Delafloxacin activity against fluoroquinolone-resistant Pseudomonas aeruginosa: in vitro activity and mutant prevention concentration
Abstract
IntroductionPseudomonas aeruginosa frequently develops resistance to fluoroquinolones limiting the usefulness of these agents for the treatment of healthcare-associated infections. This study evaluated the in vitro activity of delafloxacin in comparison with the older-generation fluoroquinolones against clinical P. aeruginosa isolates, and explored its potential to suppress the selection of resistant subpopulations.MethodsOne hundred clinical isolates were tested against ciprofloxacin, levofloxacin, and delafloxacin by broth microdilution method. Susceptibility was interpreted according to EUCAST criteria for ciprofloxacin and levofloxacin and FDA criteria for delafloxacin. Mutant prevention concentrations (MPCs) were determined for the three fluoroquinolones in 12 selected isolates using a high-inoculum agar-based method.ResultsResistance was observed in 29% of isolates for both ciprofloxacin and levofloxacin, compared with 25% for delafloxacin. Among isolates resistant to both ciprofloxacin and levofloxacin, 32.0% were susceptible or intermediate to delafloxacin. The median MPC/MIC ratio was 4 (IQR, 4–8) for delafloxacin, compared with 8 (IQR, 7–16) for ciprofloxacin and 16 (IQR, 7–64) for levofloxacin.DiscussionOverall, delafloxacin retained in vitro activity against a subset of fluoroquinolone-resistant P. aeruginosa isolates and showed a favorable mutant prevention profile in the isolates tested, with a lower median MPC/MIC ratio than ciprofloxacin and levofloxacin. These findings provide preliminary evidence supporting further investigation of delafloxacin against fluoroquinolone-resistant P. aeruginosa.
Related
- pH-Dependent Evolution of Delafloxacin and Ciprofloxacin Resistance in Pseudomonas aeruginosa from cystic fibrosis (CF) and non-CF-patients
- Host immune stress reveals a role for potassium homeostasis in Pseudomonas aeruginosa aggregate stability
- LytM family endopeptidase LmdC is controlled by regulated auto processing and proteolytic destruction in Pseudomonas aeruginosa
- Mining the Pseudomonas aeruginosa genome for regulators of type III secretion system gene expression using FT-Tn-seq
- Auranofin shows bactericidal activity in Pseudomonas aeruginosa by targeting thiol homeostasis
BibTeX
@article{cintoramairal2026delafloxacin,
title = {{Delafloxacin activity against fluoroquinolone-resistant Pseudomonas aeruginosa: in vitro activity and mutant prevention concentration}},
author = {Carmen Cintora-Mairal and José Manuel Ortiz de la Rosa and José Miguel Cisneros and José Antonio Lepe and Ángel Rodríguez-Villodres},
journal = {Frontiers in Microbiology},
year = {2026},
month = nov,
doi = {10.3389/fmicb.2026.1981206},
url = {https://www.frontiersin.org/articles/10.3389/fmicb.2026.1981206},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Delafloxacin activity against fluoroquinolone-resistant Pseudomonas aeruginosa: in vitro activity and mutant prevention concentration
AU - Carmen Cintora-Mairal
AU - José Manuel Ortiz de la Rosa
AU - José Miguel Cisneros
AU - José Antonio Lepe
AU - Ángel Rodríguez-Villodres
PY - 2026
DA - 2026/11/05
JO - Frontiers in Microbiology
DO - 10.3389/fmicb.2026.1981206
UR - https://www.frontiersin.org/articles/10.3389/fmicb.2026.1981206
AB - IntroductionPseudomonas aeruginosa frequently develops resistance to fluoroquinolones limiting the usefulness of these agents for the treatment of healthcare-associated infections. This study evaluated the in vitro activity of delafloxacin in comparison with the older-generation fluoroquinolones against clinical P. aeruginosa isolates, and explored its potential to suppress the selection of resistant subpopulations.MethodsOne hundred clinical isolates were tested against ciprofloxacin, levofloxacin, and delafloxacin by broth microdilution method. Susceptibility was interpreted according to EUCAST criteria for ciprofloxacin and levofloxacin and FDA criteria for delafloxacin. Mutant prevention concentrations (MPCs) were determined for the three fluoroquinolones in 12 selected isolates using a high-inoculum agar-based method.ResultsResistance was observed in 29% of isolates for both ciprofloxacin and levofloxacin, compared with 25% for delafloxacin. Among isolates resistant to both ciprofloxacin and levofloxacin, 32.0% were susceptible or intermediate to delafloxacin. The median MPC/MIC ratio was 4 (IQR, 4–8) for delafloxacin, compared with 8 (IQR, 7–16) for ciprofloxacin and 16 (IQR, 7–64) for levofloxacin.DiscussionOverall, delafloxacin retained in vitro activity against a subset of fluoroquinolone-resistant P. aeruginosa isolates and showed a favorable mutant prevention profile in the isolates tested, with a lower median MPC/MIC ratio than ciprofloxacin and levofloxacin. These findings provide preliminary evidence supporting further investigation of delafloxacin against fluoroquinolone-resistant P. aeruginosa.
SN - 1664-302X
ER -