Rapid diagnosis of Mycobacterium tuberculosis by multiplex polymerase chain reaction from clinical specimens.

An essential element in the control of tuberculosis is the rapid, sensitive and specific identification of the causative agent. Until now, screening and diagnosis are largely based on clinical signs, radiological examination, tuberculin tests, sputum examination under the microscope, or culture for mycobacteria. Tuberculin tests lack specificity and only give an indication of previous exposure to mycobacteria. Direct microscopic examination of sputum is neither specific nor sensitive enough, and mycobacterial isolation is time-consuming. As an alternative to these classical methods, new nucleic acid-based technologies show promise as a more rapid, sensitive, and specific means of identification of mycobacteria. Two commercial standardized nucleic acid-based amplification techniques have been reported to yield reliable results within 5 to 7 hrs. Roche Amplicor MTB (Roche Diagnostic System, Somerville, N.J.) and Gen-Probe AMTB (Gen-Probe Inc., San Diego, Calif.). The amplified target is part of the 16S rRNA gene which is common to all the mycobacteria. An attempt has been made to describe the use of the target DNA, SenX3-RegX3, in a multiplex PCR to detect and differentiate M. tuberculosis from other mycobacteria directly from clinical specimens.