Staphylococcus aureus Antimicrobial Resistance and Prescribing Practices for Skin and Soft Tissue Infections Presenting to United States Emergency Departments

Recent retrospective studies of inpatients with skin and soft tissue infections (SSTI) suggest increasing antimicrobial resistance (AMR) among staphylococcal isolates. This multicenter study evaluated AMR and prescribing practices among patients presenting from the community to emergency departments (ED) with SSTIs.

We conducted a prospective observational study of patients of any age with a purulent SSTI ≤7 days duration presenting at 12 U.S. EDs Aug 2024-Apr 2025. We excluded patients with perirectal abscess, psychiatric hold, unavailable culture specimen, or prior enrollment <30 days. We obtained clinical data through questionnaires, medical record review, and 30-day telephone follow-up. Wound cultures were obtained and S. aureus isolates underwent antimicrobial susceptibility testing.

Among 569 enrolled, median age was 43 years (IQR 30-56); 61.3% were male. SSTIs included abscesses 353 (62.0%), infected wounds 149 (26.2%), and surgical site infections 67 (11.8%). Surgical drainage was performed in 338 (59.5%), and 243 (42.7%) were hospitalized. Of 568 available specimens, 304 (53.5%) grew S. aureus, 130 (22.9%) had no growth/normal microbiota, and 79 (14%) grew beta-hemolytic Streptococcus species. Of 301 S. aureus isolates, 170 (56.7 %) demonstrated resistance to oxacillin (MRSA), 67 (23%) levofloxacin, 27 (9.0%) tetracycline, 32 (11%) clindamycin, 2 (0.7%) trimethoprim-sulfamethoxazole (TMP-SMX), 1 (0.4%) omadacycline, and 1 (0.4%) doxycycline. Among 163 participants with S. aureus discharged home from ED, 145 (89.0%) received antibiotics, of whom 141 (97.2%) received empiric therapy with in vitro activity against their isolate. TMP-SMX and doxycycline were the most commonly prescribed (54 [38%] and 68 [47%], respectively) and all isolates of treated participants were susceptible to their treatment agents.

S. aureus, predominantly MRSA, remains the primary cause of community-presenting US ED patents with purulent SSTIs, with low resistance to commonly used oral agents. Empiric antibiotic choices, especially TMP-SMX and doxycycline, were highly concordant with in vitro susceptibilities of isolated pathogens.