MRSA pneumonia

Today we saw a case of severe methicillin resistant staphylococcus aureus (MRSA) pneumonia (review). In the era of community acquired (CA-MRSA), this is becoming a significant problem.

Management includes:

• Supportive care in keeping with best practices
• Vancomycin is the 'gold standard' -- but not a great one.
  
  • aim for trough ~ 20
  • avoid in MIC greater than or equal to 2 (and maybe even 1)
    
  • addition of rifampin improves short term microbiologic cure, but interestingly was associated with increased long term mortality
• Alternatives include:
  
  • Linezolid -- often postulated, not yet proven to be superior.
    
    • the maker of linezolid was fined for off label marketing of the drug for the use in MRSA pneumonia (see one example news article here) so caveat emptor...
  • Tigecycline -- theorhetically 'better' lung kinetics than vancomycin -- not studied
  • Ceftobiprole -- under study. Has advantages in terms of tissue penetration and the fact that it is a beta-lactam
  • doxycycline or TMP/SMX -- could be an option for milder disease.
  • Daptomycin -- do not use, inferior.
• Duration of therapy 8-14 days (or longer in bacteremia with other focus) depending on resolution of clinical symptoms. Some studies show no difference between 8 and 15 days of therapy. Many experts 'prefer' 14 days.