Resistance to antituberculosis drugs is caused by poor management of tuberculosis control. It gives rise to treatment failure, relapse, further transmission of resistant tuberculosis, and multidrug-resistant tuberculosis. Widespread occurrence of multidrug-resistant tuberculosis would constitute a major threat to tuberculosis control in resource-poor countries. Although the impact of HIV on drug resistance is not yet fully understood, it is likely to exacerbate problems caused by drug resistance. In particular, HIV-related adverse effects of thiacetazone, together with the risks of transmission of HIV by parenteral administration of streptomycin, reduce the armamentarium available to tuberculosis control programmes in high HIV prevalence countries, and could encourage the development of resistance to the remaining drugs. While the prime need is to ensure, by good management and supervision, that resistance does not occur in the first place, surveillance of drug resistance is essential to determine the current scale and nature of the drug resistance problem, as well as to define the correct solutions.
PIP: Poor management of tuberculosis (TB) control is responsible for resistance to antituberculosis drugs. It leads to treatment failure, relapse, transmission of resistant TB, and multi-drug resistant TB. In developing countries, where resources are already limited, an epidemic of multi-drug resistant TB would jeopardize TB control. The effect of HIV infection is likely to worsen drug resistance-related problems. Specifically, streptomycin injections pose a risk of HIV transmission. It appears that withdrawal of thiacetazone from HIV infected TB patients causes resistance to more powerful drugs. If these 2 antibiotics cannot be used to treat TB patients, the armamentarium available to control TB in high HIV prevalence countries is reduced, which could foster resistance to the fewer remaining antibiotics. Good management and supervision is needed to prevent resistance to antituberculosis drugs. Surveillance of drug resistance is also needed to monitor the current level and characteristics of the drug resistance problem and to identify effective solutions. Specifically, at the national level, a TB surveillance system can assess the TB control program's performance and assess the need to modify the current treatment policy. It can identify districts or health centers with high levels of drug resistance and determine the risk factors for resistance. WHO will assist developing countries in developing their own surveillance systems. WHO and the International Union Against Tuberculosis and Lung Disease plan on setting up a network of supranational reference laboratories to determine the quality control and standardization of susceptibility testing needed for international comparison. WHO also plans on supporting national reference laboratories in developing countries.