Characterization and Selection of Lactobacillus plantarum and Lactobacillus paracasei for prevention of oral bacterial infections from Chinese pickle

The oral infections were mainly caused by Streptococci and Staphylococcus aureus. Antibiotic therapies can eliminate these harmful bacteria. However, it can break beneficial microbes and lead to the persistence of resistant strains. The objective of our study was to select potential probiotic strains for the prevention of oral bacterial infections and evaluate their potential probiotic properties in oral cavity. AR113 (Lactobacillus plantarum) and AR340 (Lactobacillus paracasei) with significantly antimicrobial β-hemolytic streptococci and Staphylococcus aureus activity were isolated from Chinese pickle through agar well diffusion assay. Through the analyses of probiotic properties in antibiofilm, lysozyme and hydrogen peroxide tolerance, bacterial surface properties, adherence ability, tooth degradation and anti-inflammatory activity, the AR113 and AR340 showed anti-adhesion activity of 45.2–71.1% and 20.3–56.8% against β-hemolytic streptococci and 15.4–52.6% and 30.7–65.9% against Staphylococcus aureus, respectively, at different concentration. The two strains with high hydrophobicity, autoaggregation and survival rate adhered strongly to FaDu cells. AR113 and AR340 exhibited low calcium released from teeth (0.04 μg/mL and 0.03 μg/mL, respectively). ELISA analysis showed that AR113 and AR340 significantly inhibited the LPS-induced increase of NO and TNF-α expression. Strains-fermented skim milk inhibited the growth of β-hemolytic streptococci or Staphylococcus aureus. AR113 and AR340 were considered as probiotic candidates because of their higher antibacterial activity against some oral pathogenic bacteria, no potential of primitive cariogenicity. These candidates were expected as new probiotics with potential oral health benefits and no harmful effects.