Retrospective multicenter evaluation of oral step-down versus intravenous carbapenem treatment of extended-spectrum beta-lactamase-producing Escherichia coli urinary tract infections.

OBJECTIVES

This study evaluated whether treatment with oral step-down therapy compared with intravenous carbapenems alone for extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli urinary tract infections (UTIs) impacted patient venous catheter days and clinical outcomes.

METHODS

This multicenter retrospective study at six different hospitals in a large health system included adults (≥ 18 years) admitted for ≥ 24 hours with ≥ 1 documented UTI symptom, a ceftriaxone-resistant Escherichia coli urine culture, and receipt of ≥ 1 dose of meropenem or ertapenem between August 2022 and July 2025. The primary outcome was median venous catheter line days directly associated with antibiotic use inpatient and outpatient. Secondary outcomes included pharmacist antibiotic intervention, incidence of antibiotic-related adverse events, hospital length of stay, duration of therapy, inpatient catheter line days, projected outpatient catheter line days, presence of peripherally inserted central catheter or midline, central line-associated bloodstream infection, and treatment failure (defined as escalation of antibiotics, in-hospital mortality, urgent care/emergency department visit or readmission, or recurrence of symptomatic UTI with ESBL Escherichia coli within 30 days).

RESULTS

120 patients were included, with 60 in the oral step-down and carbapenem groups, respectively. Primary outcome of median venous catheter days in the oral step-down group was 0 (IQR 0-0) vs 5 (IQR 0-7) in the carbapenem group, p < .001. Secondary outcome of treatment failure in the oral step-down group was 2 (3%) vs 8 (13%) in the carbapenem group, p < .09.

CONCLUSIONS

Oral step-down therapy for ESBL Escherichia coli UTIs was associated with a significant reduction in venous catheter line use.