<prompt> Multi drug resistant tuberculosis is resistance to?INH PyrizinamideINH RifampicinRifampicin PyrizinamideResistance to all  <response>: ANSWER: B INH RifampicinREF: Davidsons 21st edition Chapter no 19 page no 695Repeat Medicine 2013 Session 1MDR TB is defined as resistance to at least rifampicin isoniazid with or without other drug resistance.Extensively drug resistant TB is defined by resistance to at least rifampicin isoniazid in addition to any quinolone at least one injectable second line agent 