Molecular epidemiology of tuberculosis: recent developments and applications.

The standard method for the typing of Mycobacterium tuberculosis is still IS6110 restriction fragment length polymorphism (RFLP). This method has been widely used and has provided information on the variety and distribution of tuberculosis strain types across the globe. Recently, IS6110 RFLP has been used to investigate the question of reinfection versus reactivation, examine the existence of multiple infection, and track the spread of multidrug-resistant tuberculosis. There have also been efforts to increase our understanding of the biologic characteristics of IS6110. These studies have resulted in a clearer understanding of fingerprinting data and increased our understanding of the evolution and pathogenicity of this organism.