Surveillance of antituberculosis drug resistance among children from the Western Cape Province of South Africa - An upward trend

Objectives. We assessed the prevalence of antituberculosis drug resistance among children with tuberculosis (TB) in the Western Cape Province of South Africa. Methods. Drug susceptibility testing for isoniazid and rifampin was prospectively done on all children with culture-confirmed TB at Tygerberg Children's Hospital, Cape Town, from March 2005 through February 2007. Survey results were compared with results from 2 previous surveys. Results. We found 291 children had culture-confirmed TB. Resistance to isoniazid or rifampin increased from 21 of 306 (6.9%) to 41 of 319 (12.9%) and 43 of 285 (15.1%) in the first to third surveys (P=.005) and multidrug resistance from 7 of 306 (2.3%) to 18 of 319 (5.6%) and 19 of 285 (6.7%; P=.033). Although previously treated children had significantly more drug resistance than did new TB cases (19 of 66 [28.8%] vs 24 of 225 [10.7%]; odds ratio=3.39; 95% confidence interval=1.62, 7.05), evidence suggests transmission rather than acquisition of resistance. HIV infection was not significantly associated with drug resistance. Conclusions. Results indicate a high and rising prevalence of anti-TB drug resistance among children in the Western Cape, which suggests ongoing transmission of drug-resistant strains within the community. Improved control of TB in adults, including early identification and treatment of drug-resistant cases, is necessary to reduce transmission to children.