Advice on Deciding Between Oral, Intravenous Antibiotics in Skin Infections

When are oral antibiotics appropriate for patients with non-purulent skin and soft-tissue infections? A new study provides some guidance on which cases require intravenous antibiotics vs. those which can safety go the oral route. Here are the details.

OTTAWA, ONTARIO – How often are the oral antibiotic prescriptions that pharmacists fill for non-purulent skin and soft tissue infections (SSTI) actually inappropriate?

That is the question raised by a recent study in Academic Emergency Medicine questioning whether intravenous antibiotics should be used in more cases presenting to the hospital emergency department.

https://onlinelibrary.wiley.com/doi/full/10.1111/acem.13492

University of Ottawa-led researchers conducted a health records review of adults with non-purulent SSTIs treated at two tertiary care EDs. Included were 500 patients, 55.8% male and with a mean age of 64. A fourth of the patients had been diagnosed with diabetes, the report notes.

The goal was to determine how often oral antibiotic treatment failed. Failure was defined as either/or hospitalization, change in class of oral antibiotic or switch to intravenous therapy after a minimum of 48 hours of oral therapy due to worsening infection.

Results indicate that, Of 288 patients who had received a minimum of 48 hours of oral antibiotics, treatment failure occurred in 85, 29.5%. Independently associated with oral antibiotic treatment failure were:

• tachypnea at triage (odds ratio [OR] = 6.31, 95% confidence interval [CI] = 1.80 to 22.08),
• chronic ulcers (OR = 4.90, 95% CI = 1.68–14.27),
• history of methicillin-resistant Staphylococcus aureus (MRSA) colonization or infection (OR = 4.83, 95% CI = 1.51 to 15.44), and
• cellulitis in the past 12 months (OR = 2.23, 95% CI = 1.01 to 4.96).

Noting that their study was the first to evaluate predictors of oral antibiotic treatment failure for non-purulent SSTIs treated in the ED, study authors recommended, "Emergency physicians should consider these risk factors when deciding on oral versus intravenous antimicrobial therapy for outpatient management of non-purulent SSTIs."

In 2014, the Infectious Diseases Society of America (IDSA) updated its guidelines to recommend oral dicloxacillin, cephalexin, amoxicillin/clavulanate or clindamycin for mild infection.

Intravenous nafcillin or oxacillin, ceftriaxone, cefazolin or clindamycin are advised for moderate infection, while the IDSA urges use of vancomycin plus piperacillin/tazobactam for severe infection.