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.