Mycobacteria cause a variety of human diseases that differ in severity and treatment, depending on the etiologic agent. In addition, there are important public health implications because of the respiratory spread of Mycobacterium tuberculosis. The rapid identification and differentiation of mycobacteria is essential, and significant advances to these ends have been achieved in parallel with advances in molecular microbiology, but much work is still needed. The techniques of foremost importance are those that use nucleic acid amplification. These tests, some of which are commercially available, have made it feasible to rapidly detect M. tuberculosis directly in the patient specimen and are complementary to conventional laboratory testing. More recently, advances in the rapid detection and differentiation of mycobacteria has used rapid or “real-time” PCR methods. These assays, depending on the target sites selected, might detect and/or differentiate M. tuberculosis from nontuberculous mycobacteria in approximately 1 hour. Finally, rapid, user-friendly DNA sequencing (Pyrosequencing; Pyrosequencing AB, Uppsala, Sweden) has been used to further categorize mycobacteria to the species level or into clinically relevant molecular complexes, which significantly diminishes time to identification, and diminishes or eliminates the biochemical and physiological testing needed.
We present 3 scenarios of patients seen at The Cleveland Clinic Foundation, in which molecular studies were used to determine the type of mycobacteria present.