Draft genome sequence of Limosilactobacillus fermentum isolated from subgingival biofilm.

Limosilactobacillus fermentum is generally considered beneficial for vaginal and digestive health. However, strains isolated from the oral cavity, especially from periodontitis lesions, have not been thoroughly studied. Here, we report the draft genome sequence of strain KHUD_007 isolated from the subgingival biofilm of a Korean patient with periodontitis.

Genomic and phenotypic comparison of Prevotella intermedia strains possessing different virulence in vivo.

Prevotella intermedia readily colonizes healthy dental biofilm and is associated with periodontal diseases. The viscous exopolysaccharide (EPS)-producing capability is known as a major virulence factor of P. intermedia 17 (Pi17). However, the inter-strain difference in P. intermedia regarding virulence-associated phenotype is not well studied. We compared in vivo virulence and whole genome sequences using five wild-type strains: ATCC 49046 (Pi49046), ATCC 15032 (Pi15032), ATCC 15033 (Pi15033), ATCC 25611 (Pi25611), and Pi17. Non-EPS producing Pi25611 was the least virulent in insect and mammalian models. Unexpectedly, Pi49046 did not produce viscous EPS but was the most virulent, followed by Pi17. Genomes of the five strains were quite similar but revealed subtle differences such as copy number variations and single nucleotide polymorphisms. Variations between strains were found in genes encoding glycosyltransferases and genes involved in the acquisition of carbohydrates and iron/haem. Based on these genetic variations, further analyses were performed. Phylogenetic and structural analyses discovered phosphoglycosyltransferases of Pi49046 and Pi17 have evolved to contain additional loops that may confer substrate specificity. Pi17, Pi15032, and Pi15033 displayed increased growth by various carbohydrates. Meanwhile, Pi49046 exhibited the highest activities for haemolysis and haem accumulation, as well as co-aggregation with Porphyromonas gingivalis harbouring fimA type II, which is more tied to periodontitis than other fimA types. Collectively, subtle genetic differences related to glycosylation and acquisition of carbohydrates and iron/haem may contribute to the diversity of virulence and phenotypic traits among P. intermedia strains. These variations may also reflect versatile strategies for within-host adaptation of P. intermedia.

Effects of Sodium Tripolyphosphate on Oral Commensal and Pathogenic Bacteria.

Polyphosphate (polyP) is a food additive with antimicrobial activity. Here we evaluated the effects of sodium tripolyphosphate (polyP3, Na5P3O10) on four major oral bacterial species, in both single- and mixed-culture. PolyP3 inhibited three opportunistic pathogenic species: Fusobacterium nucleatum, Prevotella intermedia, and Porphyromonas gingivalis. On the contrary, a commensal bacterium Streptococcus gordonii was relatively less susceptible to polyP3 than the pathogens. When all bacterial species were co-cultured, polyP3 (≥ 0.09%) significantly reduced their total growth and biofilm formation, among which the three pathogenic bacteria were selectively inhibited. Collectively, polyP3 may be an alternative antibacterial agent to control oral pathogenic bacteria.Polyphosphate (polyP) is a food additive with antimicrobial activity. Here we evaluated the effects of sodium tripolyphosphate (polyP3, Na5P3O10) on four major oral bacterial species, in both single- and mixed-culture. PolyP3 inhibited three opportunistic pathogenic species: Fusobacterium nucleatum, Prevotella intermedia, and Porphyromonas gingivalis. On the contrary, a commensal bacterium Streptococcus gordonii was relatively less susceptible to polyP3 than the pathogens. When all bacterial species were co-cultured, polyP3 (≥ 0.09%) significantly reduced their total growth and biofilm formation, among which the three pathogenic bacteria were selectively inhibited. Collectively, polyP3 may be an alternative antibacterial agent to control oral pathogenic bacteria.

A Polysaccharide-Based Antibacterial Coating with Improved Durability for Clear Overlay Appliances.

Clear overlay appliances (COAs) are widely used in orthodontic fields because they offer many advantages, such as cost-effectiveness, good formability, and good optical characteristics. However, it is necessary to frequently replace COAs because the thermoplastic polymers that are used to fabricate COAs have poor abrasion resistance and have a tendency to induce bacterial accumulation. Here, we have developed polysaccharide-based antibacterial multilayer films with enhanced durability, intended for COA applications. First, multilayer films composed of carboxymethylcellulose (CMC) and chitosan (CHI) were fabricated on polyethylene terephthalate glycol-modified (PETG), which was preferred material for COA fabrication, via a layer-by-layer (LbL) technique. Next, chemical cross-linking was introduced within the LbL-assembled multilayer films. The LbL-assembled CMC/CHI film, which was made porous and rough by the cross-linking, formed a superhydrophilic surface to prevent the adhesion of bacteria and exhibited a bacterial reduction ratio of ∼75%. Furthermore, the cross-linking of the multilayer film coated on the PETG also improved the chemical resistance and mechanical stability of the PETG under simulated intraoral conditions with artificial saliva, by increasing the bond strength between the polysaccharide chains. We attempted to accumulate datasets using our experimental design and to develop sophisticated methods to assess nanoscale changes through large-scale measurements.