Resistance to Antituberculosis Drugs in Pulmonary Tuberculosis

Background

Incidence of drug resistance and pattern of susceptibility to antitubercular drugs in pulmonary tuberculosis amongst soldiers and their families was studied for four years at a military hospital in northwest India.

Methods

Identification and susceptibility tests were carried out as per procedures laid out in laboratory manual of Tuberculosis Research Centre (TRC), Chennai.

Results

Of the 172 strains of Mycobacterium tuberculosis (MTB) isolated from sputum samples, 150 (87.21%) were sensitive and 22 (12.79%) showed resistance to one or more antitubercular drugs. Acquired drug resistance was observed in 7 (31.82%) and primary drug resistance in 15 (68.18%) cases. Among 22 drug resistant cases, who were on short course chemotherapy (SCC), resistance to single drug was observed in 12 (54.54%), two drugs in 7 (31.82%) and to three or more drugs in 3 (13.64%) isolates. Fourteen (18.14%) strains were resistant to Streptomycin, 8 (4.65%) to Rifampicin, 11 (6.40%) to Isoniazid, 1 (0.58%) to Pyrazinamide and 2 (1.16%) to Ethambutol. Multidrug resistance was observed in 5 (2.91%) cases, of which resistance to Isoniazid and Rifampicin was present in 2 (1.16%) and their combination with other drugs in other 3 (1.74%) isolates.

Conclusions

Drug susceptibility pattern to antitubercular drugs is discussed and compared with studies from other centres.Key Words: Drug resistance, Antitubercular drugs, Mycobacterium tuberculosis