In Vitro Activity of Gepotidacin against Gram-Negative and Gram-Positive Anaerobes.

Gepotidacin (formerly GSK2140944) is a first-in-class triazaacenaphthylene antibacterial currently in phase III clinical trials. When tested against Gram-negative (n = 333) and Gram-positive (n = 225) anaerobes by agar dilution, gepotidacin inhibited 90% of isolates at concentrations of 4 and 2 µg/mL, respectively. Given gepotidacin's in vitro activity against the anaerobic isolates tested, further study is warranted to better understand the utility of gepotidacin in the treatment of infections caused by clinically relevant anaerobic organisms.

Interactions between Gepotidacin and Escherichia coli Gyrase and Topoisomerase IV: Genetic and Biochemical Evidence for Well-Balanced Dual-Targeting.

Antimicrobial resistance is a global threat to human health. Therefore, efforts have been made to develop new antibacterial agents that address this critical medical issue. Gepotidacin is a novel, bactericidal, first-in-class triazaacenaphthylene antibacterial in clinical development. Recently, phase III clinical trials for gepotidacin treatment of uncomplicated urinary tract infections caused by uropathogens, including Escherichia coli, were stopped for demonstrated efficacy. Because of the clinical promise of gepotidacin, it is important to understand how the compound interacts with its cellular targets, gyrase and topoisomerase IV, from E. coli. Consequently, we determined how gyrase and topoisomerase IV mutations in amino acid residues that are involved in gepotidacin interactions affect the susceptibility of E. coli cells to the compound and characterized the effects of gepotidacin on the activities of purified wild-type and mutant gyrase and topoisomerase IV. Gepotidacin displayed well-balanced dual-targeting of gyrase and topoisomerase IV in E. coli cells, which was reflected in a similar inhibition of the catalytic activities of these enzymes by the compound. Gepotidacin induced gyrase/topoisomerase IV-mediated single-stranded, but not double-stranded, DNA breaks. Mutations in GyrA and ParC amino acid residues that interact with gepotidacin altered the activity of the compound against the enzymes and, when present in both gyrase and topoisomerase IV, reduced the antibacterial activity of gepotidacin against this mutant strain. Our studies provide insights regarding the well-balanced dual-targeting of gyrase and topoisomerase IV by gepotidacin in E. coli.

Antibacterial Activity of the Novel Drug Gepotidacin against Stenotrophomonas maltophilia-An In Vitro and In Vivo Study.

Stenotrophomonas maltophilia is increasingly recognized as a nosocomial bacterial pathogen with a multi-drug resistance profile. In this study, the novel drug gepotidacin, the first compound of the novel triazaacenaphthylene topoisomerase inhibitor antibiotics class, was evaluated on its activity against clinical S. maltophilia isolates. Ninety-nine S. maltophilia isolates plus reference strain K279a (N = 100) were tested on their susceptibility towards gepotidacin in a broth microdilution. Additional susceptibility testing was performed towards the commonly applied combination trimethoprim/sulfamethoxazole (TMP/SXT), moxifloxacin, and levofloxacin. The time-kill kinetic of gepotidacin was observed in a time-kill assay. The greater wax moth Galleria mellonella was used to determine the activity of gepotidacin against S. maltophilia in vivo. Gepotidacin showed minimum inhibitory concentrations (MICs) between 0.25 and 16 mg/L (MIC50: 2 mg/L; MIC90: 8 mg/L), independently of its susceptibility towards TMP/SXT. The five TMP/SXT resistant strains exhibited gepotidacin MICs from 1 to 4 mg/L. The S. maltophilia strains resistant to the assessed fluoroquinolones showed in parts high MICs of gepotidacin. The time-kill assay revealed a time- and strain-dependent killing effect of gepotidacin. In vivo, injection of gepotidacin increased the survival rate of the larvae from 61 % to 90 % after 2 days. This study showed antimicrobial effects of gepotidacin towards S. maltophilia.