Treatment and prevention of multidrug-resistant tuberculosis

Abstract

Multidrug-resistant tuberculosis (MDRTB), which is defined as combined resistance to isoniazid and rifampicin, is a 'man-made' disease that is caused by improper treatment, inadequate drug supplies or poor patient supervision. Patients with MDRTB face chronic disability and death, and represent an infectious hazard for the community. Cure rates of 96% have been achieved but require prompt recognition of the disease, rapid accurate susceptibility results, and early administration of an individualised re-treatment regimen. Such regimens are usually based on a quinolone and an injectable agent (i.e. an aminoglycoside or capreomycin) supplemented by other 'second-line' drugs. This therapy is prolonged (e.g. 24 months), expensive, and has multiple adverse effects. Prevention of MDRTB is therefore of paramount importance. The World Health Organization (WHO) has recommended a multifaceted programme, known by the acronym DOTS (directly observed therapy, short-course), that promotes effective treatment of drug-susceptible TB as the prime method of limiting drug resistance. DOTS was part of a successful MDRTB control programme in New York City, which also included treatment of prevalent MDRTB cases, streamlined laboratory testing, effective infection control procedures and wider application of screening and preventive therapy (although the optimal chemotherapy for MDRTB infection remains undefined). Industrialised countries have the resources to treat patients with MDRTB and to mount these extensive control programmes. Unfortunately, MDRTB is also prevalent in Asia, South America and the former Soviet Union. First world countries have a vested interest, as well as a moral responsibility, to assist in controlling MDRTB in these 'hot spots'.