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Humoral IgG antibodies to oral microbiota in a population at risk for root-surface caries.

Mutans streptococci have been strongly implicated in the initiation of dental caries on coronal surfaces. Their role in development of root-surface caries is less clear. The etiologic agents of both types of dental caries are likely to elicit systemic immune responses. The objective of the present study, therefore, was to study the association of clinical variables of disease with humoral IgG antibodies to nine oral micro-organisms in 314 adult subjects, aged 45-65 years, who were at risk for root-surface caries. Antibody activity to Streptococcus mutans strain Ingbritt, S. mutans/S. sobrinus GTFs, S. faecalis strain 19433, Actinomyces viscosus strain WVU 626, Actinomyces naeslundii strain 12, Lactobacillus casei, Actinobacillus actinomycetemcomitans strain Y4, Porphyromonas gingivalis strain 381, Eikenella corrodens strain 1073, and Wolinella recta strain 371 was measured by ELISA. Pearson correlation coefficients among log10 antibody levels within subjects revealed marked positive correlations among subgingival bacteria, generally weak positive correlations among supragingival micro-organisms, and no correlations between elements of the supragingival battery with the subgingival battery. IgG antibody levels to mutans streptococcal antigens were significantly correlated with subject DMF scores (r = 0.23; p less than 0.0001). No significant correlation was seen between DMF scores and antibody to any other supragingival micro-organism tested. Further relationships between levels of S. mutans antibody and individual clinical variables were analyzed by step-wise multiple linear regression, resulting in a model that was highly significant (p = 0.0001), with an r2 = 0.14. Numbers of missing teeth, coronal caries, root-surface caries, and root-surface restorations were each positively associated with antibody levels to mutans streptococci.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Comparison of erythritol and xylitol saliva stimulants in the control of dental plaque and mutans streptococci.

The effect of 2-month usage of saliva-stimulating pastils containing either erythritol or xylitol was studied in a cohort of 30 subjects assigned to the respective polyol groups (n = 15). The daily consumption level of both polyols was 5.2 g, used in 5 daily chewing episodes. The mean weight of total plaque mass (collectable during a standard period of 3 min from all available tooth surfaces) was reduced significantly in the xylitol-group, while no such effect was observed in the erythritol-group. This reduction in plaque mass was accompanied by a significant reduction in the turbidity readings (A(660)) of aqueous plaque suspensions; no such effect was observed in the erythritol-group. However, plaque protein levels did not differ between baseline and endpoint in either polyol group. The plaque and salivary levels of Streptococcus mutans and plaque levels of total streptococci were reduced significantly in the xylitol-group, while no such effect was detected in the erythritol-group. However, either polyol regimen had no effect on plaque levels of S. sobrinus. The results suggest that systematic use of xylitol-containing saliva stimulants may be more effective in controlling some oral-hygiene-related and caries-associated parameters than similar use of erythritol-containing products. The results also speak for a special relationship between xylitol and S. mutans. However, owing to the great potential of erythritol as a caries-reducing agent -- based on the tetritol nature of erythritol -- the present laboratory results should be considered preliminary and subject to verifying clinical studies.

Administration, Oral↗

The ability of selected oral microorganisms to emit red fluorescence.

Some novel caries detection and excavation devices rely on the ability of bacteria to produce red fluorescing compounds. The aim of this study was to examine the ability of selected oral microorganisms to emit red fluorescence. Streptococcus mutans, S. oralis, S. salivarius, S. sobrinus, Lactobacillus fermentans, L. casei, L. rhamnosus, Actinomyces naeslundi, A. israelii, Prevotella intermedia, and Fusobacterium nucleatum were inoculated onto Columbia agar with haemin and vitamin K and incubated anaerobically for up to 7 days in the dark. The resulting bacterial colonies were excited using filtered xenon light (405 +/- 20 nm) and digitally photographed through a 530-nm high-pass filter. The red and green portions of the colony fluorescence were analyzed using a computer program and the red/green ratio was calculated. All colonies emitted both red and green fluorescence. The green outweighed the red portion for the following species (in descending order) S. oralis, S. salivarius, S. mutans, F. nucleatum and S. sobrinus. The red portion was higher for the following species (in descending order) P. intermedia, A. naeslundi, A. israelii, L. fermentans, L. rhamnosus and L. casei. With all the bacteria examined, one color portion generally outweighed the other, giving the visual impression of either red or green fluorescence. We conclude that red fluorescence is well suited to detection of the bacteria which cause dentin caries but it is not suitable as an indicator of the presence and activity of the streptococci involved in initial caries.

Bacteria, Anaerobic↗

Labeling of binding sites for beta 2-microglobulin (beta 2m) on nonfibrillar surface structures of mutans streptococci by immunogold and beta 2m-gold electron microscopy.

As little detail is known about the surface structure of streptococci in the mutans group and the relationship of surface structure to host ligand-binding functions, the twofold purpose of this investigation was to examine in detail, by a range of electron microscopic techniques, the surface structures of streptococci in the different species of the mutans group and to investigate the distribution of beta 2-microglobulin (beta 2m)-binding sites on such structures. Strains representing Streptococcus mutans, S. cricetus, S. rattus, S. sobrinus, and four fresh isolates were studied by shadowcasting and histochemical staining of whole-mounted cells as well as by ultrathin and thick sectioning of embedded specimens. beta 2m-binding site distribution was visualized by indirect immunogold electron microscopy and by direct bacterial binding of beta 2m-conjugated gold probes. Shadowcast preparations revealed binding of gold probes to the cell surface of known beta 2m-binding strains but not to their polar fibrillar appendages. These long fibrils, common to all strains, were trypsin and sonication sensitive and stained with lead citrate but not with uranyl acetate or ruthenium red. More gold particles were bound by the indirect technique. For grid-mounted bacteria, the gold was mostly bound in clusters at the periphery of the cells. When gold probes were reacted in suspension with bacteria before mounting onto grids, a more even distribution of the gold was seen, but the bacteria were aggregated. Heating the bacteria eliminated beta 2m-gold binding but had no effect on the morphology of the fibrils. Thick sections of embedded bacteria prereacted with beta 2m-conjugated gold probes were analyzed by stereo imaging. A wispy, uranyl acetate-stained fuzzy layer, distinct from the fibrils seen by shadowcasting and extending up to one cell diameter from the cell wall, contained the gold probes. These findings introduce a concept that binding sites for some salivary ligands on mutans streptococci may be clustered on very delicate, nonfibrillar structures extending much further from the cell wall than previously appreciated. As for beta 2m, which composes part of the human histocompatibility antigens, part of the bacterial surface would be coated at a distance from its body with a protein not necessarily recognized as foreign by the host.

Animals↗

HLA, salivary IgA and mutans streptococci--is there a relation?

The aim of the present studies was to investigate a possible relationship between the human leukocyte antigen (HLA) complex, colonization of mutans streptococci and salivary immunoglobulin A (IgA) antibodies against mutans streptococcal antigens. In the first study a strong inverse relationship between HLA-DR4 and levels of mutans streptococci was observed for a group of renal transplant patients (I). In a group with healthy blood-donors a similar trend was observed (I). This tendency was also seen for a selected population investigated in the second study (II). Since the HLA molecules regulate the production of antibodies in saliva, the salivary IgA activity to three oral streptococci in a population of HLA-DR4-positive and DR4-negative subjects was investigated in the following study (III). It was found that the HLA-DR4-positive subjects, especially the DRB1*0401 and DRB1*0404 subgroups, showed a weaker IgA activity, in particular to Streptococcus mutans, as compared to the HLA-DR4-negative. However, immune response patterns revealed by Western blotting are often complex and for further studies with larger study populations it was crucial to unravel the nature of the detected antigens. In the fourth study (IV), untreated saliva, as well as saliva, in which cell-surface reactive IgA had been absorbed with whole bacteria cells, were analysed in Western blot against different oral streptococci. The high molecular bands, that were absent after absorption, likely represented cell-surface antigens and were thus of interest as they might be involved in adhesion mechanisms and available for blocking in vivo. In the next study (V), the salivary IgA activity to cell-surface antigens of three oral streptococci in relation to different HLA-DRB1*4 alleles was studied in a larger population. The immunoblots were analysed in a computer program and intensity graphs revealed that the DRB1*0401 and *0404 subgroups, compared to other DRB1*04 types, showed fewer as well as less intense immunoblot bands to antigens from S. mutans, S. sobrinus and streptococcal antigen (SA) I/II, but not S. parasanguis. The main conclusion from this thesis is that the HLA profile of the individual seems to influence the salivary IgA response to mutans streptococcal antigens and might thus also affect the conditions for the bacteria in the oral cavity.

Adhesins, Bacterial↗

Studies concerning the glucosyltransferase of Streptococcus sanguis.

We have shown in previous studies that the glucosyltransferase (Gtf) enzymes of Streptococcus mutans have distinct properties when adsorbed to a surface. In the present study, we compared the activity of Gtf from Streptococcus sanguis, designated GtfSs, in solution and on the surface of saliva-coated hydroxyapatite (sHA) beads, and determined the ability of its product glucan to support the adherence of oral microorganisms. Gtf from S. sanguis 804 NCTC 10904 was purified from culture supernatant fluids by means of hydroxyapatite chromatography. Enzyme and the substrate were prepared in buffers at pH values from 3.5 to 7.5. Maximum activity of GtfSs occurred between pH 5.5 and pH 6.5, whether in solution or adsorbed onto a surface. The solubilized and insolubilized enzymes showed highest activity at 40 degrees C; activity was reduced by 50(+/-2)% at 20 and 30 degrees C. The enzyme did not form glucans in either phase at 10 or 60 degrees C. The K(m), determined from Lineweaver-Burk plots, for the enzyme in solution was 4.3(+/-0.4) mmol/l sucrose, and the K(m) for the enzyme on sHA beads was 5.0(+/-1.0) mmol/l sucrose. The ability of the GtfSs glucan synthesized on the surface of sHA beads to support the adherence of oral bacteria was investigated. (3)H-thymidine-labeled bacteria (S. mutans GS-5, S. sobrinus 6715, S. sobrinus 6716, S. sanguis 10904, Actinomyces viscosus OMZ105E, A. viscosus 2085, and A. viscosus 2086) were incubated with sHA beads coated with GtfSs glucan. S. mutans GS-5 displayed the highest level of binding numerically. These results show that the GtfSs of S. sanguis is active on sHA beads, that the pH optimum for activity on a surface differs slightly from that in solution, and that its product glucan can support the adherence of oral microorganisms.

Actinomyces viscosus↗

Evaluation of the capacity of oral streptococci to produce hydrogen peroxide.

The capacity of 11 strains of oral streptococcal species (Streptococcus sanguis, S. oralis, S. mitis and S. sobrinus) to produce hydrogen peroxide (H2O2) was studied in vitro. Detection of this property in solid media, particularly with trypticase soy agar-benzidine-peroxidase, was more sensitive than in liquid media. The addition of carbohydrates (arabinose, xylose, mannose, sorbose and lactose), sorbitol and saccharine to buffered trypticase soy broth increased H2O2 production in S. oralis NCTC 11427, although the concentrations obtained with some substrates (glucose, galactose, mannitol and xylitol) were lower than those obtained in controls. In S. sanguis NCTC 7863, H2O2 production was detected only with galactose, sorbitol, lactose and saccharin.

Carbohydrate Metabolism↗

Production of glucosyltransferases by clinical mutans streptococcal isolates as determined by semiquantitative cross-dot assay.

Forty-four clinical isolates of mutans streptococci were examined by a semiquantitative cross-dot assay for in vitro production of glucosyltransferases GTF-I, GTF-SI and GTF-S of Streptococcus mutans, and GTF-I of Strep. sobrinus, using monospecific antibodies. The isolates were obtained from 12 1.5- to 3-year old children, six caries-active and six caries-free, and from their mothers. The isolates were selected originally from 243 isolates and they represented 35 genetically distinct types as analysed by serotyping and ribotyping. 27 isolates were of serotype c, nine of serotype e and eight of serotype g. Mother child pairs shared nine ribotypes, suggesting vertical transmission. The results showed that, when cultured in Todd-Hewitt broth supplemented with 1% glucose, all Strep. mutans isolates produced GTF-I and GTF-S and all except two produced GTF-SI of Strep. mutans. All Strep. sobrinus isolates produced GTF-I of Strep. sobrinus. The Strep. mutans GTF-I, GTF-SI and GTF-S production of isolates exhibiting a different ribotype showed variability. The variability of GTF-SI and GTF-S production was less pronounced for serotype e isolates. The GTF-I production by Strep. sobrinus isolates did not vary. Transmitted strains produced the same levels of GTFs as strains that were distinct (not transmitted). Strep. mutans isolates of caries-active children produced the same levels of GTF-I and GTF-S, but tended to produce lower levels of GTF-SI than isolates of caries-free children. In conclusion, the results suggested that Strep. mutans isolates exhibiting a different ribotype often had differences in production of GTFs. However, no clear superiority of the high-producer over the low-producer strains was found in regard to their colonization or caries promotion in young children.

Adult↗

Interaction of salivary fibronectin with oral streptococci.

Immunoreactive Fibronectin (Fn) has been demonstrated in stimulated human parotid saliva by western blot analysis and also found to be a component of the artificial tooth pellicles derived from hydroxyapatite (HA) beads coated with parotid saliva. Saliva depleted of gelatin-binding components showed a significantly lower degree of reactivity with anti-Fn antibodies than did the control saliva when tested by and enzyme-linked immunosorbent assay (ELISA). Depletion of gelatin-binding components from saliva was also found to affect the degree of saliva-mediated aggregation of four of the seven oral streptococci tested [Streptococcus mutans strains GS-5 and OMZ 176, S. sobrinus, and S. rattus]. Similarly, the adherence of the same four micro-organisms to the artificial tooth pellicles (derived form saliva which had previously been depleted of gelatin-binding component) was significantly inhibited (37-53%) when compared with the control saliva-coated HA beads. Pre-treatment of streptococci with 100 micrograms of soluble Fn also caused a 34-57% inhibition of adherence of the same oral streptococci to saliva-treated HA beads. Quantitation of Fn in human parotid saliva showed that the amounts of immunoreactive Fn varied form 2 to 6 micrograms/mL of parotid saliva. Furthermore, the Fn from parotid saliva was found to be adsorbed onto the bacterial surfaces, as demonstrated by immunofluorescence and ELISA. The presence of Fn in parotid saliva and its ability to bind to HA beads (artificial pellicles), in conjunction with the ability of soluble Fn to inhibit the adherence of streptococcal strains to the artificial tooth pellicles, suggest that the microbial ecology of the oral cavity may, in part, be influenced by the interactions mediated by salivary fibronectin.

Adhesiveness↗

Plaque pH and microflora of dental plaque on sound and carious root surfaces.

Given the hypothesis that root caries is the result of acid formation by acidogenic micro-organisms, the present study was performed to relate sucrose-induced pH response of dental plaque on root surfaces to the microbial composition of the overlying plaque. Seventeen caries-active elderly Chinese with poor oral hygiene and with both sound and carious root surfaces were examined. Plaque pH was measured before and up to one hour after a controlled sucrose mouthrinse. Plaque samples for microbiologic analyses were collected from 2 sound and 2 or 3 carious pH-measurement sites in each subject. The prevalence of the following micro-organisms was assessed as % of total viable counts on Brucella agar: Prevotella intermedia, Prevotella melaninogenica, Fusobacterium nucleatum, Campylobacter rectus, Capnocytophaga spp., Actinomyces viscosus, Actinomyces naeslundi, Streptococcus spp., S. sanguis, S. mitis, S. mutans, S. sobrinus, Lactobacillus spp., and Candida spp. There was no difference in plaque pH response on sound and carious root surfaces. The plaque pH response was more pronounced in the maxilla than in the mandible for both sound and carious sites. There was no difference in microbial composition of dental plaque on sound and carious root surfaces. The pH response to sucrose was the same regardless of the presence or absence of mutans streptococci. Our results thus do not readily support the traditional concept of caries formation.

Aged↗

Effect of Porphyromonas gingivalis ATCC 33277 vesicle on adherence of Streptococcus mutans OMZ 70 to the experimental pellicle.

The vesicles of Porphyromonas gingivalis ATCC 33277 strongly aggregated Streptococcus cricetus, S. rattus, and S. mutans, but poorly aggregated S. sobrinus. The adherence of S. mutans OMZ 70 to hydroxyapatite (HA) coated with whole saliva was increased in parallel with the quantity of the vesicles. The significant increase of adherence of S. mutans OMZ 70 by the vesicles was also observed on the HA coated with parotid saliva, submandibular saliva, serum, and type I collagen. These findings suggest that the vesicles may act as a bridge between mutans streptococcus and the tooth surface.

Animals↗

Post-pH effect in oral streptococci.

OBJECTIVES: To study the post-pH effect (PpHE) in 11 strains of oral streptococci belonging to Streptococcus sanguis, S. mitis, S. gordonii, S. mutans and S. sobrinus by using the BacT/Alert microbial detection system. METHODS: The bacterial cultures were exposed to a different pH (3.6, 4.0, 4.6, 5.0, 5.6, 7.0, 7.5, 8.0 and 8.6) for 1 h, and then returned to a neutral medium. The automated BacT/Alert system determined resumed microbial growth by measuring CO2 generation. The PpHE expresses the time difference between resumed growth (after pH shock) and optimal growth (pH 7.0 used as the control). RESULTS: PpHE was found to be minimal for alkaline pH values, and to be strain and species dependent. CONCLUSIONS: The PpHE may be useful as an ecological determinant or as an indicator of the cariogenicity of oral streptococci.

Carbon Dioxide↗

The influence of morphological variation on Candida albicans adhesion to denture acrylic in vitro.

Using denture acrylic pieces coated with either whole human stimulated saliva or oral streptococci, the binding ability of three different Candida albicans strains was investigated. The C. albicans strains include a clinical isolate with the commonly observed, smooth, round colonial morphology (strain 613p), a morphological variant spontaneously derived from the clinical isolate strain 613p (strain 613m1BK) and a clinical isolate from an oral lesion that was also a morphological variant upon primary isolation (strain 228). Levels of adhesion to the acrylic pieces were determined radiometrically using C. albicans cells metabolically labelled with [35S]-methionine. Whole stimulated saliva significantly increased the binding of all strains compared to uncoated acrylic. However, the level of binding of strain 613p to saliva-coated acrylic was significantly greater than the levels observed for the morphological variant strain 613m1BK. Coating acrylic pieces with either Streptococcus sanguis NCTC 10904, Strep. mutans GS-5 or Strep. sobrinus ATCC 27352 instead of saliva resulted in significantly greater binding by strain 613p compared to uncoated acrylic. Pre-coating the acrylic with the oral streptococci did not significantly increase the binding of morphological variant strains 613m1BK and 228 compared to uncoated acrylic. In general, preincubation of adherent streptococci with sucrose to induce the synthesis of extracellular carbohydrate polymers did not significantly increase the binding levels of the C. albicans strains above those observed using streptococci in buffer alone. Compared to its parental strain 613p, morphological variant strain 613m1BK adhered poorly to denture acrylic coated with either salivary constituents or oral streptococci, while strain 228 adhered to the same substrates at an intermediate level. Furthermore, physical disaggregation of clusters of the morphological variant strain 613m1BK did not appear to increase its binding capacity to saliva-coated denture acrylic. The effect of whole stimulated saliva on the adherence of C. albicans 613p to a variety of plastic substrates in addition to denture acrylic was examined. Overall, saliva pre-coating of the various plastics promoted C. albicans 613p adhesion. The adhesion of strain 613p to denture acrylic coated with whole stimulated saliva from each of five different donors or with parotid and submandibular/sublingual saliva from each of two donors was also examined. Regardless of donor, a coating of whole stimulated saliva significantly increased the binding of strain 613p to denture acrylic compared to uncoated acrylic. In addition, a coating of parotid saliva significantly increased the binding of strain 613p to denture acrylic compared to submandibular/sublingual saliva.

Acrylic Resins↗

Molecular cloning and characterization of scrB, the structural gene for the Streptococcus mutans phosphoenolpyruvate-dependent sucrose phosphotransferase system sucrose-6-phosphate hydrolase.

A DNA fragment encoding the sucrose-6-phosphate hydrolase component of the Streptococcus mutans phosphoenolpyruvate-dependent sucrose phosphotransferase system has been recovered from a plasmid-based genomic library of strain GS5. The locus, designated scrB, was found to reside within a 2.9-kilobase-pair restriction fragment present on the chimeric molecule pVA1343 (7.3 kilobase pairs). Minicell analysis of pVA1343-directed translation products revealed that the scrB product synthesized in Escherichia coli V1343 was a single peptide of Mr 57,000. This polypeptide was reactive with antiserum prepared against S. mutans intracellular invertase, which has been previously shown to have an Mr of 43,000 to 48,000. The basis of this difference in Mr was not established but may represent a posttranslational proteolytic event which occurred in S. mutans but not in recombinant V1343. Sucrose-6-phosphate hydrolase purified to homogeneity from V1343 exhibited Michaelis constants of 180 mM for sucrose and 0.08 mM for sucrose-6-phosphate. Deletion analysis of pVA1343 facilitated the assignment of a coding region for the hydrolase within the insert, as well as an orientation for the transcription of scrB. scrB-defective strains of S. mutans constructed by additive integration of an insertionally inactivated scrB locus exhibited the sucrose sensitivity characteristic of this mutant class. Similar loci were detected by DNA-DNA hybridization in additional strains of S. mutans and two strains of Streptococcus cricetus, but not in single strain representatives of S. rattus, S. sobrinus, S. sanguis I and II, S. salivarius, or S. mitis.

Animals↗

Adherent bacteria cells in five dental materials: sonication effect.

Adherent bacterial cells on the surfaces of two dental porcelain ceramics, three composite resins and human enamel were examined using four types of bacteria strains. Their adherent cells were counted on saliva-coated and uncoated material surfaces after sonication, and contact angle and zeta potential were measured for each adherent cell tested. A correlation between contact angle and bacterial cells on an uncoated surface was found to be higher in two Streptococcus sanguis cells than in S. mutans Ingbritt and S. sobrinus OMZ 176, whereas there appeared to be a higher correlation between S. mutans Ingbritt or S. sobrinus OMZ 176 and zeta potential on the uncoated surface. On the saliva-coated surface, a significantly high correlation was found between the adherent cells, with the exception of S. sanguis ATCC 10 557, and the zeta potential. Contact angle and zeta potential values were small when the surfaces of the materials were coated with saliva, as compared with those on the uncoated surface. The sonication condition (120 s) of adherent cells on the surface of the material significantly depended on the types of bacteria cells, showing that S. mutans Ingbritt (>50-60%) had a greater removal percentage than the others (<50%).

Journal Article↗

[The role of Streptococcus mutans in human caries].

Definite proof has been found that S. mutans, and probably S. sobrinus and lactobacilli, are responsible for caries in man. The aciduria of S. mutans encourages the selection inside the plaque and is directly responsible for its cariogenicity. Other aciduric species, as S. sobrinus, cause caries on the smooth surface of the tooth, where the principal causes of the rampant caries reside. If during the eruption of the tooth the fissures become colonized in depth by S. mutans, the development of caries becomes a highly probable event. Instead, if the colonization of the tooth by S. mutans takes place after the fissure depth have been occupied by other microbic species not cariogenic, it is probable that the caries will not manifest or will appear in a less severe form. In conclusion, the knowledge already acquired on the ecology of S. mutans and the mechanism of cariogenesis clearly indicate that all factors that interfere with the colonization of the tooth by S. mutans can greatly reduce the incidence of caries in man.

Bacterial Adhesion↗

Prevalence of mutans streptococci in 93 members from six Brazilian families.

Several studies report that mutans streptococci (MS) are closely associated with caries in humans and that there is a correlation between the number of carious lesions and the levels of MS in the saliva of children and adults. The presence of MS in the saliva of 93 members of six Brazilian families with at least 3 generations was investigated. Samples of whole unstimulated saliva were collected and diluted. Aliquots of 50 microliters of each suspension were dropped onto SB20 agar and incubated in a candle jar at 37 degrees C for 72 h. Colonies resembling MS were counted, collected, seeded in thioglycoilate medium and subjected to biochemical typing. Mutans streptococci were isolated from 80 subjects (86.0%) and the counts ranged from 3.0 x 10(2) (log 2.477) to 1.6 x 10(8) (log 8.204) CFU/ml of saliva. All of the 73 adults were colonized by MS, but the bacteria were detected in only 7 (35.0%) of the 20 children evaluated. Streptococcus mutans occurred in 78 subjects (97.5%), and 51 (63.7%) were monocolonized. S. sobrinus occurred in 29 individuals (36.3%) and 2 (2.5%) were monocolonized. Twenty-seven (33.8%) subjects were multicolonized with S. mutans and S. sobrinus. This study showed a high prevalence (86.0%) of mutans streptococci in the saliva of members of the studied families, which suggests the risk of intrafamilial transmission.

Adult↗

Intrafamilial distribution of mutans streptococci in Japanese families and possibility of father-to-child transmission.

The purpose of this study was to investigate the intrafamilial distribution of mutans streptococci in Japanese families using chromosomal DNA fingerprinting with three endonucleases; EcoRI, HindIII and HaeIII. The analysis of 1,908 isolates cultured from the dental plaque of 76 subjects from 20 families (20 married couples and 36 of their children) resulted in the identification of 144 genotypes containing 114 strains of Streptococcus mutans (serotype c, 66.7%; e, 12.5%) and 30 strains of S. sobrinus (d, 13.2%; g, 7.6%). A mean of 1.89 genotypes (from one to four) was harbored in individual subjects, and a mean of 4.10 genotypes from two to seven was harbored in individual families. Among the 70 genotypes found in the children, 36 (51.4%) were in agreement with their mothers and 22 (31.4%) were in agreement with their fathers. The other genotypes (18.6%) did not correspond with the parents. Homologous strains between parents were found in only two couples. This result showed that fathers or others as well as mothers can be sources of transmission. Further, the serotype d, e and g strains showed significantly higher probabilities of transmission than serotype c.

Adult↗