Infective Endocarditis and Antimicrobial Timing: A Case for Delay?

Elisavet Stavropoulou; Bruno Ledergerber; Nicolas Fourré; Virgile Zimmermann; Jana Epprecht; Nicoleta Ianculescu; Pierre Monney; Georgios Tzimas; Michelle Frank; Laurence Senn; Lars Niclauss; Matthias Kirsch; Mathias Van Hemelrijck; Omer Dzemali; Benoit Guery; Barbara Hasse; Matthaios Papadimitriou-Olivgeris

doi:10.1093/ofid/ofaf628

Infective Endocarditis and Antimicrobial Timing: A Case for Delay?

Open Forum Infect Dis. 2025 Oct 7;12(10):ofaf628. doi: 10.1093/ofid/ofaf628. eCollection 2025 Oct.

Authors

Elisavet Stavropoulou¹, Bruno Ledergerber², Nicolas Fourré¹, Virgile Zimmermann¹, Jana Epprecht², Nicoleta Ianculescu³, Pierre Monney³, Georgios Tzimas³, Michelle Frank⁴, Laurence Senn^{1

5}, Lars Niclauss⁶, Matthias Kirsch⁶, Mathias Van Hemelrijck⁷, Omer Dzemali^{7

8

9}, Benoit Guery¹, Barbara Hasse², Matthaios Papadimitriou-Olivgeris¹⁰

Affiliations

¹ Infectious Diseases Service, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
² Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich and University of Zurich, Zurich, Switzerland.
³ Department of Cardiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
⁴ Department of Cardiology, University Hospital Zurich and University of Zurich, Zurich, Switzerland.
⁵ Infection Prevention and Control Unit, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
⁶ Department of Cardiac Surgery, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
⁷ Department of Cardiac Surgery, University Hospital Zurich and University of Zurich, Zurich, Switzerland.
⁸ Department of Cardiac Surgery, City Hospital of Zurich-Triemli, Zurich, Switzerland.
⁹ Center for Experimental and Translational Cardiology, University of Zurich, Zurich, Switzerland.
¹⁰ Infectious Diseases Service, Hospital of Valais and Institut Central des Hôpitaux, Sion, Switzerland.

Abstract

Background: In patients with suspected infective endocarditis (IE), current guidelines recommend prompt initiation of empiric antimicrobial treatment after obtaining blood cultures. However, the clinical benefit of immediate treatment in hemodynamically stable patients remains uncertain. This study assessed the impact of deferring antimicrobial treatment in patients with suspected IE.

Methods: We conducted a multicenter cohort study of adult patients with bacteremia and clinical suspicion of IE from 2 university hospitals (2015-24). Patients presenting with sepsis, intensive care unit admission, neutropenia, or a clearly identifiably focus other than IE were excluded. All cases were adjudicated by a dedicated Endocarditis Team as either IE or not IE. The primary outcome for all episodes was 30-day mortality; for confirmed IE cases, the composite outcome included 30-day mortality, new embolic events, or new bone and joint infection.

Results: Among 1230 episodes, empirical antimicrobial treatment was initiated immediately (Group I) after blood culture collection in 675 episodes (55%) and deferred until preliminary blood culture results (Group D) in 555 episodes (45%). Thirty-day mortality was 5% (59 episodes), with no difference between Groups I and D (5% vs 5%; P = .894). Of 597 confirmed IE episodes (49%) IE, 327 (55%) were in Group I and 270 (45%) in Group D. The composite primary endpoint occurred in 157 episodes (26%), with no difference between groups (28% vs 24%; P = .304).

Conclusions: In clinically stable patients with suspected IE, deferring antimicrobial treatment until available blood culture results was not associated with worse clinical outcomes.

Keywords: Staphylococcus aureus; antimicrobial treatment; bloodstream infection; empiric treatment; infective endocarditis.