Per-operative antibiotic treatment in cardiovascular surgery: the influence of methicillin versus cephalothin on post-operative infections and bacterial colonization.

This paper reports the results of a prospective study of antibiotic prophylaxis in 543 patients undergoing open-heart surgery. All patients were given per-operatively either methicillin, 1 g four times a day, or cephalothin, 1 g four times a day. There was no significant difference in the frequency of postoperative infections between the two groups. It was established that per-operative antibiotic prophylaxis selected resistant coagulase-negative staphylococci (CNS) in the nasal flora of cardiac surgery patients, that this change occurred to the same degree whether methicillin or cephalothin was used, that cephalothin favoured colonization with antibiotic resistant species other than CNS. It was found that the staff of the intensive care unit formed a reservoir of multi-resistant CNS.