Skip to Main content Skip to Navigation
Journal articles

Inducible expression eliminates the fitness cost of vancomycin resistance in enterococci.

Abstract : Inducible vancomycin resistance in enterococci is due to a sophisticated mechanism that combines synthesis of cell wall peptidoglycan precursors with low affinity for glycopeptides and elimination of the normal target precursors. Although this dual mechanism, which involves seven genes organized in two operons, is predicted to have a high fitness cost, resistant enterococci have disseminated worldwide. We have evaluated the biological cost of VanB-type resistance due to acquisition of conjugative transposon Tn1549 in Enterococcus faecium and Enterococcus faecalis. Because fitness was dependent on the integration site of Tn1549, an isogenic set of E. faecalis was constructed to determine the cost of inducible or constitutive expression of resistance or of carriage of Tn1549. A luciferase gene was inserted in the integrase gene of the transposon to allow differential quantification of the strains in cocultures and in the digestive tract of gnotobiotic mice. Both in vitro and in vivo, carriage of inactivated or inducible Tn1549 had no cost for the host in the absence of induction by vancomycin. In contrast, induced or constitutively resistant strains not only had reduced fitness but were severely impaired in colonization ability and dissemination among mice. These data indicate that tight regulation of resistance expression drastically reduces the biological cost associated with vancomycin resistance in Enterococcus spp. and accounts for the widespread dissemination of these strains. Our findings are in agreement with the observation that regulation of expression is common in horizontally acquired resistance and represents an efficient evolutionary pathway for resistance determinants to become selectively neutral.
Complete list of metadatas

Cited literature [30 references]  Display  Hide  Download

https://hal-pasteur.archives-ouvertes.fr/pasteur-00552977
Contributor : Anne Lassailly-Bondaz <>
Submitted on : Thursday, January 6, 2011 - 11:48:59 AM
Last modification on : Monday, January 13, 2020 - 5:08:05 PM
Long-term archiving on: : Thursday, April 7, 2011 - 2:49:34 AM

File

16964.full.pdf
Files produced by the author(s)

Identifiers

Collections

Citation

Marie-Laure Foucault, Florence Depardieu, Patrice Courvalin, Catherine Grillot-Courvalin. Inducible expression eliminates the fitness cost of vancomycin resistance in enterococci.. Proceedings of the National Academy of Sciences of the United States of America , National Academy of Sciences, 2010, 107 (39), pp.16964-9. ⟨10.1073/pnas.1006855107⟩. ⟨pasteur-00552977⟩

Share

Metrics

Record views

740

Files downloads

624