DETECTION AND IDENTIFICATION OF MYCOBACTERIA IN CLINICAL SPECIMENS

通过常规方法检测和鉴定分枝杆菌属的抗酸杆菌需要从患者标本中培养生物体，然后测试分离物的各种表型特征。这些方法可能需要几天到一个月或更长时间。一些用于检测生长的抗酸杆菌培养物的高特异性分子探针的发展大大减少了鉴定某些分枝杆菌分离株的时间。近年来，聚合酶链反应和等温核酸扩增技术已被用于检测临床样品中的结核分枝杆菌，提供了高度的特异性和合理的灵敏度。目前，还没有商业上可用的扩增分析系统能够检测多种分枝杆菌，同时排除临床样品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，以调查压力循环技术的有效性，以提高核酸从分枝杆菌细胞释放的效率。与贝克曼公司的Jang B. Rampal博士合作，为人类样本中20种最常见的分枝杆菌物种开发更好的终点检测方法，目前仍在继续。实验已经成功地进行了一种方法，可以同时检测六种常见临床分离的分枝杆菌物种的核酸扩增产物的存在或不存在。

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.