<prompt> XDR means extensive drug resistance toHR1 FluoroquinoloneMinimum of 1 injectable drugAll of the above  <response>: Ans. d All of the aboveRef.: K. Park 23rd ed. 199-200Definition of Extensive Drug Resistance Resistance to both isoniazid H and rifampicin, and Resistance to 1 fluoroquinolones and Resistance to one 2nd line injectables out of 3 kanamycin, amikacin, capreomycin.Older Definition of XDR Resistance of isoniazid H and rifampicin both Resistance to any 3rd line drugs.Also KnowMultiple drug resistance MDR means resistance to resistance to isoniazid H and rifampicin R. 