Antibiotic Prophylaxis of Surgical Site Infections

There are an estimated 0.5 –1 million surgical site infections annually in the United States. Surgical site infection is estimated to occur in roughly 4% of general or vascular operations. For most major procedures, the use of prophylactic antibiotics has been demonstrated to reduce the incidence of surgical site infections significantly. For example, antibiotic prophylaxis in colorectal surgery reduces the incidence of surgical site infection from 25–50% to below 20%. In addition, in a case control study of Medicare beneficiaries, the use of preoperative antibiotics within 2 hours of surgery was associated with a twofold reduction in 60-day mortality. Prophylactic antibiotics are considered standard care for all but "clean" surgical procedures. Clean procedures are those that are elective, nontraumatic, not associated with acute inflammation, and that do not enter the respiratory, gastrointestinal, biliary, or genitourinary tract. The surgical site infection rate for clean procedures is thought to be roughly 2%. However, in certain clean procedures, such as those that involve the insertion of a foreign body or breast cancer surgery, antibiotic prophylaxis is still recommended because the consequences of infection are serious. Antibiotic prophylaxis recommendations for a variety of procedures are shown in Table.

Multiple studies have evaluated the effectiveness of different antibiotic regimens for various surgical procedures. In most cases, no single antibiotic regimen has been shown to be superior. Several general conclusions can be drawn from these data. First, substantial evidence suggests that a single dose of an appropriate intravenous antibiotic—or combination of antibiotics—is as effective as multiple-dose regimens that extend into the postoperative period. For longer procedures, the dose should be repeated every 3–4 hours to ensure maintenance of a therapeutic serum level. In colorectal surgery, however, three doses of an intravenous cephalosporin have been shown to reduce surgical site infection incidence compared with a single dose. Similarly, at least 24 hours of postoperative antibiotic therapy is recommended after cardiac surgery. Second, for most procedures, a first-generation cephalosporin is as effective as later-generation agents. However, in a large randomized trial of colorectal surgery patients, the use of prophylactic ertapenem significantly reduced the surgical site infection rate compared to that for cefotetan. Third, prophylactic antibiotics should be given intravenously at induction of anesthesia or roughly 30–60 minutes prior to the skin incision. Although the type of procedure is the main factor determining the risk of developing a surgical site infection, certain patient factors have been associated with increased risk, including diabetes, older age, obesity, heavy alcohol consumption, admission from a long-term care facility, and multiple medical comorbidities.

Other strategies to prevent surgical site infections have proven to be controversial. Evidence suggests that nasal carriage with Staphylococcus aureus is associated with a twofold to ninefold increased risk of surgical site and catheter-related infections in surgical patients. Treatment of nasal carriers of S aureus with 2% mupirocin ointment (twice daily intranasally for 3 days) prior to cardiac surgery decreases the risk of surgical site infections. However, in a 2008 cohort study, universal screening for methicillin-resistant S aureus in surgical patients failed to reduce infection rates from this pathogen. An early finding that high concentration oxygen delivered in the immediate postoperative period reduced surgical site infections was not verified in subsequent trials. Thus, high-flow supplemental oxygen specifically to prevent these infections is not recommended. Preoperative bathing with antiseptic agents and preoperative hair removal are common practices but have not demonstrated a reduction in surgical site infections in randomized trials. The use of razors for hair removal actually seems to increase the risk of surgical site infections and is therefore specifically not recommended. If preoperative hair removal is indicated, the use of clippers is preferred.

Casey AL et al. Progress in the prevention of surgical site infection. Curr Opin Infect Dis. 2009 Aug;22(4):370–5. [PMID: 19448534]

Fonseca SNS et al. Implementing 1-dose antibiotic prophylaxis for prevention of surgical site infection. Arch Surg. 2006 Nov;141(11):1109–13. [PMID: 17116804]

Fujita S et al. Randomized multicenter trial of antibiotic prophylaxis in elective colorectal surgery: single dose vs 3 doses of a second generation cephalosporin without metronidazole or oral antibiotics. Arch Surg. 2007 Jul;142(7):657–661. [PMID: 17638804].