Increasing antituberculosis drug resistance in the United Kingdom: analysis of National Surveillance Data.

OBJECTIVE: To identify recent trends in, and factors associated with, resistance to antituberculosis drugs in England, Wales, and Northern Ireland. DESIGN: Cohort of tuberculosis cases reported to the enhanced tuberculosis surveillance system matched to data on drug susceptibility and national strain typing data. SETTING: England, Wales, and Northern Ireland 1998-2005. MAIN OUTCOME MEASURES: Unadjusted and adjusted odds ratios for drug resistance and associated factors. Proportion of multidrug resistant tuberculosis cases clustered. RESULTS: 28 620 culture confirmed cases were available for analysis. The proportion of cases resistant to isoniazid increased from 5% to 7%. Rifampicin resistance increased from 1.0% to 1.2% and multidrug resistance from 0.8% to 0.9%. Ethambutol and pyrazinamide resistance remained stable at around 0.4% and 0.6%, respectively. Regression analyses showed a significant increase in isoniazid resistance outside London (odds ratio 1.04, 95% confidence interval 1.01 to 1.07, a year, associated with changes in age (0.98, 0.98 to 0.99, a year), place of birth (1.49, 1.16 to 1.92), and ethnicity (P