PSHP 2026 Residency Conference

Purpose: The purpose of this study was to compare outcomes in obese patients with aerobic gram-negative rod (GNR) bacteremia treated with either high- or low-bioavailability antibiotics for oral stepdown therapy.
Methods: This retrospective single‑center cohort study compared clinical outcomes in adult patients with a body mass index ≥ 30 kg/m2 who received oral stepdown with either a high‑bioavailability (sulfamethoxazole-trimethoprim, fluoroquinolones) or low‑bioavailability (beta-lactams) agent for uncomplicated GNR bacteremia. All patient and clinical data were obtained from the electronic health record by automated reports and manual review, then compiled in Excel. Patients were identified from Lehigh Valley Health Network Cedar Crest, Muhlenberg, Hecktown Oaks, Hazleton, Schuylkill, Pocono, and Carbon campuses. The primary outcome was 30-day bacteremia recurrence, which was analyzed descriptively due to limited events. Secondary outcomes were 90-day bacteremia recurrence, 30- and 90-day all-cause mortality, length of stay, and 30- and 90-day all-cause readmission, which were analyzed using both descriptive and inferential statistics.
Results: A total of 203 individuals were included, with 127 in the high‑bioavailability group and 76 in the low‑bioavailability group. Urinary sources accounted for 75% of infections, E. coli for 66% of pathogens, and most patients received 3 days of IV therapy followed by 7 days of oral step‑down, typically with a fluoroquinolone (55%). No bacteremia recurrences occurred at 30 days, and only one recurrence was observed in the low‑bioavailability group at 90 days. All secondary outcomes were similar between groups, apart from all‑cause 30‑day readmission, which was higher in the high‑bioavailability step‑down group.
Conclusion: One 90‑day bacteremia recurrence occurred in a patient receiving oral cefpodoxime 100 mg twice daily, a notably low dose. The findings of this study suggest that oral stepdown for uncomplicated GNR bacteremia in obesity may be more nuanced than distinguishing between the bioavailability of agents. Clinical factors and real‑world dosing practices may influence outcomes, extending beyond what oral bioavailability alone can predict.