DETECTION AND IDENTIFICATION OF MYCOBACTERIA IN CLINICAL SPECIMENS

通过常规程序检测和鉴定分枝杆菌属的抗酸杆菌需要从患者样本中培养微生物，然后测试分离株的各种表型特征。这些方法可能需要数天到1个月或更长时间。几种用于检测生长抗酸杆菌培养物的高度特异的分子探针的开发，大大缩短了一些分枝杆菌分离株的鉴定时间。近年来，聚合酶链式反应和等温核酸扩增技术被用于检测临床标本中的结核分枝杆菌，具有高度的特异性和合理的敏感性。目前，还没有商业化的扩增分析系统能够检测多种分枝杆菌，同时排除临床样本中常见的其他细菌的交叉反应信号。我们已经开始了一项新的努力，以研究压力循环技术在提高分枝杆菌细胞核酸释放效率方面的有效性。与Beckman Corporation的Jang B.Rampal博士合作，为人类样本中最常见的20种分枝杆菌物种开发了更好的终点检测方法，这一合作仍在继续。用一种同时检测六种常见临床分离的分枝杆菌核酸扩增产物的方法成功地进行了实验。

Detection and identification of acid-fast bacilli of the genus Mycobacterium by conventional procedures requires growing the organisms from patient specimens and then testing the isolates for various phenotypic characteristics. These methods may require days to 1 or more months. The development of a few highly specific molecular probes for testing cultures growing acid-fast bacilli has greatly reduced the time to identification of some mycobacterial isolates. Recently, the polymerase chain reaction and isothermal nucleic acid amplification techniques have been used in assays that offer a high degree of specificity and reasonable sensitivity for detection of Mycobacterium tuberculosis in clinical samples. At present, there are no commercially available amplification assay systems that are capable of detecting multiple Mycobacterium species while excluding cross-reactive signals from other bacteria commonly present in clinical samples. We have initiated a new effort to investigate the usefulness of a pressure cycling technique to improve the efficiency of nucleic acid release from mycobacterial cells. The collaboration with Dr. Jang B. Rampal of Beckman Corporation to develop a better end point detection method for the 20 some most commonly encountered Mycobacterium species from human samples has continued. Experiments have been successfully performed with a method that simultaneously detects the presence or absence of nucleic acid amplifi-cation products from six common clinically isolated Mycobacterium species.