Management of Gram-Negative Bloodstream Infections With Oral Antibiotics in Solid Organ Transplant Recipients

Transitioning from intravenous (IV) to oral antibiotics upon clinical stability in gram-negative rod (GNR) bloodstream infections (BSI) in immunocompetent patients is effective, with comparable clinical success rates as IV therapy. Studies have historically excluded solid organ transplant (SOT) recipients. This study aims to describe the clinical outcomes of SOT patients who transitioned to oral therapy to manage GNR BSIs.

This retrospective observational cohort was conducted at the Medical University of South Carolina Health between January 2018 and August 2023. SOT recipients 18 years or older with a positive monomicrobial GNR blood culture and a susceptible oral agent were included. The primary outcome was composite clinical success, encompassing the absence of 30-day mortality, microbiology recurrence, or worsening symptoms without therapy modification.

Two hundred and one patients were screened, with 60 meeting the criteria for analysis. The median age was 58 (IQR 50-67) years, 56.7% were male, and 70% had a kidney transplant. The most common causative pathogen was Escherichia coli (58.3%), and the most frequently used oral agents were fluoroquinolones (90.0%). The primary outcome of clinical success was achieved in 90% of patients. The median duration of total therapy was 14 (IQR 13-14) days, which included 4 (IQR 3-5) days of IV therapy and 10 (IQR 8-11) days of oral therapy.

This study outlines our institutional experience with transitioning to oral therapy to manage gram-negative BSI in SOT recipients, demonstrating high clinical success rates. Larger prospective studies in this population are necessary to substantiate and validate our findings.