What is the next best step for a patient with a non-healing wound infected with Staphylococcus aureus, previously treated with cephalexin (Cefalexin) and Clindamycin (Clindamycin), presenting with a red and weeping wound?

Surgical Wound Debridement and Reassessment

The next best step is to perform surgical debridement of the wound to remove necrotic tissue and evaluate for deeper infection, as this non-healing post-surgical wound with persistent signs of infection despite two courses of appropriate antibiotics indicates inadequate source control.

Rationale for Surgical Intervention

The patient has failed two courses of antibiotics (cephalexin and clindamycin) despite documented sensitivity of the Staphylococcus aureus to both agents 1. The most important therapy for a surgical site infection is to open the incision, evacuate infected material, and perform adequate debridement 1. When a wound fails to respond to appropriate antibiotic therapy, the primary issue is typically inadequate drainage or the presence of necrotic tissue that requires surgical management 1.

Key Clinical Indicators for Surgical Debridement

• Failure to respond to appropriate antibiotics after 7 days of cephalexin followed by 7 days of clindamycin, despite documented bacterial sensitivity 1
• Persistent wound drainage ("red and weeping") suggests ongoing infection that has not been adequately source-controlled 1
• Surgical debridement is necessary to remove necrotic tissue, which provides an excellent medium for bacterial growth and prevents antibiotic penetration 1, 2

Immediate Management Steps

1. Surgical Consultation and Wound Exploration

• Perform surgical debridement to remove all necrotic and infected tissue 1
• Evaluate the depth of infection to rule out deeper tissue involvement or abscess formation 1
• Obtain intraoperative tissue cultures (not just wound swabs) for more accurate microbiological diagnosis 1
• Assess for any underlying complications such as retained foreign material or compromised blood supply 2

2. Wound Management Protocol

• Allow the wound to heal by secondary intention with regular dressing changes after adequate debridement 1
• Ensure adequate wound irrigation to remove foreign matter and decrease bacterial load 2
• Consider the possibility that the initial lesion removal may have left devitalized tissue that is now serving as a nidus for persistent infection 1

3. Antibiotic Considerations

Hold antibiotics temporarily until after surgical debridement and intraoperative cultures are obtained 1. The evidence shows that:

• For surgical site infections with adequate drainage, antibiotics may provide minimal additional benefit 1, 3
• Studies demonstrate that incision and drainage alone can achieve 90.5% cure rates even for MRSA infections without antibiotics 3
• If systemic signs develop (temperature >38.5°C, heart rate >110 bpm, or erythema extending >5 cm beyond wound margins), then a short course of antibiotics (24-48 hours) may be warranted 1

4. Reassess for Complications

Given the persistent nature of this infection, evaluate for:

• Underlying osteomyelitis if the wound overlies bone, particularly given the lower leg location 1
• Vascular insufficiency that may be impairing wound healing in the lower extremity 1
• Unrecognized deeper infection such as deep incisional surgical site infection extending below the fascia 1

Common Pitfalls to Avoid

• Do not continue empiric antibiotics indefinitely without addressing inadequate source control - this is the most common error in managing non-healing surgical wounds 1
• Do not rely solely on wound swab cultures - intraoperative tissue cultures provide more accurate microbiological data 1
• Do not assume antibiotic failure means resistant organisms when the culture shows sensitivity - inadequate debridement is the more likely culprit 1, 3
• Do not overlook the need for serial debridements - patients often require return to the operating room 24-36 hours after initial debridement until no further necrotic tissue is found 1

Post-Debridement Antibiotic Strategy

If systemic signs of infection are present after debridement, consider:

• Cloxacillin or cefazolin for methicillin-sensitive S. aureus (which this isolate is) 1
• Continue antibiotics only until debridement is no longer necessary, clinical improvement occurs, and fever has been absent for 48-72 hours 1
• The organism is already documented as sensitive to multiple agents, so antibiotic choice is less critical than adequate surgical management 1