Anthony Montedonico, Sara Dionne
Background: Bloodstream infections (BSIs) identified in solid organ deceased donors present important considerations for recipient safety and organ utilization. While transmission from bacteremic donors is uncommon when appropriately managed, characterization of donor bloodstream pathogens remains critical for risk assessment and communication between procurement organizations and transplant centers. This study evaluated blood culture results from over eleven thousand deceased organ donors to determine overall positivity patterns, the distribution of commonly isolated organisms, and the occurrence of rare but potentially virulent pathogens.
Methods: A retrospective review of blood culture results obtained during donor evaluation among solid organ deceased donors was conducted. Blood culture bottles were incubated in BD BacTec or BacT instruments (Becton Dickinson, Franklin Lakes, NJ. BioMérieux, 376 Chemin de l’Orme, 69280 Marcy-l’Étoile, France). Cultures exhibiting turbidity (growth) were subjected to Gram staining and subsequently plated onto a variety of solid media to facilitate organism isolation and identification. Microorganism identification was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MADLI-TOF MS, Bruker; 40 Manning Road, Billerica, MA 01821, USA) and the API ® biochemical identification system (BioMérieux).
All data used in this analysis was obtained from our Laboratory Information Management System and analyzed. Results from 11,856 blood culture specimens tested between 2020-2025 were analyzed. Of these, 486 deceased donors had growth and were included in the detailed analysis.
Results: Gram-positive bacteria accounted for the vast majority of bloodstream isolates (80.8%), followed by Gram-negative organisms(12.2%). The most frequently isolated organisms were typical Gram-positive bloodstream pathogens, consistent with prior reports from donor surveillance studies. The percent positiivity for growth in blood culture samples from 2020-2025 is shown in Figure 1.The most common organisms recovered from blood cultures as well as rarely recovered organisms with potential clinical significance are summarized in Figure 2.
Conclusions: Blood stream infections among solid organ deceased donors are predominantly caused by Gram-positive organisms, with a smaller proportion attributable to Gram-negative and other pathogens. Although uncommon, the identification of rare and potentially virulent organisms highlights the importance of continued microbiologic surveillance and organism-specific risk assessment in deceased donors to reduce transplant infection risk. Timely communication of laboratory findings between procurement organizations and transplant teams remains essential to guide antimicrobial management and ensure safe organ utilization. These findings support ongoing efforts to maximize organ transplantation while minimizing infectious risk to recipients.
