Choi Y J, Hu Y, Mahmood A
Department of Pathology, Bronx-Lebanon Hospital Center, New York 10457, USA.
Am J Clin Pathol. 1996 Feb;105(2):200-4. doi: 10.1093/ajcp/105.2.200.
Various investigators have reported rapid detection of Mycobacterium tuberculosis (MTB) in clinical samples by polymerase chain reaction (PCR). To improve the specificity and efficiency of PCR, the authors adopted a variety of conditions, then analyzed sputum specimens from 217 patients clinically suspected of having MTB. Sputum samples were sonicated to obtain MTB DNA. The DNA was subjected to PCR using primer sets from the region of 650-900 in MTB. The PCR product was detected by direct gel electrophoresis and Southern blot hybridization using digoxigenin-labeled MTB-specific probe. The results of smears, cultures, and PCR were concordant in 93% (202) of the 217 specimens and discordant in 7% (15). Fifteen of the discordant specimens, all from patients who had received antituberculosis medications for days to months, were PCR positive. Of these, 11 were culture negative and 3 were smear negative. Only one specimen was false negative on PCR. Our results indicate that PCR is the method of choice when clinical suspicion is high, but smears or cultures are negative. When smears are positive, PCR permits rapid distinction between MTB and other mycobacterial infections. Because PCR can detect nonviable MTB DNA, positive PCR should be interpreted in conjunction with clinical information.
多位研究者报告了通过聚合酶链反应（PCR）在临床样本中快速检测结核分枝杆菌（MTB）的方法。为提高PCR的特异性和效率，作者采用了多种条件，随后分析了217例临床疑似患有MTB患者的痰液标本。将痰液样本进行超声处理以获取MTB DNA。使用来自MTB中650 - 900区域的引物对该DNA进行PCR。通过直接凝胶电泳和使用地高辛标记的MTB特异性探针的Southern印迹杂交检测PCR产物。217份标本中，涂片、培养和PCR结果一致的占93%（202份），不一致的占7%（15份）。15份结果不一致的标本均来自已接受抗结核药物治疗数天至数月的患者，这些标本PCR呈阳性。其中，11份培养阴性，3份涂片阴性。仅1份标本PCR为假阴性。我们的结果表明，当临床高度怀疑但涂片或培养结果为阴性时，PCR是首选方法。当涂片呈阳性时，PCR可快速区分MTB感染与其他分枝杆菌感染。由于PCR可检测无活力的MTB DNA，PCR阳性结果应结合临床信息进行解读。
