Frevel T, Schäfer K L, Tötsch M, Böcker W, Dockhorn-Dworniczak B
Gerhard-Domagk-Institute of Pathology, Westfälische Wilhelms-University, Münster, Germany.
Mol Pathol. 1999 Oct;52(5):283-8. doi: 10.1136/mp.52.5.283.
The incidence of mycobacterial infections has increased during the past five years. A prompt diagnosis is indispensable for initiating appropriate treatment. Because culturing of mycobacteria takes three to six weeks and sensitivity of microscopic detection of acid fast bacilli is low, amplification methods provide promising possibilities. Recently, the polymerase chain reaction (PCR) has been shown to be useful for confirming a mycobacterial infection, especially in cases with unexpected histological findings or lack of suitable material for culturing.
To evaluate the impact of PCR based techniques in the detection of mycobacterial infections in uncultured routine histological specimens as an alternative to surgical pathology.
Two hundred and twenty nine formalin fixed and paraffin wax embedded samples from 141 patients with clinical or histological suspicion of a mycobacterial infection were investigated using three different PCR assays and Southern blotting. PCR results were compared with histology and culture and the patients' clinical findings.
When using culture as the reference method, the sensitivity for the detection of mycobacteria of the tuberculosis complex was 90%, specificity was 92%, the positive predictive value was 81%, and the negative predictive value was 96%. The sensitivity for the detection of nontuberculous mycobacteria was 100% and specificity was 78%, the positive predictive value was 26%, and the negative predictive value was 100%. The patients' clinical findings supported the PCR positive results, indicating a mycobacterial infection in 11 of 18 initially culture negative cases and in 21 of 35 PCR positive cases without culture results.
These results indicate that PCR based techniques are sensitive, specific, and rapid methods for the detection of mycobacteria in routinely processed paraffin wax embedded and formalin fixed histological samples.
在过去五年中，分枝杆菌感染的发病率有所上升。及时诊断对于启动适当的治疗至关重要。由于分枝杆菌培养需要三到六周时间，且抗酸杆菌显微镜检测的灵敏度较低，因此扩增方法提供了有前景的可能性。最近，聚合酶链反应（PCR）已被证明可用于确诊分枝杆菌感染，特别是在组织学检查结果意外或缺乏合适培养材料的情况下。
评估基于PCR的技术在未培养的常规组织学标本中检测分枝杆菌感染的效果，作为手术病理学的替代方法。
使用三种不同的PCR检测方法和Southern印迹法，对141例临床或组织学怀疑有分枝杆菌感染的患者的229份福尔马林固定石蜡包埋样本进行了研究。将PCR结果与组织学、培养结果以及患者的临床发现进行了比较。
以培养作为参考方法时，结核分枝杆菌复合群的分枝杆菌检测灵敏度为90%，特异性为92%，阳性预测值为81%，阴性预测值为96%。非结核分枝杆菌的检测灵敏度为100%，特异性为78%，阳性预测值为26%，阴性预测值为100%。患者的临床发现支持PCR阳性结果，表明在18例最初培养阴性的病例中有11例以及35例PCR阳性但无培养结果的病例中有21例存在分枝杆菌感染。
这些结果表明，基于PCR的技术是在常规处理后的石蜡包埋和福尔马林固定组织学样本中检测分枝杆菌的灵敏、特异且快速的方法。
