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Characterization of sparfloxacin-resistant mutants of Staphylococcus aureus obtained in vitro.

Authors
Type
Published Article
Journal
International Journal of Antimicrobial Agents
0924-8579
Publisher
Elsevier
Publication Date
Volume
18
Issue
2
Pages
107–112
Identifiers
PMID: 11516932
Source
Medline
License
Unknown

Abstract

A sparfloxacin-susceptible clinical isolate of Staphylococcus aureus was grown in increased concentrations of sparfoxacin. The presence of mutations in gyrA, gyrB, grlA and grlB genes was analyzed. The primary point mutation was located in the gyrA gene (Glu-88 to Lys). Two further mutation steps appeared in the amino acid change Ser-80 to Tyr in GrlA. No mutations occurred in the gyrB or grlB genes. Efflux pumps involved in the increase of resistance were also found to affect norfloxacin and ciprofloxacin. This effect may be related to NorA. An overexpression of NorA, may be associated with the increase of the MIC of norfloxacin from 32 mg/l to >200 mg/l in the final mutant. The MICs levels of sparfloxacin were affected by unknown mechanism.

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