Multidrug-resistant tuberculosis

Multidrug-resistant tuberculosis (MDR-TB) is a form of tuberculosis (TB) infection caused by bacteria that are resistant to treatment with at least two of the most powerful first-line anti-TB medications (drugs), isoniazid and rifampin. Some forms of TB are also resistant to second-line medications, and are called extensively drug-resistant TB (XDR-TB).

Causes

MDR-TB is caused by Mycobacterium tuberculosis that is resistant to at least isoniazid and rifampin, the two most potent TB drugs. Such drug resistance is caused by two key mechanisms: spontaneous mutation and inadequate treatment.

Diagnosis

Diagnosis of MDR-TB involves laboratory testing to determine the drugs to which the bacteria are susceptible. This often involves the use of culture and sensitivity testing, as well as molecular techniques such as polymerase chain reaction (PCR).

Treatment

Treatment of MDR-TB involves the use of second-line drugs, usually four or more anti-TB drugs for a prolonged period of time. The treatment can be expensive, has many side effects, and can be fatal.

Epidemiology

MDR-TB is a serious public health problem that threatens progress made in TB care and control worldwide. It is present in virtually all countries surveyed.

Prevention

Prevention of MDR-TB involves prompt detection of drug-resistant TB and proper treatment with second-line drugs.

See also

• Tuberculosis treatment
• Extensively drug-resistant tuberculosis
• Tuberculosis diagnosis