Prevalence of primary drug resistant Mycobacterium tuberculosis in Mashhad, Iran

Multidrug resistant tuberculosis (MDR-TB) has been a cause of concern in both developed and developing countries. Surveillance data on primary drug resistance in Mycobacterium tuberculosis are important to design tuberculosis control programmes. There is a paucity of information about primary drug resistance in mycobacterium in Iran. We undertook this hospital-based study to assess the prevalence of primary of drug resistant in M. tuberculosis in Mashhad, Iran.

A total of 105 M. tuberculosis isolates from cases with pulmonary and extrapulmonary tuberculosis, who did not have prior history of anti-tuberculosis treatment, were tested for the drug susceptibility by indirect proportion susceptibility test as per the standard guidelines.

Of the 105 isolate tested, 93 were from pulmonary specimens; and the remaining were extrapulmonary. 79.6 per cent of pulmonary and 50 per cent of extrapulmonary specimens were smear positive. Resistance to at least one drug was shown by 29.5 per cent, while 2.9 per cent were resistant to more than one drug. MDR-TB was found at 1 per cent of strains.

Our study showed a high level of resistance to streptomycin and very low resistance to other drugs. To achieve the higher cure rate, replacement of streptomycin by ethambutol and strict implementation of DOTs may be considered.