Epi Profile Section 8 - Drug Resistant Tuberculosis
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 drug 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 for INH resistance alone. Therapy can take 18 months, compared to six to nine months for drug-susceptible TB, and is treated like MDR-TB, as described below.
- Multidrug-resistant TB (MDR-TB) - TB that is resistant to at least two essential first-line medications 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 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) - 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, typically requiring six different medications with treatment lasting over 24 months.
Figure 5. Number of Multidrug-resistant TB and Pre-XDR Cases, Texas, 2015-2019
*There were no XDR-TB cases reported in Texas between 2015 and 2019;
2019 data is considered provisional data.
Table 10. Number of Different Types of Drug Resistant TB Cases, Texas, 2015 -2019
| Drug Resistant Profile |
2015 |
2016 |
2017 |
2018 |
2019 |
|---|---|---|---|---|---|
| No Resistance |
849 |
808 |
618 |
744 |
767 |
| Isoniazid Mono-Resistant |
26 |
36 |
19 |
32 |
38 |
| Rifampin Mono-Resistant |
0 |
1 |
0 |
1 |
0 |
| Other Resistance* |
100 |
66 |
73 |
77 |
77 |
| MDR (but not Pre-XDR) |
9 |
9 |
8 |
7 |
8 |
| Pre-XDR |
0 |
2 |
3 |
1 |
3 |
| XDR |
0 |
0 |
0 |
0 |
0 |
| Not Performed** |
343 |
325 |
396 |
267 |
266 |
| Total Number of TB Cases |
1,327 |
1,247 |
1,118 |
1,129 |
1,159 |
| * Any drug-resistant tuberculosis, not including Isoniazid monoresistance, rifampin monoresistance, MDR, pre-XDR, and XDR. ** Represents TB cases where sputum sample was not collected for drug resistance test or test was not performed. |
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Table of Contents | An Overview of Tuberculosis in Texas | Geographic Distribution of Tuberculosis in Texas | Affected Populations | Case Diagnosis | Recent Transmission | Mortality | Risk Factors Associated with Tuberculosis | Drug Resistant TB | Public Health Follow-Up Outcomes | Reporting Requirements | References