Treatment Duration for MSSA Septic Bursitis
For methicillin-sensitive Staphylococcus aureus (MSSA) septic bursitis, a short course of 7 days or less of antibiotic therapy is sufficient in non-immunosuppressed patients who undergo adequate surgical drainage, with no evidence that longer courses improve outcomes.
Evidence-Based Duration Recommendations
The strongest available evidence demonstrates that adjuvant antibiotic therapy can be safely limited to ≤7 days following surgical bursectomy in hospitalized patients with severe infectious bursitis. A retrospective study of 343 episodes of infectious bursitis (85% caused by S. aureus) found no association between total antibiotic duration and cure rates, with immunosuppression being the only predictor of recurrence rather than antibiotic duration 1. In multivariate analysis, 8-14 days of antibiotics (OR 0.6) or >14 days (OR 0.9) showed no advantage over ≤7 days of treatment 1.
A separate study of 82 severe septic bursitis cases treated with cloxacillin-based regimens achieved complete resolution in 98.8% of patients, though specific duration data were not uniformly reported. The mean intravenous component was approximately 11 days in most patients, with transition to oral therapy until resolution 2, 3.
Surgical Management Is Critical
Surgical debridement and drainage remain the mainstay of therapy and should be performed whenever feasible, as antibiotics serve only an adjuvant role. 4 The high success rate (95%) without open surgical drainage in one series suggests that adequate bursal aspiration combined with appropriate antibiotics may suffice in selected cases 3.
One-stage bursectomy with closure achieved cure in 85% of hospitalized cases when combined with antibiotics. 1 Endoscopic bursectomy may decrease morbidity compared to open procedures for patients requiring surgical intervention 5.
Antibiotic Selection for MSSA
For MSSA septic bursitis, cloxacillin 2 g IV every 4 hours (or equivalent anti-staphylococcal penicillin such as nafcillin) should be used as first-line therapy. 2 Once clinical improvement occurs, transition to oral cloxacillin 1 g every 6 hours or cephalexin 500 mg every 6 hours is appropriate 2.
Cefazolin 1-2 g IV every 8 hours is the preferred alternative for hospitalized patients requiring intravenous therapy. 4
For patients with severe presentation including extensive cellulitis or systemic toxicity, adding gentamicin 240 mg/day IV for 5-7 days to cloxacillin may be considered, though this increases the duration of IV therapy without clear outcome benefit. 2
Treatment Algorithm
- Days 0-2: Initiate IV anti-staphylococcal therapy (cloxacillin, nafcillin, or cefazolin) immediately after obtaining bursal fluid culture 2, 3
- Days 3-7: Continue IV therapy with clinical reassessment; transition to oral therapy once fever resolves and local signs improve 1, 2
- Day 7: In non-immunosuppressed patients with adequate source control, antibiotics can be discontinued if clinical resolution is achieved 1
- Beyond 7 days: Extension is warranted only for immunosuppressed patients, inadequate source control, or persistent signs of infection 1
Special Populations Requiring Longer Therapy
Immunosuppressed patients have a 5.6-fold increased risk of recurrence and may require antibiotic courses extending beyond 7 days. 1 However, even in this population, the optimal duration remains undefined 5.
Patients with concurrent bacteremia, endocarditis, or osteomyelitis require treatment durations appropriate for those conditions (typically 4-6 weeks), not for the bursitis itself. 4, 6
Common Pitfalls to Avoid
Do not reflexively prescribe 10-14 day courses based on tradition; the evidence supports shorter therapy when adequate drainage is achieved. 1 The median total antibiotic duration of 13 days in one large series likely represents historical practice rather than evidence-based necessity 1.
Do not rely on antibiotics alone without adequate drainage; failure to drain purulent collections leads to treatment failure regardless of antibiotic choice. 4
Do not extend therapy based solely on residual erythema or swelling, as inflammation may persist for days after bacterial eradication. Extending treatment is indicated only if warmth, tenderness, or erythema are expanding or if systemic signs persist 1.
Monitoring and Follow-Up
Reassess patients within 48-72 hours to verify clinical response. 7 Treatment failure should prompt evaluation for inadequate drainage, resistant organisms, or alternative diagnoses such as gout or rheumatoid bursitis 5.
The intravenous component can typically be limited to 3-7 days with transition to oral therapy once clinical improvement is evident. 1, 2 The median IV duration of 3 days in the largest available series supports early transition to oral therapy 1.