Drug resistance patterns among pulmonary tuberculosis patients in a tertiary care hospital in northern Karnataka

Background: Resistance to anti-tuberculosis (anti-TB) drugs is becoming a major and alarming threat in most regions worldwide and India ranks second in the world in harboring multi-drug resistant cases (MDR)-TB. The study was carried out to evaluate the drug resistance pattern to first-line anti-TB drugs in Northern Karnataka. Materials and Methods: A prospective study was conducted at a tertiary care hospital between January 2011 and June 2012. A total of 110 sputum samples were examined for the acid-fast bacilli (AFB) culture. A total of 48 AFB culture-positive samples were subjected for AFB drug sensitivity testing (DST). DST was done for isoniazid (INH), rifampicin (RIF), pyrazinamide (PZA), ethambutol and streptomycin (SM) after isolation by using the resistance proportion method. Results: Of the 48 AFB culture positive specimens, 12 (25.0%) cases were sensitive to all the five drugs while 36 (75.0%) cases showed resistance to one or more drugs. Among these, the resistance to RIF was highest (91.9%), while resistance to SM, INH, PZA and ETB was observed in 72.2%, 72.2%, 63.9% and 52.8%, respectively. The resistance to all five drugs was highest (41.7%), while MDR isolates were obtained in 69.4% of the cases. Illiteracy, low socio economic status, previous history of TB and alcoholism were found to have statistically significant association for the development of MDR. Conclusions: The proportion of drug resistance in the present study was 75.0% and MDR was present in 69.4% of cases. Therefore during initiation of new case, proper explaining and completion of the treatment is very important to avoid the development of future drug resistance in pulmonary TB patients.