Association between unrecognized donor bloodstream infection and outcomes in solid organ transplant recipients: a...

The study aimed to evaluate the association between unrecognized donor bloodstream infection (BSI), unknown at organ procurement, and recipient 1-year survival. Incidence of donor-derived infections (DDIs) was assessed as a secondary outcome.

Prospective study including all solid organ transplant recipients conducted at Mediterranean Institute for Transplantation and Advanced Specialized Therapy from 2016 to 2022. Recipients from donors with unrecognized BSI were compared with unexposed recipients. Data were prospectively collected within our active surveillance system, implemented to promptly recognize donor BSI and manage recipients to mitigate unexpected DDIs. The association between donor unrecognized BSI and recipient 1-year survival was evaluated using survival curves adjusted for confounders at multivariable analysis with Cox proportional-hazard models.

A total of 968 solid organ transplant recipients were included (472 livers, 330 kidneys, 86 hearts, and 80 lungs); 136 (14%) recipients had a donor with unrecognized BSI. Among 150 blood culture isolates, 67% (100 of 150) were susceptible, whereas 33% (50 of 150) were multidrug-resistant (MDR). Ninety skin contaminants were excluded from analysis. Carbapenem-resistant Enterobacterales (CRE) were the most common MDR microorganisms (20 of 50, 40%). One-year survival probability was comparable between recipients from donors with and without unrecognized BSI (adjusted hazard ratio, 1.32; 95% CI, 0.86-2.03, p 0.12). However, after stratification by microorganism type, recipients from donors with unrecognized MDR BSI had lower 1-year survival probability compared with recipients from blood culture-negative donors (adjusted hazard ratio, 2.29; 95% CI, 1.08-4.87, p 0.04). Five DDIs caused by CRE occurred, all in liver recipients. CRE transmission rate was 25% (5 of 20). These cases were promptly treated with no deaths attributable to the infection.

In our cohort, 14% of recipients received organs from donors with BSI but only five CRE DDIs were observed. Receiving organs from donors with unrecognized MDR BSI may adversely affect recipient outcomes; further studies are needed to determine whether newer antimicrobial agents can mitigate this risk.