Chapter 26 : Fluoroquinolones

Abstract:

The majority of new fluoroquinolones have two ionizable functions: the 3-carboxyl group and a protonizable site at position 7, such as a 7-piperazinyl heterocycle. The majority of fluoroquinolones have good antistaphylococcal activity. Sitafloxacin, moxifloxacin, gatifloxacin, trovafloxacin, and gemifloxacin have excellent activity, while for grepafloxacin and gatifloxacin, the MIC50s are, respectively, 0.125 and 0.25 µg/ml. DC-756 is as active as sitafloxacin (DU-6859a), one of the most active fluoroquinolones against gram-positive cocci, against Staphylococcus aureus, Streptococcus pneumoniae, and Streptococcus pyogenes. KRQ 10099 is an analog of ofloxacin bearing a bicyclic nucleus instead of a piperazinyl moiety. KRQ 10018 is an 8-methyl-2-pyridone derivative. Against reference strains, KRQ 10018 is extremely active against gram-positive cocci, including ciprofloxacin-resistant S. aureus isolates and ofloxacin-resistant Staphylococcus epidermidis. The majority of fluoroquinolones are eliminated principally renally and/or biliarly. The major system is CYP1A2, the activity of which may be inhibited by the fluoroquinolones. In addition to its antiviral activity, zidovudine possesses a certain antibacterial activity against Enterobacteriaceae through its action on bacterial DNA. As a result of its activity on DNA, zidovudine might modify the activity of the fluoroquinolones. The currently available fluoroquinolones are not treatments for acute forms of malaria, but they may abolish a pauciparasitic form if administered simultaneously for another disease.