Probiotic Potential of Lactic Acid Bacterial Strains Isolated from Human Oral Microbiome

Lactic acid bacteria are widely studied microorganisms and are one of the prevalent groups of bacteria in the oral cavity microbiome. This work aimed to isolate new lactic acid bacterial strains from the human oral cavity and evaluate their characteristics and probiotic potential. Twelve strains were isolated and identified as belonging to several genera in the family Lactobacillaceae. Screening for antimicrobial activity was held, where two of the strains showed antagonistic activity against Streptococcus mutans and most of the strains expressed inhibition against Escherichia coli, Bacillus subtilis, and Bacillus cereus. The ability of the studied strains to autoaggregate and bind to mucin was assessed, showing autoaggregative properties and mucin binding at 5 logs CFU/mL. The survival ability in simulated oral and gastrointestinal conditions and growth dynamics with different gastrointestinal stress factors was studied. Most of the strains showed a good growth potential in the presence of oral and gastrointestinal stress factors. All tested strains exhibited high survival rates in the simulated oral environment, thus having the potential for colonizing the oral cavity and their beneficial properties to be applied. These results are a good basis for continuing the research into these strains so they can be included in new functional products for oral health.