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National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention 

Division of Tuberculosis Elimination

TB Elimination

Multidrug-Resistant Tuberculosis (MDR TB)

What is tuberculosis (TB)?

Tuberculosis (TB) is a disease caused by bacteria 

that are spread from person to person through 

the air. TB usually affects the lungs, but it can also 

affect other parts of the body, such as the brain, 

the kidneys, or the spine. In most cases, TB is 

treatable and curable; however, persons with TB 

can die if they do not get proper treatment.

What is multidrug-resistant 

tuberculosis (MDR TB)?

Multidrug-resistant TB (MDR TB) is caused by an 

organism that is resistant to at least isoniazid and 

rifampin, the two most potent TB drugs. These 

drugs are used to treat all persons with TB disease.

What is extensively drug resistant 

tuberculosis (XDR TB)?

Extensively drug resistant TB (XDR TB) is a rare 

type of MDR TB that is resistant to isoniazid and 

rifampin, plus any fluoroquinolone and at least one 

of three injectable second-line drugs (i.e., amikacin, 

kanamycin, or capreomycin).

Because XDR TB is resistant to the most potent TB 

drugs, patients are left with treatment options that 

are much less effective. 

XDR TB is of special concern for persons with HIV 

infection or other conditions that can weaken the 

immune system. These persons are more likely to 

develop TB disease once they are infected, and also 

have a higher risk of death once they develop TB.

How is TB spread?

Drug-susceptible TB and drug-resistant TB are 

spread the same way. TB bacteria are put into the 

air when a person with TB disease of the lungs or 

throat coughs, sneezes, speaks, or sings. These 

bacteria can float in the air for several hours, 

depending on the environment. Persons who 

breathe in the air containing these TB bacteria can 

become infected. 

TB is not spread by

• Shaking someone’s hand 

• Sharing food or drink 

• Touching bed linens or toilet seats 

• Sharing toothbrushes 

• Kissing 

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. 

Who is at risk for getting MDR TB?

Drug resistance is more common in people who: 

• Do not take their TB medicine regularly 

• Do not take all of their TB medicine as told by 

their doctor or nurse 

• Develop TB disease again, after having taken TB 

medicine in the past 

• Come from areas of the world where drugresistant TB is common 

• Have spent time with someone known to have 

drug-resistant TB disease 

How can MDR TB be prevented?

The most important thing a person can do to 

prevent the spread of MDR TB is to take all of their 

medications exactly as prescribed by their health 

care provider. No doses should be missed and 

treatment should not be stopped early. Patients 

should tell their health care provider if they are 

having trouble taking the medications. If patients 

plan to travel, they should talk to their health 

care providers and make sure they have enough 

medicine to last while away. 
May 2012

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, you should 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.

Is there a vaccine to prevent TB?

Yes, there is a vaccine for TB disease called 

Bacille Calmette-Guérin (BCG). It is used in 

some countries to prevent severe forms of 

TB in children. However, BCG is not generally 

recommended in the United States because 

it has limited effectiveness for preventing TB 

overall.

What should I do if I think I have 

been exposed to someone with TB 

disease?

If you think you have been exposed to someone 

with TB disease, you should contact your doctor 

or local health department about getting a TB 

skin test or TB blood test. And tell the doctor or 

nurse when you spent time with this person.

What are the symptoms of 

TB disease?

The general symptoms of TB disease include 

feelings of sickness or weakness, weight loss, 

fever, and night sweats. The symptoms of TB 

disease of the lungs may also include coughing, 

chest pain, and coughing up blood. Symptoms 

of TB disease in other parts of the body 

depend on the area affected. If you have these 

symptoms, you should contact your doctor or 

local health department.

Additional Information

1. CDC. MMDR TB: MMWRs. http://www.

cdc.gov/tb/publications/guidelines/

MDR_TB.htm

2. CDC. Questions and Answers About TB. 

http://www.cdc.gov/tb/publications/

faqs/default.htm

3. CDC. TB: General Information. 

http://www.cdc.gov/tb/publications/

factsheets/general/tb.htm

4. CDC. Tuberculin Skin Testing. 

http://www.cdc.gov/tb/publications/

factsheets/testing/skintesting.htm

5. CDC. TB Information for International 

Travelers. http://www.cdc.gov/tb/

publications/factsheets/general/

tbtravelinfo.htm

http://www.cdc.gov/tb