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PubMedDate not supplied

Detection of Streptococcus mutans and Streptococcus sobrinus on the permanent first molars of the Mosuo people in China.

Streptococcus mutans and Streptococcus sobrinus are associated with the development of dental caries. The purpose of this study was to differentiate these bacteria by morphology, biochemical characteristics and PCR, and to compare their occurrence with the prevalence of dental caries in the Mosuo people. Plaque samples were collected from the permanent first molar in 126 Mosuo people (83 females, 43 males, aged 25-55 years, average age 36.1 +/- 7.73). Dental status was recorded as DMFT by WHO caries diagnostic criteria. Males had a significantly lower prevalence of caries and DMFT than females: 11.4 vs. 86.9% and 1.65 vs. 6.95, respectively (p<0.001). Morphological and biochemical tests gave unreliable results. The prevalence of S. mutans and S. sobrinus was 75.4 and 57.1%, respectively. 26.5% of females and 53.5% of males were positive for S. mutans alone, 18.1% of females and 16.3% of males were positive for S. sobrinus alone, while 50.6% of females and 18.6% of males were positive for both S. mutans and S. sobrinus and 4.8% of females and 11.6% of males were negative for both species. The DMFT scores of subjects positive for both S. mutans and S. sobrinus were significantly higher than of those positive for either S. mutans or S. sobrinus alone. These results indicate that subjects harboring both S. mutans and S. sobrinus have a significantly higher prevalence of dental caries than those with S. mutans or S. sobrinus alone.

Adult↗
PubMedDate not supplied

Colonization of Streptococcus mutans and Streptococcus sobrinus genotypes and caries development in children to mothers harboring both species.

The major route of early acquisition of mutans streptococci in humans is a vertical transmission from mother to child. The purpose of this longitudinal study was to examine the acquisition, distribution and persistence of Streptococcus mutans and Streptococcus sobrinus in children whose mothers harbored both species and to study the caries incidence in relation to colonization of these bacteria. Fifteen mother-child pairs were followed during the child's first 7 years. Stimulated salivary samples were taken from the mothers and the children. Plaque samples were also collected from the teeth and the tongue of the children. The samples were analyzed by cultivating techniques together with genomic fingerprinting and hybridizing. The caries experience was evaluated on the sampling occasions and retrospectively using the records of caries registrations from the community clinics. During the 7-year period 10 of the 15 children acquired mutans streptococci. Only 4 of them were colonized by both S. mutans and S. sobrinus despite the fact that their mothers harbored both species. In 2 of the children S. sobrinus was found later than S. mutans. A total of 26 genotypes were found in the children and 9 of them were identical to their mothers. New genotypes and a gain-loss pattern were noted especially in the children but also in their mothers. The groups of teeth first positive for the two species were the deciduous molars. The caries experience was low during the study period with 8 children showing no caries.

Child↗
PubMed1992

Antibacterial activity of cefixime against Streptococcus pneumoniae, Streptococcus pyogenes, and Haemophilus influenzae in the presence of Moraxella (Branhamella) catarrhalis.

We measured the sizes of the inhibition zones of oral beta-lactam antibiotics for Streptococcus pneumoniae, Streptococcus pyogenes and Haemophilus influenzae in the presence of beta-lactamase-producing-Moraxella (Branhamella) catarrhalis by the agar double-layer method. The sizes of the zones of amoxicillin for S. pneumoniae alone were the largest, followed in a descending order by those of cefixime and cefaclor. In the presence of 10(7) CFU/ml of M.(B.) catarrhalis, however, significant reduction of the sizes of the zones was seen with amoxicillin and cefaclor; inhibition with cefixime was nearly unchanged. Similar results were observed in those for S. pyogenes. These variable findings were attributed to the difference in stability of these drugs to the beta-lactamase produced by M.(B.) catarrhalis. When the susceptibility of H. influenzae in the presence of 10(8) CFU/ml of M.(B.) catarrhalis to cefixime, cefoteram, cefpodoxime, cefotiam and cefuroxime was examined, the sizes of the inhibition zones of all the drugs were reduced by the presence of 10(8) CFU/ml of M.(B.) catarrhalis, but those of cefixime were the largest of all the drugs tested. Our agar double-layer method is simple and useful for evaluating the influence of beta-lactamase-producing organism, as M.(B.) catarrhalis, on the disk susceptibility of other pathogens to antibiotics.

Cefixime↗
PubMed1989

Effect of neuraminidase on the adherence to salivary pellicle of Streptococcus sanguis and Streptococcus mitis.

Neuraminidase-sensitive adherence to experimental salivary pellicles was studied using eight strains of Streptococcus sanguis and five strains of Streptococcus mitis. Approximately 60% of the strains of each species showed significantly lower adherence to neuraminidase-treated versus untreated saliva-coated hydroxyapatite. In addition, the adherence of several of these streptococcal strains to saliva-coated hydroxyapatite and neuraminidase-treated saliva-coated hydroxyapatite was inhibited using galactose and N-acetyl-D-galactosamine. Results from these studies suggested that several salivary receptors mediate adherence of these species.

Acetylgalactosamine↗
PubMed1991

Differences in cariogenicity between fresh isolates of Streptococcus sobrinus and Streptococcus mutans.

Streptococcus sobrinus is known to possess cariogenic properties in vitro. It can produce acid in large amounts and it has the capacity to adhere to enamel and other surfaces. However, most studies on cariogenicity have been performed with laboratory strains that have been subcultured over long periods of time. Therefore, the cariogenicity and acidogenicity of 9 fresh isolates of both S. sobrinus and Streptococcus mutans from human dental plaque were compared. The bacteria were inoculated into the oral cavity of rats. The rats were fed diet SSP 20/5, containing 20% sucrose and 5% glucose. After the experimental period of 42 days, the amount of caries was assessed and bacterial counts were determined using monoclonal antibodies. Four out of 9 S. sobrinus strains and 3 out of 9 S. mutans strains did not colonize the rats. Colonizing strains constituted 39-78% of the total anaerobic cultivable microflora. The numbers of advanced dentinal lesions in the fissures of the rats colonized with S. mutans were significantly lower than those colonized with S. sobrinus (p less than 0.05). S. sobrinus produced acid more rapidly than S. mutans in a pH-stat system at pH values between 6.5 and 5.0 (p less than 0.01). The results indicate that fresh isolates of S. sobrinus are more cariogenic in rats than fresh isolates of S. mutans. This is possibly due to differences in glycolytic properties of these two species.

Animals↗
PubMed1991

Dental location of Streptococcus mutans and Streptococcus sobrinus in humans harboring both species.

The distribution and prevalence of Streptococcus mutans and Streptococcus sobrinus were determined in plaque samples from the cervical areas of all buccal, lingual and approximal tooth surfaces and from the fissures of all occlusal sites in 40 subjects harboring both species. S. mutans was detected more often and in higher numbers than S. sobrinus. There were more teeth detected with S. mutans only than with S. sobrinus only. Most teeth harbored both of these mutans streptococci species, indicating a positive association. The highest numbers of CFU for both species were detected on the molars, with the lowest incidence on the anterior teeth. The presence of S. mutans was relatively similar on all teeth tested, while the presence of S. sobrinus was relatively higher on the molars compared to the anterior teeth. S. mutans and S. sobrinus were found to colonize the buccal surfaces in almost equal numbers. On all other surfaces, S. mutans was detected more frequently or in higher numbers compared to S. sobrinus. No significant differences could be found in the relative proportions of S. mutans and S. sobrinus between sound, decayed or filled tooth surfaces.

Adolescent↗
PubMed1992

Viability of Streptococcus mutans and Streptococcus sobrinus in whole saliva with varying concentrations of indigenous antimicrobial agents.

We have studied the possible relationship between indigenous salivary antimicrobial agents, indigenous mutans streptococci and the capability of added mutans streptococci to grow in saliva. Stimulated whole saliva was collected from 19 healthy donors. Saliva samples were sterilized, supplemented with glucose and inoculated with Streptococcus mutans or Streptococcus sobrinus. The mixtures were incubated for 20 h followed by counting of viable cells. Saliva samples were analysed, both before and after sterilization, for indigenous antimicrobial agents and the bacterial flora. The subjects could be divided into two groups: those (n = 9) whose saliva promoted and those (n = 10) whose saliva inhibited the growth of the inoculated streptococci. A statistically significant correlation (+0.82, p < 0.001) was found between the numbers of viable cells of S. mutans and S. sobrinus after incubation in saliva. The sterilization procedure reduced the content of all antimicrobial proteins. Salivary antimicrobial factors, or levels of indigenous mutans streptococci, did not differ between the two groups. We conclude that none of the individual salivary antimicrobial factors alone can explain the large individual differences in growth-promoting or growth-inhibiting patterns of saliva on S. mutans and S. sobrinus. Inter-individually, saliva either supports or inhibits the growth of mutans streptococci, indicating a similar response of these two species in relation to the properties of saliva.

Adult↗
PubMed1992

Invasion of Streptococcus mutans, Streptococcus intermedius and Propionibacterium acnes into the teeth of gnotobiotic rats.

Germ-free rats, fed a modified cariogenic diet 2000 with a reduced sucrose content of 25%, were inoculated with a strain of Streptococcus mutans, Streptococcus intermedius or Propionibacterium acnes, respectively. After 100 days on the diet, the rats were sacrificed. Microscopic examination of stained decalcified tooth sections revealed marked destruction of the outer zones of the dentin infected with S. mutans. The destruction was closely associated with the formation of glucan-mediated large aggregates of S. mutans. The aggregates, however, were rarely formed in the deep zones of the infected dentin. Inoculation with S. intermedius and P. acnes had little effect on the microscopic outline of the decalcified tooth sections. However, the staining behavior of the sections with Mallory's method, Alcian blue-PAS and silver was like that of the tooth sections infected with S. mutans, even in the central and inner zones of the dentin. The histochemical alterations of the deep zones of the dentin induced by the three infected bacteria appeared to be due to their proteolytic rather than to their acidogenic activities.

Animals↗
PubMed1993

Distribution of Streptococcus mutans and Streptococcus sobrinus at sub-sites in human approximal dental plaque.

The distribution and prevalence of Streptococcus mutans and Streptococcus sobrinus were determined at three sub-sites in human approximal plaque: away from (A), to the side of (S) and below (B) the contact area. Small plaque samples were taken from all three sub-sites on clinically sound approximal surfaces of a single premolar from each of 21 schoolchildren. S. mutans was detected significantly more often and in higher proportions than S. sobrinus from sub-sites A (p = 0.019), S (p = 0.034) and B (p = 0.004). S. mutans was detected in highest proportions from the B site compared to the A site (p = 0.025); there were no significant differences in the isolation frequency or prevalence of S. sobrinus from any of the sub-sites. S. mutans and S. sobrinus were never isolated together from the A sub-sites and were recovered together most commonly from the B sub-sites (p < 0.01). It is concluded that S. mutans and S. sobrinus preferentially colonise the most caries-prone site apical to the contact area.

Bacteria, Anaerobic↗
PubMed1994

Effects of subinhibitory concentrations of chemical agents on hydrophobicity and in vitro adherence of Streptococcus mutans and Streptococcus sanguis.

The aim of this investigation was to determine whether sublethal concentrations of chlorhexidine (Cx), hexetidine (Hx), cetylpyridinium chloride (Cc), sodium dodecyl sulfate (SDS), sanguinarine (Sg), sodium fluoride (NaF), and ammonium fluoride (NH4F) could affect hydrophobicity and adhesion of Streptococcus sanguis and Streptococcus mutans to saliva-coated hydroxyapatite (S-HA). Determination of the minimum inhibitory concentrations (MICs) showed that both species were susceptible to all agents tested. Growth in the presence of sub-MIC concentrations of Cx, SDS, Cc, NaF, or NH4F did not change significantly the hydrophobicity of S. sanguis cells when compared to the control which lacked any agent. However, growth in the presence of Hx or Sg resulted in a significant reduction in their hydrophobicity. Sub-MIC levels of SDS or Sg in the growth medium resulted in S. mutans cells with increased affinity for hexadecane compared with the control. The adherence of S. sanguis was changed significantly only by Hx or Sg, resulting in less cells adhering to S-HA. However, S. mutans cells previously incubated with NaF, NH4F, or Sg showed a higher adherence to S-HA than the control. The mechanisms of interference with adherence are at present not completely understood. Thus, antimicrobial agents at sub-MIC concentrations can interfere selectively with hydrophobicity and/or adhesion of oral streptococci.

Adsorption↗
PubMed1995

Effects of sugar restriction on Streptococcus mutans and Streptococcus sobrinus in saliva and dental plaque.

The effect of sugar restriction on the oral levels of mutans streptococci was studied in 20 subjects fulfilling three criteria: (1) having more than 300,000 CFU mutans streptococci/ml saliva, (2) harbouring both Streptococcus mutans and Streptococcus sobrinus in saliva, and (3) eating sugar frequently. The subjects were randomly divided into a test group (n = 12), who were asked to refrain from using sugar-containing foods between meals and to reduce sugar in main meals for 6 weeks, and a control group (n = 8), who did not receive any dietary advice. Saliva and plaque samples were collected at baseline and at 3, 6 and 12 weeks. The results showed that the levels of S. mutans and S. sobrinus decreased in saliva and plaque during the 6-week sugar restriction period. The decrese in mutans streptococci was more pronounced on buccal than on approximal tooth surfaces. Both species seemed to react in a similar way to the sugar restriction in saliva as well as in dental plaque. At the follow-up examination at 12 weeks, i.e. 6 weeks after completing the sugar restriction period, the numbers of S. mutans and S. sobrinus had increased again, but were still lower when compared to the baseline values.

Adult↗
PubMed1978

Compounds which affect the adherence of Streptococcus sanguis and Streptococcus mutans to hydroxyapatite.

Several compounds were evaluated in an in vitro assay system for their ability to block the adherence of Streptococcus sanguis to saliva-coated hydroxyapatite and Streptococcus mutans to dextran-coated hydroxyapatitite. Fatty acids, ranging from C-12 to C-20, the enzyme amylase, chlorhexidine, human sera, and several serum proteins blocked S sanguis adherence to saliva-coated hydroxyapatite. Chlorhexidine blocked S mutans adherence to dextran-coated hydroxyapatite, but human sera and serum proteins did not. The effects of these compounds on the adherence of these organisms to hydroxyapatite may help in the development of specific plaque control methods for use in human populations.

Adhesiveness↗
PubMed1984

Neuraminidase activity: a biochemical marker to distinguish Streptococcus mitis from Streptococcus sanguis.

Selected reference and freshly isolated strains of Streptococcus mitis (mitior) and Streptococcus sanguis were assayed for cell-associated neuraminidase activity by their ability to hydrolyze [3H-] sialyllactitol. A cell-associated neuraminidase was detected with S. mitis and S. sanguis serotype II (reclassified as S. mitis) but not with S. sanguis serotypes I and III. Neuraminidase activity of S. mitis correlated with this organism's inability to hydrolyze arginine, aesculin, and few, if any, sugars. The findings indicate that the presence of cell-associated neuraminidase activity is useful for the taxonomic classification of S. mitis.

Arginine↗
PubMed1985

Anaerobic and aerobic metabolism of sorbitol in Streptococcus sanguis and Streptococcus mitior.

Sorbitol-fermenting strains of Streptococcus sanguis and Streptococcus mitior were grown both anaerobically and in the presence of oxygen in a sorbitol-containing complex medium. Washed-cell suspensions were incubated with an excess of sorbitol, and the production of lactate, formate, ethanol, and acetate was analyzed. Moreover, we determined the lactate dehydrogenase and pyruvate formate-lyase activities in cell-free extracts of anaerobically grown cells. The anaerobically grown cells produced lactate, formate, ethanol, and acetate under anaerobic conditions. When these cells were exposed to air, the amounts of formate, ethanol, and acetate were reduced in comparison with those of the strictly anaerobic cells. Cells grown in the presence of oxygen only produced detectable levels of lactate and acetate. Anaerobically grown cells possessed lactate dehydrogenase and pyruvate formate-lyase activities under strictly anaerobic conditions. The level of pyruvate formate-lyase was dramatically reduced when cells were exposed to air, while the level of lactate dehydrogenase was about the same as that under strictly anaerobic conditions. Thus, the results indicate that S. sanguis and S. mitior both metabolize sorbitol differently under anaerobic and aerobic conditions. This difference may depend on the oxygen-sensitivity of the pyruvate formatelyase of these micro-organisms.

Acetates↗
PubMed1988

Homology of glucosyltransferase gene and protein sequences from Streptococcus sobrinus and Streptococcus mutans.

The sequences of glucosyltransferase genes from Streptococcus sobrinus (gtfI) and Streptococcus mutans (gftB) were compared and show a high degree of homology. There is a 57.7% homology of nucleotides in the genes and a 56.7% homology of amino acids in the deduced protein sequences. The G + C content for the protein-coding region is 43.6% for S. sobrinus and 41.2% for S. mutans. Internal repeating sequences present in both proteins exhibit some difference in sequence pattern.

Amino Acid Sequence↗
PubMed1991

Synergistic degradation of mucin by Streptococcus oralis and Streptococcus sanguis in mixed chemostat cultures.

Oral streptococci can grow in mucin by utilizing the oligosaccharide chains as a source of carbohydrate. The degradation of the oligosaccharides by these species is accomplished by exoglycosidase activities. In this experiment, it was investigated whether strains from different species could cooperate in the release of sugars from the mucin oligosaccharide. To this end, Streptococcus sanguis Ny 584 and Streptococcus oralis strain Ny 586 were grown continuously in a chemically-defined medium, with pig gastric mucin as the growth-limiting source of carbohydrate. In pure cultures, strain Ny 586 attained approximately three-fold-higher cell densities than did strain Ny 584 in the mucin medium. This was in accordance with the observation that S. oralis Ny 586 exhibited fucosidase activity, as indicated by the presence of fucose in the culture fluid. In contrast, strain Ny 584 has no fucosidase activity against mucin, and therefore cannot attack fucose-ending oligosaccharide chains. Stable mixed cultures of the strains were obtained. It appeared that S. sanguis Ny 584 reached significantly higher cell densities in mixed cultures with S. oralis Ny 586 than in pure culture. Stimulation of the growth of strain Ny 584 was probably due to the generation of non-fucose-ending oligosaccharide chains by fucosidase from strain Ny 586. It is concluded that the synergistic degradation of oligosaccharides in glycoproteins is a potential factor influencing the streptococcal populations in the mouth.

Colony Count, Microbial↗
PubMed1997

Pathway for uptake and degradation of X-prolyl tripeptides in Streptococcus mutans VA-29R and Streptococcus sanguis ATCC 10556.

The growth of Streptococcus mutans and Streptococcus sanguis in the oral environment requires that these micro-organisms be able to degrade salivary proteins and to assimilate the resulting peptides as an amino nitrogen source. Our research is aimed at the definition of the proteolytic enzyme systems in these oral streptococci which allow them to utilize such substrates. In the present work, the nature of the hydrolytic activity expressed by S. mutans VA-29R and S. sanguis ATCC 10556 against X-Pro4-nitroanilide and X-Pro-Y tripeptide substrates was investigated. This activity was predominantly associated with a cytoplasmic dipeptidyl peptidase which preferentially catalyzes the release of an N-terminal dipeptide from substrates in which proline is the penultimate residue. These streptococci also possess a second cytoplasmic peptidase, pepD, which catalyzes the hydrolysis of X-Pro dipeptides. We found that Gly-Pro-Ala or Ala-Pro-Gly were transported into the bacterial cells only when an energy source such as glucose was present. Peptide uptake was time-dependent, and selective exodus of peptide-derived amino acids from the bacterial cells occurred during peptide uptake. Results from these studies provide evidence that S. mutans VA-29R and S. sanguis ATCC 10556 possess a pathway for the complete degradation of X-Pro tripeptides. Transport of the peptides into cells prior to hydrolysis provides an efficient way by which all amino acids of a peptide may be obtained at an energy expense equivalent to that associated with the transport of just one amino acid. In light of the abundance of proline in salivary polypeptides, this degradative pathway could be an important component in the proteolytic pathway for salivary polypeptide utilization in these oral streptococci.

Aminopeptidases↗
PubMed2000

Bactericidal activity of moxifloxacin compared to grepafloxacin and clarithromycin against Streptococcus pneumoniae and Streptococcus pyogenes investigated using an in vitro pharmacodynamic model.

The aim of the present investigation was to study and compare the killing activity of two new fluoroquinolone compounds, moxifloxacin and grepafloxacin, and a new generation macrolide, clarithromycin, against three clinical isolates of Streptococcus pneumoniae (penicillin-susceptible, -intermediate and -resistant) and two Streptococcus pyogenes (erythromycin-susceptible and -resistant) strains by simulating their human pharmacokinetics in a pharmacodynamic model. Results were achieved by measuring the reduction in viable bacterial count during the 24-h experimental period. All three antimicrobials led to a continuous reduction in the bacterial counts of penicillin-susceptible S. pneumoniae and erythromycin-susceptible S. pyogenes strains, the maximal reduction observed after 8-10 hours being 5-6 logs for moxifloxacin and 3 logs for grepafloxacin; clarithromycin exhibited a similar reduction of 5 logs only after 24 h. No regrowth was observed for any strain after 24 h with any of the antibiotics. The bactericidal activity of both the fluoroquinolones was not affected by penicillin resistance of S. pneumoniae and erythromycin resistance of S. pyogenes. In contrast, clarithromycin was not able to reduce the bacterial count of penicillin-resistant S. pneumoniae and erythromycin-resistant S. pyogenes strains. Moxifloxacin exhibited, within 24 h, higher and faster bactericidal activity than grepafloxacin and clarithromycin against S. pneumoniae, and was not affected by penicillin resistance. These results suggest that moxifloxacin is a promising new agent for treatment of streptococcal infections.

Anti-Bacterial Agents↗