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Inhibition of Streptococcus mutans adsorption to hydroxyapatite by low-molecular-weight chitosans.

The role of Streptococcus mutans in the initiation of dental caries has been recognized and attributed, at least in part, to its ability to colonize the tooth surface. Therefore, factors which prevent S. mutans attachment to hydroxyapatite (HA) are of considerable interest for the prophylaxis of this infectious disease. Chitosan, a chitin derivative by N-deacetylation, is an interesting candidate in this respect, since it stimulates the ordered regeneration of oral soft tissues, prevents the deleterious action of organic acid, and exhibits bactericidal action against several pathogens. In the present work, the efficacy of a low-molecular-weight chitosan (LMWC) and its derivatives N-carboxymethyl chitosan (NCMC) and imidazolyl chitosan (IMIC) in preventing S. mutans attachment to HA beads was assessed. The effects of chitosan on both sucrose-dependent and -independent adherence were evaluated. In both cases, when saliva-coated or uncoated HA beads were treated with any of the chitosans, a reduction in S. mutans adsorption ranging from 47 to 66% was observed. When HA beads were coated with saliva after the treatment with chitosan, neither carbohydrate caused a statistically significant reduction in S. mutans adsorption, suggesting that saliva deposition restores HA binding properties. Bacteria grown in the presence of chitosan subminimal inhibitory concentrations (sub-MICs) ranging from 12 to 500 micrograms mL-1 adsorbed poorly to HA and exhibited a lower affinity toward xylene than untreated controls. In the presence of chitosan sub-MICs up to 60 micrograms mL-1, an increase in the percentage of detached bacteria from two- to nine-fold was observed. The desorptive effect of chitosan was weaker when S. mutans had adhered to saliva-coated HA in the presence of sucrose. These results demonstrate that the presence of minor amounts of modified chitosans prevents S. mutans adsorption to HA and suggest that colonization of the tooth surface might be impaired by the use of toothpastes, mouthrinses, or chewing gums containing any of the tested polysaccharides.

Adsorption↗

Mode of delivery and other maternal factors influence the acquisition of Streptococcus mutans in infants.

S. mutans plays a key role in dental caries. The extent to which perinatal events influence the acquisition of S. mutans is unclear. We hypothesized that several maternal factors, including the mode of delivery, influence the initial acquisition of S. mutans in infants. A prospective cohort study was conducted in 156 mother-infant pairs. The study found that maternal gestational age (p = 0.04), S. mutans level (p = 0.02), caries score (p = 0.02), sexually transmitted disease (STD) infection experience (p = 0.01), and family income (p = 0.03) had significant effects on the acquisition of S. mutans. Among infants who became infected, those delivered by Caesarean section acquired S. mutans 11.7 mos earlier than did vaginally delivered infants (p = 0.038). C-section infants harbored a single genotype of S. mutans that was identical to that of their mothers (100% fidelity). Analysis of the data demonstrated the possible perinatal influences on infants' acquisition of a member of the cariogenic microbiota, and its potential effect on caries outcome.

Analysis of Variance↗

Extract of Juglandaceae regia inhibits growth, in-vitro adherence, acid production and aggregation of Streptococcus mutans.

Aqueous and alcoholic extracts from Juglandaceae regia, used as chewing sticks to maintain oral hygiene, were tested for their ability to inhibit the growth and some physiological functions of Streptococcus mutans. Both the aqueous and the alcoholic extract strongly inhibited the growth, in-vitro adherence, acid production and glucan-induced aggregation of S. mutans. At a concentration of 8% w/v, the aqueous extract produced a 95% inhibition (P < 0.05) of adherence of S. mutans to glass and a 40% inhibition (P < 0.05) of adherence to tooth surface. The alcoholic extract at a concentration of 10% w/v produced a 95% inhibition (P < 0.05) of adherence of S. mutans to glass and a 56% inhibition (P < 0.05) of adherence to tooth surface. At concentrations of 2% w/v the aqueous and alcoholic extracts significantly inhibited (P < 0.05) glucan-induced aggregation of S. mutans and the in-vitro salivary glycolytic reaction for up to 5 h. Bactericidal effects on S. mutans were also evident. At a concentration of 10% w/v, the zone of inhibition observed with the aqueous extract was 12+/-0.01 mm and that observed with the alcoholic extract was 12.6+/-0.02 mm. As the in-vitro studies had shown that both the aqueous and the alcoholic extract of J. regia, at concentrations of 10% w/v, could inhibit the growth as well as the acid-producing ability of S. mutans, they were tested at the same concentration for their activity in-vivo. Three subjects were employed. Parameters monitored were salivary bacterial count and salivary glycolysis. Mouth-rinsing with the aqueous but not the alcoholic extract significantly reduced total streptococcal counts in the salivary samples obtained up to, and including, 3 h after rinsing, compared with the counts obtained pre-rinsing or after placebo rinsing. Mouth-rinsing with the aqueous extract produced a 65%, 27% and 78% reduction (P < 0.05) in the streptococcal count in the salivary samples obtained 10 min, 1 h and 3 h after rinsing, respectively. Both the aqueous and the alcoholic extract also inhibited the glycolytic reaction by the salivary bacteria for up to 90 min post-rinsing. This study provides evidence to justify the use of J. regia sticks as an aid to maintain oral hygiene.

Acids↗

Partial elimination of Streptococcus mutans from selected tooth surfaces after restoration of carious lesions and SnF2 prophylaxis.

This study examined the prevalence of Streptococcus mutans in dental plaque from carious and noncarious sites before and after routine dental treatment in five young men in the US Navy. S mutans was isolated in 96.3% of the samples from carious sites and in 63.3% of the samples from noncarious sites before treatment. After all carious lesions had been restored, the prevalence of S mutans was significantly reduced, but many of the carious and noncarious sites still had detectable levels of S mutans. A further reduction in S mutans was observed after conventional 8.9% stannous fluoride paste prophylaxis and 10% stannous fluoride topical application; however, in no instance was the organism completely eliminated. About 12 to 18 months after the initial examination, new carious lesions were seen in four men who were available for reexamination. Plaque samples of new lesions had high levels of S mutans. Therefore the restorations of lesions and the stannous fluoride prophylaxis treatments given under the conditions of the study were effective but incomplete measures for eliminating S mutans from the tooth surfaces of Navy personnel and were inadequate procedures for arresting the carious process.

Adolescent↗

Prevalence of Streptococcus mutans and lactobacilli in 18-month-old children with cleft lip and/or palate.

The prevalence of Streptococcus mutans and lactobacilli was determined in 62 18-month-old Dutch children with a cleft lip and/or palate. Plaque and saliva samples were collected, a dental examination was performed, and the parents were interviewed with a structured questionnaire regarding general health, dietary habits, fluoride exposure, and socioeconomic class. Appropriate dilutions of the plaque and saliva samples were cultured on selective media to count all viable bacteria, S. mutans and lactobacilli. S. mutans was detected in the saliva of 45% of the children, and lactobacilli was detected in 16%. Also, S. mutans was detected in 48% of the plaque samples and lactobacilli in 8%. Of all of the variables examined, consumption of more than three snacks and beverages between main meals was significantly associated with presence of S. mutans in saliva. Preoperative infant orthopedic treatment (i.e., wearing an acrylic plate from shortly after birth) was significantly associated with presence of lactobacilli in saliva. The presence of S. mutans in the plaque samples was also significantly associated with presence of lactobacilli in saliva. These results indicate that children with oral cleft are at an increased risk of being infected by S. mutans and lactobacilli at a very early age. Such early colonization indicates a high risk for caries in the primary dentition.

Analysis of Variance↗

Feasibility of eradication of mutans streptococci from oral cavities.

OBJECTIVES: Dental caries prevention programs using chlorhexidine (CHX) have been proposed, but CHX's effect in reducing levels of mutans streptococci (S. mutans and S. sobrinus) appears to last for only a few months. The aim of this study was to attempt to eradicate mutans streptococci from the oral cavity using intensive professional mechanical tooth cleaning (PMTC) and topical application of CHX in custom-made trays. METHODS: Seven adult dentate subjects participated in this study (mean age 53.7+/-5.6, age range 46 to 62, mean DMFT, 9.1+/-4.2). For each subject, PMTC was carried out eight times within ten days. After each PMTC, 1% CHX was applied twice to the tooth surface using custom-made trays. In addition, as home treatment, subjects were required to carry out tooth brushing three times a day, and apply 0.2% CHX in custom trays after brushing in the morning and evening. In addition, subjects rinsed with 0.2% CHX solution after lunch. Salivary levels of mutans streptococci were evaluated using Dentocult-SM at baseline and on days 9, 20, 70, 120. RESULTS: Mutans streptococci were eradicated by day 120 from 4 of the 7 seven subjects participating in this study. Those 3 subjects still harboring mutans streptococci exhibited deep periodontal pocketing. CONCLUSIONS: Eradication of mutans streptococci from the oral cavity is feasible using a combination of CHX application in custom-made trays and intensive PMTC.

Aged↗

[Effects of immune bovine whey on sucrose-dependent adherence of Streptococcus mutans].

OBJECTIVE: The aim of this experiment is to explore the possible anti-carious mechanisms of immune bovine whey. METHODS: The immune milk was collected from cows immunized with cell associated glucosyltransferase(GFT) over-expression strain B-29-33 of Streptococcus mutans(S. mutans) MT8148. The control milk was obtained from non-immunized cows. The immune and control bovine whey were prepared by removing fat and casein. The effects of two kinds of bovine whey on sucrose-dependent adherence of S. mutans MT8148 were examined by using TTY media with five different volumes of the immune and the control milk, 100, 300, 500, 700 and 900 microliters respectively. The adherent rates were determined by reading the optical density. The adherent morphology was observed by using a scanning electron microscope(SEM). RESULTS: There was no significant difference in adherence of S. mutans MT8148 cells to the smooth glass surface among five doses with those of the control whey. The immune bovine whey inhibited the adherence of S. mutans. The adherent percentage was 84.37% at 100 microliters and decreased by 58.59% at 900 microliters. The inhibition was does-dependent. The difference of adherent morphology between the immune and control whey was noticeable at 900 microliters. The SEM revealed that cells of S. mutans MT8148 with the control whey were covered by large quantities of gelatinous material, but cells with the immune whey were clearly distinguished. CONCLUSION: The immune whey has inhibitory potential against the sucrose-dependent adherence of S. mutans.

Animals↗

[The inhibitive effect of IgY toothpaste against oral Streptococcus mutans].

PURPOSE: To study the effect of the toothpaste containing IgY against oral Streptococcus mutans. METHODS: 140 subjects were divided into 2 groups randomly (test group and control group). Before the beginning of the test, every subject underwent a elution period in order to lessen the other interference factors, then used different toothpastes were used respectively and the test began. Streptococcus mutans values were determined with Dentocult SM Strip just before test, at 1, 3, 7, 30 days after toothpaste used and 14 days after stopping toothpaste used. RESULTS: (1) In test group,Streptococcus mutans values decreased at 1 day after toothpaste used. In control group Streptococcus mutans values decreased at 3 days after toothpaste used. (2) Streptococcus mutans values decreased gradually in each groups after toothpaste used. (3) In test group, 2 weeks after stopping toothpaste used, Streptococcus mutans values were still suppressed. CONCLUSION: The application of the toothpaste containing IgY may reduce oral Streptococcus mutans levels significantly.

Child↗

[The study of salivary-SIgA reaction to Streptococcus mutans in acid environment].

OBJECTIVE: To test the salivary immunoglobulin A antibody activity to Streptococcus mutans in normal with in acid environment. METHODS: Streptococcus mutans strains were isolated from 20 volunteers, serotyped by biochemical test and PCR, and genotyped by AP-PCR. Unstimulated secretions from submandibular glands and sublingual glands were collected from volunteers by modified collectors. Each identified Streptococcus mutans genotype was cultured in two groups: control group was cultured in BHI broth pH7.2 at 37 degrees C for 2 h; acid shock group were cultured in TYEG broth (pH5.5) at 37 degrees C for 2 h. Analysis of SIgA activity to Streptococcus mutans genotypes in different groups was detected by Western blot. RESULTS: (1) The SIgA of each individual could response to his own Streptococcus mutans strains and the reference strains; (2) The same individual had different SIgA activity to different genotype strains; (3) There were no significant difference between acid groups and control groups, in spite that some bands had strong or weak intensity. CONCLUSIONS: Although Streptococcus mutans could express acid shock proteins in stress, the present study suggests that these new proteins have no qualitative effect on the reaction of SIgA to Streptococcus mutans.

Adult↗

Sodium bicarbonate and hydrogen peroxide: the effect on the growth of Streptococcus mutans.

PURPOSE: This in vitro experiment studied the effects of sodium bicarbonate and hydrogen peroxide on the cariogenic bacteria Streptococcus mutans through analysis with a spectrophotometer. METHODS: The growth of S. mutans was analyzed using seven different environments. Twelve wells in each of the seven rows of a multi-well plate were used to incubate the test materials. In combinations of 10 microl distilled water, 100 microl broth, 10 microl 10% sucrose, 10 microl S. mutans, 10 microl 10% sodium bicarbonate, and 10 microl 3% hydrogen peroxide, seven different environments were created for testing. Environments had either sodium bicarbonate or hydrogen peroxide with S. mutans, or a combination of sodium bicarbonate and hydrogen peroxide with S. mutans. The plate was incubated at 37 degrees C and measured at 0, 18, 20, 22, 24, 26, 28, 30, and 42 hours by optical density with a spectrophotometer. RESULTS: Results showed bacterial growth was prevented by sodium bicarbonate, hydrogen peroxide, and the combination of sodium bicarbonate and hydrogen peroxide. Although hydrogen peroxide is bacteriocidal and sodium bicarbonate is bacteriostatic, there were no significant differences among the three treatment groups in spectrophotometer readings at any of the nine readings over 42 hours. CONCLUSION: There was no significant difference among the effects of hydrogen peroxide, sodium bicarbonate, or the sodium bicarbonate and hydrogen peroxide combination, as measured by optical density. The hydrogen peroxide, sodium bicarbonate, and the sodium bicarbonate and hydrogen peroxide combination prevented bacterial growth of S. mutans. The results show that products containing these agents have the ability to stop the growth of S. mutans. Products containing sodium bicarbonate and/or hydrogen peroxide may be useful to caries-prone patients. More studies are needed to confirm these results on patients.

Dentifrices↗

[Construction of a virulence-related gene library of Streptococcus mutans by suppression subtractive hybridization].

OBJECTIVE: To construct a suppression subtractive library of virulence-related genes from c serotype Streptococcus mutans (S. mutans), and lay foundations for screening the virulent genes. METHODS: After being isolated from virulent and avirulent strain of S. mutans respectively, the intact and high-pure genomic DNA was digested with three appropriate four-base-cutting restriction endonueleases to produce fragments of optimal length. The digested DNA of the virulent strain ligated with adaptor was used as tester DNA, and that of the avirulent strain as driver DNA. Then the suppression subtractive hybridization was carried out, and the efficiency of ligation and subtraction detected respectively. The subtracted fragments were inserted into vector pCR2. 1 using T/A cloning kit, and transformed into E. coli TOP10F' competent cells. Those white colonies were selected to construct the suppression subtractive library. RESULTS: Alu I chosen from three restriction endonucleases was verified to be suitable for preparing restriction fragments from S. mutans genomic DNA. Through electrophoresis of Alu I -digested DNA, a smear ranged from 0.1 to 2.0 kb was observed. The ligation efficiency of tester DNA with adaptor was at least higher than 25 percent. The subtraction efficiency of suppression subtractive hybridization confirmed the success in enrichment of differential genes between virulent and avirulent strain of S. mutans. In the subtracted group, the appearance time of the 23S rRNA gene both in tester and driver DNA was later than that in the unsubtracted group by six cycles. It suggested that suppression subtractive hybridization happened indeed. After the subtracted fragments were cloned, 96 colonies were picked up for constructing the suppression subtractive library of virulence-related genes of S. mutans. CONCLUSION: Suppression subtractive hybridization allows rapid and easy construction of virulence-related gene library of S. mutans.

Escherichia coli↗

[Genetic diversity of F-ATPase subunits gene uncA amplified from Streptococcus mutans clinical isolates].

OBJECTIVE: To study the genetic diversity of F-ATPase alpha subunit gene uncA derived from Streptococcus mutans (S. mutans) clinical isolates and to investigate the relationship between the genetic diversity of acidurance factor and S. mutans aciduric ability, also and the cariogenicity. METHODS: Sixty-four S. mutans strains derived from 34 caries-active individuals and 30 caries-free individuals, including 18 strains displaying high acid tolerance and 20 strains displaying low acid tolerance. Gene uncA was amplified with specific primers from S. mutans genomic DNA, then the PCR products were analyzed by RFLP and sequenced. RESULTS: Two genotypes A and B of PCR-RFLP were revealed when digested with Hph I. Mbo II also produced two different pattern C and D. The distributions of A and B genotype strains with different caries-sensitivity groups were different (P < 0.05), and the proportion of A genotype strains from caries-activity group was higher than that from caries-free one. The distributions of C and D genotype strains with different acidurance strains were different (P < 0.05), and the proportion of C genotype strains from high acid tolerance group was higher than that from low acid tolerance group. These amplified uncA genes from different group were sequenced and there existed variation of Hph I and Mbo II recognized sites. CONCLUSIONS: This study indicates that uncA gene of S. mutans F-ATPase obviously displayed genetic diversity. The different Hph I-RFLP and Mbo II-RFLP genotypes could be related to the cariogenicity and acid tolerance of S. mutans strains.

Bacterial Proton-Translocating ATPases↗

Antibody responses to mutans streptococci in children.

Because mutans streptococci (Streptococcus mutans, S. sobrinus) are considered the main causative bacteria in human dental caries, immune responses to these bacteria have aroused much research interest over the last two decades. Studies in man have focused mainly on salivary and serum antibodies developing naturally in response to oral colonization by mutans streptococci, or in relation to the development of dental caries. Although both salivary (IgA) and serum-derived (IgG) antibodies have been shown in many studies to protect against the adherence of and to interfere with the metabolism of mutans streptococci, no conclusive evidence relating to their clinical significance is available. In young children, serum IgG antibodies to S. mutans seem more important than salivary IgA antibodies in relation to protection against dental caries. In studies in animals and, recently, in man, monoclonal IgG antibodies to S. mutans protein antigen I/II ("adhesin") have provided effective protection against mutans streptococci. Whether they could also prevent dental caries in man is not yet known.

Antibodies, Bacterial↗

Examination of parotid saliva for antibodies reacting with Streptococcus mutans, lipoteichoic acid and peptidoglycan by the enzyme-linked immunosorbent assay.

Human parotid saliva was investigated for the presence of IgA antibodies reacting with Streptococcus mutans, lipotechoic acid (LTA) and peptidoglycan. By using an enzyme-linked immunosorbent assay, ELISA, it was shown that the salivas of 12 subjects contained antibodies reacting with S. mutans serotype c and d and with LTA. Six salivas were tested against peptidoglycan but these tests indicated only low levels of antibodies. Absorption of saliva with whole cells of S. mutans inhibited the homologous reaction by up to 87% and the reaction with LTA by up to 52%. Also prior treatment of saliva with LTA caused a decrease in the salivary IgA reaction with LTA and with whole cells of S. mutans. Addition of peptidoglycan to saliva did not markedly affect the salivary IgA reaction with S. mutans. The data show that LTA may be responsible for part of the salivary IgA reaction with whole cells of S. mutans. The significance of LTA in this reaction may vary between different subjects and for different serotypes of S. mutans.

Adolescent↗

Serological studies on strains of Theileria mutans isolated in East Africa using the indirect fluorescent antibody technique.

The serological response of cattle infected with Theileria mutans (Aitong) by cyclical and mechanical transmission was studied using the indirect fluorescent antibody technique with T. mutans piroplasm and schizont antigens. Cattle infected by either method show high antibody titres against piroplasm antigens which persist for periods of over one year. Only cattle with tick-induced infections had an antibody response to schizont antigen. The serological cross-reactions of T. mutans (Ationg) with other strains of T. mutans isolated in East and South Africa sere investigated as were the serological cross-reaction of T, mutans (Aitong) and other species of Theileria. It was concluded that isolated of Theileria in East Africa which behaved like T. mutans were serologically indistinguishable using the IFA technique while other species of Theileria were easily distinguishable from T. mutans.

Animals↗

Amino acid requirements of Streptococcus mutans and other oral streptococci.

The amino acid requirements of Streptococcus mutans strains AHT, OMZ-61, FA-1, BHT, GS-5, JC-2, Ingbritt, At6T, OMZ-176, 6715, Streptococcus salivarius HHT, Streptococcus sanguis OMZ-9, and strain 72x46 were determined in a chemically defined medium. When grown anaerobically in the presence of sodium carbonate (or bicarbonate for a few strains), few amino acids were required. All strains tested required cystine (or cystine) as a nutrient. Three strains (S. mutans OMZ-176, FA-1, and BHT) required glutamate (and/or glutamine). A third amino acid (lysine for S. mutans FA-1 and histidine for S. mutans OMZ-176) was required by two of the three strains which required glutamate. The amino acids mentioned above were required for all conditions of incubation (and inoculum) tested. The requirements for several other amino acids were conditional, that is, dependent on the incubation conditions and inoculum used. For example, when carbonate was not added, glutamate was required by S. mutans GS-5. Aerobic incubations, with carbonate or bicarbonate added, resluted in requirements for glutamate and leucine by several strains. With these incubation conditions, one strain required isoleucine (S. mutans FA-1), another valine (S. mutans AHT), and a third tyrosine (72x46). Aerobic incubations in the absence of carbonate or bicarbonate further increased the number of amino acids required by several strains. Furthermore, when stationary-phase cultures replaced exponentially growing cultures as an inoculum, several strains required additional amino acids, presumably for the initiation of growth.

Amino Acids↗

Interdental localization of Streptococcus mutans as related to dental caries experience.

The consistency of colonization of tooth surfaces by Streptococcus mutans was studied by sampling four approximal molar surfaces of 9- to 13-year-old children at weekly intervals. It was found that surfaces which harbored detectable levels of the organism tended to be consistently positive, whereas surfaces which were free of detectable levels of the organism also tended to remain that way. Of the total surfaces studied, 81.7% were either consistently positive or consistently negative throughout five consecutive weekly samplings. These data indicate that S. mutans does not uniformly colonize the surfaces of teeth. The consistent localized patterns of colonization observed suggest that S. mutans is not readily transmitted from one tooth surface to another within the mouth. Scanning electron microscope observations revealed that S. mutans colonized the teeth of monoinfected gnotobiotic rats as discrete localized colonies, whereas strains of Actinomyces naeslundii colonized in a more generalized manner. Efforts to sterilize tooth surfaces by application of iodine solution indicated that the populations of S. mutans on some surfaces could be affected for at least 11 to 13 weeks after treatment. The number of tooth surfaces colonized by detectable proportions of S. mutans was found to be far lower in a group of 18 children from Charlotte, N.C., with a low past caries experience than in 20 children from Danvers, Mass., with a high caries experience. The number of tooth surfaces infected with S. mutans therefore strongly paralleled the caries experience of these populations.

Actinomyces↗

Non-mutans streptococci in patients receiving radiotherapy in the head and neck area.

OBJECTIVE: To study mutans and non-mutans streptococci in patients after radiotherapy of the head and neck. METHODS: Oral rinse samples collected from nasopharyngeal carcinoma patients before and after radiotherapy were diluted and cultured on nonselective and selective media for enumeration of total cultivable plaque flora, mutans and non-mutans streptococci and lactobacilli. Non-mutans streptococci were identified biochemically and by 16S rDNA sequence homology analysis. RESULTS: After irradiation, mutans streptococci were not isolated; the levels of Streptococcus mitis and lactobacilli increased significantly. The level of Streptococcus salivarius increased, but the significance was the borderline. The level of Streptococcus sanguis decreased significantly after irradiation. The abundance of other oral streptococci species showed no significant changes. CONCLUSIONS: S. mitis and S. salivarius are the predominant non-mutans streptococci in the high-caries-risk oral flora following radiotherapy.

Adult↗