• | a rapidly advancing soft tissue infection that is associated with systemic toxicity |
• | many organisms, including aerobes and anaerobes, may be isolated, often in combination |
• | frozen tissue sections: massive polymorphonuclear cell infiltrate in the fascia and subcutaneous tissue |
• | clindamycin may be better choice than PCN because its efficacy is not affected by inoculum size; furthermore there is some evidence that clindamycin suppresses toxin production by strep |
streptococcal necrotizing fasciitis:
• | invasive group A strep; virulence due to… |
• | surface M proteins (facilitate tissue adherence and invasiveness) |
• | pyrogenic exotoxins: exert a local toxic effect as well as contributing to systemic involvement by acting as superantigens (in fact some cases of streptococcal NF may progress to streptococcal toxic shock syndrome) |
pathogenesis
• | group A strep – site of an injury on extremities |
• | group B strep – post-partum infected incisions |
• | (above = clinically indistinguishable) |
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