The diagnostic mycobacteriology laboratory of the 1990s

The diagnostic mycobacterial laboratory of the 1990s must respond to a change in the clinical spectrum of mycobacterial infections brought about by an increase in the number of patients who are immunocompromised, are indigent, or have temporary or permanent implanted devices. Emerging pathogens such as Mycobacterium haemophilum and Mycobacterium genavense, multidrug-resistant strains of Mycobacterium tuberculosis, and catheter infections with rapidly growing mycobacteria are examples of new issues. Fortunately, new methods for detection and identification of microbes have been or are being developed. Procedures that, when applied directly to clinical specimens or actively growing cultures, dramatically reduce the time to diagnosis of mycobacterial infections include radiometric broth, lysis-centrifugation, and biphasic systems for specimen culture, and DNA probes, high-performance liquid chromatography, DNA hybridization, restriction fragment length polymorphism, and gene amplification for organism detection and identification. At present, in vitro antimicrobial susceptibility tests are most helpful in guiding treatment of infections caused by M. tuberculosis and rapidly growing mycobacteria.