Multidrug-Resistant Tuberculosis (MDR TB)
What is tuberculosis (TB)?
Tuberculosis (TB) is a disease caused by
germs 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; 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 TB that is resistant to at
least two of the best anti-TB drugs, isoniazid and rifampicin. These
drugs are considered first-line drugs and 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 relatively rare type
of MDR TB. XDR TB is defined as TB which 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
Because XDR TB is resistant to first-line and secondline drugs,
patients are left with treatment options that are much less
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 MDR TB are spread the same way. TB germs
are put into the air when a person with TB disease of the lungs or
throat coughs, sneezes, speaks, or sings. These germs can float in
the air for several hours, depending on the environment. Persons who
breathe in the air containing these TB germs can become infected.
TB is not spread by
- shaking someone’s hand
- sharing food or drink
- touching bed linens or toilet seats
- sharing toothbrushes
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
- develop active TB disease again, after having taken TB medicine
in the past
- come from areas of the world where drug-resistant TB is common
- have spent time with someone known to have drug-resistant TB
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
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
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
Is there a vaccine to prevent TB?
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
What should I do if I think I have been exposed to someone with
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
special 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.
CDC. Multidrug-Resistant TB (MDR
CDC. Questions and Answers
About TB (2007).
CDC. Tuberculosis: General Information (2006).
CDC. Tuberculin Skin Testing (2006).
CDC. Tuberculosis Information for International