Basics

• Definition: Short-term antibiotic shielding during surgical procedures with high infection risk. The aim is to prevent or reduce postoperative complications such as superficial and deep wound infections, pneumonia, sepsis, or urinary tract infections.
• Indications: The infection risk of a procedure depends on the contamination level of the wound and specific risk factors:
  • Aseptic Wounds: Intact mucous membrane. Wound infection rate of 2% → perioperative antibiotic prophylaxis not indicated. Exceptions include implantation of foreign material, joint and bone surgeries.
  • Contaminated Wounds: Mucous membrane is injured. General indication for antibiotic prophylaxis.
  • Septic Wounds: Severe bacterial contamination or open trauma with significant dirt. The wound infection rate of 25% can be reduced to 5% with systemic antibiotic administration. However, this is technically considered antibiotic therapy.
• Risk Factors: These conditions generally require antibiotic prophylaxis:
  • Patients aged 70 and older.
  • Diabetes mellitus.
  • Immunosuppression (e.g., corticosteroid therapy, chemotherapy).
  • Malnutrition/obesity.
  • Consumptive diseases.
  • Chronic bronchitis/emphysema.
  • Heavy smokers.
  • Endocarditis.
  • Foreign body implants.
  • Palliative and recurrent surgeries.
• Note: Catheters and drains are not an indication for antibiotic prophylaxis.
• Common Pathogens:
  • Respiratory tract: Staphylococcus and Streptococcus.
  • Gastrointestinal and urogenital tract: Enterococcus and intestinal bacteria (E. coli, Klebsiella, Proteus, Anaerobes).

Principle and Practical Approach in Antibiotic Prophylaxis

• Antibiotic Administration: An antibiotic is administered such that its serum and/or tissue levels inhibit the growth of common pathogens in the surgical area or kill existing germs throughout the duration of the surgery.
• Single-dose Prophylaxis: Typically, a single antibiotic dose is given at the induction of anesthesia or at the beginning of the surgery. Important: If the antibiotic is administered more than 1 hour after the skin incision or longer than 1 hour before the surgery begins or after blood occlusion starts, the rate of postoperative complications significantly increases. For surgeries lasting longer than 3 hours, with a short half-life of the antibiotic or significant blood loss (greater than 1 liter), a second dose (repeat dose) may be necessary.
• Advantages of Single-dose Prophylaxis:
  • Lower resistance development.
  • Fewer side effects.
  • Reduced costs.
• Extended Prophylaxis: In some cases, perioperative antibiotic prophylaxis should be continued beyond the “prophylactic window” (from skin incision to end of surgery). Examples include:
  • Open fractures (older than 12 hours).
  • Bowel resections with ischemic necrosis without free perforation.
  • Appendectomy in case of gangrenous appendicitis.
  • Bowel injuries following trauma.
  • Gastroduodenal perforation (without confirmed abdominal infection).
  • Liquor shunt surgeries.
  • Post-transplantation.
• Common Antibiotics Used: Cephalosporins of the first and second generation and/or Amoxicillin/Clavulanic acid are commonly used. In gastrointestinal surgery, anaerobic antibiotics (e.g., Metronidazole) are often added. “Reserve antibiotics” like Vancomycin should not be used unless there is an MRSA infection.

Additional Notes:

• For patients with β-lactam allergy, alternatives often include Clindamycin or Vancomycin.
• Vancomycin may be used if there’s a history of MRSA.
• Timing: Antibiotics should generally be administered within 60 minutes before surgical incision (120 minutes for Vancomycin or fluoroquinolones).
• Duration: Single-dose prophylaxis is usually sufficient, and duration should be less than 24 hours for all procedures.