A study on pattern of initial and acquired drug resistance for isoniazid and rifampicin in A.F.B. positive sputum smears of pulmonary tuberculosis patients at a Medical College in North Eastern Uttar Pradesh, India

Background: Despite availability of good quality anti-tubercular drugs and its administration through Directly Observed Therapy Short Course (DOTS) strategy of Revised National Tuberculosis Control Programme (RNTCP), tuberculosis remains a major cause of morbidity and mortality in India. The emergence of drug resistance necessitates the timely detection of susceptibility of anti-TB drugs. This can help in appropriate modification in treatment strategies.Methods: A total of 50 patients of pulmonary TB with AFB positive sputum smears attending the OPD of TB and Chest department of B.R.D. Medical College, Gorakhpur were included. Patients were grouped based on history into new (cat-I) and previously treated patients (cat-II). Cat-II patients were further subdivided into defaulter, treatment failure and relapse groups. The culture and DST of AFB positive sputum smears of these patients was done in VersaTREK™®. At the end of study, patients were grouped according to age, sex, category and drug sensitivity pattern for Isoniazid (INH) and Rifampicin (RIF) viz mono resistance (resistance to either INH or RIF) or multi drug resistance (M.D.R.) and the resultant data were analysed.Results: Of the total 50 patients included in this study, 18 (36%) patients were sensitive to both the drugs INH and RIF, of which 11 (22%) were of cat-I and 7 (14%) of category-II. Twenty-two (44%) patients were resistant to INH only of which 8 (16%) were of cat-I and 14 (28%) of cat-II. One (2%) case of cat-I showed resistance to RIF only, while M.D.R. type of resistance is seen in 1 (2%) patient of cat-I and 8 (16%) patients of cat-II. Pattern of resistance to both INH and RIF together (i.e. M.D.R. type) showed significant difference between cat-I and cat-II.Conclusions: Most of the patients showing resistance to INH, RIF or both INH and RIF (M.D.R.) belonged to category-II (previously treated) patients