Surgical site infections
A surgical site infection (SSI) is infection at or near an operative incision within 30 days of surgery, or 90 days with an implant. Diagnosis rests on purulent drainage, culture, or a surgeon opening the wound. Treatment is source control, drainage and debridement of necrotic tissue, plus culture-directed antibiotics.
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What this article covers
- Overview
A surgical site infection (SSI) is an infection that develops at or near a surgical incision within 30 days of the operation, or within 90 days if an implant was placed.
- Epidemiology
SSIs account for 23% of all healthcare-associated infections, ranking with pneumonia as the most common.
- Risk factors
Hyperglycemia: perioperative glucose above 180 mg/dL impairs neutrophil function and wound healing.
- Pathophysiology
Most SSIs arise from the patient's own flora: skin organisms such as Staphylococcus aureus and coagulase-negative staphylococci for clean procedures that do not enter a hollow viscus, and…
- Clinical features
Superficial incisional infection: limited to skin and subcutaneous tissue, with pain, swelling, erythema, warmth, and purulent drainage, typically within 30 days.
- Differential diagnosis
Necrotizing fasciitis: the dangerous mimic, but pain is out of proportion to examination and crepitus or bullae are present, with mortality approaching 25% if debridement is delayed.
- Diagnosis
The diagnosis of superficial incisional SSI is established when infection occurs within 30 days plus at least one of purulent drainage, organisms identified from aseptically obtained fluid or tissue…
- Management
First, establish source control: open and drain any purulent superficial incisional infection at the bedside; deep incisional and organ-space infections require formal debridement of necrotic tissue…
- Complications
Wound dehiscence: hypoxia, anemia, malnutrition, diabetes, obesity, and steroid use can raise dehiscence risk as high as 30%.
- Prognosis
Superficial incisional infections generally resolve fully with drainage, local wound care, and a short antibiotic course, with low morbidity and no effect on long-term outcome.
- Prevention
Optimize modifiable host factors: maintain perioperative glucose below 180 mg/dL for the first 48 hours, reduce immunosuppressive drug doses, stop tobacco use at least 30 days before surgery, and correct malnutrition preoperatively.
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- Postoperative fever
Fever of at least 38.0°C after surgery, worked up by the timing of onset rather than a single test. Most cases are self-limited, but the evaluation must exclude pulmonary embolism, necrotizing fasciitis, and malignant hyperthermia while directing source-specific treatment such as empiric antibiotics, anticoagulation, or urgent debridement.
- Necrotizing fasciitis
Necrotizing fasciitis is a rapidly progressive, life-threatening infection of the subcutaneous tissue and superficial fascia driven by vessel thrombosis and bacterial exotoxin production. The hallmark is pain out of proportion to visible skin findings, with crepitus, bullae, and woody induration in advanced disease. Diagnosis is confirmed by direct surgical exploration; the LRINEC score aids risk stratification. Treatment is emergent surgical debridement combined with broad-spectrum empiric antibiotics.
- Fournier gangrene
Fournier gangrene is a rapidly progressive polymicrobial necrotizing fasciitis of the perineum and genitalia, usually arising from a perianal, urethral, or scrotal skin breach. The diagnosis is clinical, confirmed at surgical exploration, and first-line treatment is immediate broad-spectrum intravenous antibiotics paired with emergent, repeated surgical debridement.
- Cellulitis
Cellulitis is a nonpurulent, spreading infection of the deep dermis and subcutaneous fat, usually caused by beta-hemolytic streptococci, diagnosed clinically and treated with antibiotics alone since there is no collection to drain.
- Sepsis
Sepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection, identified by an acute rise in SOFA score of 2 points or more in a patient with known or suspected infection. Survival depends on recognizing the pattern early and completing the hour-1 bundle: lactate, blood cultures before antibiotics, broad-spectrum antibiotics such as cefepime 2 g IV every 8 hours, and 30 mL/kg crystalloid for hypotension or a lactate of 4 mmol/L or higher.
- Central line-associated bloodstream infection
Central line-associated bloodstream infection (CLABSI) is bacteremia or fungemia in a patient with a central venous catheter that is not explained by infection at another site, confirmed by a matching catheter-tip culture or differential quantitative blood cultures. First-line treatment is prompt catheter removal plus empiric vancomycin with gram-negative coverage, narrowed to a pathogen-directed course of 7 to 14 days, or at least 4 weeks for Staphylococcus aureus.