CDC Logo Tuberculosis Information CD-ROM   Image of people
jump over main navigation bar to content area
TB Guidelines
Surveillance Reports
Slide Sets
TB-Related MMWRs and Reports
Education/Training Materials
Ordering Information


U.S. Department of Health and Human Services


Core Curriculum on Tuberculosis, 2000

Chapter 2
Transmission and Pathogenesis

Drug-Resistant Tuberculosis

Drug-resistant TB is transmitted in the same way as drug-susceptible TB. The earlier outbreaks of multidrug-resistant TB support the findings that drug-resistant TB is no less infectious than drug-susceptible TB, although prolonged periods of infectiousness that often occur in patients with drug-resistant TB may facilitate transmission.

Drug resistance is divided into two types: primary resistance and secondary (or acquired) resistance. Primary resistance develops in persons who are initially infected with resistant organisms. Secondary resistance, or acquired resistance, develops during TB therapy, either because the patient was treated with an inadequate regimen or because the patient did not take the prescribed regimen appropriately.


Released October 2008
Centers for Disease Control and Prevention
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
Division of Tuberculosis Elimination -

Please send comments/suggestions/requests to:, or to
CDC/Division of Tuberculosis Elimination
Communications, Education, and Behavioral Studies Branch
1600 Clifton Rd., NE - Mailstop E-10, Atlanta, GA 30333