Action of secondary metabolites of Lactobacillus strains against caries causing microorganism Streptococcus mutans, oral care in vitro study

Oral health has a direct impact on an individual’s wellbeing and quality of life. Probiotics are increasingly being recognized as an effective preventive measure in dental hygiene. The goal of the present study was to evaluate the action of secondary metabolites of Lactobacillus strains against caries causing microorganism Streptococcus mutans. Lactobacillus reuteri was isolated from probiotic chewable tablet and lab reference strains Lactobacillus plantarum and Lactobacillus casei were also taken for the study. Isolated strain from chewable tablet was confirmed to be Lactobacillus reuteri based on colony morphology, physiological and biochemical characterization. All the strains were cultured in respective culture media and cell free supernatant was collected to observe the antagonistic activity against Streptococcus mutans. Antimicrobial efficacy was observed through zone of inhibition against all the strains with Lactobacillus reuteri 9.24±0.07 mm, Lactobacillus plantarum 14.42±0.02 mm and Lactobacillus casei 10.12±0.02 mm, Mean ± SME and no zone of inhibition was observed for MRS broth blank control. Lactobacillus reuteri and Lactobacillus casei strains were confirmed to be bacteriostatic while Lactobacillus plantarum was confirmed to be bactericidal. Inhibitory effect of Lactobacillus strains on other Lactobacillus strains and Streptococcus mutans on Lactobacillus strains was also observed showing no inhibition against the strains. Results confirmed that all the three strains were effective against Streptococcus mutans and lab reference strains Lactobacillus plantarum and Lactobacillus casei can also be used in formulations like gummies, chewable tablets and lozenges as the delivery carrier for oral probiotics products for oral care against caries causing microorganism Streptococcus mutans.