title: Candida albicans in oral biofilms could prevent caries.
abstract: Streptococcus mutans is a Gram-positive bacterium involved in development to caries, the most common infectious disease of our time. Streptococcus mutans interacts with other microbes, like the fungus Candida albicans and both are commonly isolated from patients with caries. Since the role of C. albicans in caries remains unknown, our aim was to unravel this using an in vitro dual-species cariogenic oral biofilm model. Biofilms were grown for 24-72 h on glass cover slips or hydroxyapatite (HA) disks to mimic the surface of teeth. Medium pH, lactic acid production capacity and calcium release from HA disks were determined. All 24-h biofilms had external pH values below the critical pH of 5.5 where enamel dissolves. In contrast, 72-h dual-species biofilms had significantly higher pH (above the critical pH) and consequently decreased calcium release compared to single-species S. mutans biofilms. Counter intuitively, lactic acid production and growth of S. mutans were increased in 72-h dual-species biofilms. Candida albicans modulates the pH in dual-species biofilms to values above the critical pH where enamel dissolves. Our results suggest that C. albicans is not by definition a cariogenic microorganism; it could prevent caries by actively increasing pH preventing mineral loss.
authors.affiliation: Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Amsterdam, The Netherlands.
authors.forename: Hubertine Marjoleine
authors.initials: HM
authors.lastname: Willems
authors.affiliation: Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Amsterdam, The Netherlands.
authors.forename: Kevin
authors.initials: K
authors.lastname: Kos
authors.affiliation: Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Amsterdam, The Netherlands.
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Jabra-Rizk
authors.affiliation: Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Amsterdam, The Netherlands b.krom@acta.nl.
authors.forename: Bastiaan P
authors.initials: BP
authors.lastname: Krom
mesh_terms: D018441:Biofilms; D002118:Calcium / Q000378:metabolism; D002176:Candida albicans / Q000502:physiology*; D015169:Colony Count, Microbial; D003731:Dental Caries / Q000517:prevention & control*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000096:biosynthesis; D056265:Microbial Interactions; D009055:Mouth / Q000382:microbiology*; D013295:Streptococcus mutans / Q000502:physiology
chemical_list: D019344:Lactic Acid; D002118:Calcium
keywords: Candida albicans; Streptococcus mutans; interspecies interaction; oral biofilm