What is multidrug-resistant tuberculosis (MDR TB)?

Multidrug-resistant TB (MDR TB) is TB that is resistant to at least two of the best drugs used to treat TB, isoniazid and rifampicin. These drugs are considered first-line drugs and are used to treat most people with TB disease.

What is extensively drug resistant tuberculosis (XDR TB)?

Extensively drug resistant TB (XDR TB) is a rare type of MDR TB. XDR TB is defined as TB that is resistant to isoniazid and rifampin, plus resistant to any fluoroquinolone and at least one of three injectable second-line drugs (i.e., amikacin, kanamycin or capreomycin).

Because XDR TB is resistant to first-line and second-line drugs, patients are left with treatment options that are much less effective. XDR TB is of special concern for people with HIV infection or other conditions that weaken the immune system. These people are more likely to develop TB disease once they are infected, and also have a higher risk of death once they develop TB.

How does drug resistance happen?

Resistance to anti-TB drugs can occur when these drugs are misused or mismanaged. Examples include when patients do not complete their full course of treatment; when health care providers prescribe the wrong treatment, the wrong dose or length of time for taking the drugs; when the supply of drugs is not always available; or when the drugs are of poor quality.

How can MDR TB be prevented?

The most important way to prevent the spread of MDR TB is to take all medications exactly as prescribed. No doses should be missed and treatment should not be stopped early. Patients should tell their doctor if they are having trouble taking the medications. If patients plan to travel, they should make sure they have enough medicine to last while away.

Health care providers can help prevent MDR TB by quickly diagnosing cases, following recommended treatment guidelines, monitoring patients’ response to treatment, and making sure therapy is completed.

Another way to prevent getting MDR TB is to avoid exposure to known MDR TB patients in closed or crowded places such as hospitals, prisons or homeless shelters.

If you work in hospitals or health care settings where TB patients are likely to be seen, consult infection control or occupational health experts. Ask about administrative and environmental procedures for preventing exposure to TB. Once those procedures are implemented, additional measures could include using personal respiratory protective devices.

Where can I get more information?

The Tuberculosis Treatment & Control Clinic is located in the northeast parking lot of the Ravenholt Public Health Center at 625 Shadow Lane, Las Vegas, Nevada, 89106. Appointments are highly recommended and can be scheduled by calling (702) 759-1370.