<prompt> In a post operative intensive care unit, five patients developed post-operative wound infection on the same wound. Which of the following is the best method to prevent cross infection among patients in the same ward?Fumigate the wardPractice proper hand washingDisinfect the ward with sodium hypochloriteGive antibiotics to all other patients in the ward  <response>: Hand washing remains the single most impoant and effective method for preventing the spread of infectious disease. Ref: Reichels Care of the Elderly: Clinical Aspects of Aging By Joseph J. Gallo, 5th Edition, Page 300; Harrisons Principles of Internal Medicine, 18th Edition, Page 1114. 