What Is the Best Empiric Therapy for Community-Acquired Cellulitis?

Key Points

  • Due to the significant increase in MRSA prevalence as a cause of community-acquired cellulitis, prescribed antibiotics must provide coverage for this organism.
  • For outpatients, trimethoprim/sulfamethoxazole (possibly in combination with a beta-lactam antibiotic), clindamycin, and linezolid can be used to treat community-acquired cellulitis.
  • For patients who require parenteral antibiotics, vancomycin, daptomycin, tigecycline, and linezolid have a demonstrated effectiveness against MRSA infections.
  • For patients who present with an abscess caused by CA-MRSA, an incision and drainage procedure is essential.

Additional Reading

  • Daum RS. Clinical practice. Skin and soft-tissue infections caused by methicillin-resistant Staphylococcus aureus. N Engl J Med. 2007;357(4):380-390.
  • Moran GJ, Krishnadasan A, Gorwitz RJ, et al. Methicillin-resistant S. aureus infections among patients in the emergency department. N Engl J Med. 2006;355(7):666-674.

Editor’s note: This month’s KCQ first appeared in July 2009, and since that time it has been one of our website’s most-read articles, generating 23,000-plus pageviews.

Case

A previously healthy 55-year-old white female presents to the ED with a three-day history of pain and erythema in her right hand. Examination reveals fluctuance as well. She is diagnosed with an abscess with surrounding cellulitis. The abscess is incised, drained, and cultured, and she is sent home on oral trimethoprim/sulfamethoxazole. The following day, her cellulitis has worsened. She is hospitalized and commenced on intravenous vancomycin. What is the best empiric therapy for community-acquired cellulitis?

The diagnosis of cellulitis is based primarily on clinical manifestations. Due to low diagnostic yields, blood cultures, needle aspiration, or punch biopsy specimens usually are not helpful in the setting of simple cellulitis.

Background

Cellulitis is defined as a skin and soft-tissue infection (SSTI), which develops as a result of bacterial entry via breaches in the skin barrier. Typically, it involves the dermis and subcutaneous tissue and is associated with local tenderness, erythema, swelling and fever. Cellulitis usually affects the lower extremities, but it can affect other locations, resulting in diagnoses such as periorbital, abdominal wall, buccal, and perianal cellulitis.1,2

Gram-positive organisms, especially Staphylococcus aureus and beta hemolytic streptococci, are the most common causes of cellulitis. Although it is less common, cellulitis can be caused by gram-negative organisms. The recent significant increase in the prevalence of SSTIs due to community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has led to changes in the selection of antibiotics that were most commonly utilized to empirically treat cellulitis.

The diagnosis of cellulitis is based primarily on clinical manifestations. Due to low diagnostic yields, blood cultures, needle aspiration, or punch biopsy specimens usually are not helpful in the setting of simple cellulitis.3 Therefore, antibiotic therapy is almost universally started empirically. Starting appropriate initial antibiotic therapy improves patient outcomes by reducing mortality rates, length of stay, and inpatient costs.4

Leave a Reply

Your email address will not be published. Required fields are marked *