Controversies in antimicrobial prophylaxis.

This paper examines four controversies in antimicrobial prophylaxis. Duration of prophylaxis: Antimicrobial agents must be present in the tissues throughout the operation. Usually, a single preoperative or intraoperative dose will suffice; postoperative doses are unnecessary. Third-generation cephalosporins: no clinical evidence supports their use for surgical prophylaxis. Optimal prophylaxis for colorectal surgery: the information is conflicting, but oral agents combined with a parenteral antibiotic may be optimal. Prophylaxis for patients with indwelling prosthetic joints or vascular grafts: prophylaxis is unnecessary for procedures like dental work that cause transient bacteremia, but established infections should receive prompt, vigorous antimicrobial therapy.