<prompt> As per RNTCP guidelines, Multi drug resistance MDR TB is defined as resistance to:RifampicinRifampicin and isoniazideRifampicin, isoniazide and ethambutolNone of the above  <response>: Confirmed MDR-TB case: MDR-TB suspect is one who is sputum culture positive and whose TB is due to Mycobacterium tuberculosis that are resistant in-vitro to at least isoniazid and rifampicin the culture and DST result being from an RNTCP accredited laboratory. Ref: Park 21st edition, page 178. 