# P-921. A medication use evaluation of cefiderocol for the treatment of multi-drug-resistant gram-negative infections at a tertiary care medical center: a healthcare/quality improvement project

## TL;DR

This study evaluates cefiderocol use for treating drug-resistant gram-negative infections, finding high adherence to guidelines but rising costs and mortality in some cases.

## Contribution

The study provides real-world data on cefiderocol use and outcomes in a healthcare setting with increasing antimicrobial resistance.

## Key findings

- Cefiderocol was used appropriately in 98.4% of cases according to IDSA guidelines.
- Mortality was highest for Acinetobacter baumannii infections at 71%.
- Hospital costs for cefiderocol increased significantly from 2021 to 2024.

## Abstract

Cefiderocol (CFDC) is a novel advanced cephalosporin with broad activity against gram-negative bacilli, including those with multi-drug resistance. It acts as a siderophore, binding to extracellular iron which then facilitates its transport across the gram-negative cell membrane. There has been a steady rise in antimicrobial resistance at our institution, infections caused by carbapenem-resistant (CR) pathogens, and therefore an increased need for advanced generation agents such as CFDC.Table 1:CFDC use pattern/demographics: 2021-2024Table 2:Clinical Outcomes

CFDC use pattern/demographics: 2021-2024

Clinical Outcomes

We performed a single center retrospective chart review of CFDC use for resistant gram-negative infections from 2021-2024. Patients met inclusion criteria if they received CFDC for definitive management of clinical infection based on antimicrobial susceptibilities. Clinical characteristics were identified including pathogens, sites of infection, duration of therapy and patient outcomes including 30-day overall mortality. Appropriate use of CFDC was defined based on IDSA’s 2024 Guidance on the Treatment of Antimicrobial Resistant Gram-Negative Infections in addition to our local antibiotic stewardship guidelines.Table 3:Organism MortalityTable 4:Duration and Cost by Year

Organism Mortality

Duration and Cost by Year

63 patients with an average age of 58 were treated from 2021– 2024 with CFDC for a Mean Duration of 15.6 days and length of stay of 73 days. We identified 55 CR isolates; E. coli and P. aeruginosa accounting for >45% (Table: 3). ID consultation was obtained in 96.8% (61/63) orders of CFDC, with 52% of those patients requiring an ICU escalation due to respiratory failure or hemodynamic instability. Overall mortality was found to be 32%, with the highest rates occurring in Acinetobacter baumannii (71%; 5/7) (Table 3). Appropriate use of CFDC as defined by IDSA guidance was seen in 98.4% (62/63) of patients. Cumulative Hospital CFDC costs per year increased from $155,580 in 2021 to $749,140 in 2024 (Table: 4).

Despite good adherence to IDSA guidelines, CFDC usage has increased at our institution, and this parallels the rise in CR infections. The treatment of CR infections with CFDC has resulted in a significant financial burden to our institution.

All Authors: No reported disclosures