New norfloxacin resistance gene in Pseudomonas aeruginosa PAO.
A new type of norfloxacin-resistant mutant of Pseudomonas aeruginosa PAO was isolated. This mutant showed cross resistance to imipenem and chloramphenicol and hypersusceptibility to beta-lactam and aminoglycoside antibiotics. The new norfloxacin resistance gene nfxC was mapped near catA (46 min) on the PAO chromosome. Norfloxacin accumulation was decreased in the nfxC mutant; furthermore, the rate of imipenem diffusion through the outer membrane of the nfxC mutant was lower than that of the parent strain. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of outer membrane proteins showed a decrease of a 46-kilodalton protein and an increase of a 50-kilodalton protein in the nfxC mutant. We conclude the nfxC is a new norfloxacin resistance gene that affects outer membrane permeability to quinolones and other antimicrobial agents.
Fukuda
H
H
Central Research Laboratories, Kyorin Pharmaceutical Co. Ltd., Tochigi-ken, Japan.
Hosaka
M
M
Hirai
K
K
Iyobe
S
S
D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D002462:Cell Membrane / Q000502:physiology; D002874:Chromosome Mapping; D004352:Drug Resistance, Microbial / Q000235:genetics*; D015378:Imipenem / Q000493:pharmacokinetics; D008826:Microbial Sensitivity Tests; D009154:Mutation; D009643:Norfloxacin / Q000493:pharmacokinetics / Q000494:pharmacology*; D010539:Permeability; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000378:metabolism
D001425:Bacterial Outer Membrane Proteins; D015378:Imipenem; D009643:Norfloxacin