Molecular fingerprinting of Mycobacterium tuberculosis: how can it help the clinician?

In just a few years, molecular fingerprinting of Mycobacterium tuberculosis has provided clinicians with significant insight into the epidemiology of tuberculosis. This methodology has allowed for a new understanding of the extent of new transmission of tuberculosis among residents of various communities and within institutions. It has also allowed for differentiation between episodes of reinfection and relapse, a task hitherto almost impossible to accomplish. In addition, molecular fingerprinting has allowed assessment of situations where laboratory cross-contamination is suspected. Thus, this technology has in many ways made clinicians reexamine many of their long-held beliefs regarding tuberculosis. In this report, Drs. Behr and Small provide a lucid description of molecular fingerprinting of M. tuberculosis, its current uses, and its future potential value.