Tuberculosis has resurged in the United Kingdom over the past two decades, with 8000 cases being reported in 2006.1 Previous reports have indicated a stable proportion of drug resistance in people with tuberculosis in the UK from 1993 to 1999.2 In the accompanying paper, Kruijshaar and colleagues present an updated analysis of trends in drug resistance in tuberculosis cases in the UK.3

Kruijshaar and colleagues report an increasing proportion of isoniazid resistance (from 5% to 6.9%) and modest increases in the proportions of rifampicin resistance (1.0% to 1.2%) and multidrug resistance (0.8% to 0.9%).3 However, the true burden of drug resistant tuberculosis is better shown by the incidence of resistant cases, rather than the proportion of cases that are resistant.4 Although the increase in the proportion of resistant cases is modest, when combined with the rising incidence, the increase in numbers of resistant cases is greater than …