Category: Professional Posters
Purpose: Step-down from intravenous to oral antimicrobial therapy in Enterobacteriaceae bloodstream infections can reduce costs, length of stay, and complications from intravenous therapy. This study was designed to assess the efficacy of various oral antibiotic step-down regimens in hospitalized patients with Enterobacteriaceae bloodstream infections from a confirmed urinary source. Secondarily, this study also aimed to assess unwanted adverse effects from antimicrobial therapy such as Clostridiodes difficile infections and development of antibiotic resistance.
Methods: This study was a retrospective electronic medical record review approved by the Institutional Review Board. Hospitalized patients 19 years and older from October 1, 2017 through September 30, 2018 were assessed for inclusion with a laboratory report of blood and urine cultures positive for the same Enterobacteriaceae species or a positive blood culture with an Enterobacteriaceae species plus confirmed diagnosis of pyelonephritis (fever/flank pain or radiographic imaging). In addition, transition from intravenous to oral antibiotics was required for inclusion. Patients were excluded if any of the following applied: polymicrobial infection(s), neutropenia, isolation of extended spectrum beta-lactamase producing organisms, or pregnancy. Data collection included patient demographics, comorbidities, culture and susceptibility data, antibiotic allergies, therapy administered, planned duration, hospital length of stay, and intensive care unit length of stay. This study evaluated outcomes in three patient groups based on oral antimicrobial regimen prescribed (fluoroquinolone, beta-lactam, or other). The primary outcome was identification of treatment failure, which was defined as repeated healthcare encounter(s) within 30 days of discharge with bacteremia of the same species. Secondary outcomes assessed were development of Clostridiodes difficile infection and/or development of antimicrobial resistance.
Results: A total of 129 patients met inclusion criteria for our study. Fluoroquinolones were prescribed most frequently (n=76), followed by beta lactams (n=48) and other oral antibiotics which included doxycycline and sulfamethoxazole/trimethoprim (n=5). CT confirmed pyelonephritis was seen in 14 % of patients while 13.2% exhibited documented urinary obstruction. Escherichia coli was the primary pathogen isolated (76%) followed by Klebsiella pneumoniae (12%). Mean oral antibiotic length of therapy was 10.5 ± 4.3 days while average IV therapy duration was 3.8 ± 2.3 days. Total average length of antibiotic therapy was 14.2 ± 4.7 days. There were no differences between the three groups in regards to duration of therapy. The primary outcome of treatment failure was identified in two patients (fluoroquinolone, n=1; beta lactam, n=1; other, n=0). Differences in treatment failure were not significant among the three oral antibiotic groups (p = 0.876). Secondary outcomes assessed included one (20%) Clostridiodes difficile infection in the other group versus none in the fluoroquinolone and beta lactam groups (p = 0.035). In addition, development of a resistant pathogen was identified in 8 patients (fluoroquinolone, n=5; beta lactam, n=3; other, n=0), however this was not statistically significant (p = 0.719).
Conclusion: This study supports similar efficacy of oral beta lactam and fluoroquinolone regimens for step-down therapy in Enterobacteriaceae bacteremias from a urinary source. While the development of resistant organisms and Clostridiodes difficile infection were similar among these two groups, the patient population and outcome rates were small. Future large scale studies are required to confirm the appropriateness of fluoroquinolone sparing oral step-down regimens for Enterobacteriaceae bloodstream infections from a urinary source.