Decrease in vancomycin-resistant Enterococcus colonization associated with a reduction in carbapenem use as empiric therapy for febrile neutropenia in patients with acute leukemia.

ABSTRACT

OBJECTIVE: To compare the effects of empiric carbapenems versus cycling cefepime and piperacillin/tazobactam on the rates of vancomycin-resistant Enterococcus (VRE) colonization, bloodstream infections, and outcomes of patients admitted with acute leukemia. DESIGN: Retrospective clinical study with VRE molecular strain typing and gastrointestinal microbiome comparison. SETTING: A regional referral center for acute leukemia. PATIENTS 342 consecutive patients admitted with newly diagnosed acute leukemia. METHODS: In September 2015, we changed our empiric antibiotic of choice for neutropenic fever from a carbapenem to the cycling regimen. We studied 214 consecutive patients during the carbapenem period and 128 during the cycling period. Surveillance for VRE stool colonization was conducted weekly. Representative stool samples were analyzed for VRE MLST types and changes in the composition and diversity of the fecal microbiota. RESULTS: The change in empiric antibiotics was associated with a significant decrease in VRE colonization (hazard ratio [HR], 0.35; 95% confidence interval [CI], 0.27-0.66), a switch in the dominant VRE MLST types on the unit, and some modifications in the gastrointestinal microbiome. There were no differences in total gram-positive or gram-negative BSIs. During the carbapenem period, we observed higher absolute numbers of Candida spp and fewer ESBL BSIs, but these did not reach statistical significance. Patients during the carbapenem period had longer lengths of stay and durations of severe neutropenia and 10% higher hospital cost. CONCLUSIONS: Carbapenem-sparing empiric antibiotic regimens may have advantages related to VRE ecology, gastrointestinal dysbiosis, duration of neutropenia, cost and length of stay.