Incidence and Factors of Bacterial Zoonotic Infection in Solid Organ Transplant Recipients

Infection remains a leading cause of morbidity and mortality among solid organ transplant (SOT) recipients, yet zoonotic pathogens as a distinct category remain underrecognized. We investigated the incidence, and risk factors of bacterial zoonotic infections after transplantation using a large multicenter database.

We queried the TriNetX database in from 2014-2024 to identify adult SOT recipients who developed bacterial zoonotic infections. We identified twelve bacterial zoonoses using ICD-10 codes: anthrax, brucellosis, cat scratch disease, glanders, leprosy, leptospirosis, tularemia, parrot fever, pasteurellosis, plague, Q fever, and rat-bite fever.

Sixty-one SOT recipients (0.03%) developed a bacterial zoonotic infection, corresponding to an incidence of 4.87 per 100 000 person-years. The median time from transplantation to infection was 736 days (IQR, 298-1970), with 72.1% of infections occurring more than one year after transplantation. The hospitalization rate was 41.0%, and the 90-day all-cause mortality rate was 6.6%. The three most common infections were Q fever, cat scratch disease, and pasteurellosis. No cases of anthrax, tularemia, plague, or rat-bite fever were identified. Black recipients had a 49% lower risk of bacterial zoonotic infection than White recipients.

Bacterial zoonotic infections were uncommon and occurred predominantly during the late post-transplant period. The lower risk observed among Black recipients reflects differences in animal and environmental exposure that this study could not measure, rather than biological susceptibility. Animal safety counseling should extend beyond the early post-transplant period and continue as part of long-term post-transplant care.