Risk factors and drug-resistance patterns among pulmonary tuberculosis patients in northern Karnataka region, India.

Background: India is one of the high tuberculosis (TB)-burden countries in the world. Resistance to anti-tuberculosis (anti-TB) drugs has already become an important and alarming threat in most of the regions worldwide. India ranks second in the world in harbouring multi-drug resistant cases (MDRTB). Prevalence of MDR-TB mirrors the functional state and efficacy of TB control programmes and realistic attitude of the community towards implementation of such programmes. The most important risk factor in the development of MDRTB is improper implementation in the guidelines in the management of TB, and high rate of defaults on the part of the patients. The study was carried out to evaluate the drug resistance pattern to first line anti-TB drugs in Northern Karnataka region, India.

Materials And Methods: A prospective study was conducted at J. N. Medical College and its associated Hospitals, Belgaum. Between January 2011 and December 2012, 150 sputum samples of suspected pulmonary TB patients based on the history were examined for the AFB culture by Lowenstein-Jensen (LJ) culture technique. A total of two early morning samples were collected for the smear [Ziehl-Neelsen (ZN) staining] and culture methods. It was observed that ZN staining for AFB was positive in 113 patients (75%), while AFB culture by LJ medium yielded growth in 66 cases (44%). Thus, a total of 66 AFB culture-positive samples by LJ medium were subjected for AFB drug-sensitivity testing (DST). DST was done for Isoniazid (INH), Rifampicin (RIF), Pyrazinamide (PZA), Ethambutol (EMB) and Streptomycin (SM) after isolation by using the resistance proportion method.

Results: A total of 66 AFB culture-positive specimens, 20 (30.3%) cases were sensitive to all the five drugs while 46 (69.7%) cases showed resistance to one or more drugs. Among these, the resistance to rifampicin was highest (80.4%), while resistance to isoniazid, pyrazinamide, ethambutol and streptomycin were observed to be 60%, 58.7%, 52.1% and 63%, respectively. It was also observed that, resistance to all five drugs was highest (39.18%). MDR isolates were obtained in 52.2% 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 prevalence of drug resistance in the present study was observed to be 69.7%. More than half of the cases were multi-drug resistant. The most common resistant pattern observed in this study was resistance to all the first-line drugs. 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 the society.