Editor: Gianfranco Donelli
Brucella melitensis 16M produces a mannan and other extracellular matrix components typical of a biofilm
Article first published online: 20 APR 2010
© 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved
FEMS Immunology & Medical Microbiology
Special Issue: Biofilms
Volume 59, Issue 3, pages 364–377, August 2010
How to Cite
Godefroid, M., Svensson, M. V., Cambier, P., Uzureau, S., Mirabella, A., De Bolle, X., Van Cutsem, P., Widmalm, G. and Letesson, J.-J. (2010), Brucella melitensis 16M produces a mannan and other extracellular matrix components typical of a biofilm. FEMS Immunology & Medical Microbiology, 59: 364–377. doi: 10.1111/j.1574-695X.2010.00689.x
- Issue published online: 13 JUL 2010
- Article first published online: 20 APR 2010
- Received 23 November 2009; revised 18 March 2010; accepted 31 March 2010.Final version published online 20 May 2010.
Mutations in the Brucella melitensis quorum-sensing (QS) system are involved in the formation of clumps containing an exopolysaccharide. Here, we show that the overexpression of a gene called aiiD in B. melitensis gives rise to a similar clumping phenotype. The AiiD enzyme degrades AHL molecules and leads therefore to a QS-deficient strain. We demonstrated the presence of exopolysaccharide and DNA, two classical components of extracellular matrices, in clumps produced by this strain. We also observed that the production of outer membrane vesicles is strongly increased in the aiiD-overexpressing strain. Moreover, this strain allowed us to purify the exopolysaccharide and to obtain its composition and the first structural information on the complex exopolysaccharide produced by B. melitensis 16M, which was found to have a molecular weight of about 16 kDa and to be composed of glucosamine, glucose and mostly mannose. In addition, we found the presence of 2- and/or 6-substituted mannosyl residues, which provide the first insights into the linkages involved in this polymer. We used a classical biofilm attachment assay and an HeLa cell infection model to demonstrate that the clumping strain is more adherent to polystyrene plates and to HeLa cell surfaces than the wild-type one. Taken together, these data reinforce the evidence that B. melitensis could form biofilms in its lifecycle.