Rolling circle amplification and multiplex allele-specific PCR for rapid detection of katG and inhA gene mutations in Mycobacterium tuberculosis.

The aim of the study was to compare a novel, rolling circle amplification (RCA) assay for detection of common isoniazid (INH) resistance mutations in Mycobacterium tuberculosis with a multiplex allele-specific PCR (MAS-PCR) and sequencing of katG and the fabG1-inhA promoter region. One or more mutations were identified by RCA, MAS-PCR, and sequencing in 21 (68%), 22 (71%), and 23 (74%), respectively, of 31 epidemiologically unrelated INH-resistant isolates, and in none of 8 INH-susceptible isolates. The RCA assay is a rapid, inexpensive, and practical screening method for INH resistance in M. tuberculosis in countries with high prevalence of INH resistance.