Antibiotic choice :  Coverage in for polymicrobial, Gram-positive Gram-negative and anaerobic.

** make sure LRINEC score rule out necrotizing fasciitis,

Hard signs:  Bullae, skin anesthesia, rapidly spreading erythema, crepitus, skin necrosis or ecchymosis

PE: pain out of portion, dusky or violaceous discoloration black, crepitus, skin necrosis, fever hypotension tachycardia, firmness on palpation due to facial inflammation and edema

** MRI to rule out osteomyelitis

 

Gram-positive cocci:  Staphylococcus including MRSA, Streptococcus

Gram-negative rod:  E coli, Pseudomonas

Anaerobes:  Bacteroides, peptostreptococcus especially in necrosis or foul smelling wound

Mild infection with no systemic signs limited to skin and subcutaneous tissue

Primary Gram-positive cocci MRSA coverage with cephalexin TMP SMX

Moderate to severe infection with deeper tissue involvement systemic signs or risk of resistance

Broad-spectrum coverage including anaerobic MRSA with Zosyn, vanco, daptomycin, ertapenem does not cover Pseudomonas or MRSA, vanco plus cefepime or meropenem for Gram-negative and MRSA

Pseudomonas suspicious for stocking wound and chronic ulcer recent antibiotic exposure

Levofloxacin, meropenem, cefepime, Zosyn

Mild 1-2 weeks

Moderate to severe 2-4 weeks 

Osteomyelitis 4-6 weeks may require bone biopsy and surgical debridement 

Diabetic foot infection requires 3 weeks' duration after amputation