Objectives: To determine the mutations in katG
and rpoB genes in confirmed multi-drug resistant tuberculosis isolates and to find the frequency of mutations
sup] The assay detects mutations in the rpoB gene for RFP resistance, katG
gene for INH resistance, and inhA regulatory region gene for low-level INH resistance.
Isoniazid is a prodrug that is converted to an active intermediates (Isonicotinoyl acyl radical) by the catalase-peroxidase enzyme encoded by the katG
gene of M.
The two mutation probes for the katG
gene detected mutations at the codons S315T1 (katG
MUT1) and S315T2 (katG
Detection of the mutations in katG
315 and inhA -15 of Mycobacterium tuberculosis strains isolated from Chinese patients.
In a minority of situations where both inhA and KatG
mutations are present (precluding use of either Eto or high-dose INH), an alternative agent, such as clofazimine or para-aminosalicylate, is considered for addition to the regimen to ensure a minimum of four effective drugs.
The assay has an additional advantage over other line probe assays because the Genotype MTBDRplus assay identifies mutations in the rpoB gene (coding for the [beta]-subunit of the RNA polymerase) for detection of RIF resistance, mutations in the katG
gene (coding for the catalase peroxidase) for high-level INH resistance, and mutations in the promoter region of inhA gene (coding for the NADH enoyl ACP reductase) for low-levels INH resistance.
32,33) The tests involve DNA extraction, multiplex NAAT, solid phase reverse hybridization on the test strip, and detection of mutations such as in the rpoB gene, in the katG
gene and the inhA gene promoter regions.
The non-pigmented mutants potentially expressed more catalases (katE, katG
12) The sensitivity of LPAs for rifampicin resistance is very high, but sensitivity for isoniazid resistance is lower due to the presence of mutations outside the regions of the inhA and katG
genes that LPAs can detect.
Para la determinacion del perfil de sensibilidad a los antituberculosos rifampicina (RIF) e isoniacida (INH) se realizo la lectura de las tiras observando la presencia o ausencia de sondas para detectar la secuencia silvestre o mutada de los genes rpoB, katG