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 Aubry, A.
Right arrow Articles by Fisher, L. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Aubry, A.
Right arrow Articles by Fisher, L. M.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, January 2006, p. 104-112, Vol. 50, No. 1
0066-4804/06/$08.00+0     doi:10.1128/AAC.50.1.104-112.2006
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

Novel Gyrase Mutations in Quinolone-Resistant and -Hypersusceptible Clinical Isolates of Mycobacterium tuberculosis: Functional Analysis of Mutant Enzymes

Alexandra Aubry,1,2* Nicolas Veziris,2 Emmanuelle Cambau,2,{dagger} Chantal Truffot-Pernot,2 Vincent Jarlier,2 and L. Mark Fisher1*

Molecular Genetics Group, Molecular and Metabolic Signalling Centre, Division of Basic Medical Sciences, St. George's, University of London, London SW17 0RE, United Kingdom,1 Laboratoire de Bactériologie, Faculté de Médecine Pierre et Marie Curie, Université Paris VI, Paris, France2

Received 13 July 2005/ Returned for modification 6 September 2005/ Accepted 27 October 2005

Mutations in the DNA gyrase GyrA2GyrB2 complex are associated with resistance to quinolones in Mycobacterium tuberculosis. As fluoroquinolones are being used increasingly in the treatment of tuberculosis, we characterized several multidrug-resistant clinical isolates of M. tuberculosis carrying mutations in the genes encoding the GyrA or GyrB subunits associated with quinolone resistance or hypersusceptibility. In addition to the reported putative quinolone resistance mutations in GyrA, i.e., A90V, D94G, and D94H, we found that the GyrB N510D mutation was also associated with ofloxacin resistance. Surprisingly, several isolates bearing a novel combination of gyrA T80A and A90G changes were hypersusceptible to ofloxacin. M. tuberculosis GyrA and GyrB subunits (wild type [WT] and mutants) were overexpressed in Escherichia coli, purified to homogeneity, and used to reconstitute highly active gyrase complexes. Mutant proteins were produced similarly from engineered gyrA and gyrB alleles by mutagenesis. MICs, enzyme inhibition, and drug-induced DNA cleavage were determined for moxifloxacin, gatifloxacin, ofloxacin, levofloxacin, and enoxacin. Mutant gyrase complexes bearing GyrA A90V, D94G, and D94H and GyrB N510D were resistant to quinolone inhibition (MICs and 50% inhibitory concentrations [IC50s] at least 3.5-fold higher than the concentrations for the WT), and all, except the GyrB mutant, were less efficiently trapped as a quinolone cleavage complex. In marked contrast, gyrase complexes bearing GyrA T80A or A90G were hypersusceptible to the action of many quinolones, an effect that was reinforced for complexes bearing both mutations (MICs and IC50s up to 14-fold lower than the values for the WT). This is the first detailed enzymatic analysis of hypersusceptibility and resistance in M. tuberculosis.

* Corresponding author. Mailing address for Alexandra Aubry: Faculté de Médecine Pierre et Marie Curie, Université Paris VI, 91, boulevard de l'Hôpital, 75634 Paris Cedex 13, France. Phone: 33 1 40 77 97 46. Fax: 33 1 45 82 75 77. E-mail: aubry{at}chups.jussieu.fr. Mailing address for L. Mark Fisher: Division of Basic Medical Sciences, St. George's, University of London, London SW17 0RE, United Kingdom. Phone: 44 208 725 5782. Fax: 44 208 725 2992. E-mail: lfisher{at}sgul.ac.uk.

{dagger} Present address: Laboratoire de Bactériologie-Virologie-Hygiène, Centre Hospitalo-Universitaire Henri Mondor, Assistance Publique-Hôpitaux de Paris, Faculté de Médecine de Créteil, Université Paris XII, Paris, France.

Antimicrobial Agents and Chemotherapy, January 2006, p. 104-112, Vol. 50, No. 1
0066-4804/06/$08.00+0     doi:10.1128/AAC.50.1.104-112.2006
Copyright © 2006, 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 © 2006 by the American Society for Microbiology. All rights reserved.