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The New (and Improved) Flesh-eating Staph
Lawrence Eron MD FACP
I.
II
III.
IV.
MRSA infections
A. Health-care associated-126,000 annually; cost $2.5 billion annually
1. Infections of skin, lung, and blood-stream
2. Resistant to cotrimoxazole, tetracyclines, clindamycin
B. Community-acquired
1. Infections of skin and soft tissue
2. Sensitive to cotrimoxazole>tetracyclines>clindamycin
3. Encodes for 19 different toxins
4. May be necrotizing
5. When to use and not use fluoroquinolones
C. Risk factors
1. Drug addiction, hemodialysis, insulin-requiring diabetes
2. Hospitalization or antibiotics in last three months
3. Pacific Islander
Classification of cellulitis
A. Class 1-mild cellulitis, afebrile, no cormorbidities; use po antibiotics
B. Class 2-febrile, larger area of cellulitis; consider OPAT (outpatient
parenteral antibiotic therapy)
C. Class 3-limb-threatening disease; admit to hospital
D. Class 4-necrotizing fasciitis & sepsis syndrome; admit to ICU
Treatment of cellulitis-I&D if fluctuant
A. Oral antibiotics
1. Oldies-cotrimoxazole, mino/doxycycline, clindamycin
2. New and expensive-linezolid (Zyvox)-more potent
-moxifloxacin (Avelox)- expanded spectrum
B. Parenteral antibiotics
i. Oldies-vancomycin
ii. New and expensive-daptomycin (Cubicin)-more
bactericidal
-tigecycline (Tygacil)-expanded spectrum
-dalbavancin-once weekly!
Flesh-eating disease
A. Streptococcus
1. Infection of skin/skin structure
2. Due to streptococcal pyrogenic exotoxins
3. Modified by host immunity
4. Treatment-debridement
-clindamycin plus penicillin
-?gammaglobulin
B. Staphylococcus aureus
1. Infections of skin/skin structure, lung
2. Associated with Panton-Valentin leukotoxin and other toxins
V.
VI.
Why MRSA is increasing?
A. Antibiotic use
B. Poor hand hygiene
What we can do about it
A. Better hand hygiene
B. Barrier precautions
C. Decontamination of the environment and equipment
D. Device bundles
E. Active surveillance-“Search and Destroy” lowered MRSA prevalence in
Denmark in 1960’s from 35% to zero! Johns Hopkins and Pittsburgh have
reduced MRSA by 70% using this approach.
References
Annaya & Dellinger, Necrotizing soft-tissue infection: diagnosis and management. Clin
Infect Dis 2007; 44: 705-10.
Bradley, Eradication or decolonization of methicillin-resistant Staphylococcus aureus
carriage: What are we doing and why are we doing it? Clin Infect Dis 2007: 44: 186-9.
Deresinski, Methicillin-resistant Staphylococcus aureus: an evolutionary, epidemiologic,
and therapeutic odyssey. Clin Infect Dis 2005; 40: 562-73
Moellering, The growing menace of community-acquired methicillin-resistant
Staphylococcus aureus, Ann Intern Med 2006; 144: 368-70
Miller et al, Necrotizing fasciitis caused by community-associated methicillin-resistant
Staphylococcus aureus in Los Angeles, NEJM 2005; 352: 1445-53.