UMEM Educational Pearls

Category: Pharmacology & Therapeutics

Title: Add Strep Coverage to Outpatient Cellulitis Treatment Regimens

Keywords: cellulitis, cephalexin, sulfamethoxazole/trimethoprim, Bactrim, streptococcus (PubMed Search)

Posted: 5/20/2013 by Bryan Hayes, PharmD (Emailed: 6/1/2013) (Updated: 5/31/2013)
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In the current era of community-acquired MRSA (CA-MRSA), most of our outpatient treatment options for cellulitis aim to cover MRSA. Choices include sulfamethoxazole/trimethoprim (SMZ-TMP), doxycycline, linezolid, and clindamycin (depending on local susceptibility patterns).

A New Study

  • In a double-blind, placebo-controlled trial 146 patients with cellulitis were randomized to receive cephalexin alone or cephalexin + SMZ-TMP for 7-14 days
  • Lots of exclusion criteria basically narrowed the patient population to uncomplicated cellultits with no history of diabetes or other immunocompromising conditions
  • Cure rates up to 30 days post-treatment were the same between the two groups (>80%)

Take Home Clinical Points

  • Even in communities with high prevalence of MRSA, uncomplicated cellulitis cases without pus generally seem to be strep species.
  • Therefore, make sure to include an anti-streptococcal component (such as cephalexin) to the MRSA agent (doxycycline or SMZ-TMP). Clindamycin has sufficient strep coverage by itself (but may not adequately cover MRSA).
  • Given the potential for MRSA infections to deteriorate quickly and the inability to differentiate staph from strep without cultures, MRSA coverage should still be considered.


Pallin DJ, et al. Clinical Trial: Comparative Effectiveness of Cephalexin Plus Trimethoprim-Sulfamethoxazole Versus Cephalexin Alone for Treatment of Uncomplicated Cellulitis: A Randomized Controlled Trial. Clinical Infectious Diseases 2013;56(12):1754-62. [PMID 23457080]

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