title: Mechanisms of quinolone resistance in clinical isolates: accumulation of sparfloxacin and of fluoroquinolones of various hydrophobicity, and analysis of membrane composition.
abstract: The accumulation of sparfloxacin and three other fluoroquinolones of decreasing hydrophobicity, pefloxacin, ofloxacin, and ciprofloxacin, into randomly chosen fluoroquinolone-sensitive and -resistant clinical isolates of bacteria (four Enterobacteriaceae, one Pseudomonas aeruginosa and one Staphylococcus aureus) was measured. There was good correlation between the concentration of drug that inhibited early DNA synthesis in whole cells and the MIC values of the same drug regardless of organism sensitivity or the quinolone. A decrease in permeability in resistant strains compared with sensitive, due to a modification of outer membrane proteins was often involved in resistance. But, in all cases other mutations may also be involved explaining the relatively high level of resistance of the strains. In two resistant strains the DNA gyrase was purified and found to be resistant to inhibition by quinolones. The use of quinolones of differing hydrophobicity emphasized the importance of this property in the uptake of quinolones by bacterial cells, and provided evidence that sparfloxacin used both porin and the self-promoted uptake pathway for it's uptake.
authors.affiliation: Centre National de la Recherche Scientifique, CERCOA, Thiais, France.
authors.forename: A
authors.initials: A
authors.lastname: Denis
authors.forename: N J
authors.initials: NJ
authors.lastname: Moreau
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000378:metabolism; D001424:Bacterial Infections / Q000382:microbiology*; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D004269:DNA, Bacterial / Q000096:biosynthesis; D004278:DNA, Superhelical / Q000378:metabolism; D004352:Drug Resistance, Microbial; D004755:Enterobacteriaceae / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D024841:Fluoroquinolones; D008274:Magnesium / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D015363:Quinolones / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000890:Anti-Infective Agents; D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; D004278:DNA, Superhelical; D024841:Fluoroquinolones; D015363:Quinolones; D004250:DNA Topoisomerases, Type II; D008274:Magnesium; C061363:sparfloxacin