Prevalence of Primary Resistance to First Line Anti Tuberculosis Drugs and its Relation with Conversion of Smear Positive Pulmonary Tuberculosis

Emergence of drug resistant tuberculosis is a global concern. It might cause reduction in the rate of smear conversion in pulmonary tuberculosis. The aim of the present study was to examine the role of primary first line anti tuberculosis drugs resistance on the rate of sputum conversion. In a cohort study between 2005 and 2006، all smear positive pulmonary tuberculosis patients (90 cases) treated in Tabriz Tuberculosis and Lung Disease Research Center were included. Sputum smear and culture taken before and then 15 days and monthly for 6 months after standard four drug (INH، RIF، PZN، ETM) treatment were assessed. There were 90 smear positive patients (47 males and 43 females) in the study period. The mean time was 1. 5 and 1 month for smear and culture negativity، respectively. Only one case was resistant to INH، RIF، and STM، for whom second line drugs were started. Other four resistant cases had positive smear until six months of treatment but their cultures were negative at the end of second month. At the seventh month، their smears were also negative. Drug resistant tuberculosis is very infrequent in Tabriz and this mandates prompt surveillance and treatment of the patients in order to prevent emergence of drug resistant tuberculosis.