<prompt> Multi-drug resistance tuberculosis implies resistance to at least -Any two antitubercular drugsIsoniazid and ethambutolRifampicin and ethambutolIsoniazid and rifampicin  <response>: Multidrug-resistant TB is defined by resistance to atleast rifampicin isoniazid, with or without other drug resistance . Extensively drug resistant TB is defined as resistance to atleast rifampicin isoniazid in addition to any quinolone atleast one injectable second -line agent. Reference: Harrison20th edition pg 1056 