<prompt> When do we have to start antibiotics to prevent post-operative infection?2 days before surgeryAfter surgery1 week before surgery1 hour before surgery continue after surgery  <response>: Prophylactic antibiotics are administered before the skin incision is made. Repeat dosing occurs at an appropriate interval, usually 3 hours for abdominal cases or twice the half-life of the antibiotic.Perioperative antibiotic prophylaxis generally is not continued beyond the day of surgery. 