AAC
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ince, D.
Right arrow Articles by Hooper, D. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ince, D.
Right arrow Articles by Hooper, D. C.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, November 2002, p. 3370-3380, Vol. 46, No. 11
0066-4804/02/$04.00+0     DOI: 10.1128/AAC.46.11.3370-3380.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

Dual Targeting of DNA Gyrase and Topoisomerase IV: Target Interactions of Garenoxacin (BMS-284756, T-3811ME), a New Desfluoroquinolone

Dilek Ince, Xiamei Zhang, L. Christine Silver, and David C. Hooper*

Division of Infectious Disease and Medical Services, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114-2696

Received 20 March 2002/ Returned for modification 10 June 2002/ Accepted 23 July 2002

We determined the target enzyme interactions of garenoxacin (BMS-284756, T-3811ME), a novel desfluoroquinolone, in Staphylococcus aureus by genetic and biochemical studies. We found garenoxacin to be four- to eightfold more active than ciprofloxacin against wild-type S. aureus. A single topoisomerase IV or gyrase mutation caused only a 2- to 4-fold increase in the MIC of garenoxacin, whereas a combination of mutations in both loci caused a substantial increase (128-fold). Overexpression of the NorA efflux pump had minimal effect on resistance to garenoxacin. With garenoxacin at twice the MIC, selection of resistant mutants (<7.4 x 10-12 to 4.0 x 10-11) was 5 to 6 log units less than that with ciprofloxacin. Mutations inside or outside the quinolone resistance-determining regions (QRDR) of either topoisomerase IV, or gyrase, or both were selected in single-step mutants, suggesting dual targeting of topoisomerase IV and gyrase. Three of the novel mutations were shown by genetic experiments to be responsible for resistance. Studies with purified topoisomerase IV and gyrase from S. aureus also showed that garenoxacin had similar activity against topoisomerase IV and gyrase (50% inhibitory concentration, 1.25 to 2.5 and 1.25 µg/ml, respectively), and although its activity against topoisomerase IV was 2-fold greater than that of ciprofloxacin, its activity against gyrase was 10-fold greater. This study provides the first genetic and biochemical data supporting the dual targeting of topoisomerase IV and gyrase in S. aureus by a quinolone as well as providing genetic proof for the expansion of the QRDRs to include the 5' terminus of grlB and the 3' terminus of gyrA.

* Corresponding author. Mailing address: Division of Infectious Disease, Massachusetts General Hospital, 55 Fruit St., Boston, MA 02114-2696. Phone: (617) 726-3812. Fax: (617) 726-7416. E-mail: dhooper{at}partners.org.

Antimicrobial Agents and Chemotherapy, November 2002, p. 3370-3380, Vol. 46, No. 11
0066-4804/02/$04.00+0     DOI: 10.1128/AAC.46.11.3370-3380.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Clin. Vaccine Immunol. Clin. Microbiol. Rev.
J. Clin. Microbiol. ALL ASM JOURNALS

Copyright © 2002 by the American Society for Microbiology. All rights reserved.