P-1474. Antimicrobial Therapy of <i>Enterococcus faecium</i> Bacteremia: A Retrospective Comparison of Outcomes with IV or Oral Antimicrobial Therapy

Abstract Background Enterococci are one of the most common causes of hospital-associated infections. Enterococcus faecium has particularly been associated with prolonged hospitalizations, frequent comorbid conditions, and high rates of mortality. Methods This is a single-center, retrospective study of antibiotic use and outcomes in adult patients with Enterococcus faecium bacteremia from 2018-2022. Results 111 patients had monomicrobial E. faecium bacteremia. The median age was 58 years (IQR 46.5, 68.5 years) and 63/111 (57%) of patients were male. Of isolates that underwent susceptibility testing, 15/109 (14%) were susceptible to ampicillin and 33/109 (30%) were susceptible to vancomycin. The median length of hospitalization for E. faecium bacteremia was significantly longer than for E. faecalis bacteremia (26 days versus 12 days, p&amp;lt; 0.01). Nearly a third of patients with E. faecium bacteremia died or were discharged to hospice during their index hospitalization (34/111, 31%) compared with 24/136 (18%) of patients with E. faecalis bacteremia (p=0.017). The 30-, 60-, and 90-day mortality was 25%, 32%, and 36% for E. faecium bacteremia and 15%, 18%, and 25% for E. faecalis bacteremia. Most patients with E. faecium bacteremia were treated with only intravenous (IV) antibiotics. Of the patients who received E. faecium directed antimicrobial therapy, 35/106 (33%) received a combination of IV and oral antimicrobials. Patients treated with IV therapy alone had a higher rate of mortality at 30, 60, and 90 days than those treated with a combination of oral and IV therapy (IV versus oral: 34% versus 3% 30-day mortality, 39% versus 15% 60-day mortality, and 44% versus 18% 90-day mortality). E. faecium bacteremia recurrence within 5 to 90 days occurred in 15/111 (14%) patients. Of these patients, 10/15 received only IV antimicrobials, whereas 5/15 received some oral therapy. Conclusion E. faecium bacteremia was associated with prolonged hospitalizations and high rates of mortality when compared with E. faecalis bacteremia. Patients treated with a combination of oral and IV therapy did not have an increased risk of mortality or bacteremia recurrence. The difference in outcomes is likely related to severity of disease and comorbid factors affecting clinicians’ antimicrobial choice. Disclosures All Authors: No reported disclosures