Risk Factors for Extended-Spectrum β-lactamase Producing Enterobacterales Bloodstream Infection Among Solid-Organ Transplant Recipients

Background. Approximately 40% of all Enterobacterales (EB) bloodstream infections (BSIs) among solid organ transplant recipients (SOTRs) are due to extended-spectrum beta-lactamase (ESBL)-producing organisms, but risk factors for such infections remain ill defined in this population. We sought to determine the risk factors for ESBL-EB BSIs among SOTRs. Methods. A multicenter case-control study was performed. All SOTRs with an EB BSI at the Hospital of the University of Pennsylvania and University of Maryland Medical Center between 1 January 2007 and 30 June 2018 and at The Johns Hopkins Hospital between 1 January 2005 and 31 December 2015 were included. Cases were those with an ESBL-EB BSI. Controls were those with a non-ESBL-EB BSI. Multivariable logistic regression was performed to determine risk factors for ESBL-EB BSI. Results. There were 988 episodes of EB BSI, of which 395 (40%) were due to an ESBL-EB. On multivariable analysis, the independent risk factors for ESBL-EB BSI included: ESBL-EB on prior culture (aOR, 12.75; 95% CI, 3.23-50.33;P < .001), a corticosteroid-containing immunosuppression regimen (aOR 1.30; 95% CI 1.03-1.65; P = .030), acute rejection treated with corticosteroids (aOR 1.18; 95% CI 1.16-1.19; P < .001), and exposure to third-generation cephalosporins (aOR 1.95; 95% CI 1.48-2.57; P < .001), echinocandins (aOR 1.61; 95% CI 1.08-2.40; P = .020), and trimethoprim-sulfamethoxazole (aOR 1.35; 95% CI 1.10-1.64; P = .003). Conclusions. We identified several novel risk factors that are uniquely important to the SOTR population, including exposure to trimethoprim-sulfamethoxazole and corticosteroid-containing immunosuppressive regimens. Further studies exploring these associations and testing interventions aimed at these modifiable risk factors among SOTRs are needed.

Automated summary

The study identified several risk factors for ESBL-EB BSIs among solid organ transplant recipients, including prior ESBL-EB colonization, corticosteroid-containing immunosuppression regimen, corticosteroid treatment for acute rejection, and exposure to certain antibiotics. Further studies and interventions are needed to explore and address these modifiable risk factors in this population.