Skip to Main Content


Source: Kanji S. Antimicrobial prophylaxis in surgery. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach. 10th ed. New York, NY: McGraw-Hill; 2017. Accessed March 29, 2017.


  • Prophylactic administration of antibiotics to prevent development of surgical-site infection (SSI).

    • Presumptive antibiotic therapy administered when infection suspected but not yet proven.

  • SSIs by definition occur by postoperative day 30 except for those associated with prosthesis implantation, in which period extends to 1 year.

    • Classified as:

      • Incisional (eg, cellulitis of incision site)

        • Superficial (skin or SC tissue)

        • Deep (fascial and muscle layers)

      • Involving organ or space (eg, with meningitis)


  • SSIs occur in ~3–6% of patients and prolong hospitalization by average of 7 days.

    • Most common postoperative complication.

  • Third most frequent cause of nosocomial infections among hospitalized patients.

    • Primary cause (40%) of nosocomial infections in surgical patients.


  • Traditional classification system developed by National Research Council (NRC) stratifying surgical procedures by infection risk in Table 1.

    • NRC wound classification for specific procedure determined intraoperatively and is primary determinant of whether antibiotic prophylaxis warranted.

  • NRC classification system does not account for influence of:

    • Underlying patient risk factors including:

      • Comorbidities (eg, diabetes)

      • Altered immune response (eg, HIV, hepatitis C)

      • Nutritional status.

    • Operation factors including:

      • Duration of surgical scrub and operation.

      • Implantation of prosthetic materials.

      • Surgical technique.

  • Study on the Efficacy of Nosocomial Infection Control (SENIC) analyzed more than 100,000 surgery cases.

    • Identified risk factors associated with increased incidence of SSI:

      • Abdominal operations.

      • Operations lasting >2 hours.

      • Contaminated or dirty procedures.

      • >3 underlying medical diagnoses.

    • Stratification of NRC classification described in Table 1 by number of SENIC risk factors present resulted in variation of infection rates by as much as factor of 15 within same operative category.

  • SENIC risk assessment technique has been modified to include American Society of Anesthesiologists preoperative assessment score.

    • American Society of Anesthesiologists score ≥3 was associated with increased SSI risk.

TABLE 1.aNational Research Council Wound Classification, Risk of Surgical-Site Infection (SSI), and Indication for Antibiotics

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.