Prophylactic antibiotics in surgery: a rationale for the family physician.

Antibiotic administration can effectively reduce the risk of postoperative wound infection under specific circumstances. Maximal protection is obtained when an antibacterial concentration of a bacteriologically appropriate antibiotic regimen is circulating within target tissues at the time of bacterial contamination. This protection is obtained during a finite period, usually not exceeding four hours following bacterial seeding of tissues. The preservation of intact host defense mechanisms is of ultimate importance in preventing wound infection. When defenses are compromised or when an inoculum is of a size that can overwhelm host defenses, the perioperative administration of antibiotics can significantly reduce infection risk. However, antibiotic use must not lead to a relaxation of good surgical judgment and technique.