HIV and multidrug-resistant tuberculosis: overlapping epidemics.

People infected with Mycobacterium tuberculosis and HIV are much more likely to develop active tuberculosis (TB) than people with M. tuberculosis but without HIV [1]. Patients infected with multidrugresistant (MDR)-TB (defined as resistance to at least rifampicin and isoniazid, the two most powerful antiTB drugs) require longer, more expensive treatment regimens than drug-susceptible TB, with poorer treatment success [2, 3]. Therefore, MDR-TB poses a major challenge to the control of TB, with an estimated global disease incidence in 2012 of ,450 000 cases (95% CI 300 000–600 000) [4]. Although HIV is a powerful risk factor for all forms of TB and institutional outbreaks of MDR-TB among people living with HIV have been reported [5], population-level data on the association between HIV infection and MDR-TB are limited.