Susceptibility pattern among pulmonary and extrapulmonary isolates of Mycobacterium tuberculosis in north India

Drug resistant tuberculosis (TB) is an increasing problem worldwide. We retrospectively identified Mycobacterium tuberculosis isolates from treatment failure pulmonary TB (362), and extrapulmonary TB (338) patients (18-70 years) during a 4 year period (June, 2002-July, 2006). Drug susceptibility testing was carried out for the first line anti-tuberculosis drugs using standard proportion method. Of the treatment failure pulmonary TB, and extrapulmonary TB isolates, 51.9 and 47.3% were pan susceptible, respectively. The rest of the isolates were resistant to at least one of the drugs. Overall, multidrug resistance (MDR) was detected in 16.6% isolates and was higher in treatment failure pulmonary TB as compared to extra-pulmonary TB cases. Periodic monitoring of the level of drug resistance in both pulmonary and extrapulmonary TB is important to assess the true picture of drug resistance in M. tuberculosis, and is hence crucial for robust implementation of effective TB control programs.