Department of Laboratory Medicine, Cleveland Clinic, Cleveland, OH 44195.
Microbiol Spectr. 2016 Dec;4(6). doi: 10.1128/microbiolspec.TNMI7-0022-2016.
The laboratory, which utilizes some of the most sophisticated and rapidly changing technologies, plays a critical role in the diagnosis of tuberculosis. Some of these tools are being employed in resource-challenged countries for the rapid detection and characterization of Mycobacterium tuberculosis. Foremost, the laboratory defines appropriate specimen criteria for optimal test performance. The direct detection of mycobacteria in the clinical specimen, predominantly done by acid-fast staining, may eventually be replaced by rapid-cycle PCR. The widespread use of the Xpert MTB/RIF (Cepheid) assay, which detects both M. tuberculosis and key genetic determinants of rifampin resistance, is important for the early detection of multidrug-resistant strains. Culture, using both broth and solid media, remains the standard for establishing the laboratory-based diagnosis of tuberculosis. Cultured isolates are identified far less commonly by traditional biochemical profiling and more commonly by molecular methods, such as DNA probes and broad-range PCR with DNA sequencing. Non-nucleic acid-based methods of identification, such as high-performance liquid chromatography and, more recently, matrix-assisted laser desorption/ionization-time of flight mass spectrometry, may also be used for identification. Cultured isolates of M. tuberculosis should be submitted for susceptibility testing according to standard guidelines. The use of broth-based susceptibility testing is recommended to significantly decrease the time to result. Cultured isolates may also be submitted for strain typing for epidemiologic purposes. The use of massive parallel sequencing, also known as next-generation sequencing, promises to continue to this molecular revolution in mycobacteriology, as whole-genome sequencing provides identification, susceptibility, and typing information simultaneously.
该实验室采用了一些最先进且快速发展的技术，在结核病诊断中发挥着至关重要的作用。其中一些工具正在资源有限的国家用于快速检测和鉴定结核分枝杆菌。首先，实验室为优化测试性能定义了适当的标本标准。通过直接检测临床标本中的分枝杆菌，主要通过抗酸染色，最终可能会被快速循环 PCR 取代。广泛使用 Xpert MTB/RIF（Cepheid）检测试剂盒，该检测试剂盒可同时检测结核分枝杆菌和利福平耐药的关键基因决定簇，对于早期发现耐多药菌株非常重要。使用肉汤和固体培养基进行培养仍然是建立结核病实验室诊断的标准方法。培养分离物的鉴定方法越来越少地采用传统的生化特征分析，而更多地采用分子方法，如 DNA 探针和广泛的 PCR 与 DNA 测序。基于非核酸的鉴定方法，如高效液相色谱法，以及最近的基质辅助激光解吸/电离-飞行时间质谱法，也可用于鉴定。根据标准指南，应将培养的结核分枝杆菌分离物送检进行药敏试验。建议使用肉汤基础药敏试验来显著缩短结果报告时间。培养分离物也可用于流行病学目的的菌株分型。大规模平行测序，也称为下一代测序，有望继续推动分枝杆菌学的分子革命，因为全基因组测序可同时提供鉴定、药敏和分型信息。
