JAC Advance Access originally published online on July 27, 2007
Journal of Antimicrobial Chemotherapy 2007 60(4):872-876; doi:10.1093/jac/dkm284
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Most Escherichia coli strains overproducing chromosomal AmpC ß-lactamase belong to phylogenetic group A
1 Laboratoire de Bactériologie-Hygiène, CHU, Nantes, France 2 JE 2437, Génétique des Interactions hôte-microorganisme, Faculté de Pharmacie, Université de Nantes, France
Received 11 May 2007; returned 4 July 2007; revised 11 June 2007; accepted 6 July 2007
* Correspondence address. Laboratoire de Bactériologie, JE 2437, Faculté de Pharmacie, Université de Nantes, 1 rue Gaston Veil, 44035 Nantes Cédex 01, France. Tel: +33-2-40-41-29-48; Fax: +33-2-40-41-29-52; E-mail: nathalie.caroff{at}univ-nantes.fr
Objectives: To determine the phylogenetic group and the production of different virulence factors (VFs) of a collection of Escherichia coli strains overproducing their chromosomal AmpC cephalosporinase.
Methods: Fifty-five E. coli strains, isolated over a 12 year period, and previously identified as AmpC overproducers by increased MICs of third-generation cephalosporins without extended-spectrum ß-lactamase production (negative double-disc synergy test), were phylogrouped by multiplex PCR. As a comparison, 100 E. coli clinical isolates, susceptible to all ß-lactams, were also tested by the same method. The ampC promoter sequence was determined for all these isolates. ERIC-2 PCR (where ERIC stands for enterobacterial repetitive intergenic consensus) was used to compare the isolates. Search for virulence-associated genes (papG alleles, sfa/foc, hly and iucC) was performed by multiplex PCR for the 55 AmpC overproducers.
Results: Most of the AmpC overproducers (47/55) belonged to phylogenetic group A, correlated with a low prevalence of the main VFs in these strains. The – 32, –42 and – 11 mutations, responsible for AmpC overproduction, were usually associated with DNA polymorphisms at positions – 88, – 82, –18, +1 and + 58 in the ampC promoter. In the control susceptible isolates, these polymorphisms were detected in 13 ampC promoters (9 group B1 and 4 group A). These polymorphisms were never associated with the main phylogenetic group B2, representing 66% of the susceptible isolates.
Conclusions: AmpC overproduction was clearly correlated with non-virulent commensal phylogenetic groups A and B1, and absence of the main E. coli VFs. Susceptible isolates harbouring the same sequence polymorphisms as AmpC overproducers also belonged to commensal phylogenetic groups.
Keywords: E. coli , virulence , cephalosporinase , promoter
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  A. S. Bukh, H. C. Schonheyder, J. M. G. Emmersen, M. Sogaard, S. Bastholm, and P. Roslev Escherichia coli phylogenetic groups are associated with site of infection and level of antibiotic resistance in community-acquired bacteraemia: a 10 year population-based study in Denmark J. Antimicrob. Chemother., July 1, 2009; 64(1): 163 - 168. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. F. Mataseje, N. Neumann, B. Crago, P. Baudry, G. G. Zhanel, M. Louie, M. R. Mulvey, and and the ARO Water Study Group Characterization of Cefoxitin-Resistant Escherichia coli Isolates from Recreational Beaches and Private Drinking Water in Canada between 2004 and 2006 Antimicrob. Agents Chemother., July 1, 2009; 53(7): 3126 - 3130. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Guillouzouic, N. Caroff, S. Dauvergne, D. Lepelletier, A. Perrin Guyomard, I. Kempf, A. Reynaud, and S. Corvec MLST typing of Escherichia coli isolates overproducing AmpC {beta}-lactamase J. Antimicrob. Chemother., June 1, 2009; 63(6): 1290 - 1292. [Full Text] [PDF]
|
|
|
|
 |
|
 G. A. Jacoby AmpC {beta}-Lactamases Clin. Microbiol. Rev., January 1, 2009; 22(1): 161 - 182. [Abstract] [Full Text] [PDF]
|
|