We obtained a clinical isolate of Providencia stuartii showing a high level of resistance to norfloxacin and to other 4-quinolones, whose target is the enzyme DNA-gyrase. This strain showed resistance also to beta-lactam and aminoglycoside antibiotics. In order to detect modification of DNA-gyrase, we performed supercoiling assays in vitro in presence of norfloxacin and ciprofloxacin. Furthermore, outer membrane proteins, which are involved in permeability mechanisms, were analyzed on SDS-polyacrylamide gels. Results showed that both modifications in DNA-gyrase and changes in outer membrane proteins can be held responsible for resistance to 4-quinolones; moreover, these modification are probably supported by a third mechanism of resistance.

Modifications of DNA-gyrase and of permeability in a norfloxacin-resistant clinical isolate of Providencia stuartii.

PAGANI, LAURA;DEBIAGGI, MAURIZIA;CEREDA, PAOLO MARTINO;ROMERO, EGIDIO
1987-01-01

Abstract

We obtained a clinical isolate of Providencia stuartii showing a high level of resistance to norfloxacin and to other 4-quinolones, whose target is the enzyme DNA-gyrase. This strain showed resistance also to beta-lactam and aminoglycoside antibiotics. In order to detect modification of DNA-gyrase, we performed supercoiling assays in vitro in presence of norfloxacin and ciprofloxacin. Furthermore, outer membrane proteins, which are involved in permeability mechanisms, were analyzed on SDS-polyacrylamide gels. Results showed that both modifications in DNA-gyrase and changes in outer membrane proteins can be held responsible for resistance to 4-quinolones; moreover, these modification are probably supported by a third mechanism of resistance.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11571/444283
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