# P-1340. Activity of Delafloxacin and Comparator Agents Against Bacterial Isolates From Patients with Diabetic Foot Infection in the United States and Europe (2017–2023)

## TL;DR

This study compares the effectiveness of delafloxacin and other antibiotics against bacteria causing diabetic foot infections in the US and Europe from 2017 to 2023.

## Contribution

The study provides updated data on delafloxacin's in vitro activity against DFI pathogens in two regions over six years.

## Key findings

- Delafloxacin showed high susceptibility rates against Staphylococcus aureus, including MRSA, in both the US and Europe.
- Delafloxacin was effective against Enterobacterales and Pseudomonas aeruginosa isolates from patients with diabetic foot infections.
- The drug may serve as a broad-spectrum treatment option for DFI, though further clinical studies are needed.

## Abstract

Delafloxacin (DLX) is a fluoroquinolone antibacterial with oral and intravenous treatment options approved in ≥50 countries for treatment of acute bacterial skin and skin structure infection or community-acquired pneumonia in adults. Indicated organisms in the United States (US) include: staphylococci (S. aureus [SA] both MSSA and MRSA, S. haemolyticus and S. lugdunensis), streptococci (S. pyogenes, S. agalactiae and S. anginosus group), Enterococcus faecalis (EF), Enterobacterales (Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae species complex) and Pseudomonas aeruginosa (PSA).The in vitro activity of DLX, ciprofloxacin (CIP), levofloxacin (LEV), moxifloxacin (MOX), minocycline and meropenem-vaborbactam were determined against bacterial isolates from patients with diabetic foot infection (DFI) in the US and Europe (EUR).

Isolates from patients with DFI were collected in the SENTRY Surveillance Program (2017–2023) from sites in the US and EUR. Broth microdilution MIC testing was conducted according to CLSI methods. CLSI, EUCAST, and FDA breakpoint criteria (2025) were applied. Isolate identifications were determined at the collection site and confirmed using MALDI-TOF MS (as needed).

The most common DFI pathogens were SA (35.7%), Enterobacterales (33.4%), PSA (9.8%), streptococci (9.0%) and EF (4.7%). Overall, 87.5% (FDA) of SA isolates from patients with DFI in the US were susceptible to DLX (including 96.7% of MSSA and 73.3% of MRSA) as were 83.8% of SA isolates from EUR (including 96.9% of MSSA and 41.0% of MRSA) (Table 1). Corresponding LEV and MOX susceptibilities for SA isolates from the US were 66.4% (FDA). DLX, CIP and LEV were active (FDA) against 70.6%, 82.6% and 83.5% of Enterobacterales isolates from the US and 68.1%, 75.9% and 80.2% (FDA) of Enterobacterales isolates from EUR, respectively (Table 2). DLX, CIP and LEV were active (FDA) against 71.0%, 83.9% and 74.2% of PSA isolates from the US and 62.2%, 75.6% and 62.2% (FDA) of PSA isolates from EUR, respectively (Table 3).

DLX may provide a useful treatment option (alone or in combination) for patients with DFI including those where a broad-spectrum agent is desired. Additional clinical studies against DFI are needed.

Michael D. Huband, BS, Melinta Therapeutics: Advisor/Consultant|Melinta Therapeutics: Grant/Research Support Marisa Winkler, MD, PhD, Basilea: Advisor/Consultant|Basilea: Grant/Research Support|GSK: Advisor/Consultant|GSK: Grant/Research Support|Melinta Therapeutics: Advisor/Consultant|Melinta Therapeutics: Grant/Research Support|Mundipharma: Advisor/Consultant|Mundipharma: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support|Pulmocide: Advisor/Consultant|Pulmocide: Grant/Research Support Kelley A. Fedler, BS, Melinta Therapeutics: Grant/Research Support Mariana Castanheira, PhD, Melinta Therapeutics: Advisor/Consultant|Melinta Therapeutics: Grant/Research Support