MRSA
                                ====
þ Risks:
 - Outbreak investigations among athletes with CA-MRSA outbreaks yield risk factors:
  + Skin trauma, abrasions
  + Lineman or linebacker position in football
  + Male depilation (below neck)
  + Physical contact with index MRSA cases
  + Sharing equipment (whirlpool baths)
  + Higher BMI
    MMWR 52: 793, 2003.
    CID 39: 1446, 2004.

þ Drugs:
 - Per Scott Curry (Mercy ID) 2009:
   Consider using first:
 - TMP-SMX
  + Affordable, excellent response rate
  + Excellent oral bioavailablility; use 1-3 DS tablets BID
  + SULFA allergy limits use, bacteriostatic
  + Poor penetration into abscesses
 - Doxycyline
  + Affordable
  + Esophagitis, vaginitis, photosensitivity
  + Have to ask micro lab to run Sensitivity test
  + Dose 100 mg po BID
 - Clindamycin
  + Use with extreme caution around UPMC
  + $$$, AAD even if no C. difficile
  + Request D-test (inducible clinda resistance) and use only if NEG
  + QID dosing makes inconvienient
 - Vancomycin, daptomycin, tigecycline
   Only available parenterally for inpatient use
 - Newer agents for outpatient use
 - Linezolid
  + $$$$$$ 
  + Few short term SE, but long term use a/w neuropathy,
  + Controversial association with thrombocytopenia 
  + Dosing 600 mg po BID.
  + Resistance will emerge
 - Dalbevancin
  + Glycopeptide like vanco, but ½ life of 7 days
  + Could be given x one IV dose in clinic weekly
  + Not yet available in Pittsburgh
 - Fluoroquinolones!
  + Don’t believe our S reports!!!
  + Cipro not FDA approved for S. aureus
  + Higher generation FQs claim greater activity against Gram-positive 
    pathogens, but gyrA and topoisomerase mutations can arise while on 
    therapy, and frequently do
 - Rifampin:
  + Never use as monotherapy, resistance emerges quickly
  + Use in combination therapy should be guided by ID
  + Multiple drug interactions (OCPs) 

þ Treatment Guidelines
 - SSTI classifications (Eron)
  + Class I: Systemically well and no co-morbdities (PVD, DM, obesity, venous 
    stasis
  + Class II: Febrile and healthy or well + above co-morbidities
  + Class III Toxic-appearing or multiple co-morbidities above
  + Class IV: Critically ill, limb-threatening infection, e.g., necrotizing 
    fasciitis 
 - Class I: 
  + I&D of simple abscesses, no abx
  + b-lactam therapy if abx chosen
  + Don’t add 2nd line MRSA agents even if risk factors for MRSA identified
 - Class II
  + If managed as an outpatient, add MRSA-effective drug (do NOT omit b-lactam 
    since need to cover GAS, GBS)
  + Drain, drain, drain!
  + Culture before abx.
 - Class III and IV, hospitalize

old notes:
 - Bactrim 10 mg/kg/day: 4 Bactrim-DS a day for 70kg person (2 PO BID); 2 PO
   BID is not adequate for big patients
 - Alternative is doxycycline (NOT plain TCN) 100 BID.
 - May be resistant to erythro, lab checks for inducible clinda resistance
 - Clinda: community-aquired resistance less than 5%