Extent and origin of resistance to antituberculosis drugs in the Netherlands, 1993 to 2011

The elimination of tuberculosis (TB) is threatened by an apparent increase in the level of resistance in Mycobacterium tuberculosis. In the Netherlands, where the majority of TB patients are migrants, resistance may also be increasing. We conducted a retrospective study, using 18,294 M. tuberculosis isolates from TB cases notified between 1993 and 2011. We investigated the trends in antituberculosis drug resistance, focusing on the country of birth of the patients and whether resistance had developed during treatment or was the result of transmission of resistant M. tuberculosis strains. For both scenarios, we determined whether this had happened in or outside the Netherlands. Antituberculosis drug resistance was found in 13% of all cases analysed and showed an increasing trend among patients who had been born in the Netherlands (p