Effect of a Lactobacillus Salivarius Probiotic on a Double-Species Streptococcus Mutans and Candida Albicans Caries Biofilm

Abstract

The aim of the study was to evaluate the anti-cariogenic effects of <i>Lactobacillus salivarius</i> by reducing pathogenic species and biofilm mass in a double-species biofilm model. Coexistence of <i>S. mutans</i> with <i>C. albicans</i> can cause dental caries progression or recurrence of the disease in the future. Fifty-nine children with diagnosed early childhood caries (ECC) were recruited onto the study. The condition of the children's dentition was defined according to the World Health Organization guidelines. The participants were divided into children with initial enamel demineralization and children showing dentin damage. The study was performed on the <i>S. mutans</i> and <i>C. albicans</i> clinical strains, isolated from dental plaque of patients with ECC. The effect of a probiotic containing <i>Lactobacillus salivarius</i> on the ability of <i>S. mutans</i> and <i>C. albicans</i> to produce a double-species biofilm was investigated in an in vitro model. The biomass of the formed/non-degraded biofilm was analyzed on the basis of its crystal violet staining. The number of colonies of <i>S. mutans</i> and <i>C. albicans</i> (CFU/mL, colony forming units/mL) forming the biofilm was determined. Microorganism morphology in the biofilm was evaluated using a scanning electron microscope (SEM). In vitro analysis demonstrated that the presence of <i>S. mutans</i> increased the number of <i>C. albicans</i> colonies (CFU/mL); the double-species biofilm mass and hyphal forms produced in it by the yeast. <i>L. salivarius</i> inhibited the cariogenic biofilm formation of <i>C. albicans</i> and <i>S. mutans</i>. Under the influence of the probiotic; the biofilm mass and the number of <i>S. mutans</i>; <i>C. albicans</i> and <i>S. mutans</i> with <i>C. albicans</i> colonies in the biofilm was decreased. Moreover; it can be noted that after the addition of the probiotic; fungi did not form hyphae or germ tubes of pathogenic potential. These results suggest that <i>L. salivarius</i> can secrete intermediates capable of inhibiting the formation of cariogenic <i>S. mutans</i> and <i>C. albicans</i> biofilm; and may inhibit fungal morphological transformation and thereby reduce the pathogenicity of <i>C. albicans</i>; weakening its pathogenic potential. Further research is required to prove or disprove the long-term effects of the preparation and to achieve preventive methods.