The Sound of Evolution
Gemifloxacin
Mechanism of action:
Gemifloxacin is a fluoroquinolone antibiotic and a fourth-generation quinolone derivative. Its antibacterial activity targets bacterial DNA gyrase (DNA gyrase, bacterial topoisomerase II), which is responsible for relieving the supercoiled structure generated during bacterial DNA replication. When gemifloxacin binds to the DNA-enzyme complex, it prevents re-ligation after DNA strand cleavage, so DNA replication cannot continue. In addition, gemifloxacin also inhibits bacterial topoisomerase IV, an enzyme responsible for separating daughter DNA molecules during bacterial cell division. Once inhibited, bacteria cannot complete cell division properly.
Reference(s):
1. Ruiz J et al. (2003). In vitro activity of gemifloxacin against clinical isolates of Neisseria gonorrhoeae with and without mutations in the gyrA gene. Int J Antimicrob Agents.
2. Alkorta M et al. (2005). In vivo activity of gemifloxacin, moxifloxacin and levofloxacin against pneumococci with gyrA and parC point mutations in a sepsis mouse model measured with the all or nothing mortality end-point. Int J Antimicrob Agents.