Antimicrobial Stewardship in a Hematological Malignancy Unit: Carbapenem Reduction and Decreased Vancomycin-Resistant Enterococcus Infection

Abstract Background Antibiotic stewardship is challenging in hematological malignancy patients. Methods We performed a quasiexperimental implementation study of 2 antimicrobial stewardship interventions in a hematological malignancy unit: monthly antibiotic cycling for febrile neutropenia that included cefepime (± metronidazole) and piperacillin-tazobactam and a clinical prediction rule to guide anti-vancomycin-resistant Enterococcus faecium (VRE) therapy. We used interrupted time-series analysis to compare antibiotic use and logistic regression in order to adjust observed unit-level changes in resistant infections by background community rates. Results A total of 2434 admissions spanning 3 years pre- and 2 years postimplementation were included. Unadjusted carbapenem and daptomycin use decreased significantly. In interrupted time-series analysis, carbapenem use decreased by −230 days of therapy (DOT)/1000 patient-days (95% confidence interval [CI], −290 to −180; P < .001). Both VRE colonization (odds ratio [OR], 0.64; 95% CI, 0.51 to 0.81; P < .001) and infection (OR, 0.41; 95% CI, 0.2 to 0.9; P = .02) decreased after implementation. This shift may have had a greater effect on daptomycin prescribing (−160 DOT/1000 patient-days; 95% CI, −200 to −120; P < .001) than did the VRE clinical prediction score (−30 DOT/1000 patient-days; 95% CI, −50 to 0; P = .08). Also, 46.2% of Pseudomonas aeruginosa isolates were carbapenem-resistant preimplementation compared with 25.0% postimplementation (P = .32). Unit-level changes in methicillin-resistant Staphylococcus aureus and extended-spectrum beta lactamase (ESBL) incidence were explained by background community-level trends, while changes in AmpC ESBL and VRE appeared to be independent. The program was not associated with increased mortality. Conclusions An antibiotic cycling-based strategy for febrile neutropenia effectively reduced carbapenem use, which may have resulted in decreased VRE colonization and infection and perhaps, in turn, decreased daptomycin prescribing. Antimicrobial stewardship is challenging in patients with hematological malignancy. After implementation of 2 stewardship initiatives, monthly gram-negative antibiotic cycling and a vancomycin-resistant Enterococcus faecium (VRE) prediction tool, carbapenem use was significantly reduced. This may have resulted in a secondary benefit of reducing VRE colonization and infection and subsequent daptomycin use.