Multidrug-resistant tuberculosis in the United States, 2011-2016: patient characteristics and risk factors

OBJECTIVE: To determine risk factors for multidrug-resistant tuberculosis (MDR-TB) and describe MDR-TB according to three characteristics: previous TB disease, recent transmission of MDR-TB, and reactivation of latent MDR-TB infection. SETTING AND DESIGN: We used 2011-2016 surveillance data from the US National Tuberculosis Surveillance System and National Tuberculosis Genotyping Service and used logistic regression models to estimate risk factors associated with MDR-TB. RESULTS: A total of 615/45 209 (1.4%) cases were confirmed as MDR-TB; 111/615 (18%) reported previous TB disease; 41/615 (6.7%) were attributed to recent MDR-TB transmission; and 449/615 (73%) to reactivation. Only 12/41 (29%) patients with TB attributed to recent transmission were known to be contacts of someone with MDR-TB. For non-US-born patients, the adjusted odds ratios of having MDR-TB were 32.6 (95%CI 14.6-72.6) among those who were known to be contacts of someone with MDR-TB and 6.5 (95%CI 5.1-8.3) among those who had had previous TB disease. CONCLUSION: The majority of MDR-TB cases in the United States were associated with previous TB disease or reactivation of latent MDR-TB infection; only a small proportion of MDR-TB cases were associated with recent transmission.