Molecular genetic analysis of nucleotide polymorphisms associated with rifampin and isoniazid resistance in human isolates of mycobacterium tuberculosis

The emergence of resistance antituberculosis drugs is a relevant matter worldwide. Genotypic methods allow earlier detection of resistance. DNA sequencing-based approaches are considered the reference assay to detect the nucleotide polymorphism associated with drugs resistance. We characterized the resistant isolates in our area by sequencing (50 strains RIF resistant). Some mutations were found within rpobeta subunit region in all RIF resistant strains. Eighty eight percent of INH - resistant strains showed mutation in KatG codon 315 and twelve percent showed mutation in inhA codon. The genotypic methods, Real-Time PCR and INNO LIPA RIF TB are restricted to detection of only the most frequent mutations. A full concordance of the results of the Real-Time PCR (RIF TB strains) with sequencing data was obtained. Our design could be a model for new, rapid genotypic methods able to simultaneously detect a wide variety of antibiotic resistance.