Drug-Resistant Tuberculosis: Types, Risks, Prevention and Treatment

Some tuberculosis (TB) germs are resistant to the medicines used to treat TB disease, meaning those medicines can no longer kill them. Drug-resistant TB disease is caused by germs resistant to at least one of the most effective TB medicines. It is hard and expensive to treat, and should be treated by a TB medical expert.

Types

• Multidrug-resistant TB (MDR TB) is caused by germs resistant to the two main TB medicines, isoniazid and rifampin.
• Pre-extensively drug-resistant TB (pre-XDR TB) and extensively drug-resistant TB (XDR TB) are more serious, rare forms of MDR TB, resistant to nearly all the medicines used to treat TB.

Who is at higher risk

Drug-resistant TB is more common in people who:

• have spent time with someone known to have it;
• come from parts of the world where it is common;
• develop TB disease again after earlier treatment; or
• do not take all their TB medicines, or do not take them regularly.

How it arises

Through exposure. Drug-resistant TB spreads the same way as other TB: through the air, when a person with TB disease of the lungs or throat coughs, speaks or sings. The germs can stay in the air for several hours, and spread more easily indoors or in poorly ventilated places, such as a closed vehicle, than outdoors. People who spend time with someone sick with drug-resistant TB can be infected with the resistant germs.

Through misuse of TB medicines. Resistance can also develop when treatment is misused or mismanaged — when people do not finish a full course, when providers prescribe the wrong dose or length of treatment, when proper medicines are unavailable, or when the medicines are of poor quality.

Prevention

The most important way to prevent drug-resistant TB is for everyone being treated for TB disease to take all their medicines exactly as prescribed: no missed doses, and no stopping early. Tell your health care provider if you have trouble taking the medicines — if they make you vomit, or you get a fever or rash.

Diagnosis

Testing for TB disease includes laboratory tests to find TB germs. When germs are found, laboratories run further tests to see whether they are resistant to any TB medicines.

Treatment

Treating and curing drug-resistant TB is complicated. It requires special medicines, can take months or even years, and the medicines can cause side effects. People with MDR or XDR TB are at greater risk of severe illness and death. They need a TB expert who can choose the best medicines and closely watch treatment to make sure it is working.

Sources

• Centers for Disease Control and Prevention, "About Drug-Resistant Tuberculosis Disease": https://www.cdc.gov/tb/about/drug-resistant.html