Primary Drug-resistant Tuberculosis in Children

Setting: The Western Cape Province of South Africa, an area with a high tuberculosis (TB) incidence where initial isoniazid (INH) resistance and multidrug resistance (MDR) among adults was 3.9% and 1.1%, respectively, during 1992-1993.

Objective: To determine the drug resistance incidence among children as compared to adults, to compare the clinical features of drug-resistant and drug-susceptible TB, and the degree of INH resistance in isoniazid-resistant isolates.

Methods: All Mycobacterium tuberculosis cultures obtained from children (0-13 years) at a regional hospital were prospectively collected from August 1994 to April 1998 and susceptibility testing done on each child's specimens. Degree of INH resistance was determined in available resistant isolates. The children's clinical records were reviewed.

Results: Susceptibility results were available in 306/338 children with cultures of M. tuberculosis; 21 isolates (6.9%) were INH-resistant, and seven were MDR. Taking into account study limitations, the incidence of INH resistance was 5.6% and MDR 1% in children aged <5 years. Clinical features were similar in children with drug-susceptible and drug-resistant TB.

Conclusion: The incidence of drug resistance in childhood tuberculosis in Western Cape is low, and probably reflects the level of primary drug resistance amongst organisms currently circulating in the community.