IDSA Updates Guidelines on Infectious Diseases

The Infectious Diseases Society of America (IDSA) recently updated its 2005 guidelines for the diagnosis and treatment of skin and soft tissue infections (SSTIs) due to the spread of methicillin-resistant Staphylococcus aureus (MRSA). The updated guidelines were published online in Clinical Infectious Diseases [2014; DOI:10.1093/cid/ciu296].

Each year, SSTIs result in >6 million physicians' office visits, with prevalence dramatically increasing due to MRSA. Emergency department visits for SSTIs nearly tripled in a decade, between 1995 (1.2 million) and 2005 (3.4 million). A 10-person panel of SSTI experts developed the updated guidelines, which support the individualized management of SSTIs. Here are some highlights from the guidelines.

A new algorithm addresses purulent versus nonpurulent staphylococcal infections (abscesses, furuncles, carbuncles), helping the clinician to classify the infection as mild, moderate, or severe and to treat appropriately. Fever >100.4°F, leukocytosis, tachycardia, tachypnea, and immunocompromise may signal severe SSTIs. These are the first guidelines to offer extensive recommendations for treating SSTIs in immunocompromised patients, including those with organ transplant.

Even mild or moderate nonpurulent cases typically require antibiotics, sometimes given intravenously. Severe nonpurulent SSTIs, such as necrotizing fasciitis or group A streptococcal (GAS) gangrene, should be surgically debrided.

The updated guidelines offer extensive teaching initiatives to better educate clinicians regarding varied SSTI presentations, ranging from simple infections resolving without antibiotics to potentially fatal conditions mandating prompt, correct diagnosis and treatment. Patient history should include geographic and host factors, as well as animal exposure.

Bacteria causing SSTIs include skin flora or fresh- or saltwater pathogens, entering through open wounds, surgical incisions, animal bites, human bites, or penetrating skin injuries. Interpersonal contact, particularly among sports teams or in gyms, schools, and prisons, may transmit MRSA and other SSTI pathogens. MRSA or other staphylococci cause approximately half of SSTIs.

Studies through 2009 showed that >90% of emergency clinicians still prescribed antibiotics after skin abscess drainage, and 1 in 3 providers failed to provide GAS coverage for simple cellulitis, perhaps due to an unsupported fear of community-acquired MRSA. With appropriate incision and drainage, skin abscesses often heal, so recommendations to withhold antibiotics are unlikely to directly affect patient outcomes.

If the new guidelines are widely accepted and implemented, the authors anticipate improved diagnosis, treatment, antibiotic stewardship, and outcomes.—Kerri Fitzgerald