Emerg Infect DiseidEmerging Infectious Diseases1080-60401080-6059Centers for Disease Control117477302631921Research ArticlerpoB Gene mutations in rifampin-resistant Mycobacterium tuberculosis identified by polymerase chain reaction single-stranded conformational polymorphism.Bobadilla-del-ValleM.Ponce-de-LeonA.Arenas-HuerteroC.Vargas-AlarconG.Kato-MaedaM.SmallP. M.CouaryP.Ruiz-PalaciosG. M.Sifuentes-OsornioJ.Laboratory of Clinical Microbiology, Instituto Nacional de Ciencas Médicas y Nutritión Salvador Zubiran, Mexico City, Mexico.Nov-Dec20017610101013

The use of polymerase chain reaction-single-stranded conformational polymorphism (PCR-SSCP) to study rpoB gene mutations in rifampin-resistant (RIFr) Mycobacterium tuberculosis has yielded contradictory results. To determine the sensitivity of this method, we analyzed 35 RIFr strains and 11 rifampin-susceptible (RIFs) strains, using the DNA sequencing of the core region of rpoB for comparison. Of the RIFr, 24 had a PCR-SSCP pattern identical to that of H37Rv; the other 11 had four different patterns. The 11 RIFs had PCR-SSCP patterns identical to that of H37Rv. The sensitivity of the assay was 31.4%; its specificity was 100%. We observed a strong correlation between the degree of resistance and the type of mutation.