Multi drug resistant T.B is defined as resistance to
multidrug-resistant TB (MDR-TB)--a form of the disease caused by bacilli resistant at least to isoniazid and rifampin--occurred in 2013. Ref Harrison 19th edition pg 1103
INH and pyrizinamide
INH and Rifampicin
Rifampicin and Pyrizinamide
Resistance to all first line of drugs
Respiratory system