Prevalence of primary multidrug resistance to anti-tuberculosis drugs in Pakistan

Pakistan ranks sixth in the world in terms of tuberculosis (TB) burden, with a World Health Organization estimated incidence of 181 per 100000, or 286000 new cases annually. Hospital-based data indicate a significant problem of multidrug-resistant TB (MDR-TB) in the country and highlight the need to assess its extent at community level. In this cross-sectional study, sputum samples from 742 untreated newly diagnosed pulmonary TB patients from all over the country were used.

To assess the prevalence of primary drug resistance in Pakistan.

Of 672 culture-positive patients, 76 (11.3%) showed resistance to one or more drugs. Resistance to streptomycin (10 microg/ml) was found in 36 (5.4%) patients, isoniazid (INH) (1 microg/ml) in 51 (7.6%), rifampicin (RMP) (5 microg/ml) in 15 (2.2%), ethambutol (10 microg/ml) in 12 (1.8%) and pyrazinamide in 22 (3.3%) samples. Forty-six (6.8%) of the isolates tested were resistant to a single drug, 10 (1.5%) to two drugs, 12 (1.8%) to three drugs, and 6 (0.9%) to four drugs, while 2 (0.3%) isolates were resistant to all five first-line agents. Primary MDR-TB was 1.8% (n=12) (INH 1 microg/ml, RMP 5 microg/ml).

The results of this study show a prevalence of primary MDR-TB in Pakistan of <2%, which needs to be addressed through an effective DOTS strategy.