Evaluating the Impact of Long-Term Outpatient Ertapenem (ETP) Vs. Ceftriaxone (CTX) on Clinical Success and Development of Resistance for Documented Enterobacteriaceae Infections

Ceftriaxone and ertapenem are two commonly prescribed outpatient once-daily parenteral antimicrobials with activity against Enterobacteriaceae. However, there is minimal data evaluating the impact of long-term CTX and ETP therapy on development of resistance. Therefore, the goals of this study were to compare the development of resistance, incidence of Clostridium difficile colitis and clinical outcomes. We conducted a single center, retrospective, case cohort study of all adult patients who completed at least 2 weeks of outpatient therapy. A list of adult patients receiving home ETP or CTX between 2011 and 2014 were screened for inclusion. The primary outcome was development of resistance during therapy or within 6 months of completing therapy, and secondary outcomes were mortality, readmission, clinical failure, C. difficileinfection and antibiotic cost. 1,989 patients were screened and 188 were included: 115 patients in the ETP group and 73 in the CTX group. The most common reason for exclusion was lack of documented Enterobacteriaceae infection. Resistance developed in 13 (6.9%) of all patients, but there was no difference in the development of resistance between groups (ETP 7/115 (6.1%) vs. 6/73 (8.2%), P = 0.57). Similar rates of C. difficile colitis occurred between groups: 7 (6.1%) patients receiving ETP and 4 patients receiving CTX. There was no difference in mortality, clinical failure or readmission. The total cost per treatment course per patient was significantly more expensive in the ETP group ($3,604 vs $221, P = <0.001). ETP and CTX demonstrated similar rates of mortality, clinical failure, readmission, and the development of resistance or C. difficile colitis. However, ETP therapy was significantly more expensive, and could be a target for stewardship intervention in select patients receiving home antibiotic therapy. All authors: No reported disclosures.