JAC Advance Access published online on October 10, 2007
Journal of Antimicrobial Chemotherapy, doi:10.1093/jac/dkm382
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Role of the ammonium group in the diffusion of quaternary ammonium compounds in Streptococcus mutans biofilms
1 Department of Chemistry, Université de Montréal, CP 6128, Succ. Centre-Ville, Montréal, Québec, Canada H3C 3J7 2 Department of Stomatology, Faculty of Dentistry, Université de Montréal, CP 6128, Centre-Ville, Montréal, Québec, Canada H3C 3J7
Received 4 June 2007; returned 22 June 2007; revised 21 August 2007; accepted 10 September 2007
* Corresponding author. Tel: +1-514-343-5936; Fax: +1-514-343-7586; E-mail: michel.lafleur{at}umontreal.ca
Objectives: Cetylpyridinium chloride (CPC), a quaternary ammonium compound, was shown to interact irreversibly with Streptococcus mutans biofilms, leading to a slow diffusion compared with poly(ethylene glycol) (PEG) molecules of similar size. The objective of this work is to determine if the retardation of CPC diffusion and its strong binding to biofilms is caused by interactions between the ammonium group of CPC and the exopolysaccharide (EPS) matrix.
Methods: First, we characterized the diffusion of two analogues of CPC in S. mutans biofilms: dodecylpyridinium chloride (DPC), carrying a shorter alkyl chain than CPC, and tetramethylene bispyridinium chloride (TMBPC), a compound carrying two positively charged ammonium groups. Second, we cultured biofilms with different densities of EPS and examined the impact of this density on the transport properties of CPC. The diffusion of these compounds was probed using infrared spectroscopy with attenuated total reflectance sampling.
Results: The diffusion of CPC, DPC and TMBPC in S. mutans biofilm is slower than that of PEG10k. In addition, TMBPC and DPC, as PEG10k, could be readily washed out from the biofilms while CPC association was practically irreversible. The penetration of CPC through the EPS matrix was found to be not significantly affected by the increased EPS density, whereas the penetration of PEG with a molar mass of 10k was considerably reduced.
Conclusions: These results suggest that the interactions between the quaternary ammonium groups and the EPS matrices are not the prime contribution of the strong CPC binding, and the alkyl chain length plays a role in this association, likely through hydrophobic interactions.
Key Words: bacteria , S. mutans , FTIR spectroscopy , diffusion , PEG
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  J. J. Harrison, R. J. Turner, D. A. Joo, M. A. Stan, C. S. Chan, N. D. Allan, H. A. Vrionis, M. E. Olson, and H. Ceri Copper and Quaternary Ammonium Cations Exert Synergistic Bactericidal and Antibiofilm Activity against Pseudomonas aeruginosa Antimicrob. Agents Chemother., August 1, 2008; 52(8): 2870 - 2881. [Abstract] [Full Text] [PDF]
|
|