Analyzing Antibiotic Prescribing Patterns Following Blood Culture Diagnostics in an Emergency Department Setting: A Monocentric Retrospective Study

Introduction: Blood culture (BC) results serve as a determinant in shaping both diagnostic and therapeutic strategies for the effective management of (systemic bloodstream) infections. Despite its crucial role, there exists a limited body of literature scrutinizing the BC diagnostics and antibiotic prescriptions, particularly within the Emergency Departments (ED).

Goals: In this study, we explore the landscape of BC diagnostics and antibiotic prescribing in the ED.

Materials & Methods: Adult patients admitted to the ED at the University Medical Center Goettingen between June and July 2023 and with at least one pair of BCs within the first 48 hours were included. The outcome was defined as blood culture positivity (BCP) in at least one BC.

Results: In total 413 patients were included. Approximately 80% of patients had ≥2 BCs collected and 20% had only one BC. The BCP rate was 21% (n=88). The three most common pathogens were Escherichia coli (20%), Staphylococcus aureus (7%) and Klebsiella oxytoca (7%). The most prevalent potential contaminants were Staphylococcus hominis, Staphylococcus epidermidis, and Cutibacterium acnes (35%). Overall, 69% of patients (n=286) in whom BC was made underwent antibiotic treatment in the ED (28% received ≥2 antibiotics). Of these, 25% had a positive BC (n=74). The top 5 antibiotics prescribed were: piperacillin/tazobactam, ceftriaxone, ampicillin/sulbactam, azithromycin, and metronidazole.

Summary: The results of our study aim to contribute valuable insights into optimizing BC diagnostics and antibiotic stewardship protocols, enhancing rational prescriptions and antibiotic interventions for bloodstream infections in the EDs.