1591. Antibiotic Utilization Trends in Veterans Affairs (VA) Patients with Carbapenem Resistant Enterobacteriaceae (CRE) Infections

Background Carbapenem-resistant Enterobacteriaceae (CRE) are classified as an “urgent threat” to public health. Historically, colistin and tigecycline had been considered the drugs of choice for CRE infections, while other agents such as aminoglycosides and carbapenems had been used as adjunctive therapy. However, the FDA approval of ceftazidime-avibactam in 2015, meropenem-vaborbactam in 2017, and plazomicin in 2018 has expanded treatment options. Our purpose was to assess trends in CRE treatment for “new” antibiotics (ceftazidime-avibactam, meropenem-vaborbactam, plazomicin) as compared with other antibiotics with CRE activity. Methods This was a retrospective cohort study describing treatment of CRE blood stream infections (BSI) across 134 VA facilities from 2012-2018. Patients were censored at their first positive blood culture with CRE. Categorical data was assessed with a Fisher’s exact test or chi-square test. Trends test and logistic regression were used to describe changes in CRE treatment over time. Results 724 patients with positive blood cultures for CRE were identified during the study period. Most patients were male (94%), white (32%) or Hispanic (38%), and the mean age was 71.5+11.9. Of those patients that received antibiotics (N=697), 53.4% carbapenems, 40.3% received aminoglycosides, 39.3% received polymyxins, 32.9% penicillins, 32.6% extended spectrum cephalosporins, 26.1% fluoroquinolones, 11.6% ceftazidime/avibactam, and 0.4% ceftolazone/tazobactam. Over the study period, there was decreased utilization of aminoglycosides (P < 0.0026) and colistin (P< 0.002) and increases in extended spectrum cephalosporins (P < 0.001) and ceftazidime/avibactam (P < 0.001). Conclusion Utilization of “older” agents such as aminoglycosides and polymyxins for the treatment of CRE blood stream infections is decreasing in the VA. Treating CRE with ceftazidime/avibactam, a newly approved antibiotic, and extended spectrum cephalosporins are increasing. Disclosures All Authors: No reported disclosures