Extensively Drug-Resistant Tuberculosis (XDR TB)
||Extensively Drug-Resistant Tuberculosis
What is XDR TB?
Extensively drug-resistant tuberculosis (XDR TB) is a relatively
rare type of multidrug-resistant tuberculosis (MDR TB). It is
resistant to almost all drugs used to treat TB, including the two
best first-line drugs: isoniazid and rifampin. XDR TB is also
resistant to the best second-line medications: fluoroquinolones and
at least one of three injectable drugs (i.e., amikacin, kanamycin,
How is XDR TB spread?
Drug-susceptible (regular) TB and XDR 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
TB is not spread by
- shaking someone’s hand
- sharing food or drink
- touching bed linens or toilet seats
- sharing toothbrushes
Why is XDR TB so serious?
Because XDR TB is resistant to the most powerful firstline and
second-line drugs, patients are left with treatment options that are
much less effective and often have worse treatment outcomes. 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 disease.
Who is at risk for getting XDR TB?
Drug-resistant TB (MDR or XDR) is more common in people who:
- Do not take their TB medicine regularly
- Do not take all of their TB medicines as told by their
doctor or nurse
- Develop active TB disease again, after having taken TB
medicine in the past
- Come from areas of the world where drug-resistant TB is
- Have spent time with someone known to have drug-resistant TB
How can I prevent myself from getting TB?
Avoid close contact or prolonged time with known TB patients in
crowded, enclosed environments like clinics, hospitals, prisons, or
Can the TB vaccine (BCG) help prevent XDR 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 in adults. The effect of BCG against
XDR TB would likely be similar to the effect on drug-susceptible TB.
If I have regular (drug-susceptible) TB, how can I prevent
getting drug-resistant TB?
The most important thing is for you to continue taking all your
TB medicines exactly as prescribed. No doses should be missed and
treatment should not be stopped early. You should tell your health
care provider if you are having trouble taking the medications. If
you plan to travel, talk with your health care provider, and make
sure you have enough medicine to last while away.
Can XDR TB be treated and cured?
Yes, in some cases. Some TB control programs have shown that cure
is possible for an estimated 30% of affected people. Successful
outcomes depend greatly on the extent of the drug resistance, the
severity of the disease, and whether the patient’s immune system is
What are the symptoms of XDR TB?
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.
What should I do if I have been around someone who has XDR TB?
If you think you have been exposed to someone with TB disease,
you should contact your doctor or local health department about
TB skin test or the
QuantiFERON®-TB Gold test (QFT-G), a blood test, for TB
infection. And tell the doctor or nurse when you spent
time with this person.
How long does it take to find out if you have XDR TB?
If TB bacteria are found in the sputum (phlegm), the diagnosis of
TB can be made in a day or two, but this finding will not be able to
distinguish between drugsusceptible (regular) TB and drug-resistant
TB. To determine drug susceptibility, the bacteria need to be grown
and tested in a laboratory. Final diagnosis for TB, and especially
for XDR TB, may take from 6 to 16 weeks.
Is XDR TB a problem in the United States?
The risk of acquiring XDR TB in the United States appears to be
relatively low. However, it is important to acknowledge the ease at
which TB can spread. As long as XDR TB exists, the United States is
at risk and must address the threat.
How many cases of XDR TB have been reported in the United
In the United States, 49 cases of XDR TB have been reported
between 1993 and 2006.
Is it safe to travel
where cases of XDR TB have been reported?
Although MDR and XDR TB are occurring globally, they are still
rare. HIV-infected travelers are at greatest risk if they come in
contact with a person with MDR or XDR TB.
All travelers should avoid high risk settings where there are no
infection control measures in place. Documented places where
transmission has occurred include crowded hospitals, prisons,
homeless shelters, and other settings where susceptible persons come
in contact with persons with TB disease.
What is the risk of acquiring TB on an airplane?
The risk of acquiring any type of TB depends on several factors,
such as extent of disease in the patient with TB, duration of
exposure, and ventilation. Most important, there must be someone
with infectious TB disease on the same flight to present any risk.
If someone on the flight does have TB disease, persons on flights
lasting 8 hours or longer are at greater risk than persons on
What can health care providers do to prevent XDR TB?
Health care providers can help prevent MDR and XDR TB by quickly
diagnosing cases, following recommended treatment guidelines,
monitoring patients’ response to treatment, and making sure therapy
Providers should also ensure proper implementation of
control procedures to prevent exposure to TB in hospitals or
health-care settings where TB patients are likely to be seen.
Are immigrants putting the U.S. at increased risk for TB?
Persons applying to enter the U.S. with immigrant or refugee
visas must complete a questionnaire about any symptoms of TB they
may have and obtain a chest radiograph. If positive, the person
submits sputum specimens for examination for TB bacteria. Persons
identified as having infectious TB are not granted entry to the
United States, until they have been treated.
Why haven’t we heard about XDR TB before now?
For some years we have seen isolated cases of very highly
resistant TB around the world that we would today call XDR TB. The
drugs used to treat TB have been around a long time and drug
resistance has taken many years to develop. Over time, countries
have improved their laboratory capacity to test for drug resistance
and their ability to track the number of cases. All of these factors
have contributed to an increase in reporting of cases of
drug-resistant TB. With more cases being identified, the problem was
more closely examined, defined, and given a name.
What is CDC doing to prevent XDR TB from becoming a bigger
CDC is collaborating with other federal agencies and
international partners to raise awareness and enhance strategies for
TB prevention worldwide by
- Strengthening TB services for people living with HIV/AIDS
- Assembling outbreak response teams
- Improving access to TB drugs
- Developing international TB testing standards
- Building capacity of health care providers to diagnose and
- Reconvening the Federal TB Task Force
- Providing technical assistance to expand TB program capacity
- Supporting TB communication and education efforts
CDC. Questions and Answers
About TB (2007)
CDC. Tuberculosis: General Information
CDC. Multidrug Resistant Tuberculosis
CDC. Tuberculosis Information for International
Extensively Drug-Resistant Tuberculosis - United States, 1993--2006
CDC. CDC’s Role in Preventing