Background: Activity of gatifloxacin against clinical isolates of fluoroquinolone-resistant Staphylococcus aureus is more potent than that of other fluoroquinolones such as norfloxacin and levofloxacin. To date, few reports have described high-level resistance to gatifloxacin in clinical isolates of S. aureus, although in vitro studies have shown that mutations in both DNA gyrase and topoisomerase IV were required for gatifloxacin resistance in S. aureus.
Methods: Minimum inhibitory concentrations were determined for fluoroquinolones and other antimicrobials in a methicillin-resistant S. aureus isolate that was cultured from blood of a patient with septicemia. Fluoroquinolone resistance was characterized by DNA sequencing and microbiologic assay.
Results: The isolate showed high-level resistance to fluoroquinolones including an 8-methoxyfluoroquinolone, gatifloxacin (minimum inhibitory concentration 64 microg/ml). Amino acid mutations of Ser80Tyr and Glu84Lys in GrlA and Ser84Leu and Ser85Pro in GyrA were possibly related to this resistance in methicillin-resistant S. aureus HU2000-062, although efflux may play a minor role in resistance as well.
Conclusion: GyrA and GrlA mutations mainly conferred to 8-methoxyfluoroquinolone resistance in this isolate.
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http://dx.doi.org/10.1159/000098427 | DOI Listing |
Anticancer Agents Med Chem
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This article serves as a guide to the Tobacco-Free Generation policy (TFG) for policy-makers, drawing on experiences of negotiations regarding TFG in a wide number of jurisdictions. It explains the underlying concept: the highly addictive nature of nicotine prompts policy focus on preventing initial use by forbidding sales to those born after a prescribed cut-off birthdate, while resisting prohibition for those in older cohorts who may already be nicotine-dependent. The policy signals that there is no safe age for tobacco products.
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