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 Docquier, J.-D.
Right arrow Articles by Rossolini, G. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Docquier, J.-D.
Right arrow Articles by Rossolini, G. M.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, May 2003, p. 1522-1528, Vol. 47, No. 5
0066-4804/03/$08.00+0     DOI: 10.1128/AAC.47.5.1522-1528.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

IMP-12, a New Plasmid-Encoded Metallo-ß-Lactamase from a Pseudomonas putida Clinical Isolate

Jean-Denis Docquier,1 Maria Letizia Riccio,1 Claudia Mugnaioli,1 Francesco Luzzaro,2 Andrea Endimiani,2 Antonio Toniolo,2 Gianfranco Amicosante,3 and Gian Maria Rossolini1*

Dipartimento di Biologia Molecolare, Sezione di Microbiologia Università di Siena, I-53100 Siena,1 Laboratorio di Microbiologia, Ospedale di Circolo and Università dell'Insubria, I-21100 Varese,2 Dipartimento di Scienze e Tecnologie Biomediche, Università di L'Aquila, I-67100 L'Aquila, Italy3

Received 26 August 2002/ Returned for modification 18 November 2002/ Accepted 25 January 2003

A Pseudomonas putida strain showing broad-spectrum resistance to ß-lactams, including expanded-spectrum cephalosporins and carbapenems, was isolated from a patient with a urinary tract infection at the University Hospital of Varese in northern Italy. The isolate was found to produce metallo-ß-lactamase activity and to harbor a 50-kb plasmid, named pVA758, carrying a new blaIMP determinant, named blaIMP-12. Plasmid pVA758 was not self-transferable by conjugation to either Escherichia coli or Pseudomonas aeruginosa but could be introduced by electroporation and maintained in the latter host, where it conferred resistance or decreased susceptibility to various ß-lactams. The IMP-12 enzyme is quite divergent from other IMP variants: its closest relatives are IMP-8 and IMP-2 (89 and 88% sequence identity, respectively), and IMP-1 is 85% identical to IMP-12. The blaIMP-12 determinant is carried on an integron-borne gene cassette whose attC recombination site is related to those present in cassettes containing blaIMP-1, blaIMP-6, blaIMP-7, blaIMP-10, and blaIMP-11 and unrelated to that present in cassettes containing blaIMP-2 and blaIMP-8. IMP-12 was overproduced in E. coli by using a T7-based expression system and was purified by cation-exchange chromatography followed by gel filtration. Kinetic analysis revealed that, like other IMP variants, IMP-12 exhibits an overall preference for cephalosporins and carbapenems rather than for penicillins and does not hydrolyze temocillin and aztreonam. However, IMP-12 also exhibits some notable functional differences from other IMP variants, including uniformly poor activity toward penicillins (kcat/Km values, around 104 M-1 · s-1) and a remarkably high Km (around 900 µM) for imipenem.

* Corresponding author. Mailing address: Dipartimento di Biologia Molecolare, Sezione di Microbiologia, Università di Siena, Policlinico "Le Scotte," 53100 Siena, Italy. Phone: 39 0577 233327. Fax: 39 0577 233325. E-mail: rossolini{at}unisi.it.

Antimicrobial Agents and Chemotherapy, May 2003, p. 1522-1528, Vol. 47, No. 5
0066-4804/03/$08.00+0     DOI: 10.1128/AAC.47.5.1522-1528.2003
Copyright © 2003, 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 © 2003 by the American Society for Microbiology. All rights reserved.