A 45-year-old man presents to the emergency department with severe muscle pain, fever, and confusion for the past day. He was recently diagnosed with influenza and has been bedridden for the past four days. His past medical history includes type 2 diabetes mellitus, obesity, and hyperlipidemia. He does not take regular medications and has no known drug allergies. His vital signs are temperature 103.5°F (39.7°C), blood pressure 88/50 mmHg, heart rate 118 beats/min, and respirations 20/min. On physical examination, he appears ill and is tachycardic. His left lower extremity is erythematous, swollen, and exquisitely tender to palpation. Crepitus is noted on deep palpation. Urgent surgical consultation is requested.
In addition to vancomycin and clindamycin, which of the following antibiotics is the most appropriate initial treatment?
- A) Ampicillin-sulbactam
- B) Cefazolin
- C) Ceftriaxone
- D) Linezolid
- E) Piperacillin-tazobactam
E) Piperacillin-tazobactam
This patient presents with signs of necrotizing fasciitis, a rapidly progressive soft tissue infection that can be polymicrobial or monomicrobial. Broad-spectrum empiric antibiotic therapy, including an agent such as piperacillin-tazobactam (or imipenem or meropenem or ertapenum) plus vancomycin (to cover MRSA) are essential for treatment along with urgent surgical debridement. Linezolid may be used in place of vancomycin. Clindamycin is often included as well for anaerobic coverage and its antitoxin effects against toxin-elaborating strains of beta-hemolytic streptococci and Staphylococcus aureus.
Answer choice A: Ampicillin-sulbactam, is incorrect. Ampicillin-sulbactam does not provide adequate coverage for all potential gram-negative pathogens involved in necrotizing fasciitis, particularly Pseudomonas aeruginosa. Piperacillin-tazobactam does provide coverage against this pathogen. Ampicillin-sulbactam also does not provide adequate coverage against Enterobacteriaceae due to drug resistance.
Answer choice B: Cefazolin, is incorrect. Cefazolin does not provide adequate gram-negative coverage nor coverage against Pseudomonas aeruginosa.
Answer choice C: Ceftriaxone, is incorrect. Ceftriaxone is not sufficient because it does not provide broad-spectrum coverage of necrotizing infections.
Answer choice D: Linezolid, is incorrect. Linezolid covers methicillin-resistant Staphylococcus aureus (MRSA) but lacks broad anaerobic and gram-negative coverage necessary for necrotizing fasciitis. MRSA is already being covered with vancomycin.
Key Learning Point
Necrotizing fasciitis requires urgent surgical debridement (the primary treatment) and broad-spectrum antibiotic coverage. The Infectious Disease Society of America (IDSA) recommends piperacillin-tazobactam or a carbapenem plus vancomycin or linezolid. Clindamycin is included in some other treatment recommendations.
