Detection And Identification Of Mycobacteria In Clinical

通过常规程序检测和鉴定分枝杆菌种类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。如果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，这将是有用的。实验已经成功地用一种同时检测来自六个常见的临床分离的分枝杆菌物种的核酸扩增产物的检测版本进行。国家卫生研究院和贝克曼·库尔特公司最近提交了一份联合专利申请。由于样品制备是分子诊断分析的关键组成部分，我们发起了一项新的努力，以研究压力循环技术(PCT)在提高分枝杆菌细胞核酸释放效率方面的有用性。BBI Biotech与CRADA合作，最近将一种压力循环装置(压力循环装置)带入CPD。使用PCT作为核酸提取前的前处理，我们能够提高含有戈登分枝杆菌的悬液和结核分枝杆菌悬液的平均PCR信号。一项与约翰·霍普金斯结核病研究中心和BBI合作的前瞻性研究正在启动，以评估在通过培养或分子测试检测分枝杆菌之前，不同的PCT条件对呼吸道标本处理的效用。

Detection and identification of acid-fast bacilli of Mycobacterium species by conventional procedures requires growing the organisms from patient specimens and then testing the isolates for various phenotypic characteristics. These methods may take 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. It would be useful to have amplification assay systems that are capable of detecting multiple Mycobacterium species while excluding cross-reactive signals from other bacteria commonly present in clinical samples. Experiments have been successfully performed with an assay version that simultaneously detects the presence or absence of nucleic acid amplification products from six common clinically isolated Mycobacterium species. A joint patent application between the N.I.H. and Beckman Coulter Corporation has been recently submitted. Because sample preparation is a critical component of molecular diagnostic assays, we have initiated a new effort to investigate the usefulness of a pressure cycling technology (PCT) for improving the efficiency of nucleic acid release from mycobacterium cells. A barocycler (device for pressure cycling) has been recently brought into CPD under a CRADA with BBI Biotech. Using PCT as a pretreatment before nucleic acid extraction we were able to increase the average PCR signals from suspensions containing Mycobacterium gordonae and suspensions of Mycobacterium tuberculosis. A collaborative prospective study is being initiated with the Johns Hopkins Center for TB Research and BBI to evaluate the utility of different PCT conditions for respiratory specimen processing before mycobacterium detection by culture or molecular testing.