Tuberculosis (TB)

Basic TB Facts



Tuberculosis (TB) is caused by a bacterium called Mycobacterium tuberculosis. The bacteria usually attack the lungs, but TB bacteria can attack any part of the body such as the kidney, spine, and brain. If not treated properly, TB disease can be fatal.


How TB Spreads

TB is spread through the air from one person to another. The TB bacteria are put into the air when a person with TB disease of the lungs or throat coughs, sneezes, speaks, or sings. People nearby may breathe in these bacteria and become infected.
TB is NOT spread by

  • shaking someone’s hand
  • sharing food or drink
  • touching bed linens or toilet seats
  • sharing toothbrushes
  • kissing

Latent TB Infection and TB Disease

Not everyone infected with TB bacteria becomes sick. As a result, two TB-related conditions exist: latent TB infection and TB disease.
Latent TB Infection

TB bacteria can live in the body without making you sick. This is called latent TB infection. In most people who breathe in TB bacteria and become infected, the body is able to fight the bacteria to stop them from growing. People with latent TB infection do not feel sick and do not have any symptoms. People with latent TB infection are not infectious and cannot spread TB bacteria to others. However, if TB bacteria become active in the body and multiply, the person will go from having latent TB infection to being sick with TB disease.
TB Disease

TB bacteria become active if the immune system can't stop them from growing. When TB bacteria are active (multiplying in your body), this is called TB disease. People with TB disease are sick. They may also be able to spread the bacteria to people they spend time with every day.
Many people who have latent TB infection never develop TB disease. Some people develop TB disease soon after becoming infected (within weeks) before their immune system can fight the TB bacteria. Other people may get sick years later when their immune system becomes weak for another reason.
For people whose immune systems are weak, especially those with HIV infection, the risk of developing TB disease is much higher than for people with normal immune systems. Learn more about the difference between LTBI and TB Disease.


Symptoms of TB disease include:

  • a bad cough that lasts 3 weeks or longer
  • pain in the chest
  • coughing up blood or sputum
  • weakness or fatigue
  • weight loss
  • no appetite
  • chills
  • fever
  • sweating at night


Once a person is infected with TB bacteria, the chance of developing TB disease is higher if the person:

  • Has HIV infection;
  • Has been recently infected with TB bacteria (in the last 2 years);
  • Has other health problems, like diabetes, that make it hard for the body to fight bacteria;
  • Abuses alcohol or uses illegal drugs; or
  • Was not treated correctly for TB infection in the past

There are two kinds of tests that are used to detect TB bacteria in the body: the TB skin test (TST) and TB blood tests. These tests can be given by a health care provider or local health department. If you have a positive reaction to either of the tests, you will be given other tests to see if you have latent TB infection or TB disease.

Treatment for Latent TB Infection

If you have latent TB infection but not TB disease, your health care provider may want you be treated to keep you from developing TB disease. Treatment of latent TB infection reduces the risk that TB infection will progress to TB disease. Treatment of latent TB infection is essential to controlling and eliminating TB in the United States. The decision about taking treatment for latent TB infection will be based on your chances of developing TB disease.
Treatment for TB Disease

TB disease can be treated by taking several drugs, usually for 6 to 9 months. It is very important to finish the medicine, and take the drugs exactly as prescribed. If you stop taking the drugs too soon, you can become sick again. If you do not take the drugs correctly, the germs that are still alive may become resistant to those drugs. TB that is resistant to drugs is harder and more expensive to treat.


Drug-Resistant TB

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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, people with TB can die if they do not get proper treatment.
Sometimes TB bacteria become resistant to the drugs used to treat TB. This means that the drug can no longer kill the bacteria.
Drug-resistant TB can occur when the drugs used to treat TB are misused or mismanaged. Examples include:

  • When people do not complete the full course of treatment;
  • When health care providers prescribe the wrong treatment, the wrong dose, or wrong length of time for taking the drugs;
  • When the supply of drugs is not always available; or
  • When the drugs are of poor quality.

Drug-resistant TB is more common in people who:

  • Do not take their TB drugs regularly
  • Do not take all of their TB drugs
  • Develop TB disease again, after being treated for TB disease 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 disease

Drug-resistant TB is spread the same way that drug susceptible TB is spread. TB is spread through the air from one person to another. The TB bacteria are put into the air when a person with TB disease of the lungs or throat coughs, sneezes, speaks, or sings. People nearby may breathe in these bacteria and become infected.
Multidrug-Resistant TB (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.


Extensively Drug-resistant TB (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 people with HIV infection or other conditions that can 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.

Preventing Drug-Resistant TB

The most important way to prevent the spread of drug-resistant TB is to take all TB drugs exactly as prescribed by the health care provider. No doses should be missed and treatment should not be stopped early. People receiving treatment for TB disease should tell their health care provider if they are having trouble taking the drugs.
Health care providers can help prevent drug-resistant 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 drug-resistant TB is to avoid exposure to known drug-resistant TB patients in closed or crowded places such as hospitals, prisons, or homeless shelters. People who work in hospitals or health-care settings where TB patients are likely to be seen should consult infection control or occupational health experts.

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