TB is a bacterial disease of the lungs. Antibiotics can be used to treat TB but
they need to be taken for 6 - 9 months and this is where the problem lies.
- TB that is resistant to the 2 most commonly used antibiotics (isoniazid and
rifampin) is called multidrug resistant (MDR) TB.
- MDR TB requires treatment for 18-24 months with "second-line drugs" (there
are currenly only six second-line drugs) that are much less effective, poorly
tolerated by the patient, and far more costly.
- Extensively drug-resistant TB (XDR TB) is a subset of MDR TB caused by
strains of bacteria that are resistant to the most effective first- and second-
line drugs.
Why have these resistance strains increased?
