Prophylactic antibiotics in open heart surgery.

Two prophylactic antibiotic regimes were compared in 129 patients who had open heart surgery for mitral and/or aortic valve replacements at Guy's Hospital. The first group were prescribed cephalothin for five days beginning with premedication. The second group were prescribed the combination of cloxacillin and gentamicin for the same time. The incidence of minor infection was low. There was no statistical difference between the two antibiotic regimes. The major infections were due predominantly to Gram negative organisms and difficult to prevent by any prophylactic regime.