Donor-derived bartonellosis in Solid Organ Transplant recipients from unhoused donors in Alberta.

Bartonella quintana (BQ) infection is rarely described to be transmitted through solid organ transplant (SOT). We report a cluster of donor-derived BQ infection and attack rate from Bartonella seropositive donors. Retrospective study of SOT recipients that received an organ from an unhoused deceased donor (UDD) in Alberta in 2022-2023. Serology testing for Bartonella was performed with Indirect Immunofluorescent Assay from UDD and recipients from UDD with positive serology. Titers ≥1:64 considered positive. During the study period, 31/32 UDD had IgG to Bartonella (20 negative, 11 positives (D+) for B.quintana and/or B.henselae). 32 organs were transplanted from 11D+. Six SOT recipients developed bartonellosis secondary to BQ (4 SOT received organs from 3 D+, and 2 SOT from 1 UDD with no stored sample for testing). The attack rate for clinical disease from D+ was of 12.5% (4/32). The main presentation: skin nodules/papules (median 5.5 months) with bacillary angiomatosis in 4/6. Bartonella serology was positive in 5/6 (initially negative in 2), blood BQ-qPCR in two. None had visceral involvement. All donors had history of substance use. This outbreak of bartonellosis reinforces the potential for unexpected donor transmitted infections. Clinicians should be aware of high transmission of BQ through transplant from infected UDD.