SELECTION OF LACTIC ACID BACTERIA FOR THE PREVENTION OF DENTAL CARIES

The objective of this study was to isolate oral lactic acid bacteria, selecting those with a higher anti-cariogenic potential. 72 LAB were obtained from the dental surface of healthy children, 9 strains of which were preselected and subjected to further analysis. Antimicrobial activity was quantified against 8 native Streptococcus mutans isolates and the strain ATCC S. mutans 25175. Strains CB43, CB44, and CB45 inhibited the growth of each tested pathogen. Using the E-test technique, all 9 strains were susceptible to 13 of the 21 tested antimicrobial agents. A cariogenic model was made using human dental pieces and artificial saliva. Estimated specific growth rate for strains adhered to dental pieces was 0.63h-1±0.09(R2=0.89) for strain CB44, and 0.70h-1±0.18(R2=0.78) for strain CB45. Innocuousness of strains CB44 and CB45 was proved by treating Balb/c mice with 1x109 CFU of each strain. Animals treated with CB44 and CB45 showed no signs of disease. There were no significant differences in the hematocrit, total and differential leukocyte counts, neither IL-6 concentration in the spleen, lymph nodes, and intestines of treated mice when compared to the control group.  Strains CB44 and CB45, identified as Lactobacillus fermentum, show potential to be part of a safe oral probiotic product.