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Aureobasidium pullulans YTP6-14 was demonstrated to be an excellent multiple biosurfactant producer utilizing cheap carbon sources available in Thailand, including glycerol and cassava flour hydrolysate. A. pullulans YTP6-14 maximally produced 1.81 g/l biosurfactant in an aqueous layer (BS-AQ) in a medium containing glycerol, and 7.37 or 6.37 g/l biosurfactant in a heavy oil layer (BS-HO) in cassava flour hydrolysate or a glucose containing medium, respectively. Each BS-AQ and BS-HO had critical micelle concentration values of 41.32 mg/l and 13.51 mg/l, and both biosurfactants formed a stable food oil emulsion and reduced the amount of biofilms formed by Streptococcus sobrinus and Streptococcus mutans. BS-AQ and BS-HO were mainly composed of liamocins or exophilins and massoia lactone, respectively.

Streptococcus oralis subspecies dentisani is explored as an anti-cariogenic probiotic. Here, subjecting freshly stimulated saliva samples of 35 healthy volunteers, six epidemiologically unrelated and two related strains were isolated (prevalence around 20%) applying a newly developed three-step procedure. Furthermore, the probiotic strain S. dentisani 7746 (AB-Dentisanium®) was tested under a variety of environmental conditions for its inhibitory effect on six S. mutans , two S. sobrinus , 15 other oral or intestinal streptococci, 15 S. dentisani strains, and six representatives of other species including periodontopathogens. All except one of the S. mutans strains were inhibited by 7746 colonies or culture supernatant concentrate but only if either the test cell number was low or the producer or its bacteriocin concentration, respectively, was high. S. sanguinis OMI 332, S. salivarius OMI 315, S. parasanguinis OMI 335, S. vestibularis OMI 238, and the intestinal S. dysgalactiae OMI 339 were not inhibited, while the other 10 streptococcal strains (especially S. oralis OMI 334 and intestinal S. gallolyticus OMI 326) showed a certain degree of inhibition. From the panel of other bacterial species only Aggregatibacter actinomycetemcomitans was slightly inhibited. With the exception of OMI 285 and OMI 291 that possessed a 7746 bacteriocin-like gene cluster, all S. dentisani strains and especially type strain 7747 T were strongly inhibited by 7746. In conclusion, probiotic strain 7746 might antagonize the initiation and progression of dental caries by reducing S. mutans if not too abundant. S. dentisani strains inhibit each other, but strains with similar bacteriocin-related gene clusters, including immunity genes, are able to co-exist due to cross-resistance. In addition, development of resistance and adaptation to 7746-bacteriocins was observed during our study and needs attention. Hence, mechanisms underlying such processes need to be further investigated using omics-approaches. On the manufacturing level, probiotic strains should be continuously tested for function. Further clinical studies investigating inhibition of S. mutans by AB-Dentisanium® are required that should also monitor the impact on the oral microbiome composition including resident S. dentisani strains.

Objectives: To investigate the aspects of multi-species biofilm formation on various orthodontic adhesives with different surface characteristics., Methods: Multi-species biofilms using 13 bacterial species were grown on the surfaces of composite, compomer, and resin-modified glass-ionomer cement (RMGI). The changes in Streptococcus mutans (Sm), Streptococcus sobrinus (Ss), Porphyromonas gingivalis (Pg), Aggregatibacter actinomycetemcomitans (Aa), and total bacteria were determined at day 1 (T1) and day 4 (T2) using real-time polymerase chain reaction. Surface roughness (SR), surface free energy (SFE), and surface texture were analyzed to explain the differences in bacterial compositions among the adhesives. Repeated measures analysis of variance was used to determine time-related changes in bacterial compositions with respect to adhesive type. The Kruskal-Wallis test was used to determine differences in SR and SFE among the adhesives., Results: There were no significant differences in the adhesion of total bacteria among the adhesives; however, the adhesion of Sm, Ss, and Pg was higher to RMGI than the other adhesives. The amount of Sm, Ss, and total bacteria increased from T1 to T2, while Pg and Aa decreased from T1 to T2. RMGI showed a rougher surface relative to composite or compomer due to the presence of micro-pores and/or flaws. Compomer had the greatest SFE followed by RMGI and composite. Interestingly, SR differences were about 10 times greater than SFE differences among the adhesives., Conclusions: Considering the greater differences in SR than SFE among the adhesives, the rougher surface of RMGI may cause greater adhesion of Sm, Ss, and Pg., (© The Author 2017. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com)

Context: One traditional medicines, Hypericum perforatum L. (Hypericaceae), possesses several beneficial effects against depression, ulcers, dyspepsia, abdominal pains, burns, bacterial infections, migraine headaches, and sciatica., Objective: The present study investigates the antimicrobial activity of the ethanol extract (HP-EtOH) of H. perforatum and its sub-extracts, namely n-hexane (HP-hexane), chloroform (HP-CHCl3), ethyl acetate (HP-EtOAc), n-butanol (HP-n-BuOH), and water (HP-H2O) extracts, against Streptococcus mutans, S. sobrinus, Lactobacillus plantarum, and Enterococcus faecalis., Materials and Methods: For the evaluation of the antimicrobial activity, flowering aerial parts of H. perforatum were extracted with EtOH and then this extract was fractionated to obtain five sub-extracts in different polarities. Antimicrobial activities of HP-EtOH and its sub-extracts against Streptococcus mutans, S. sobrinus, L. plantarum, and E. faecalis were assessed by using colorimetric micro-well dilution at concentration ranges of 64-0.5 μg/ml as well as resazurin microplate and modified microtiter-plate assays between the ranges of 100 and 0.78125 μg/ml., Results: According to the results of the present study, HP-H2O sub-extract displayed strong antibacterial activity (MIC values 8 μg/mL) against S. sobrinus and L. plantarum, and exerted moderate activity against S. mutans and E. faecalis at 32 and 16 μg/mL concentrations, respectively. Other sub-extracts also demonstrated antimicrobial activity against S. sobrinus at a concentration of 16 μg/mL. HP-EtOAc and HP-n-BuOH showed antimicrobial activity against L. plantarum and HP-EtOAc and HP-H2O were also active against E. faecalis at the same concentrations (16 μg/mL)., Conclusion: According to the results, we suggest that H. perforatum could be employed as a natural antibacterial agent in oral care products.

The bacteria grow in oral cavity and product acids, which could induce dental caries. In this study, in order to obtain the relationship between procyanidin dimers from sorghum episperm (sorghum procyanidins, SPC) and its anticaries effect. The extract of SPC purified by macroporous resin was divided into three parts by gel chromatography, marked as GPC-1, GPC-2, and GPC-3 in order. The ESI-MS and MS/MS analysis indicated that the main composition of GPC-2 was procyanidin dimers. In addition, the capacities of antigrowth and antiacid on Sreptococcus sobrinus 6715 were analysised to investigate the effect of SPC dimers in protecting against dental caries. The results indicated that the minimum inhibitory concentration (MIC) of SPC dimers was 16 mg/mL. Furthermore, the SPC dimers had notable preventive effect < against the acid production of Sreptococcus sobrinus 6715 compared with the control group, which suppressed in a dose-dependent manner by pH decline. These findings indicated that SPC dimers had potential to be used as anticaries preventive medicine due to its strong capacity of antigrowth and antiacid.

Objectives: To examine the ability of a removable thermoplastic appliance (RTA) to adsorb hygienic solutions and inhibit bacterial growth and to examine the efficacy of three hygiene protocols in reducing bacterial biofilm adherence to RTA., Materials and Methods: Solution adsorption and bacterial growth inhibition were examined in vitro using paper vs RTA discs. Subsequently, 11 patients treated with RTA (mean age, 29.1 ± 4.7 years) were assigned into a sequence of three hygiene protocols: regular RTA brushing (baseline), immersion RTAs in chlorhexidine mouthwash (CHX), and using a vibrating bath with cleaning solution (VBC). For each patient, 12 upper RTAs were examined (2 baseline RTAs, 5 CHX RTAs, and 5 VBC RTAs), for a total of 132 RTAs. All RTAs were stained with gentian violet, and biofilm presence was measured using a photodensitometer., Results: The RTA discs did not adsorb CHX or cleaning solution. The later agent did not show antibacterial features. Baseline RTAs showed significant biofilm adherence (P < .001) on the posterior palatal side of the aligner and on the anterior incisal edge. CHX and VBC hygienic protocols significantly (P < .001) reduced baseline biofilm adherence by 16% and 50%, respectively. Hygienic improvement was maintained over 140 days when CHX and VBC were used. However, VBC was three times more efficient than CHX., Conclusions: This study highly recommends the use of a VBC protocol. Biofilm deposits on the RTA, especially on incisal edges and attachment dimples, could lead to inadequate tooth/RTA and attachment/RTA overlap and consequently impair tooth alignment.

Unlabelled: In orthodontics, fixed appliances placed in the oral cavity are colonized by microorganisms., Objective: The purpose of this study was to quantitatively determine the independent bacterial colonization of S. mutans and S. sobrinus in orthodontic composite resins., Material and Methods: Seven orthodontic composite adhesives for bonding brackets were selected and classified into 14 groups; (GIm, GIs) Enlight, (GIIm, GIIs) Grengloo, (GIIIm, GIIIs) Kurasper F, (GIVm, GIVs) BeautyOrtho Bond, (GVm, GVs) Transbond CC, (GVIm, GVIs) Turbo Bond II, (GVIIm, GVIIs) Blugloo. 60 blocks of 4x4x1 mm of each orthodontic composite resin were made (total 420 blocks), and gently polished with sand-paper and ultrasonically cleaned. S. mutans and S. sobrinus were independently cultivated. For the quantitative analysis, a radioactive marker was used to codify the bacteria (³H) adhered to the surface of the materials. The blocks were submerged in a solution with microorganisms previously radiolabeled and separated (210 blocks for S. mutans and 210 blocks for S. sobrinus) for 2 hours at 37 ºC. Next, the blocks were placed in a combustion system, to capture the residues and measure the radiation. The statistical analysis was calculated with the ANOVA test (Sheffè post-hoc)., Results: Significant differences of bacterial adhesion were found amongst the groups. In the GIm and GIs the significant lowest scores for both microorganisms were shown; in contrast, the values of GVII for both bacteria were significantly the highest., Conclusions: This study showed that the orthodontic composite resin evaluated in the GIm and GIs, obtained the lowest adherence of S. mutans and S. sobrinus, which may reduce the enamel demineralization and the risk of white spot lesion formation.

Aims: The aim of this study was to evaluate and to compare the effect of two fluoride varnishes and one fluoride/chlorhexidine varnish on Streptococcus mutans and Streptococcus sobrinus biofilm formation, in vitro., Study Design: Standard acrylic discs were prepared and divided into groups based on the varnish applied to the disc surface: Fluor Protector, Bifluoride 12, and Fluor Protector + Cervitec (1:1). Untreated discs served as controls. In the study groups, biofilms of S. mutans and S. sobrinus were formed over 24 h, 48 h, and 5 days. The fluoride concentrations in the monospecies biofilms and viable counts of S. mutans and S. sobrinus were investigated., Results: In all study groups, a statistically significant increase in the viable number of S. mutans and S. sobrinus cells was observed between 24 h and 5 days. In both monospecies biofilms, the greatest antibacterial efficacy was detected in the Fluor Protector and Fluor Protector + Cervitec groups at 24 h. For all groups, the amount of fluoride released was highest during the first 24 h, followed by a significant decrease over the next 4 days. A negative correlation was detected between fluoride concentration and antibacterial effect in those groups with biofilms containing both species. Despite the release of high levels of fluoride, the greatest number of viable S. mutans and S. sobrinus cells was detected in the Bifluoride 12 group., Statistics: The data were analyzed using GraphPad Prism software (ver. 3)., Conclusions: The Fluor Protector + Cervitec varnish exerted prolonged antibacterial effects on S. mutans and S. sobrinus biofilms compared to the other varnishes tested.

The purpose of this study was to investigate the effect of cranberry polyphenol fraction on mutans streptococci. Hydrophobicity is an important factor in the adherence of bacteria to the tooth surface. We found that cranberry polyphenol fraction significantly decreased the hydrophobicity of Streptococcus sobrinus 6715, Streptococcus mutans MT8148R and JC2 in a dose-dependent manner (p<0.05). Biofilm formation by S. sobrinus 6715 and S. mutans MT8148R was inhibited by 100 microg/ml cranberry polyphenol fraction (p<0.01). When dosage was increased to 500 microg/ml, biofilm formation by S. mutans JC2 was significantly inhibited (p<0.05). Addition of 500 microg/ml cranberry polyphenol fraction to medium inhibited growth of S. mutans MT8148R compared with the control (p<0.05).

Stable microbial communities associated with health can be disrupted by altered environmental conditions. Periodontal diseases are associated with changes in the resident oral microflora. For example, as gingivitis develops, a key change in the microbial composition of dental plaque is the ascendancy of Actinomyces spp. and gram-negative rods at the expense of Streptococcus spp. We describe the use of an in vitro model to replicate this population shift, first with a dual-species model (Actinomyces naeslundii and Streptococcus sobrinus) and then using a microcosm model of dental plaque. The population shift was induced by environmental changes associated with gingivitis, first by the addition of artificial gingival crevicular fluid and then by a switch to a microaerophilic atmosphere. In addition to the observed population shifts, confocal laser scanning microscopy also revealed structural changes and differences in the distribution of viable and nonviable bacteria associated with the change in environmental conditions. This model provides an appropriate system for the further understanding of microbial population shifts associated with gingivitis and for the testing of, for example, antimicrobial agents.

The objective of the study was to compare aciduricity (ability, to live in acid), acidogenicity (ability to produce acid), and intracellular polysaccharide production of mutans streptococci (MS) strains isolated from caries-active (CA, with one or more cavitated lesions) and caries-free (CF, with no clinically observable new caries in the last five years) adults. Forty-three MS strains from 17 of 17 CA adults, and 14 strains from eight of 12 CF adults were investigated. MS isolates' growth, survival, and pH reduction in pH 3.5-7.0 broths were evaluated to compare their acidogenicity and aciduricity. Extracellular water-soluble polysaccharide (WSP) and water-insoluble polysaccharide (WISP) was extracted from MS culture in BHI broth with 5 percent sucrose and assessed by a colorimetric anthrone-sulfuric acid microassay. No significant differences in mean aciduricity were found between CA and CF MS isolates (P>0.05, t test). However, significantly more CA subjects (29 percent) were colonized by MS strains with aciduricity above the average than CF subjects (13 percent, Fisher's exact test, P<0.05). Furthermore, CA MS strains produced significantly more acid at pH<5 (Mann-Whitney, P<0.05) and significantly more CA subjects were colonized with more acidogenic MS at pH<4.5 (Fisher's exact test, P<0.01). Similarly, CA MS isolates produced significantly more WISP than CF (Mann-Whitney test, P<0.01) while no statistical difference was found in WSP between the two groups. More CA subjects were colonized by multiple strains with aciduricity, acidogenicity, and polysaccharide synthesis ability above average. The study indicated that differences in acidogenicity, aciduricity, and polysaccharide synthesis in strains of MS may partially contribute to increased caries activity.

The aim of this study was to examine the diffusion of macromolecules through an in vitro biofilm model of supragingival plaque. Polyspecies biofilms containing Actinomyces naeslundii, Fusobacterium nucleatum, Streptococcus oralis, Streptococcus sobrinus, Veillonella dispar, and Candida albicans were formed on sintered hydroxyapatite disks and then incubated at room temperature for defined periods with fluorescent markers with molecular weights ranging from 3,000 to 900,000. Subsequent examination by confocal laser scanning microscopy revealed that the mean square penetration depths for all tested macromolecules except immunoglobulin M increased linearly with time, diffusion coefficients being linearly proportional to the cube roots of the molecular weights of the probes (range, 10,000 to 240,000). Compared to diffusion in bulk water, diffusion in the biofilms was markedly slower. The rate of diffusion for each probe appeared to be constant and not a function of biofilm depth. Analysis of diffusion phenomena through the biofilms suggested tortuosity as the most probable explanation for retarded diffusion. Selective binding of probes to receptors present in the biofilms could not explain the observed extent of retardation of diffusion. These results are relevant to oral health, as selective attenuated diffusion of fermentable carbohydrates and acids produced within dental plaque is thought to be essential for the development of carious lesions.

The spatial arrangements and associative behavior of Actinomyces naeslundii, Veillonella dispar, Fusobacterium nucleatum, Streptococcus sobrinus, and Streptococcus oralis strains in an in vitro model of supragingival plaque were determined. Using species-specific fluorescence-labeled antibodies in conjunction with confocal laser scanning microscopy, the volumes and distribution of the five strains were assessed during biofilm formation. The volume-derived cell numbers of each strain correlated well with respective culture data. Between 15 min and 64 h, populations of each strain increased in a manner reminiscent of batch growth. The microcolony morphologies of all members of the consortium and their distributions within the biofilm were characterized, as were interspecies associations. Biofilms formed 15 min after inoculation consisted principally of single nonaggregated cells. All five strains adhered strongly to the saliva-conditioned substratum, and therefore, coadhesion played no role during the initial phase of biofilm formation. This observation does not reflect the results of in vitro coaggregation of the five strains, which depended upon the nature of the suspension medium. While the possibility cannot be excluded that some interspecies associations observed at later stages of biofilm formation were initiated by coadhesion, increase in bacterial numbers appeared to be largely a growth phenomenon regulated by the prevailing cultivation conditions.

Living Streptococcus sobrinus cells were orally inoculated into nonimmune rabbits and rabbits immunized with formalin-killed cells of S. sobrinus through tonsillar application to examine the anticaries potential of this method of immunization. The living S. sobrinus cell numbers and the caries areas in the rabbits immunized by tonsillar application decreased to a level one-fifth of that in nonimmune rabbits.

The inhibitory effect of hop bract polyphenols (HBP) on cariogenic streptococci was investigated. It was found that the high molecular weight polyphenol (estimated about 36,000-40,000) inhibited the cellular adherence of Streptococcus mutans MT8148 (serotype C) and Streptococcus sobrinus ATCC 33478 (serotype g) at much small concentrations than the polyphenols extracted from oolong tea or green tea leaves. Furthermore, HBP also inhibited the action of glucosyltransferase, which was involved in the water-insoluble glucan synthesis, but did not suppress the growth and the acid production of the bacteria. These results suggest that HBP would be a candidate to act against dental caries caused by Mutans Streptococci.

An inhibitor of Streptococcus sobrinus endodextranase was detected in the extracellular fractions of UAB66 mutants identified following ethyl methanesulfonate mutagenesis as either devoid of dextranase activity (Dex-) or overproducing water-soluble glucan. The two groups of mutants had the same phenotype and displayed no dextranase activity in assays of extracellular fractions (H. Murchison, S. Larrimore, and R. Curtiss III, Infect. Immun. 34:1044-1055, 1981) and had been shown to be defective in adherence (Adh-) and capable of inhibiting adherence of wild-type strains during cocultivation in vitro (H. Murchison, S. Larrimore, and R. Curtiss III, Infect. Immun. 50:826-832, 1985) and in vivo in gnotobiotic rats (K. Takada, T. Shiota, R. Curtiss III, and S. M. Michalek, Infect. Immun. 50:833-843, 1985). By analysis of proteins in Western blots (immunoblots) and following blue dextran-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (BD-SDS-PAGE), it was demonstrated that these Dex- mutants did synthesize enzymatically active dextranase. From the results of mixing experiments, it was determined that these Dex- Adh- mutants produced enhanced amounts of a cell surface-localized or a cell-associated dextranase inhibitor (Dei). Dei was heat stable but trypsin sensitive. By adding excess dextranase following BD-SDS-PAGE, Dei was detected as blue bands with apparent molecular masses of 43, 40, 37, 27, and 23 kDa. Dei competitively inhibits dextranase activity and is synthesized by wild-type S. sobrinus strains, with the amount varying depending upon growth medium and stage in the growth cycle. R. M. Hamelik and M. M. McCabe (Biochem. Biophys. Res. Commun. 106:875-880, 1982) previously described a Dei in a wild-type S. sobrinus strain.

One hundred and twenty weanling rats fed diet NIH 2000 that were free of Streptococcus sobrinus and other mutans streptococci were employed in this study. Sixty rats were inoculated orally with S. sobrinus 6715. Each infected rat (donor) was paired and housed with an uninfected recipient. Saliva and serum samples were collected from 24 (12 donor and 12 recipient) rats at the baseline (day 0) and from groups of 12 recipients sacrificed on days 10, 24, 38, and 52, and the level of infection with S. sobrinus was monitored. Salivary immunoglobulin A (IgA) and IgG and serum IgM and IgG antibodies reactive with whole cells (WC), glucosyltransferase (GTF), and the serotype carbohydrate (g) of S. sobrinus were measured by an indirect enzyme-linked immunosorbent assay. Although the rats were free of S. sobrinus and other mutans streptococci at baseline, they exhibited salivary IgA and serum IgM antibodies reactive with S. sobrinus WC, GTF, and g and serum IgG antibodies reactive with WC and GTF. Infection of recipients with S. sobrinus did not induce salivary antibodies reactive with WC, GTF, or g. In contrast, increases in serum IgM and IgG antibodies reactive with WC and serum IgM antibodies reactive with g were observed.