ABSTRACT
OBJECTIVE: To evaluate the clinical application of the detection of the drug resistant genes rPOB, katG, rPSL, PncA and embB in M. tuberculosis by using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis. METHODS: Gene mutations and anti-tuberculous drug susceptibility test were analyzed in 109 M. tuberculosis isolates by PCR-SSCP and the proportion method on Lowenstein-Jensen medium, respectively. The therapeutic effect was evaluated in patients with tuberculosis. RESULTS: Isolates from more than 50% of the patients with pulmonary tuberculosis were resistant to at least two drugs. The total rates of drug resistance to rifampin (RFP), isoniazid (INH), streptomycin (SM), pyrizinamide (PZA) and ethambutol (EB) were 80.7%, 71.5%, 78.8%, 57.7%, and 48.6%, respectively. The gene mutation rates of rpoB, katG, rpsL, pncA and embB were 76%, 68%, 71%, 51% and 30%, respectively. The gene mutations were correlated with the degree of drug-resistance to M. tuberculosis. Most of the gene mutations were found in drug-resistant isolates in high concentrations. The six month cure rates of MDR-TB, confirmed by drug susceptibility test and by PCR-SSCP, were 54.8% and 62.8%, respectively (P > 0.05). CONCLUSIONS: PCR-SSCP is a sensitive and specific method for rapid detection of rpoB, katG, rpsL, pncA and embB gene mutations in M. tuberculosis. Drug resistant gene detection may be clinically useful in the therapy of tuberculosis.