Abstract
Streptococcus mutans contributes significantly to dental caries, which
arises from homoeostasic imbalance between host and microbiota. We
hypothesized that Lactobacillus sp. inhibits growth, biofilm formation
and gene expression of Streptococcus mutans. Antibacterial (agar
diffusion method) and antibiofilm (crystal violet assay) characteristics
of probiotic Lactobacillus sp. against Streptococcus mutans (ATCC 25175)
were evaluated. We investigated whether Lactobacillus casei (ATCC 393),
Lactobacillus reuteri (ATCC 23272), Lactobacillus plantarum (ATCC 14917)
or Lactobacillus salivarius (ATCC 11741) inhibit expression of
Streptococcus mutans genes involved in biofilm formation, quorum sensing
or stress survival using quantitative real-time polymerase chain
reaction (qPCR). Growth changes (OD600) in the presence of
pH-neutralized, catalase-treated or trypsin-treated Lactobacillus sp.
supernatants were assessed to identify roles of organic acids, peroxides
and bacteriocin. Susceptibility testing indicated antibacterial
(pH-dependent) and antibiofilm activities of Lactobacillus sp. against
Streptococcus mutans. Scanning electron microscopy revealed reduction in
microcolony formation and exopolysaccharide structural changes. Of the
oral normal flora, L.salivarius exhibited the highest antibiofilm and
peroxide-dependent antimicrobial activities. All biofilm-forming cells
treated with Lactobacillus sp. supernatants showed reduced expression of
genes involved in exopolysaccharide production, acid tolerance and
quorum sensing. Thus, Lactobacillus sp. can inhibit tooth decay by
limiting growth and virulence properties of Streptococcus mutans.
Original language | American English |
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Journal | Default journal |
State | Published - Jan 1 2018 |
Keywords
- probiotic Lactobacillus, Streptococcus mutans, biofilm
Disciplines
- Bacterial Infections and Mycoses
- Immunology of Infectious Disease