Prophylaxis of postoperative infections.

The antibiotic most appropriate for prophylaxis of postoperative infections depends on the nature of the operation. In aseptic (clean) operations, gram-positive postoperative infections are the primary concern, and cefazolin is recommended because of its excellent pharmacokinetics and good activity against gram-positive pathogens, including staphylococci. In those operations where violation of the digestive tract creates a contaminated field, a cefotaxime-generation cephalosporin is the agent of choice because of the excellent safety profiles and the capability of agents of this class to kill essentially all pathogenic gram-negative aerobes as well as a substantial portion of anaerobes. Selection of resistant bacteria has not been significant and is unlikely to become so with single-dose prophylaxis. Occasionally, if there is a high probability that the operative field may be heavily contaminated by anaerobes, metronidazole should be added. Dosing should be sufficient to cover the operative period. Only a single prophylactic dose is necessary, given at the time of induction of anesthesia. For particularly long operations, a second dose of those antibiotics with half-lives shorter than 60 min is required two hours after the first. Single-injection prophylaxis is effective, inexpensive, has no side effects and does not induce bacterial resistance.