Molecular Epidemiology of Extended-Spectrum Cephalosporin-Resistant Enterobacterales Bloodstream Infections Among Solid Organ Transplant Recipients

J. A. Anesi¹, E. Lautenbach¹, P. D. Tamma², K. A. Thom³, K. Alby⁴, E. A. Blumberg¹, W. Bilker¹, J. Omorogbe¹, P. Tolomeo¹, A. Werzen³, J. Han⁵

¹University of Pennsylvania, Philadelphia, PA, ²Johns Hopkins University, Baltimore, MD, ³University of Maryland, Baltimore, MD, ⁴University of North Carolina, Chapel Hill, NC, ⁵GlaxoSmithKline, Rockville, MD

Meeting: 2021 American Transplant Congress

Abstract number: 225

Keywords: Bacterial infection, Infection

Topic: Clinical Science » Infectious Disease » All Infections (Excluding Kidney & Viral Hepatitis)

Session Information

Session Name: Infectious Disease Poutpouri

Session Type: Rapid Fire Oral Abstract

Date: Monday, June 7, 2021

Session Time: 4:30pm-5:30pm

Presentation Time: 4:30pm-4:35pm

Location: Virtual

*Purpose: Solid organ transplant recipients (SOTR) have been significantly impacted by the emergence of multidrug-resistant bacteria, including extended-spectrum cephalosporin-resistant (ESC-R) Enterobacterales (EB). We determined the molecular epidemiology of ESC-R EB bloodstream infections (BSI) among SOTR.

*Methods: A retrospective cohort study was conducted at the Hospital of the University of Pennsylvania, the University of Maryland Medical Center, and The Johns Hopkins Hospital. All SOTR presenting with an ESC-R EB BSI, defined by ceftriaxone minimum inhibitory concentrations ≥1 µg/mL, between 1/1/2010 and 7/1/2018 were included. Real-time polymerase chain reaction was performed to detect beta-lactamase genes among these EB isolates. Multivariable logistic regression was performed to identify risk factors for CTX-M-mediated resistance.

*Results: A total of 286 SOTR with ESC-R EB BSI were included, of which 108 (38%) were in the first-year post-transplant, and of which 175 (61%) were kidney, 71 (25%) were liver, 28 (10%) were heart, 23 (8%) were lung, and 9 (3%) were pancreas recipients. Among the ESC-R EB isolates, 144 (50%) were found to harbor a CTX-M gene, 128 (45%) a SHV gene, 45 (16%) a TEM gene, and 5 (2%) a CMY gene (not mutually exclusive). There were 110 (38%) EB isolates that had more than one beta-lactamase gene identified, while 88 (31%) had no beta-lactamase genes detected. On multivariable analysis, CTX-M-mediated resistance was significantly more likely among those SOTR with a history of chronic kidney disease (aOR 3.28, 95% CI 1.20-8.99, P=0.02), but was significantly less likely to be observed among those on chronic sirolimus immunosuppression (aOR 0.35, 95% CI 0.13-0.94, P=0.04) and those with a history of prior EB colonization or infection of the respiratory tract (aOR 0.33, 95% CI 0.14-0.79, P=0.01). There were no significant differences in the beta-lactamase genes observed based on other baseline factors, including organ transplant type, prior antibiotic exposures, or year of BSI.

*Conclusions: Fifty percent of ESC-R EB causing BSI among SOTR harbored CTX-M beta-lactamase genes. SOTR with a history of chronic kidney disease were particularly likely to have CTX-M-mediated resistance. Future studies are needed to evaluate the performance of rapid diagnostics aimed at detecting CTX-M genes among SOTR with EB BSI.

To cite this abstract in AMA style:

Anesi JA, Lautenbach E, Tamma PD, Thom KA, Alby K, Blumberg EA, Bilker W, Omorogbe J, Tolomeo P, Werzen A, Han J. Molecular Epidemiology of Extended-Spectrum Cephalosporin-Resistant Enterobacterales Bloodstream Infections Among Solid Organ Transplant Recipients [abstract]. Am J Transplant. 2021; 21 (suppl 3). https://atcmeetingabstracts.com/abstract/molecular-epidemiology-of-extended-spectrum-cephalosporin-resistant-enterobacterales-bloodstream-infections-among-solid-organ-transplant-recipients/. Accessed May 9, 2025.

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