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Epi Profile Section 8 - Drug Resistant TB

  • Drug resistant tuberculosis (DR-TB) continues to impact TB programs in Texas. Factors include the cost to treat DR-TB strains, the limited resources given its complexity, and the duration of care that may extend up to two years or longer.  Additionally, medications used to treat DR-TB, particularly multi-drug resistant (MDR) TB, can be toxic and difficult to tolerate; they often require in-patient treatment for some if not all their care. In 2017, the CDC estimated, the cost of treating MDR TB was approximately $301,000 for one patient, when productivity loss, medications, and case management were all included. The cost for treating drug-susceptible TB was significantly less, at $47,000. While DR-TB is curable, the course of treatment often impacts a patient’s quality of life.
  • Individuals acquire DR TB in the following ways:
    1. Primary resistance - Occurs in persons who are initially diagnosed with resistant organisms. This occurs in recent transmission of drug-resistant TB, or reactivation of a latent drug resistant infection.
    2. Secondary resistance - Acquired drug resistance that develops during TB therapy. This occurs if therapy was not prescribed or taken correctly.
  • MDR TB cases consistently increased from seven cases in 2013 to eleven cases in 2016. From 2013-2016 Texas reported the third highest percentage of MDR TB cases in the US, behind California and New York, which was 7.6%.[4]


Figure 5 Multidrug-resistant TB Case Counts in Texas, 2013-2016

    Figure 5 Multidrug-resistant TB Case Counts in Texas, 2013-2016. Data in Table 9 below.
*Provisional data


Table 9 Number of Drug Resistant TB Cases in Texas from 2013 to 2016
Drug Resistant Profile





Isoniazid Mono-Resistant





Rifampin Mono-Resistant




















Total of MDR, Pre-XDR,
and XDR (%)

7 (0.6)

7 (0.6)

9 (0.7)

11 (0.9)






Types of Drug Resistant TB

  • Isoniazid (INH) mono-resistant TB - TB that is resistant to one of the essential first-line drugs needed to treat TB, isoniazid. While therapy is available with additional first-line drugs and other oral agents, this resistance is one mutation away from becoming multi-drug resistant TB, as described below.
  • Rifampin mono-resistant TB (RR) - TB that is resistant to one of the most essential first-line drugs needed to treat TB, rifampin (RIF). Medication regimens for this resistance can be more complex than in INH resistance alone. Therapy can take 18 months, compared to six to nine months for drug-susceptible TB, and is treated similar to MDR-TB, as described below.
  • Multidrug-resistant TB (MDR) - TB that is resistant to at least two essential first-line medications typically used to treat TB, INH and RIF. Treatment can last from 18 months to two years and includes a more complex and potentially difficult to tolerate regimen with many drugs.
  • Pre-extensively drug-resistant TB (Pre-XDR) - TB that is resistant to both the essential first-line medications, INH and RIF, and also resistant to either a fluoroquinolone or a second-line injectable anti-TB drug (kanamycin, capreomycin, or amikacin), but not both. Treatment can last 24 months or longer, and the medications used have many side effects that make it difficult to tolerate.
  • Extensively drug-resistant TB (XDR) - TB that is resistant to both the essential first line medications, INH and RIF, resistant to a fluoroquinolone, and resistant to a second-line injectable anti-TB drug (kanamycin, capreomycin, or amikacin). XDR-TB is the most difficult type of TB to treat, ideally requiring six different medications with the regimen lasting over 24 months.  

More information on DR-TB can be found at: (PDF) [CDC]


[4] Online Tuberculosis Information System (OTIS), National Tuberculosis Surveillance System, United States, 1993-2017. U.S. Department of Health and Human Services (US DHHS), Centers for Disease Control and Prevention (CDC), Division of TB Elimination, CDC WONDER Online Database, October 2018. Data for all years updated by June 1, 2018. Accessed at [CDC] on Jan 29, 2019 11:52:36 AM.

Table of Contents | An Overview of Tuberculosis in Texas | Distribution of Tuberculosis in Texas | Affected Populations | Case Diagnosis | Recent Transmission | Mortality | Risk Factors Associated with Tuberculosis | Drug Resistant TB | Targeted Testing | Reporting Requirements | References

Last updated June 24, 2019