Incidence and outcomes of candida bloodstream infection in solid organ transplant recipients

Importance — Current data on Candida bloodstream infection (candidemia) in solid organ transplant recipients (SOTRs) are constrained by small sample sizes. Further research may inform targeted prevention strategies for early intervention.

Objective — To determine the incidence and outcomes of candidemia in SOTRs.

Design, setting, and participants — A population-based cohort study using a provincewide mycology laboratory dataset of patients aged 18 or more years from Ontario, Canada, who received an organ allograft between January 1, 2011, and September 30, 2022, with follow-up through December 31, 2023, and linked to administrative health care data.

Exposure — Organ transplant.

Main outcomes and measures — The primary outcome was candidemia incidence, estimated using the Kaplan-Meier method, with differences across SOTRs evaluated via the log-rank test. The secondary outcome was all-cause mortality, evaluated using a Cox proportional hazards regression model with candidemia as a time-dependent variable. Analyses were adjusted for relevant covariates.

Results — This study included 10 249 SOTRs (median age, 57 [IQR, 46-64] years; 63.9% male), with kidney transplants representing the majority (59.8%). Candidemia occurred in 135 patients, with Candida albicans as the most frequent species (41.5%), followed by Nakaseomyces (Candida) glabrata (28.1%) and C parapsilosis (11.9%). The cumulative probability of candidemia was 0.87% (95% CI, 0.69%-1.05%) at 1 year, 1.33% (95% CI, 1.09%-1.57%) at 5 years, and 1.67% (95% CI, 1.34%-2.00%) at 10 years. Lung transplant recipients had the highest 10-year cumulative probability at 4.17% (95% CI, 2.96%-5.39%; log-rank P < .001). Median time to candidemia was 34 (IQR, 18.5-354) days in recipients of thoracic allografts and 174 (IQR, 20-836) days in recipients of abdominal allografts. Thirty-day mortality was 39.3% (53 of 135) and 90-day mortality was 47.4% (64 of 135) in patients with candidemia. Candidemia was associated with an increase in mortality (adjusted hazard ratio [AHR], 6.85; 95% CI, 5.59-8.39; P < .001). Fluconazole-susceptible isolates were associated with an increase in mortality (AHR, 8.45; 95% CI, 6.42-11.14; P < .001) as were fluconazole-resistant Candida isolates (AHR, 11.86; 95% CI, 6.13-22.93; P < .001).

Conclusions and relevance — In this cohort study of SOTRs, candidemia was an uncommon complication after organ transplant, with lung transplant recipients at the highest risk. Candidemia was associated with increased mortality. Further research is needed to better identify vulnerable subpopulations and to develop targeted strategies for early intervention.