Drug-sensitivity profile of clinical Mycobacterium tuberculosis isolates--a retrospective study from a chest-disease institute in India.

Multi-drug-resistant tuberculosis (MDR-TB) is a major public-health problem, because treatment is complicated and patients remain infectious for months or years, despite receiving the best available therapy. To gain better understanding of MDR-TB, a retrospective study was initiated to determine the level of drug resistance among patients in a chest-disease institute in India. Two hundred and sixty-three isolates from treatment-failure pulmonary tuberculosis patients (20-70 years) were studied. Drug-sensitivity testing was performed by the modified-proportion method. First- and second-line drugs, along with two quinolone drugs (ofloxacin and ciprofloxacin), were tested. Patients included in this study did not improve with therapy; however, 151 isolates (57.5 %) were susceptible to all four first-line antituberculosis drugs. This study reports low resistance to fluoroquinolones among the strains present in these patients.