<unk>  <unk>  is defined as tuberculosis that has evolved resistance to rifampicin and isoniazid (resistance to these first line anti-TB drugs defines Multi-drug-resistant tuberculosis, or MDR-TB), as well as to any member of the quinolone family and at least one of the following second-line TB treatments: kanamycin, capreomycin, or amikacin.  The old case definition of<unk>  is MDR-TB that is also resistant to three or more of the six classes of second-line drugs. This definition should no longer be used, but is included here because many older publications refer to it.
The principles of treatment for MDR-TB and for<unk>  are the same.  The main difference is that<unk>  is associated with a much higher mortality rate than MDR-TB, because of a reduced number of effective treatment options.  The epidemiology of<unk>  is currently not well studied, but it is believed that<unk>  does not transmit easily in healthy populations, yet is capable of causing epidemics in populations which are already stricken by HIV and therefore more susceptible to TB infection.
Extensively drug-resistant tuberculosis
Multi-drug-resistant tuberculosis
Multi-drug-resistant tuberculosis future or investigational therapies
Tuberculosis
Miliary tuberculosis
Tuberculosis secondary prevention
HIV coinfection with tuberculosis medical therapy
HIV coinfection with tuberculosis