Epidemiology, Treatment, and Outcomes of Gram-Negative Bacteremia in a Multicenter Cohort of Solid Organ Transplant Recipients.

Introduction: Little is known about the epidemiology and management of gram-negative bloodstream infections (GN-BSIs) in patients after solid organ transplant (SOT). We describe epidemiology, treatment approaches, and outcomes in a subset of patients with SOT from a larger cohort with GN-BSI.

Methods: This was a multicenter, retrospective cohort study that enrolled unique, consecutive adults with GN-BSI hospitalized at any of 24 participating hospitals between January and December 2019.

Results: Of 4581 adults in the overall cohort, 298 (6.5%) were SOT recipients, including kidney (177, 59%), liver (67, 22%), heart (23, 8%), lung (12, 4%), and multiorgan (19, 6%) recipients. The most common organisms were Escherichia coli (45%), Klebsiella pneumoniae (20%), and Pseudomonas aeruginosa (15%). Twenty-two percent of E. coli, Klebsiella spp., or Proteus spp. isolates had extended-spectrum beta-lactamase phenotype. Sixty-six (22%) subjects did not receive active empirical therapy within the first 48 h. Median treatment duration was 15 days (IQR 12-18 days). Transition to oral therapy occurred in 161 (54%) patients at a median of 4 days (IQR 3-7 days). Thirty-one patients (10%) had recurrent bacteremia, and 10% of the cohort died within 90 days.

Discussion: In this large cohort of SOT patients with GN-BSI, durations exceeded 14 days in most patients, while more than half transitioned to oral antibiotics. Approximately 1 in 5 did not receive active empirical antibiotics, highlighting the impact of drug resistance and the importance of access to rapid diagnostic tools in this patient population. Mortality aligned with published estimates from other studies.