Primary and Acquired Drug Resistance in Childhood Tuberculosis

Increased rates of multidrug-resistant tuberculosis (MDR-TB) have been reported from developing countries. We evaluated the incidence of drug resistance in children in order to determine the magnitude of the problem, in our region. To determine the resistance pattern of Mycobacterium tuberculosis to four anti-tuberculosis drugs in childhood pulmonary tuberculosis at National Research Institute of Tuberculosis and Lung Disease (NRITLD) which is a referral centre in Tehran. Treatment of the patients was based on the DOTS strategy according to the WHO protocols since 1989. Retrospective analysis of all cases of pulmonary tuberculosis with positive M. tuberculosis culture who had referred to paediatrics ward from January 1999 to August 2004. M. tuberculosis sensitivity testing was performed by the Lowenstein-Jensen medium for isoniazid (INH), rifampicin (RMP), streptomycin (SM), and ethambutol (EMB). Among 350 children (0-15years) with confirmed tuberculosis, 7 children had resistance to at least one of the four anti-TB drugs. Out of the 7 patients, 6 were Afghan refugees and one patient was Iranian. Among those 85.7% had resistance to RMP, 71.4% to INH, 57.1% to SM, and 28.6% to EMB. In addition, 28.5% of patients had resistance to all four drugs (RMP, INH, SM, EMB), 14.2% to INH, RMP, SM, 28.5% to INH, RMP and 14.2% had resistance to each of SM and RMP. In this study 2% of children with TB had resistance out of which primary resistance was detected in 57.1%. Secondary resistance was found in 42.9% of cases who had previous history of anti-TB therapy. According to 2% prevalence of drug resistance in children and high resistance to RMP in our study, more aggressive interventions should be considered. Further management and supervision in DOTS implementation is highly recommended to prevent transmission of resistant tuberculosis.)