Spoligotyping Followed by Double-Repetitive-Element PCR as Rapid Alternative to IS6110 Fingerprinting for Epidemiological Studies of Tuberculosis

A total of 129 clinical isolates of Mycobacterium tuberculosis representing 91 patients were typed by a combination of direct-repeat (DR)-based spoligotyping and an inter-IS6110–PGRS (polymorphic GC-rich region)–PCR, also designated double-repetitive-element PCR (DRE-PCR). During the first phase of this investigation, 72 clinical strains representing 52 patients were initially typed by IS6110-restriction fragment length polymorphism (RFLP) and DR-RFLP, followed by spoligotyping and DRE-PCR. In the second phase of this investigation, the discriminating ability of spoligotyping plus DRE-PCR was studied for 57 isolates from 39 patients who were suspected to be epidemiologically linked, and the typing results were later confirmed by IS6110-RFLP and DR-RFLP analyses. The molecular clustering of the isolates remained identical irrespective of the methods used. These results show that the association of two PCR-based fingerprinting techniques for molecular epidemiology of tuberculosis has a discriminating ability similar to the IS6110-RFLP reference method.