RESUMO
To estimate drug resistance in TB patients and compare it with previous studies to see the changing trends. This work was done at the TB Research center of Pakistan Medical Research Centre at Mayo hospital Lahore from 2000 to 2003. The center receives specimens from all the leading hospitals of Lahore. Five first line anti tuberculosis drugs were tested on LJ medium using proportion method. A total of 894 confirmed isolates of Mycobacterium tuberculosis [759 pulmonary and 135 extra pulmonary] from 894 patients, with and without history of previous treatment, were subjected to drug susceptibility testing about 50% of the patients had some resistance. Multiple drug resistance [MDR] was found in 12% and 23% without and with history of previous treatment respectively. Overall resistance to rifampicin was 28.6%, isoniazid 25.6%, streptomycin 23.8%, ethambutol 14.5%, and pyrazinamide 29.3%. Statistically significant difference was seen between primary and acquired resistances. Results when compared with the previous studies from the same area showed a gradual increase in drug resistance. Resistance to anti tuberculosis drugs in Lahore is high and needs to be addressed in the national tuberculosis control program and in the implementation of DOTS program in the country