Open Access Highly Accessed Research article

Damage of Streptococcus mutans biofilms by carolacton, a secondary metabolite from the myxobacterium Sorangium cellulosum

Brigitte Kunze1, Michael Reck1, Andreas Dötsch2, André Lemme1, Dietmar Schummer4, Herbert Irschik3, Heinrich Steinmetz3 and Irene Wagner-Döbler1*

  • * Corresponding author: Irene Wagner-Döbler

Author Affiliations

1 Group Microbial Communication, Helmholtz-Centre for Infection Research, Braunschweig, Germany

2 Group Chronic Pseudomonas Infections, Helmholtz-Centre for Infection Research, Braunschweig, Germany

3 Group Microbial Drugs, Helmholtz-Centre for Infection Research, Braunschweig, Germany

4 Sanofi-Aventis Deutschland GmbH, Natural Products, Geb. H811, Brüningstr., 65929 Frankfurt, Germany

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BMC Microbiology 2010, 10:199  doi:10.1186/1471-2180-10-199

Published: 26 July 2010



Streptococcus mutans is a major pathogen in human dental caries. One of its important virulence properties is the ability to form biofilms (dental plaque) on tooth surfaces. Eradication of such biofilms is extremely difficult. We therefore screened a library of secondary metabolites from myxobacteria for their ability to damage biofilms of S. mutans.


Here we show that carolacton, a secondary metabolite isolated from Sorangium cellulosum, has high antibacterial activity against biofilms of S. mutans. Planktonic growth of bacteria was only slightly impaired and no acute cytotoxicity against mouse fibroblasts could be observed. Carolacton caused death of S. mutans biofilm cells, elongation of cell chains, and changes in cell morphology. At a concentration of 10 nM carolacton, biofilm damage was already at 35% under anaerobic conditions. A knock-out mutant for comD, encoding a histidine kinase specific for the competence stimulating peptide (CSP), was slightly less sensitive to carolacton than the wildtype. Expression of the competence related alternate sigma factor ComX was strongly reduced by carolacton, as determined by a pcomX luciferase reporter strain.


Carolacton possibly interferes with the density dependent signalling systems in S. mutans and may represent a novel approach for the prevention of dental caries.