Should we routinely cover for methicillin-resistant Staphylococcus aureus (MRSA) when treating patients for cellulitis?

No! Despite the MRSA epidemic, β-hemolytic streptococci (BHS) are still considered the primary cause of non-purulent cellulitis (e.g. without abscesses, or infections involving deep soft tissues, wounds, or ulcer).

In a prospective study of patients admitted to the hospital for “diffuse,  non-culturable “(i.e. many of our patients), most had serological evidence of acute  BHS, and >95% responded to a β-lactam antibiotic treatment (1) . 

The current Infectious Diseases Society of America guidelines do not endorse empiric coverage of  MRSA for non-purulent cellulitis,  unless there is systemic toxicity or poor response to  β-lactam  monotherapy (2). More specifically, the guidelines recommend a  β-lactam antibiotic for treatment of non-purulent cellulitis in hospitalized patients with modification to MRSA coverage if no clinical response.

One advantage to β-lactam monotherapy is the ease of switch to an equivalent oral antibiotic (e.g. cephalexin) when transitioning from parenteral antibiotic therapy.  

References

1. Jeng A, Beheshti M, Li J, et al. The role of beta-hemolytic streptococci in causing diffuse nonculturable cellulitis: a prospective investigation. Medicine (Baltimore) 2010;89:217-26. https://www.ncbi.nlm.nih.gov/pubmed/20616661

2. Liu C, Bayer A, Cosgrove SE, et al. Clinical practice guidelines by the Infectious Diseases Society of America for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children. Clin Infect Dis 2011;52:e18-55. https://www.ncbi.nlm.nih.gov/pubmed/21208910

 

Should we routinely cover for methicillin-resistant Staphylococcus aureus (MRSA) when treating patients for cellulitis?