271 - Clinical Outcomes Treating Gram-Negative Bacteremia with Oral Beta-Lactams vs. Trimethoprim-Sulfamethoxazole or Fluoroquinolone Step-Down Therapy

Background: Recently, studies about gram-negative bacteremia have shown that shorter courses and early step-down therapy with oral agents have equivalent outcomes compared to longer courses with intravenous therapy. The question remains, however, as to which oral agents may be most appropriate for oral conversion therapy. At Cone Health it has been common practice to de-escalate to oral beta-lactams due to local susceptibility patterns and safety concerns with fluoroquinolones. This study retrospectively evaluated the 30-day clinical outcomes of patients treated with oral beta-lactams as step-down therapy vs. fluoroquinolones and trimethoprim-sulfamethoxazole (TMP-SMX).

Methods: In this IRB approved, retrospective review, 200 patients with gram-negative rod bacteremia were screened. Sixty-seven patients were excluded due to inpatient mortality (17), transfer to another facility (7), hospice care (6), or receipt of intravenous antibiotics only (37). The most common organism isolated was E. coli at 57% (75/133) and a majority of cases had a genitourinary source, 79/133 (59%). The primary endpoints were 30-day readmission and mortality. Secondary endpoints included total length of antibiotic therapy and length of IV therapy.

Results: Of the 133 patients included, 101 (76%) received an oral beta-lactam and 32 (24%) received either a fluoroquinolone or TMP-SMX. In the beta-lactam group 22/101 (21.8%) were re-admitted within 30-days compared to 5/32 (15.6%) in the fluoroquinolone and TMP-SMX group (p=0.412). Each group had one patient re-admitted due to recurrence of bacteremia. The majority of patients in the beta-lactam group were re-admitted for a non-infectious reason (82%).  Only 1 (1%) patient in the beta-lactam group died within 30 days of discharge compared to 2 (6%) in the fluoroquinolone group (p=0.165). Average total length of therapy in the beta-lactam group was 12.8 days compared to 14 days in the fluoroquinolone and TMP-SMX group (p=0.065). Average length of IV therapy was 3 days in the beta-lactam group and 4 days in the fluoroquinolone and TMP-SMX group (p=0.99).

Conclusion: At our institution, we have not noted any significant difference in 30-day bacteremia recurrence or mortality between those who receive oral beta-lactams or fluoroquinolones/TMP-SMX.