Combined carbenicillin and gentamicin for prophylaxis of post-operative infection following major abdominal surgery.

Bacteriological studies with carbenicillin and gentamicin individually and with the combination of these antibiotics suggest their effect to be additive in action and often synergistic. Of sixty-five organisms tested the majority Gram-negative, forty-seven were resistant to ampicillin, thirty-seven to carbenicillin, twenty-four to gentamicin and only six to carbenicillin plus gentamicin. Out of sixty-seven patients undergoing major abdominal surgery, thirty were randomly allocated to receive carbenicillin plus gentamicin post-operatively and of these one developed an infection. The other thirty-seven patients received either ampicillin or no antibiotic and nine developed infections. The combined antibiotic regime seems suitable for prophylaxis for patients undergoing major abdominal surgery with a high risk of infection.