*Purpose: Solid organ transplant (SOT) recipients are more likely to develop antimicrobial-resistant infections versus the general population, but few transplant centers have developed SOT-specific antibiograms to guide empiric therapy in this population. Here, we describe the development of a kidney transplant (KT)-specific urinary isolate antibiogram and compare antimicrobial susceptibility rates to a hospital-wide urinary isolate antibiogram.

*Methods: This is a single center retrospective study, performed at a 700 bed academic center that provides comprehensive organ transplant services. All adult KT recipients who underwent transplant 1/1/13-12/31/17 were included. The first post-KT urinary isolate per subject was included in the KT-specific antibiogram. All annual hospital-wide antibiograms from the study period were combined into a single summative antibiogram. Antimicrobial susceptibility rates were compared between the KT-specific and the hospital-wide antibiograms using Fisher’s exact test.

*Results: During the study period, 1,071 patients underwent KT. 385 KT recipients had positive urine cultures (35.9%). Escherichia coli was the most common organism isolated (n=109, 28.3%), followed by Klebsiella pneumoniae (n=68, 17.7%). E. coli isolates from KT recipients were statistically significantly less susceptible to ampicillin (33.3% vs 48.5%, P=0.002), cefazolin (59.8% vs 74.8%, P=0.004), piperacillin-tazobactam (92.0% vs 96.4%, P=0.045), tobramycin (11.1% vs 89.8%, P<0.0001), and trimethoprim-sulfamethoxazole (36.7% vs 75.3%, P<0.0001) compared to 2,660 isolates hospital-wide. K. pneumoniae isolates from KT recipients were also statistically significantly less susceptible to cefazolin (69.2% vs 82.0%, P=0.028), tobramycin (16.7% vs 90.7%, P<0.0001), and trimethoprim-sulfamethoxazole (47.1% vs 85.0%, P<0.0001), as well as amikacin (66.7% vs 98.8%, P=0.0004), compared to 1,010 isolates hospital-wide.

*Conclusions: This study demonstrates significantly higher rates of antimicrobial resistance in urinary isolates of KT recipients compared to the general hospital population. This study relied solely on microbiologic data; a positive urine culture was used as a surrogate for urinary tract infection (UTI). One cannot infer that each positive urine culture is demonstrative of a clinically relevant UTI, but rather it can demonstrate the “worst case scenario” of resistant organisms which may colonize the patient. Inadequate empiric treatment of infection in SOT recipients is associated with poorer outcomes, such as increased rates of infection recurrence and mortality. SOT-specific antibiograms can assist providers in predicting adequate empiric therapy, which may lead to improved outcomes.

« Back to 2020 American Transplant Congress