Usual and unusual antibacterial effects of quinolones.
Recently documented antibacterial effects of quinolones are reviewed. DNA gyrase is most likely to be the primary target site for these agents. Quinolones rapidly kill susceptible bacteria; the mechanisms of the bactericidal activity, still poorly understood, probably involve new protein synthesis. Quinolones alter membrane integrity before cell death, leading to leakage of cytoplasmic constituents. In Gram-negative bacteria, quinolones act as chelating agents for outer membrane divalent cations, disorganizing the bacterial lipopolysaccharide layer and facilitating the further entry of quinolone molecules in a 'self-promoted' pathway. Quinolones inhibit plasmid replication and reduce the efficacy of plasmid conjugation. Subinhibitory concentrations of quinolones can interfere with bacterial virulence factors, such as bacterial adherence to the host cell, phagocytosis and production of enzymes implicated in virulence. Recent studies also indicate synergism of quinolones with oxacillin against methicillin-resistant staphylococci and describe improved activity of newer compounds against Gram-positive pathogens.
Furet
Y X
YX
Department of Microbiology, CMU, Geneva, Switzerland.
Pechère
J C
JC
D042462:4-Quinolones; D000890:Anti-Infective Agents / Q000378:metabolism* / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D004357:Drug Synergism; D006801:Humans; D008565:Membrane Proteins / Q000096:biosynthesis; D010068:Oxacillin / Q000494:pharmacology; D010957:Plasmids / Q000187:drug effects / Q000235:genetics; D013014:SOS Response, Genetics / Q000187:drug effects; D013997:Time Factors; D059005:Topoisomerase II Inhibitors
D042462:4-Quinolones; D000890:Anti-Infective Agents; D008565:Membrane Proteins; D059005:Topoisomerase II Inhibitors; D004250:DNA Topoisomerases, Type II; D010068:Oxacillin