Treatment of Surgical Site Infections
The primary treatment for surgical site infections is prompt and wide opening of the surgical incision with drainage; antibiotics should be added only when systemic signs of infection are present (temperature ≥38.5°C, heart rate ≥110 beats/min), when erythema extends >5 cm from the wound edge, or in immunocompromised patients. 1, 2
Initial Management Approach
Surgical intervention is the cornerstone of treatment:
- Remove sutures and open the incision widely to evacuate all infected material 3, 1
- Continue dressing changes until the wound heals by secondary intention 1, 2
- Obtain Gram stain and culture of purulent material to guide targeted therapy, though empiric treatment can be started based on likely pathogens 1
Most superficial incisional SSIs can be managed with incision and drainage alone without antibiotics. 2 This is a critical point that prevents unnecessary antibiotic use and resistance development.
When to Add Antibiotics
Antibiotics are indicated when any of the following are present:
- Temperature ≥38.5°C or heart rate ≥110 beats/min 3, 1, 2
- Any Systemic Inflammatory Response Syndrome (SIRS) criteria or signs of organ failure (hypotension, oliguria, decreased mental alertness) 3, 2
- Erythema extending >5 cm from the wound edge 1, 2
- Immunocompromised status 3, 1
- White blood cell count >12,000/μL 1
Antibiotic Selection by Surgical Site
For trunk or extremity operations (away from axilla/perineum):
- First choice: Cefazolin 0.5-1g every 8h IV or cephalexin 500mg every 6h orally for MSSA 1, 2
- For MRSA: Vancomycin 15 mg/kg every 12h IV, or alternatives including linezolid, daptomycin, or ceftaroline 1, 2
For operations involving intestinal or genital tracts:
- Single-drug options: Piperacillin-tazobactam, ertapenem, or other carbapenems (imipenem, meropenem) 1, 2
- Combination options: Ceftriaxone + metronidazole, or ciprofloxacin/levofloxacin + metronidazole 1, 2
These broader regimens are necessary because operations on nonsterile tissue (colonic, vaginal, biliary, or respiratory mucosa) involve both aerobic and anaerobic bacteria that can rapidly progress to involve deeper structures. 3
For operations involving axilla or perineum:
Duration of Antibiotic Therapy
A brief course of 5-7 days is typically sufficient after adequate drainage. 1 Some sources suggest even shorter courses of 24-48 hours may be adequate for superficial infections after proper surgical management. 2 Longer courses may be needed for complex infections or immunocompromised patients, but routine prolonged therapy beyond 7 days should be avoided. 1
Critical Pitfalls to Avoid
Do not rely on antibiotics alone without proper surgical drainage when an abscess is present. 1 Delayed drainage can lead to progression of infection and involvement of deeper structures. 2
Do not routinely administer antibiotics for uncomplicated SSIs after adequate drainage. 1, 2 This is the most common error—antibiotics without systemic signs of infection are unnecessary and contribute to resistance.
Assess for deeper organ/space infection if the SSI does not resolve as expected after treatment. 2 Superficial infections that fail to improve may represent manifestations of deeper infections requiring additional intervention.
Prevention Considerations
For surgical prophylaxis (distinct from treatment), cefazolin remains the preferred agent for most procedures, administered within 60-120 minutes before incision. 3, 4 Prophylaxis should be discontinued within 24 hours postoperatively for most procedures, as continued administration does not reduce infection rates but increases adverse reactions and resistance. 3