菌。如果可以通过 IFA 或钙荧光白观察到该生物体，则认为标本在显微镜下呈阳性。第二种已发表的针对肺孢子菌 cdc2 基因的实时 PCR 检测法用于判断那些在显微镜下呈阴性但 Myconostica PCR 呈阳性的标本。如果 Myconostica PCR 阳性样本与显微镜阳性结果一致，或者通过第二种 PCR 检测法呈阳性，则认为它们是真正的阳性。结果表明，Myconostica PCR 检测法在检测肺孢子菌方面比两种显微镜方法更敏感（PCR 的真实阳性率为 10.5%，IFA 为 8.0%，钙荧光白为 7.1%）。Myconostica PCR 检测法的灵敏度为 93.5%，特异性为 95.1%，阳性预测值为 70.5%，阴性预测值为 99.1%。其高阴性预测值表明 Myconostica PCR 检测法可用于排除肺孢子菌肺炎。
