| Monoresistance |
Resistance to one first-line anti-tuberculosis drug only (isoniazid, rifampin, ethambutol or pyrazinamide). |
| Polyresistance |
Resistance to more than one first-line anti-tuberculosis drug, not including the combination of isoniazid and rifampin. |
| Multidrug-resistant tuberculosis (MDR-TB) |
Resistance to isoniazid AND rifampin with or without resistance to other anti-tuberculosis drugs |
| Extensively drug-resistant tuberculosis (XDR-TB) |
Resistance to isoniazid AND rifampin AND any fluoroquinolone AND at least one of the three injectable second-line drugs (amikacin, capreomycin or kanamycin). |
