Selection of oral microbial adhesion antagonists using biotinylated Streptococcus sanguis and a human mixed oral microflora

Who will win the race in childrens' oral cavities? Streptococcus mutans or beneficial lactic acid bacteria?

Adhesion to oral soft and hard tissue is crucial for bacterial colonisation in the mouth. The aim of this work was to select strains of oral lactic acid bacteria that could be used as probiotics for oral health. To this end, the adhesive properties of some lactic acid bacteria were investigated. Seventeen lactic acid bacteria including two Streptococcus mutans strains were isolated from the oral cavity of healthy children, while other strains were isolated from fermented meat products. The bacterial strains were applied to teeth surfaces covered with saliva or without saliva. A significant diversity in adhesion capacity to teeth surfaces among the lactic acid bacteria was observed. Lactic acid bacteria isolated from the oral cavity adhered the best to teeth surfaces covered with saliva, whereas lactic acid bacteria isolated from fermented meat samples adhered the best to tooth surface without saliva. All strains of lactic acid bacteria were able to reduce the number of S. mutans cells, in particular on saliva-coated tooth surface. Therefore, they might have potential as probiotics for the oral cavity.

Inhibitory effect of cranberry juice on the colonization of Streptococci species: An in vitro study

BACKGROUND

Dental biofilm harboring oral bacteria is highly correlated with the progression of dental diseases. The existence of micro organisms as polyspecies in an oral biofilm and dental plaque has profound implications for the etiology of periodontal disease. The adhesion of streptococci to the tooth surface is the first step in the formation of dental plaque. Antiadhesive agents which can disrupt the biofilm formation can be an effective alternative to antibacterial therapy.

MATERIALS AND METHODS

A total of 10 patients both male and female between the age group of 20-40 years were included in the study. Plaque samples were taken and subjected to culturing on rabbit's blood agar plate for the growth of streptococci colonies for 24-48 h. The streptococci colonies were identified and was further subjected to subculturing for 24-48 h with disc containing ethyl alcohol+cranberry extract (Group A) and water+cranberry extract (Group B). Both these groups A and B were further divided into subgroups I, II, III, IV, and V according to concentration 1:2, 1:4, 1:40, 1:100 and 1:600 respectively.

RESULTS

Zone of inhibition of Group A with subgroup I disc was 2 mm. while with subgroups II, III, IV, V disc was 4mm. Whereas the zone of inhibition seen of Group B was same (2mm) in subgroups I, II, III, IV discs however a significant zone of inhibition (10mm) was observed in subgroup V disc.

CONCLUSION

CRANBERRY JUICE (ACTIVE INGREDIENT: Non dialyzable material) inhibits the adhesion and reverses the coaggregation of various oral micro organisms. The present study revealed that cranberry gel in highly concentrated (1:600) form has an inhibitory effect on the colonization of the streptococci species, and thus can be beneficial in the inhibition of dental plaque formation.

Pacifiers: A microbial reservoir

The permanent contact between the nipple part of pacifiers and the oral microflora offers ideal conditions for the development of biofilms. This study assessed the microbial contamination on the surface of 25 used pacifier nipples provided by day-care centers. Nine were made of silicone and 16 were made of latex. The biofilm was quantified using direct staining and microscopic observations followed by scraping and microorganism counting. The presence of a biofilm was confirmed on 80% of the pacifier nipples studied. This biofilm was mature for 36% of them. Latex pacifier nipples were more contaminated than silicone ones. The two main genera isolated were Staphylococcus and Candida. Our results confirm that nipples can be seen as potential reservoirs of infections. However, pacifiers do have some advantages; in particular, the potential protection they afford against sudden infant death syndrome. Strict rules of hygiene and an efficient antibiofilm cleaning protocol should be established to answer the worries of parents concerning the safety of pacifiers.

The prevention of plaque re-growth by toothpastes and solutions containing block copolymers with and without polypeptide

BACKGROUND/AIMS

Chemicals which have a direct effect at inhibiting or reducing bacterial adherence to tooth surfaces may subsequently inhibit plaque growth and reduce gingival inflammation. This study investigated whether two anti-adherent systems could inhibit plaque re-growth in the mouth when rinsed as a solution or as a toothpaste slurry.

METHODS

A total of 21 subjects took part in a partially blind, seven cell cross-over study which compared the effects on plaque re-growth of a binary system containing block copolymers, a ternary system containing block copolymers and polypeptide, both used as toothpaste slurry rinses, their corresponding solution rinses, a conventional fluoride toothpaste rinse, a positive control chlorhexidine rinse and a negative water control. Following a dental prophylaxis subjects then rinsed with 10 ml of one of the test products for 1 min. twice a day over a 4-day period. Throughout each trial period the subjects were not permitted to use any other forms of oral hygiene. On the fifth day (96 h), the volunteers returned to the clinic, and plaque was assessed by (1) plaque index and (2) plaque area following disclosing with a food dye. The test phase of the trial was repeated for each agent and was followed by a 10-day "washout" period.

RESULTS

Essentially neither of the anti-adherent systems inhibited plaque re-growth, whether administered in a toothpaste slurry or solution compared with the controls. If anything, neither of the test pastes were as effective as the marketed commercial paste (p<0.001). As expected plaque recorded following use of the chlorhexidine rinse was significantly less than that seen with any of the other rinses (p<0.001).

CONCLUSIONS

Using this 4-day plaque re-growth model, the findings of this study failed to show any benefit in using the anti-adherent systems, either in a rinse or toothpaste, with the aim of inhibiting or reducing plaque formation.

Cranberry high molecular weight constituents promote Streptococcus sobrinus desorption from artificial biofilm

Dental biofilm harbouring oral bacteria is highly correlated with the progression of dental diseases. Disruption of biofilm formation via anti-adhesion agents is an alternative means to the antibacterial approach. Previous studies have shown that high molecular weight non-dialysable material (NDM) derived from cranberry juice inhibits the adhesion of Escherichia coli and the coaggregation of a variety of oral bacteria. In addition, it inhibits the formation of glucans and fructans synthesised by GTF and FTF. In the present study, we examined the anti-adhesion effect of NDM on S. sobrinus. NDM promoted desorption of S. sobrinus from biofilm in the presence and absence of extracellular glucans and fructans, although the effect was more pronounced in the absence of these polysaccharides. Precoating of the bacteria with NDM reduced their ability to form biofilm. Our results indicate that NDM could be exploited as an anti-biofilm agent.

Moderation of oral bacterial adhesion on saliva-coated hydroxyapatite by polyaspartate

AIMS

Synthetic sodium alpha,beta-polyaspartate (PA) has been investigated as a moderator of adhesion and the subsequent biofilm formation by oral bacteria.

METHODS AND RESULTS

The inhibition of bacterial adhesion by PA was assessed by (i) a 30-min incubation with Streptococcus sanguis in a microtitre assay with the wells coated with hydroxyapatite (HAP) and (ii) an 18-h challenge with human salivary microflora in a HAP disc assay. In contrast to HAP-coated surfaces, clean polystyrene surfaces in the microtitre assay exhibited no anti-adhesion properties. It has been found that PA significantly and similarly adsorbs onto HAP surfaces in the presence and absence of salivary coating. The HAP disc assay also showed that PA, both in aqueous solutions and in toothpaste, reduced the level of adhered microflora and this effect was enhanced by added propylene oxide-ethylene oxide copolymers.

CONCLUSION

The principal finding from this work is the potential role for PA as an inhibitor of dental plaque formation. PA may significantly modify the salivary pellicle.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work indicates the use of PA in controlling the development of dental plaque and the formation of bacterial biofilm in general.

Synergy of binary poly(oxypropylene-oxyethylene) copolymers in reducing retention of Streptococcus sanguis to hydroxyapatite

Binary poly(oxypropylene-oxyethylene) block copolymer systems have been investigated as a non-bactericidal approach to reduce the retention of an oral bacterium, Streptococcus sanguis. Using a previously validated hydroxyapatite-coated microtitre model to simulate the tooth, the performance of copolymer pairs was measured experimentally. A synergy index and an efficacy index were defined to describe the reduction of bacterial retention by the binary systems that comprise the copolymer pairs. Relationships between the synergy and efficacy indices and their associated compositions are given. The results obtained have been rationalised using a previously developed theoretical approach in conjunction with the binding energetics of species to surfaces.