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PubMed1998

Mutacin production by Streptococcus mutans may promote transmission of bacteria from mother to child.

The production of bacteriocin-like inhibitory substances, mutacins, by mutans streptococci varies among isolates. To find if the degree of mutacin activity of an isolate was related to its transmission between mother and her child, 19 mothers and their 18-month- to 3-year-old children were sampled for their oral mutans streptococci. In addition, the stability of mutacin activity was studied with isolates from the mothers and with isolates from five unrelated 5-year-old children in 5- to 7-year follow-up studies. A total of 145 oral mutans streptococcal isolates were serotyped by immunodiffusion, ribotyped, and mutacin typed by the stab culture technique. Mutacin was produced by 88% of the strains against more than 1 of the 14 indicator strains, representing mutans streptococci, Streptococcus sanguis, Streptococcus salivarius, Streptococcus oralis, Streptococcus gordonii, and Streptococcus pyogenes. Streptococcus mutans isolates showed more inhibitory activity than did Streptococcus sobrinus isolates. Identical ribotypes had similar mutacin activity profiles within a subject, initially and in the follow-up studies, in all but two cases. The mothers harbored a total of 37 different mutans streptococcal ribotypes. Six children were negative for mutans streptococci. Transmission was probable in 9 of 20 mother-child pairs on the basis of the presence of identical strains, as determined by ribotyping and bacteriocin (mutacin) typing. S. mutans strains shared between a mother and her child showed a broader spectrum of inhibitory activity than did nontransmitted strains. In conclusion, the mutacin activity of clinical isolates is reasonably stable, and this virulence factor seems to be of clinical importance in early colonization by S. mutans.

Adolescent↗
PubMed2005

Characterization of salivary immunoglobulin A responses in children heavily exposed to the oral bacterium Streptococcus mutans: influence of specific antigen recognition in infection.

The initial infection of children by Streptococcus mutans, the main pathogen of dental caries, depends on the ability of S. mutans to adhere and accumulate on tooth surfaces. These processes involve the adhesin antigen I/II (AgI/II), glucosyltransferases (GTF) and glucan-binding protein B (GbpB), each a target for anticaries vaccines. The salivary immunoglobulin A (IgA) antibody responses to S. mutans antigens (Ags) were characterized in 21 pairs of 5- to 13-month-old children. Pairs were constructed with one early S. mutans-infected and one noninfected child matched by age, racial background, number of teeth, and salivary levels of IgA. Specific salivary IgA antibody response and S. mutans infection levels were then measured during a 1-year follow-up. Robust responses to S. mutans were detected from 6 months of age. Salivary IgA antibody to AgI/II and GTF was commonly detected in salivas of all 42 children. However, GbpB-specific IgA antibody was seldom detected in the subset of infected children (38.1% at baseline). In contrast, most of the subset of noninfected children (76.2%) showed GbpB-reactive IgA antibody during the same period. Frequencies of GbpB responses increased with age, but differences in intensities of GbpB-IgA antibody reactions were sustained between the subsets. At baseline, GbpB-reactive IgA antibody accounted for at least half of the total salivary IgA S. mutans-reactive antibody in 33.3 and 9.5% of noninfected and infected children, respectively. This study provides evidence that a robust natural response to S. mutans Ags can be achieved by 1 year of age and that IgA antibody specificities may be critical in modulating initial S. mutans infection.

Antigenic Variation↗
PubMed1999

Regulated expression of the Streptococcus mutans dlt genes correlates with intracellular polysaccharide accumulation.

Intracellular polysaccharides (IPS) are glycogen-like storage polymers which contribute significantly to Streptococcus mutans-induced cariogenesis. We previously identified and cloned a locus from the S. mutans chromosome which is required for the accumulation of IPS. Sequencing of this locus revealed at least four contiguous open reading frames, all of which are preceded by a common promoter region and are transcribed in the same direction. Analysis of the amino acid sequence deduced from the first of these open reading frames (ORF1) revealed domains which are highly conserved among D-alanine-activating enzymes (DltA) in Lactobacillus rhamnosus (formerly Lactobacillus casei) and Bacillus subtilis. The deduced amino acid sequences derived from ORF2, -3, and -4 also exhibit extensive similarity to DltB, -C, and -D, respectively, in these microorganisms. However, Southern hybridization experiments indicate that this operon maps to a locus on the S. mutans chromosome which is separate from the glgP, glgA, and glgD genes, whose products are known mediators of bacterial IPS accumulation. We therefore assigned a new dlt designation to the locus which we had formerly called glg. We maintain that the dlt genes are involved in S. mutans IPS accumulation, however, since they complement a mutation in trans which otherwise renders S. mutans IPS deficient. In this study, we found that expression of the S. mutans dlt genes is growth phase dependent and is modulated by carbohydrates internalized via the phosphoenolpyruvate phosphotransferase system (PTS). We demonstrated that the S. mutans dlt genes are expressed constitutively when non-PTS sugars are provided as the sole source of carbohydrate. Consistent with a role for the PTS in dlt expression is a similar constitutive expression of the dlt genes in an S. mutans PTS mutant grown in a chemically defined medium supplemented with glucose. In summary, these findings support a novel role for the dlt gene products in S. mutans IPS accumulation and suggest that dlt expression in this oral pathogen is subject to complex mechanisms of control imposed by growth phase, dietary carbohydrate, and other factors present in the plaque environment.

Amino Acid Sequence↗
PubMed1995

Plaque composition, fluoride tolerance and acid production of mutans streptococci before and after the suspension of the use of fluoride toothpastes.

Although fluoride toothpastes are widely used for caries prevention, little is known about the impact of fluoride dentifrices on plaque composition. Also the issue of adaptation of mutans streptococci to grow in vivo in a fluoride environment has received little attention. Such an adaptation may be of interest as it has been suggested that adapted mutans streptococci may show reduced glycolytic activity thereby being less cariogenic. In the present experiments the impact of the suspension of the use of fluoride toothpastes on plaque composition, fluoride tolerance and acid production of mutans streptococci was studied. Pooled plaque samples from the lingual surfaces of the lower incisors were collected from individuals (n = 13) just before and 7 weeks after they had replaced their fluoride toothpastes (0.1-0.15% F) with a non-fluoride one. The samples were analysed for fluoride and the numbers and proportions of streptococci, Streptococcus mutans, Streptococcus sobrinus, Actinomyces species, and lactobacilli, respectively. The fluoride tolerance of the mutans streptococci was estimated by culture of the plaque samples on TYCSB agar supplemented with of 0, 1, 2, 3, 4, and 5 mmol/l fluoride (NaF) at pH 7.2. From each plaque sample six S. mutans strains were isolated for the measurement of the rate of acid production (Vap) at pH 7 in the presence of 0, 5, and 10 mmol/l F. The overnight final pH was measured in cultures of the S. mutans strains with excess of glucose and 0, 5, and 10 mmol/l F. The results showed that the removal of the fluoride pressure from plaque did not affect the numbers or proportions of the various species and genera of bacteria. The fluoride tolerance of the mutans streptococci, and the Vap or the overnight final pH of the isolated strains had not changed. These results suggest that the use of fluoride toothpaste had not affected plaque composition, nor fluoride tolerance or acidogenicity of mutans streptococci. Probably the amount of fluoride delivered by fluoride dentifrices to dental plaque is too low to induce such adaptations.

Adaptation, Physiological↗
PubMed1984

Streptococcus mutans in saliva: intraindividual variations and relation to the number of colonized sites.

Analysis of the salivary levels of Streptococcus mutans may contribute to the evaluation of the caries risk. It is therefore important to identify factors that might influence the outcome of such analyses. This investigation consisted of three parts. The first aim was to evaluate the short-term variation of S. mutans concentration in saliva. Furthermore, we estimated the effect of discontinued oral hygiene on salivary S. mutans. We also analyzed the relation between salivary levels of S. mutans and the number of colonized approximal and occlusal sites. Tongue samples were also included in the comparison. Systematic short-term variation could not be demonstrated. A 95% confidence interval for an observed S. mutans value was obtained by multiplying and dividing the observed value by a factor of 5 (for S. mutans samples less than 10(6) or 2.3 (S. mutans greater than 10(6). One week of discontinued oral hygiene did not significantly change the level of S. mutans in saliva. Saliva samples correlated significantly with tongue samples and with the number of colonized approximal sites. The results of these studies confirm the stability of the S. mutans colonization level.

Adult↗
PubMedDate not supplied

The effects of chlorhexidine gel on Streptococcus mutans infection in 10-month-old infants: a longitudinal, placebo-controlled, double-blind trial.

PURPOSE: This study investigated the long-term effects of 0.2% chlorhexidine gel, used as a weekly brush-on gel, on Streptoccocus mutans infection in 10-month-old infants. METHODS: The investigation followed the criteria of a placebo-controlled, double-blind, longitudinal clinical trial. Infants were recruited at birth and oral microbiological swabs were taken at 3 monthly intervals, together with medical, dental, dietary and brushing histories. Children who were found to be colonized with S. mutans were randomly assigned to either the chlorhexidine-gel group (N = 50) or placebo gel group (N = 46), and parents were instructed to brush the gel on the teeth once per week for 12 weeks. In another control group (N = 210), infants did not use either chlorhexidine or placebo gels. Saliva samples were cultured using S. mutans-selective tryptone-yeast extract-cysteine-sucrose-bacitracin (TYCSB) agar. The mean age of the children was 10.2 +/- 2.6 months at the start of the trial and subjects were followed until the ages of 18 months. RESULTS: In the children with initial low S. mutans counts of < 300 CFU/mL, there was a significant percentage reduction in S. mutans counts in the chlorhexidine-gel group compared to the placebo gel and no-gel control groups after 3 months of weekly gel brushing. However, no significant differences with the placebo group were observed after 15 months of follow-up. There were 39 children (41%) who achieved reduction of their S. mutans to 0 CFU/mL. Compared to those who remained infected with S. mutans, these children had higher toothbrushing frequencies (P < .001) and toothpaste use (P < .001), as well as lower frequencies of daily feeds (P < .01), and lesser weekly frequencies of sweet solids and liquids (P < .001). CONCLUSIONS: Children with relatively low initial S. mutans counts (< 300 CFU/mL) showed a reduction in S. mutans counts in the first 3 months when 0.2% chlorhexidine gel was brushed on the teeth weekly. No differences were observed when compared with the placebo and no-treatment groups at later follow-up periods.

Anti-Infective Agents, Local↗
PubMedDate not supplied

Effects of oral health education and tooth-brushing on mutans streptococci infection in young children.

PURPOSE: The purpose of this study was to examine the effects of maternal dental health education and tooth-brushing instruction on the levels of mutans streptococci in pre-school children. METHODS: One hundred and seven children (44 boys and 63 girls) with a mean age of 20.5 months, randomly selected from a community child health clinic within a 2-week period, participated in this study. Medical, dental, and dietary information was obtained through a questionnaire. The children's mouths were examined, and plaque samples were obtained by swabbing the teeth and mucosa. A commercial microbiological kit was used to determine the presence of mutans streptococci. The mothers were instructed in tooth-brushing using a soft-scrub method. The children were recalled to the same clinic after a period of 4 weeks to obtain a second evaluation of the mutans streptococci levels. RESULTS: At the first visit, 69 of the 107 children (64%) showed positive infection with mutans streptococci. Ninety (84%) children returned for the recall examination. In the second examination, only 44 (49%) of the 90 children showed positive results for mutans streptococci. The difference in number of children who tested positive is statistically significant (P < .01). At the first visit, children who did not show infection with mutans streptococci were those who reported greater frequency of tooth-brushing (P < .05) and less snacking (P < .05). There were 26 children (29%) who converted from positive to negative results for mutans streptococci infection between the first and second visits (P < .01). This conversion from positive to negative infection was attributed mainly to increased tooth-brushing, as other dental health habits remained the same. CONCLUSIONS: Infection with mutans streptococci in young children is associated with increased snacking frequency and inadequate tooth-brushing. A single dental health education session and tooth-brushing instruction to mothers results in approximately a 25% reduction in mutans streptococci infection in young children from a relatively high socioeconomic status.

Child, Preschool↗
PubMed2003

[Detection of the transmitted strains and non-transmitted strains of Mutans streptococci by AP-PCR].

OBJECTIVE: Dental caries is a transmissible infectious disease in which S. mutans plays the major role. The purpose of this study was to detect the S. mutans transmitted strains and non-transmitted strains by AP-PCR fingerprint for laying the foundation of study on the relation between bacterial properties of S. mutans and its transmission. METHODS: Plaque samples were obtained from buccal surfaces of 20 3-4 years old children and their mothers. Caries experience was scored by dmft (DM-FT). Diet regime, breast feeding and care of the children were recorded. 200 Isolates of S. mutans were detected by S. mutans B medium and confirmed biochemically. DNA from each isolate was purified and AP-PCR fingerprinting was conducted. Amplicons were separated by electrophoresis in 1.5% agarose gels. RESULTS: 45 different patterns among the 200 isolates were found. There were 10 mothers (50%) and 15(75%) children owning one genotype while 10 mothers and 5 children owning more than one (2 mothers owning 5 types). The data showed that the mothers harbored a more heterogeneous population of S. mutans than their children. Comparisons in genotypes between children and their mothers discovered that 16(80%) children harbored the same genotypes as their mothers, indicating high transmission in the group of people. Detection of the S. mutans transmitted strains and non-transmitted strains in mothers demonstrated that 10 (50%) mothers harbored not only transmitted strains but also non-transmitted strains, suggesting that different strains had different ability of transmission. CONCLUSION: AP-PCR was capable of detecting the S. mutans transmitted strains and non-transmitted strains. Some S. mutans genotypes had higher ability of transmission than others.

Child, Preschool↗
PubMed2004

[Preliminary study on gene related to acid tolerance of Streptococcus mutans].

OBJECTIVE: To construct an acid-sensitive mutant of Streptococcus mutans (S. mutans) by transposon mutagenesis and to find a new gene related to the acid tolerance of S. mutans. METHODS: The transposon Tn917 was delivered into S. mutans UA159 by the temperature-sensitive plasmid pTV1-OK bearing Tn917 and transposition of Tn917 was induced after incubation at non-permissive temperature (42 degrees C). Transposants harboring Tn917 in the chromosome were screened for the selection of mutant that had diminished growth at low pH. Southern analysis was performed with EcoRI (no cut within Tn917) digests of S. mutans UA159 and the selected aid-sensitive mutant, with DIG-labeled probe of 4.3 kb KpnI fragment of pTV1-OK containing Tn917. Genetic backcross experiment was performed by transforming the genome of the mutant to another S. mutans strain MT8148 to determine the linkage of Tn917 insertion to the change of phenotype (acid-sensitivity). Comparison of the abilities to grow at low pH, the glycolytic pH drop and killing pH values were done between the acid-sensitive mutant and the parent strain. The asymmetric PCR method was used to obtain the fragment flanking Tn917 and the PCR products were cloned to pMD18-T vector for sequencing. RESULTS: One mutant that showed no growth at pH 5.0 was isolated from 2 316 transposants and was named as b23. Southern analysis and genetic backcross experiment confirmed the linkage between single Tn917 insertion into the chromosome and the phenotypic change (acid sensitive). b23 was less acid tolerant than UA159 in that it showed poorer growth at low pH and higher glycolytic pH minimum and higher killing pH. BLAST results indicated that Tn917 inserted into the genome of S. mutans UA159 at the site of 996 123 bp. CONCLUSION: An acid-sensitive mutant of S. mutans was successfully constructed and a new gene that is responsible for the acid tolerance in S. mutans UA159 was revealed.

Genes, Bacterial↗
PubMed1992

WHO pathfinder caries survey in Beijing extended with data for prevalence of mutans streptococci.

A pathfinder caries survey was carried out in Beijing, People's Republic of China, using WHO standard methodologies, in order to estimate the trend by comparing the results with the 1981 caries survey, performed in the same area. Simultaneously, the levels of mutans streptococci in the group were estimated in order to define the proportion of children with high and low mutans levels. Twelve-year-old children were randomly selected from schools in five districts within the city limits. Examinations for caries were performed according to 'WHO Oral Health Surveys' by two calibrated examiners. A total of 178 children were examined for caries and 156 of them were randomly selected for saliva sampling of mutans streptococci, using the 'Strip mutans' method. The number of colonies adhering to the strips were compared with a chart, supplied by the manufacturer, and given a score between 0 and 3, indicating low to very high saliva mutans counts, respectively. The results showed a mean DMFT of 1.87 (1.61-0.06-0.20, for decayed, missing and filled teeth respectively); 66.3 per cent of the children were affected. Fourteen per cent had mutans class 0, 28 per cent class 1, 35 per cent class 2 and 23 per cent class 3. The mean DFT, for each mutans class was 0.82, 1.48, 2.09 and 2.69, respectively. The differences were statistically significant (P = 0.0015). In the lowest mutans class, 50 per cent had caries and the mean number of teeth requiring conservative care was 0.68. For the high mutans group, the corresponding values were 72 per cent and 2.11 teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed2005

Effect of a chlorhexidine varnish on Streptococcus mutans in saliva.

The aim of the present work was to evaluate the effect of a thymol/chlorhexidine varnish at 1% on Streptococcus mutans (S. mutans) in saliva applied after teaching and evaluating an oral hygiene technique and dressing the cavities to reduce the bacterial load. Streptococcus mutans levels in saliva samples and dental status were evaluated in 38 girls between 6 and 13 years of age with high risk of caries. The girls were then trained and assessed in oral hygiene. On day seven, oral hygiene assessment was repeated and supragingival plaque control was performed. After 15 days (day 21) another culture was performed and the level of S. mutans in saliva samples was determined. Evaluation and reinforcement of the oral hygiene technique were repeated and the cavities were dressed to reduce the bacterial load. At 36 days from the onset of the experiment, culture S. mutans counts were performed; evaluation and reinforcement of the oral hygiene technique were undertaken and the girls were divided randomly into two groups: 1 The teeth of the experimental group were painted with a varnish containing 1% chlorhexidine and thymol. 2 The teeth of the control group were painted with a placebo varnish containing only thymol. After a further 15 days (day 51), another culture and S. mutans counts were performed. The results showed a gradual reduction in the S. mutans counts in saliva in each subsequent experimental period analyzed. Significant differences between the experimental group and the control group were recorded after treatment. It can be concluded that the levels of S. mutans decreased in each subsequent experimental period and that the application of a 1% chlorhexidine varnish elicited a significant reduction in S. mutans levels.

Administration, Topical↗
PubMed1994

Cloning and characterisation of a repetitive DNA sequence from Theileria mutans: application as a species-specific probe.

Repetitive DNA sequences were isolated from a Theileria mutans genomic library by screening with T. mutans total DNA. DNA sequence analysis demonstrated that a section of one of the clones contained a complex series of overlapping perfect repeats ranging between 99 and 20 bp in size. The T. mutans repetitive sequence did not contain large open reading frames (ORFs), unlike T. parva Tpr repetitive DNA sequences. When used as a hybridisation probe the repetitive sequence revealed restriction-fragment-length polymorphisms (RFLPs) between the EcoRI-digested DNAs of two T. mutans stocks. The T. mutans repetitive probe gave a signal with 1 ng of purified T. mutans piroplasm DNA and detected T. mutans sequences in whole-blood DNA isolated from an experimentally infected animal when the piroplasm parasitaemia was equal to or above 0.4%. Oligonucleotide primers derived from the repetitive sequence allowed more sensitive detection of T. mutans DNA by polymerase chain reaction (PCR) amplification. Using the PCR, T. mutans DNA was amplified from an experimentally infected animal with a parasitaemia of < 0.1%.

Animals↗
PubMed1975

Virulence of Streptococcus mutans: a sensitive method for evaluating cariogenicity in young gnotobiotic rats.

Gnotobiotic rats infected with Streptococcus mutans 6715 at 19 days of age and fed a purified diet (305) containing 5% sucrose developed extensive caries lesions on all molar surfaces within 16 days (35 days of age). Approximately twice as many lesions developed when infected rats were maintained until 45 days of age, whereas noninfected rats did not develop caries when fed diet 305. Gnotobiotic rats infected with S. mutans 6715 and fed a purified diet containing no sucrose (300) until day 25 and subsequently fed diet 305 for 10 days developed lesions similar to rats fed diet 305 for 16 days. Furthermore, rats infected with S. mutans 6715 and fed diet 300 until 45 days of age developed approximately one-half the smooth surface lesions as infected rats fed diet 305 for the same length of time. The level of caries on buccal and proximal molar surfaces in 45-day-old gnotobiotic rats varied when animals were infected with S. mutans AHT, BHT, NCTC 10449, 6715, or LM-7. Animals infected with S. mutans AHT showed more severe lesions on the buccal surfaces than those observed in animals infected with the other strains of S. mutans tested, whereas S. mutans 6715 caused significantly more caries on proximal surfaces. On the other hand, rats infected with S. mutans LM-7 exhibited the lowest level of caries on all molar surfaces of the five strains of S. mutans tested.

Animals↗
PubMed1988

Colonization of rat molar teeth by mutans streptococci with different salivary agglutination characteristics.

The oral implantation of salivary agglutination-positive and -negative mutans streptococci was studied using streptomycin resistant (StrR) organisms. StrR Streptococcus mutans strains Ingbritt and NCTC 10449 are agglutinated by rat saliva and the StrR strains Streptococcus sobrinus 6715-13 and Strep. mutans GS5 are not. Four groups of Sprague-Dawley rats were inoculated orally with each organism (one per group) and fed a sucrose diet. A further two groups of animals were similarly inoculated with either the agglutination-positive Strep. mutans Ingbritt or the agglutination-negative Strep. sobrinus 6715-13 and fed a glucose diet. StrR streptococci were recovered from smooth-surface dental plaque of all animals on the sucrose diet with no significant difference in the recovery of agglutination-positive Strep. mutans strains Ingbritt and NCTC 10449 and agglutination-negative Strep. mutans GS5. However, the recovery of agglutination-negative Strep. sobrinus 6715-13 from smooth-surface plaque of animals on either the sucrose or the glucose diets was significantly lower than that of the other strains. Agglutination-positive Strep. mutans Ingbritt colonized smooth enamel surfaces of animals on the sucrose and the glucose diets in numbers that were not significantly different. However, the colonization of such surfaces by agglutination-negative Strep. sobrinus 6715-13 was significantly enhanced by the sucrose diet. Agglutination-positive and -negative StrR mutans streptococci were recovered from fissure plaque of all inoculated sucrose-fed animals in numbers that were not significantly different. Successful colonization of smooth enamel surfaces by the StrR streptococci resulted in increased smooth-surface caries.(ABSTRACT TRUNCATED AT 250 WORDS)

Agglutination↗
PubMed1990

Monoclonal antibodies for enumeration and identification of mutans streptococci in epidemiological studies.

Two members of the mutans streptococci, Streptococcus mutans and Strep. sobrinus, are often found in human dental plaque. Different cariogenic characteristics between these species have been reported and therefore these species should be detected and identified separately. Identification of mutans streptococci based on sugar fermentation is troublesome and easily leads to erroneous conclusions. Furthermore, the recovery for the two species differs on selective media. This causes incorrect enumeration of Strep. mutans and Strep. sobrinus in clinical samples. The aim of this study was to develop an improved method for simultaneous identification and enumeration of Strep. mutans and Strep. sobrinus in dental plaque and saliva samples. The immunoblot technique described is based on growth of the microorganisms on non-selective media, followed by immunological detection with specific monoclonal antibodies. With the immunoblot significantly more plaque samples containing Strep. sobrinus were detected than on the selective medium TYCSB (p less than 0.01). The number of plaque samples harbouring Strep. mutans was equal on TYCSB and immunoblot. However, the numbers of c.f.u. of Strep. mutans and Strep. sobrinus detected with the blot were significantly higher than those obtained on TYCSB (p less than 0.01). The recovery of Strep. sobrinus on primary isolations on TYCSB appeared to be inhibited in 29 out of the 45 Strep. sobrinus-containing plaque samples. False-positive and false-negative reactions with the immunoblot were not found. The results indicate that the presence and numbers of Strep. sobrinus and Strep. mutans can be studied reliably using the immunoblot technique.

Adult↗
PubMed2005

Genotyping of Streptococcus mutans by using arbitrarily primed polymerase chain reaction in children with Down Syndrome.

OBJECTIVE: The aim of this study was to compare the caries prevalence between Down Syndrome (DS) and non-DS children and to investigate the difference between the genotypes of Streptococcus mutans (S. mutans) colonized in both DS and non-DS groups. DESIGN: Sixty children with DS and 64 non-DS children aged between 7 and 12 years old were included to this study. All erupted teeth were evaluated according to the criteria recommended by the World Health Organization. Unstimulated saliva samples were carried out from the children and cultivated on S. mutans selective Tryptone-yeast-cystine (TYC) agar with 0.2 U/ml bacitracin and 15% sucrose. Molecular typing of S. mutans strains was performed by using arbitrarily primed polymerase chain reaction (AP-PCR) with OPA-05 primer. All data were analysed by using SPSS (SPSS Inc., Chicago, IL, USA) 11.0 software program for windows. RESULTS: The caries index scores were found significantly lower in DS individuals than the non-DS group (p < 0.05). The salivary S. mutans levels between DS and non-DS groups did not show significant difference (p > 0.05). The difference between dental caries and salivary S. mutans levels also was not statistically significant (p > 0.05). According to the results of the AP-PCR typing, all profiles of S. mutans which colonized in DS group were different from the control group. The relationship between these different profiles and dental caries prevalence was statistically significant (p < 0.05). CONCLUSION: The profiles of S. mutans colonized in DS group might be a reason of low caries prevalence.

Case-Control Studies↗
PubMed2006

In vitro inhibitory effects of Polygonum cuspidatum on bacterial viability and virulence factors of Streptococcus mutans and Streptococcus sobrinus.

OBJECTIVES: Polygonum cuspidatum has been used in Korean folk medicine to improve oral hygiene. This study was performed to evaluate the effects of methanol extract from root of P. cuspidatum (MEP) on bacterial viability and the virulence factors of Streptococcus mutans and Streptococcus sobrinus. METHODS: To test the effects of MEP on bacterial viability, we determined the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) against 20 bacterial strains, including S. mutans and S. sobrinus, using a micro-dilution assay. In case of S. mutans and S. sobrinus, the assays for time-kill and bacterial growth rate at sub-MIC concentrations were also performed. To determine effects of the extract on the virulence factors of S. mutans and S. sobrinus, the assays for sucrose-dependent adherence, water-insoluble glucan formation, glycolytic acid production, and acid tolerance were performed at sub-MIC levels. Phytochemical analysis for constituents of MEP was carried out. RESULTS: MEP showed a broad antibacterial range (MIC 0.5-4 mg/ml). The MBC was two to four times higher than the MIC. The time-kill curves showed S. mutans and S. sobrinus were significantly killed after 1h of incubation. At sub-MIC levels, doubling times of S. mutans and S. sobrinus dose-dependently increased up to 211% and 123%, respectively. At sub-MIC levels, MEP also showed inhibitory effects on the virulence factors of S. mutans and S. sobrinus in a dose-dependent fashion. Phytochemical analysis revealed the presence of alkaloids, sterol/terpenes, tannins, flavonoids, and carbohydrates. CONCLUSION: These data indicate that MEP has inhibitory effects on bacterial viability at higher concentrations (> or =MIC) and the virulence factors of S. mutans and S. sobrinus at sub-MIC concentrations, suggesting that it might be useful for the control of dental plaque formation and subsequent dental caries formation.

Anti-Bacterial Agents↗
PubMed2004

Inhibitory effect of some herbal extracts on adherence of Streptococcus mutans.

The objective of this study was to investigate the inhibitory effect of the crude extracts from some herbs on adherence of Streptococcus mutans (S. mutans) ATCC 25175 and TPF-1 in vitro. Six herbs, Andrographis paniculata; Cassia alata; Chinese black tea (Camellia sinensis); guava (Psidium guajava); Harrisonia perforata and Streblus asper, were extracted with 50 or 95% ethanol and dried. Herbal extracted solution at 0.5% concentration (w/v) was initially tested for bacterial adherence on glass surfaces. In order to identify type and effective concentration of the extracts, the extracts that showed the inhibition on glass surfaces were then tested on saliva-coated hydroxyapatite by the use of radiolabeled bacteria. To study the mechanism of action, the effect of the extracts at such concentration on glucosyltransferase and glucan-binding lectin activities were examined. It was found that all extracts, but Streblus asper, showed significant inhibitory effect on bacterial adherence to glass surfaces. For the saliva-coated hydroxyapatite adherence assay, Andrographis paniculata, Cassia alata, Chinese black tea and Harrisonia perforata could inhibit adherence of S. mutans ATCC 25175. Chinese black tea was the strongest inhibitor followed by Andrographis paniculata, Cassia alata and Harrisonia perforata, respectively. For S. mutans TPF-1, adherence inhibition was observed from Andrographis paniculata and Cassia alata at similar levels. The lowest concentrations of the extracts that inhibited the adherence at least 50% were 0.5% of Andrographis paniculata, 0.5% of Cassia alata, 0.3% of Chinese black tea and 0.5% of Harrisonia perforata for S. mutans ATCC 25175. For S. mutans TPF-1, the effective concentrations were 0.5% of Andrographis paniculata and 0.4% of Cassia alata. All extracts at such concentrations decreased the activity of glucosyltransferase from both strains. Only Andrographis paniculata and Cassia alata eliminated or decreased the activity of glucan-binding lectin from both strains. These findings suggested that Andrographis paniculata, Cassia alata, Chinese black tea and Harrisonia perforata could inhibit adherence of S. mutans ATCC 25175, while Andrographis paniculata and Cassia alata had an effect on S. mutans TPF-1 in vitro at the concentrations employed in this study.

Bacterial Adhesion↗