Retrospective cohort study of oral switch versus intravenous antibiotics for carbapenem-resistant enterobacterales and Pseudomonas aeruginosa infections on hospital discharge.

OBJECTIVES

To compare outcomes of oral switch versus intravenous antibiotics for the treatment of carbapenem-resistant Enterobacterales (CRE) and Pseudomonas aeruginosa (CRPA) infections at hospital discharge.

METHODS

Institutional review board approved, retrospective cohort of adults infected with CRE or CRPA who received oral switch or intravenous antibiotics at hospital discharge from January 1, 2017, to April 30, 2024. Patients were included if they were eligible for oral switch and infected with an isolate susceptible to one or more oral antibiotics; non-bacteremic urinary tract infections were excluded. The primary outcome was 30-day clinical success at end of therapy, defined as lack of infection-related hospitalization, infection-related recurrence, or change/escalation of therapy. Secondary outcomes included hospital length of stay (LOS) and 30-day all-cause mortality from end of therapy.

RESULTS

Fifty-five patients were included; 51% received oral switch antibiotics and 49% received intravenous antibiotics. Thirty-three percent of patients had CRE, 67% had CRPA, and 38% of cultures were polymicrobial. The most common infection types were pneumonia (33%), intra-abdominal (26%), and bone/joint (22%). The median (interquartile range [IQR]) duration of outpatient therapy was 12 (6-25) days versus 20 (4-34) days for the oral switch and intravenous antibiotic groups, respectively (p = 0.341). 30-day clinical success was 61% in the oral switch and 48% in the intravenous antibiotic groups (p = 0.349); the median (IQR) hospital LOS for the oral switch and intravenous antibiotic groups was 14 (9-25) days and 16 (9-49) days, respectively (p = 0.165); 30-day mortality was 4% in the oral switch group and 15% in the intravenous antibiotic group (p = 0.193).

CONCLUSION

A limited sample of patients who received oral switch antibiotics had similar outcomes to intravenous outpatient treatment of carbapenem-resistant organisms, with a shorter hospital LOS.