Diagnosis of mycobacterium tuberculosis infection by Guinea pig inoculation

Abstract

Drug resistance has emerged as a major problem in management of pulmonary tuberculosis (PT) with increase in its incidence.Sixty patients who presented to a tertiary referral chest centre with drug resistant PT were included in the study out of 835 clinically diagnosed cases of PT treated between January 2000 and May 2002. They were studied to see the incidence, pattern of drug resistance and response to treatment.7.2% of the clinically diagnosed cases of PT had drug resistance and 14.8% of the 403 strains of mycobacterium tuberculosis (MTB) tested were resistant to one or more antitubercular drugs (ATD). 40 cases (66.7%) had initial resistance and acquired resistance was seen in 20(33.3%) out of the 60 cases of drug resistant PT. Single drug resistance was observed in 21 cases (35%), two drug resistance in 19 (31.7%) and 20(33.3%) cases showed resistance to three or more drugs. Individual drug resistance breakup was: INH(H) – 36(8.9%), Rifampicin (R)-38(9.4%), Ethambutol (E) – 14(3.5%), Streptomycin (S) – 34(8.4%), Pyrazinamide (Z) – 2(0.5%), Ciprofloxacin (C) – 2(0.5%), Ethionamide (N) – 2(0.5%), Cycloserine – 1(0.3%) and Kanamycin – 1(0.3%). 98.3% showed sputum conversion after starting reserve drugs. Average period of sputum conversion was 10 weeks. 3.3% were HIV positive.Incidence of drug resistance was not as high as reported by some other workers and majority of the cases showed satisfactory outcome.