Activity of Delafloxacin and Finafloxacin against Mycoplasma hominis and Species.

The activity of two new fluoroquinolones, delafloxacin and finafloxacin, were evaluated against and spp. The MICs of delafloxacin, finafloxacin, and two classical fluoroquinolones (moxifloxacin and levofloxacin) were tested against 29 and 67 spp. isolates using the broth microdilution method. The molecular mechanisms underlying fluoroquinolone resistance were also investigated. Delafloxacin exhibited low MICs against and spp., including the levofloxacin-resistant isolates. For , delafloxacin showed low MIC value of 1 μg/mL (MIC range, <0.031 -1 μg/mL) compared to 8 μg/mL for finafloxacin, 16 μg/mL for moxifloxacin, and 32 μg/mL for levofloxacin. For and , delafloxacin had low MIC values (, 2 μg/mL; , 4 μg/mL) compared to 16 -32 μg/mL for finafloxacin, 16 μg/mL for moxifloxacin, and 32 - >32 μg/mL for levofloxacin. The two mutations GyrA S153L and ParC S91I were commonly identified in fluoroquinolone-resistant , and ParC S83L was the most frequent mutation identified in fluoroquinolone-resistant spp. Delafloxacin displayed lower MICs against fluoroquinolone-resistant isolates of both and spp. that have mutations in the quinolone resistance determining regions (QRDRs) than the two classical fluoroquinolones. Delafloxacin is a promising fluoroquinolone with low MICs against fluoroquinolone-resistant and spp. Our study confirms the potential clinical use of delafloxacin in treating antimicrobial-resistant and spp. infections. Fluoroquinolone resistance in Mycoplasma hominis and spp. is on the rise globally, which has compromised the efficacy of the currently available antimicrobial agents. This study evaluated the antimicrobial activity of two new fluoroquinolones, delafloxacin and finafloxacin, for the first time, against and spp. clinical isolates. Delafloxacin and finafloxacin displayed different antimicrobial susceptibility profiles against and spp. . Delafloxacin was found to be more effective against and spp. than three classical fluoroquinolones (finafloxacin, moxifloxacin, and levofloxacin). Finafloxacin displayed activity similar to moxifloxacin but superior to levofloxacin against and spp. Our findings demonstrate that delafloxacin is a promising fluoroquinolone with outstanding activity against fluoroquinolone-resistant and spp.