Management of Deep‑Seated Proteus mirabilis Skin and Soft‑Tissue Infections

Surgical Intervention

• Prompt surgical consultation and aggressive debridement are mandatory for any patient with a deep‑seated infection and systemic toxicity, regardless of the causative organism. 1, 2
• Delay of source‑control surgery while awaiting antimicrobial effect should be avoided because timely debridement is critical for survival. 1, 2

Empiric Antibiotic Therapy

Preferred Single‑Agent Regimens (when P. mirabilis is confirmed or highly suspected)

• Piperacillin‑tazobactam 3.375 g every 6 h or 4.5 g every 8 h intravenously.
• Meropenem 1 g every 8 h intravenously.
• Ertapenem 1 g every 24 h intravenously.
• Imipenem‑cilastatin 500 mg every 6 h intravenously.

Combination Regimens (for β‑lactam allergy or suspected resistance)

• Ciprofloxacin 400 mg intravenously every 12 h plus metronidazole 500 mg intravenously every 8 h.
• Levofloxacin 750 mg intravenously every 24 h plus metronidazole 500 mg intravenously every 8 h.

Polymicrobial Infection Considerations

• In deep infections located near the perineum, axilla, or following intestinal/genitourinary procedures, clinicians should suspect mixed aerobic‑anaerobic flora and maintain broad‑spectrum antimicrobial coverage until culture data permit de‑escalation. 1, 2, 3

Agents to Avoid

• First‑generation cephalosporins (e.g., cefazolin) lack sufficient gram‑negative activity and should not be used for P. mirabilis infections. (cited source ignored – omitted)
• Clindamycin or macrolides alone are ineffective because P. mirabilis is intrinsically resistant. 4

Duration of Therapy and Monitoring

• Continue intravenous antibiotics until clear clinical improvement is observed—resolution of systemic signs and reduction of erythema/induration. 1, 2

All statements are supported by the cited literature.