Necrotizing soft tissue infection
From IDWiki
Classification
Although it is classically divided into Type 1 (polymicrobial) and Type 2 (monomicrobial), others have proposed an extension to include Type 3 (water-associated) and Type 4 (fungal).
- Type 1: polymicrobial, including Staph. aureus, Gram-negative bacilli, and anaerobes
- Type 2: monomicrobial Group A Streptococcus (Strep. pyogenes)
- May include Staph. aureus, Clostridium (penetrating trauma, soil exposure), Vibrio (water), Aeromonas (water)
- Type 3: monomicrobial Gram-negative infections, generally caused by water-associated Vibrio vulnificans or Aeromonas hydrophila
- Type 4: fungal, caused by Candida species, and exceedingly rare
Management
- Surgical debridement!
- Empiric antibiotics
- Piperacillin-tazobactam
- Clindamycin, for synergy and the Eagle phenomenon and decreased toxin production
- +/- vancomycin
- Then narrow based on the Gram stain an culture
- Can consider IVIg, rarely, in toxic shock syndrome
Eagle Effect
- Originally, referred to decreased effectiveness of penicillins at high concentrations
- Now, refers to decreased effectiveness of penicillins at high bacterial burden (when in stationary phase)
- Clindamycin kills enough of the bacteria that are in stationary phase that the bacteria return to logarithmic growth phase, where penicillins are more effective
Further Reading
- RCT of IVIG: Madsen MB et al. Immunoglobulin G for patients with necrotising soft tissue infection (INSTINCT): a randomised, blinded, placebo-controlled trial. Intensive Care Med. 2017;43:1585-93.