APPLICATION OF REALTIME PCR FOR DETECTING M.TUBERCULOSIS RESISTANT TO RIFAMPICIN AND ISONIAZID

Abstract

Introduction: Conventional culture methods for antibiotic susceptibility testing for M. tuberculosis may take days to several weeks. Use of realtime PCR for rapid detection of drug and multidrug resistant tuberculosis could facilitate early initiation of appropriate anti-tubercular treatment regimen thereby interrupting transmission. Objectives: 1. Determine prevalence of rifampicin-, isoniazid- and multidrug-resistant tuberculosis strain among the patients with recurrent tuberculosis. Xác định tỷ lệ các đột biến kháng rifampicin và isoniazid trong các chủng đề kháng phenotype 2. Determine proportion of the mutations concern to tuberculosis strains resistant to rifampicin và isoniazid. Methods: Doing susceptibility test by MODS assay for 50 tuberculosis strains isolated from patients with recurrent tuberculosis, realtime PCR was performed by using MTB Real-TM Resistance 4 kit to detect mutations in codon 531 of the rpoB gene related to rifampicine and mutations in codon 315 of the katG gene or in codon 209 of the inhA gene related to isoniazid. Results: Among tuberculosis strains isolated from patients with recurrent tuberculosis, there were 8% strains monoresistant to rifampicin and 60% multidrug-resistant strains. The Sacace MTB Real-TM resistance 4 kit detected 80% tuberculosis strains resistant to rifampicine with the mutation in rpoB gene codon 531 and 86,1% tuberculosis strains resistant to isoniazid with the mutation in katG gene codon 315 among the strains determined by MODS assay. Conclusion: The Sacace MTB Real-TM resistance 4 kit can’t detect rifampicine-/ isoniazid - resistant tuberculosis strains which have mutations in other codons of the above gene. Key words: M. tuberculosis, rifampicine-resistance, isoniazid-resistance, MODS, realtime PCR