Multidrug-resistant tuberculosis (MDR-TB) accounted for 91/9,421 (1.3%) of new tuberculosis (TB) cases in the United States (US) in 2014 and 80/91 (88%) of these cases occurred among foreign-born persons. Transmission accounts for 22% of MDR-TB cases in the US. Texas Center for Infectious Disease (TCID) treats patients with confirmed TB. A cluster of MDR-TB cases with matching genotypes were admitted to TCID.
Isolates were genotyped by the National TB Genotyping Service, Centers for Disease Control and Prevention. Clinical, demographic, epidemiologic, and genotype variables were collected. Public health records were examined and 4 current patients were re-interviewed to identify epidemiologic links.
Of 4 patients identified with matching TB genotypes and 1 patient currently awaiting genotypic confirmation, 5 (100%) were Hispanic, 5 (80%) were foreign born, and all lived within a 25 mile radius of each other. Patient 1 was incarcerated in Rio Grande City, Texas, in 2010, diagnosed with MDR-TB in Reynosa, Mexico, in November 2011, and successfully completed treatment in August 2014. The subsequent 4 MDR-TB patients were reported May 2014 (Patient 2), October 2015 (Patient 3), March 2016 (Patient 4) and April 2016 (Patient 5). These 4 were diagnosed in Texas and are currently undergoing treatment for MDR-TB. Patient 1 reported 23 roommates at time of diagnosis. Patient 2 was incarcerated in Rio Grande City in 2013. Patient 3 lived with Patient 2. Patient 5 worked with Patient 2. Patients 4 and 5 have a possible epidemiologic link to each other through family, although no direct contact is yet established; investigation is ongoing.
MDR-TB transmission continues to occur in the US and the cases identified in this cluster likely represent a small proportion of those with latent MDR-TB infection who are at risk for reactivation. Robust contact investigations are essential to identify the initial source case of MDR-TB and both identify and treat those with latent infection. Stigma and fear prevent identification of all contacts allowing the cycle of transmission to continue.
B. Seaworth, None
C. Navarro, None
A. Vasquez, None