Evidence Hub

In Vitro Activity of Delafloxacin Against Corynebacterium spp

Montserrat Muñoz-Rosa, Cristina Elías-López, Rosa Pedraza, Cristina Riazzo, Cristina Arjona-Torres, Isabel Machuca, Rocío Tejero-García, Julián Torre‐Cisneros et al.

Antibiotics, 2025

Abstract

Background/Objectives: The susceptibility of Corynebacterium spp. to antimicrobial agents is species-related, with increasing levels of resistance to fluoroquinolones in several species related to their continued use in clinical practice. The objectives were to determine the in vitro activity of delafloxacin in comparison with other fluoroquinolones against clinical isolates of Corynebacterium spp., to compare MICs of delafloxacin obtained with gradient strips and with reference microdilution, and to investigate the mechanisms related to fluoroquinolone resistance in the tested strains. Methods: Fifty-three clinical isolates, assigned to five species of Corynebacterium spp., were evaluated using reference microdilution for delafloxacin, ciprofloxacin, levofloxacin, and moxifloxacin (with and without reserpine or phenylalanine-arginine β-naphthylamide), and gradient strips for delafloxacin. The QRDR of the gyrA gene was amplified using primers specific to the different species, and mutations were defined after aligning against the corresponding reference sequences. Results: Delafloxacin was the most active compound with MIC50/MIC90 values of 0.5/8 mg/L. Single mutations at the QRDR were observed in isolates, with MICs of delafloxacin ranging from 0.016 to 4 mg/L, while double mutations occurred in isolates, with MICs ranging from 0.125 to 16 mg/L. The delafloxacin gradient strips showed an essential agreement of 88.7%, bias of −5%, and a Kappa index of 0.848. Conclusions:…

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free