1989
DOI: 10.1128/aac.33.11.1837
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In vitro activity of amifloxacin against outer membrane mutants of the family Enterobacteriaceae and frequency of spontaneous resistance

Abstract: Amifloxacin showed potent inhibitory activity against DNA gyrase of Escherichia coli. The difference in the susceptibilities of lipopolysaccharide-deficient Salmonella typhimurium mutants and their parent strain was less than twofold, and the difference in the susceptibilities of porin-deficient E. coli mutants and their parent strain was less than twofold. There was cross resistance among the quinolone group of agents; however, the decrease in MIC for norB mutants was slightly lower than that of other fluoroq… Show more

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Cited by 16 publications
(7 citation statements)
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“…The outer membrane permeation of tosufloxacin was more affected by the barrier of LPS than we predicted from its hydrophobicity. Similarly, it has been previously noted that the activity of amifloxacin, which is more hydrophobic than nalidixic acid, was affected little by alterations in the LPS structure (26). These findings together with our results suggest that the permeation of quinolones through a barrier of LPS, at least in part, is not limited simply by the apparent hydrophobicity of the molecules but also by the differences in basal structure (quinoline, naphthyridine, or benzoxazine nucleus) or in each specific moiety.…”
Section: Discussionsupporting
confidence: 68%
See 1 more Smart Citation
“…The outer membrane permeation of tosufloxacin was more affected by the barrier of LPS than we predicted from its hydrophobicity. Similarly, it has been previously noted that the activity of amifloxacin, which is more hydrophobic than nalidixic acid, was affected little by alterations in the LPS structure (26). These findings together with our results suggest that the permeation of quinolones through a barrier of LPS, at least in part, is not limited simply by the apparent hydrophobicity of the molecules but also by the differences in basal structure (quinoline, naphthyridine, or benzoxazine nucleus) or in each specific moiety.…”
Section: Discussionsupporting
confidence: 68%
“…One of the major resistance mechanisms is alteration of the subunit structure of DNA gyrase (1,5,10,12,14,16,20,22,27,28,30,31), and another is decreased permeability through the outer membrane from a reduced number of porins (3, 4, 6-8, 11, 13-15). In E. coli, fluoroquinolones are thought to cross the outer membrane primarily through the OmpF porin; this has been demonstrated previously with defined porin-deficient strains (4,6,13,26). Moreover, the lipopolysaccharide (LPS)-deficient (rough) mutants were more susceptible to hydrophobic quinolones than was the wild-type strain, suggesting that the passage of quinolones through the outer membrane is not limited to porins (13).…”
mentioning
confidence: 81%
“…Antibacterial susceptibility was measured by an agar dilution method using sensitivity disk agar (Nissui, Tokyo, Japan) (24).…”
Section: Methodsmentioning
confidence: 99%
“…Indeed, amifloxacin, a larger fraction of which exists in the uncharged form (Fig. 3A), appears to diffuse more significantly through the OM bilayer in comparison with norfloxacin (46). Another case involves mycobacteria, whose cell wall lipids constitute a very effective permeation barrier (25).…”
mentioning
confidence: 99%