Abstract
Drug-resistant strains of Mycobacterium tuberculosis have emerged as a major threat to global tuberculosis control. Despite the availability
of curative antituberculosis therapy for nearly half a century, inappropriate and
inadequate treatment has allowed M. tuberculosis to acquire resistance to our most important antituberculosis drugs. The epidemic
of drug-resistant tuberculosis has spread quickly in some areas due to the convergence
of resistant strains of M. tuberculosis in high-risk patients (e.g., those with human immunodeficiency virus/acquired immunodeficiency
syndrome) and high-risk environments (e.g., hospitals and prisons). The World Health
Organization (WHO) estimates that there were 650,000 cases of multidrug resistant
tuberculosis (MDR-TB) in 2010, defined as strains that are resistant to at least isoniazid
(INH) and rifampicin (RIF). Globally, WHO estimates that 3.7% of new tuberculosis
cases and 20% of re-treatment cases have MDR-TB. By the end of 2012, 84 countries
had reported at least one case of extensively drug resistant strains (XDR-TB), which
are MDR-TB strains that have acquired additional resistance to fluoroquinolones and
at least one second-line injectable. Recently, cases of “totally drug resistant” tuberculosis
have been reported. It is estimated that only 10% of all MDR-TB cases are currently
receiving therapy and only 2% are receiving quality-assured drugs. This article reviews
the management of MDR and XDR-TB and highlights the updated 2011 WHO guidelines on
the programmatic management of drug-resistant tuberculosis.
Keywords
tuberculosis - drug resistant - MDR-TB - XDR-TB - management
