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 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 Dubois, V.
Right arrow Articles by Quentin, C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Dubois, V.
Right arrow Articles by Quentin, C.
Antimicrobial Agents and Chemotherapy, March 2002, p. 638-645, Vol. 46, No. 3
0066-4804/02/$04.00+0     DOI: 10.1128/AAC.46.3.638-645.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

Molecular Characterization of a Novel Class 1 Integron Containing blaGES-1 and a Fused Product of aac(3)-Ib/aac(6")-Ib" Gene Cassettes in Pseudomonas aeruginosa

Véronique Dubois,1* Laurent Poirel,2 Caroline Marie,3 Corinne Arpin,1 Patrice Nordmann,2 and Claudine Quentin1

Laboratoire de Microbiologie, Faculté de Pharmacie, Université de Bordeaux 2,1 Laboratoire de Bactériologie, Hôpital Pellegrin, Bordeaux,3 Service de Bactériologie-Virologie, Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine Paris-Sud, Le Kremlin-Bicêtre, France2

Received 9 April 2001/ Returned for modification 29 July 2001/ Accepted 23 November 2001

As seen by the disk diffusion method, the clinical strain of Pseudomonas aeruginosa Pa695, resistant to all extended-spectrum cephalosporins and aminoglycosides, exhibited an unusual synergistic effect between ceftazidime and imipenem. This isolate produced an extended-spectrum ß-lactamase (ESBL) with a pI of 5.8 that appeared to be chromosomally encoded. Cloning experiments revealed that this ESBL was encoded by blaGES-1, previously described in an integron from Klebsiella pneumoniae. In P. aeruginosa Pa695, a higher level of resistance to ceftazidime than to ticarcillin was observed, and no synergy between the ß-lactamase inhibitors and extended-spectrum cephalosporins was detected, in contrast to the resistance pattern observed in K. pneumoniae. Further sequence analysis demonstrated that the blaGES-1 gene cassette was located in a class 1 integron, which contained another sequence corresponding to the fused aac(3)-Ib and aac(6")-Ib" gene cassettes. The fusion product was functional, as was the product of each gene cloned separately: AAC(3)-I, despite the deletion of the four last amino acids, and AAC(6"), which carried three amino acid changes compared with the most homologous sequence. The AAC(3)-I protein conferred an expected gentamicin and fortimicin resistance, and the AAC(6"), despite the Leu-119->Ser substitution, yielded resistance to kanamycin, tobramycin, and dibekacin, but slightly affected netilmicin and amikacin, and had no apparent effect on gentamicin. The fusion product conveyed a large profile of resistance, combining the AAC(6") activity with a higher level of gentamicin resistance without accompanying fortimicin resistance.

* Corresponding author. Mailing address: Laboratoire de Microbiologie, Faculté de Pharmacie, Université de Bordeaux 2, 146 rue Léo Saignat, 33076 Bordeaux Cedex, France. Phone: 33 5 57 57 10 75. Fax: 33 5 56 90 90 72. E-mail: veronique.dubois{at}bacterio.u-bordeaux2.fr.

Antimicrobial Agents and Chemotherapy, March 2002, p. 638-645, Vol. 46, No. 3
0066-4804/02/$04.00+0     DOI: 10.1128/AAC.46.3.638-645.2002
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.