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PubMed2004

"Streptococcus milleri" endocarditis caused by Streptococcus anginosus.

Unlike other viridans streptococci, members of the "Streptococcus milleri group" are often associated with abscess formation, but are only rare causes of infective endocarditis. Although it has been shown that almost all S. intermedius isolates and most S. constellatus isolates, but only 19% of S. anginosus isolates, were associated with abscess formation, no report has addressed the relative importance of the 3 species of the "S. milleri group" in infective endocarditis. During a 5-year period (April 1997 through March 2002), 6 cases of "S. milleri" endocarditis (out of 377 cases of infective endocarditis), that fulfil the Duke's criteria for the diagnosis of infective endocarditis, were encountered. All 6 "S. milleri" isolates were identified as S. anginosus by 16S ribosomal RNA (rRNA) gene sequencing. Three patients had underlying chronic rheumatic heart disease and 1 was an IV drug abuser. Five had monomicrobial bacteremia, and 1 had polymicrobial (S. anginosus, S. mitis, Granulicatella adiacens, and Slackia exigua) bacteremia. Two patients died. None of the 6 isolates were identified by the Vitek system (GPI) or the API system (20 STREP) at >95% confidence. All 6 isolates were sensitive to penicillin G (MIC 0.008-0.064 microg/mL), cefalothin, erythromycin, clindamycin, and vancomycin. Accurate identification to the species level, by 16S rRNA gene sequencing, in cases of bacteremia caused by members of the "S. milleri group", would have direct implication on the underlying disease process, hence guiding diagnosis and treatment. Infective endocarditis should be actively looked for in cases of monomicrobial S. anginosus bacteremia, especially if the organism is recovered in multiple blood cultures.

Adult↗

PubMed1988

Use of Percoll density gradients for studying the attachment of bacteria to oral epithelial cells.

An assay for studying the attachment of bacteria to oral epithelial cells has been developed which utilizes Percoll density gradient centrifugation to separate bacteria and epithelial cells. 3H-thymidine-labeled bacteria were incubated with suspensions of buccal epithelial cells in microtitration plates for 2.5 hr at 35 degrees C. The mixtures were then subjected to density gradient centrifugation in 50% Percoll. Epithelial cells with attached bacteria formed a band near the top of the tube, while unattached bacteria formed a band near the bottom. The epithelial cells were collected on membrane filters, and the number of attached bacteria was determined by scintillation counting. Binding of S. mitis C5 was found to increase with time, and equilibrium was attained within two hr. Saturation of available binding sites occurred when 10(7) S. mitis cells were incubated with 1.5 x 10(4) buccal epithelial cells. The numbers of streptococci which attached as determined with this assay were in good agreement with values obtained by direct microscopic counts. Adsorption of S. mitis C5 cells was adequately described by a Langmuir isotherm (correlation coefficient 0.998). This permitted calculation of estimates of the number of binding sites and the affinity of the organism. The assay proved reliable even when as few as 1000 epithelial cells were used. Treating the epithelial cells with neuraminidase or trypsin significantly decreased the number of S. mitis C5 cells which attached. In contrast, binding of A. naeslundii 12104 to neuraminidase-treated cells was increased, and attachment of B. gingivalis 381 was also enhanced, especially to epithelial cells which had been treated with trypsin.

Actinomyces↗

PubMed1995

The relationship between dental caries in the primary dentition and anti S. mutans serum antibodies in children with Down's syndrome.

The purpose of this study was to evaluate the status of dental caries in seventy-five subjects with Down's Syndrome, ages two to eighteen years and to evaluate the relationship between dental plaque or caries experience and serum antibody titers against S. mutans and S. mitis. These antibodies were examined since an enhanced host response to S. mutans might be responsible for the low caries prevalence in Down's Syndrome. Antibody titers were determined using the enzyme-linked immunosorbant assay (ELISA) and titers were expressed in ELISA units. The frequency of all subjects who were caries-free was 46.1%, while 61.4% of the subjects under five years were caries-free. The average DMFT score in the subjects of Hellman Dental Age group I (primary dentition) was 15.9. The highest frequency of caries occurred on occlusal surfaces, followed by proximal surfaces of the upper incisors and smooth surfaces on incisors. The severity of dental caries in the subjects with Down's Syndrome was bipolar and could be categorized as either mild or severe. In the subjects having a primary dentition, a significant positive correlation was found in the relationship between the Original Caries Severity Score (OCSS) and the plaque score. There was also a significant positive correlation between OCSS and IgM antibody titer to S. mutans. In contrast, no correlation between antibody titers to S. mitis and these variables was found. It is not clear if these antibodies are protective and responsible for the reduced caries rate seen in Down's Syndrome.

Adolescent↗

PubMed1991

Inhibition of adsorption of oral streptococci to saliva treated hydroxyapatite by chitin derivatives.

This study estimated the effects of five chitin derivatives low molecular chitosan (LMCS), ethyleneglycol chitin (PEGT), carboxymethyl chitin (PCMT), sulphated chitosan (PSSS), and phosphorylated chitin (PPPT) on the adsorption of three oral streptococci to saliva-treated hydroxyapatite (S-HA). The adsorption was evaluated by measuring the optical density of the bacterial cell suspensions released from saliva-treated hydroxyapatite by 0.5 N HCl. The adsorption of test strains to S-HA progressively decreased in proportion to each additional volume of PEGT, PPPT, or PSSS. PPPT and PSSS quite effectively inhibited the adsorption of S. mutans onto S-HA, but were less effective against S. sanguis and S. mitis. PPPT, PSSS, and PCMT all markedly promoted the desorption of S. mutans cells pre-adsorbed onto S-HA. Pretreatment of S-HA with PPPT, PSSS, or PCMT significantly decreased the subsequent adsorption of S. mutans and S. mitis. Pretreatment of these cells with PEGT also decreased their adsorption to S-HA. These findings suggest that these chitin derivatives may change the ionic natures of the S-HA and the bacterial cell surface, resulting in a less favorable interaction.

Adult↗

PubMed2005

Validation of serotyping of Streptococcus pneumoniae in Europe.

INTRODUCTION: Serotyping of pneumococci has become increasingly important as new pneumococcal vaccines are introduced and place emphasis on knowledge of national serotype-distributions and their development over time. AIM: The aim of this study was to evaluate the quality of serotyping of pneumococci in Europe, and to focus on possible problems with methods, procedures, etc. that may lead to wrong serotypings. METHODS: This study was part of a larger EU-project. Eleven reference laboratories in Europe participated in the validation of pneumococcal serotyping. The Streptococcus Unit at SSI functioned as the gold standard for use of the Neufeld test. Each laboratory was asked to type 70 blinded pneumococcal strains by use of their normal serotyping procedure and to answer to a questionnaire regarding their experience and serotyping procedure for pneumococci. The 70 strains were chosen to represent all the 23 pneumococcal types included in the 23-valent pneumococcal vaccine plus a number of other less common types. RESULTS: A total of 735 serotypings was performed. Five laboratories performed complete serotyping whereas the remaining six laboratories performed partial or variable serotyping into groups or types that did not belong to groups. In general, a high degree of consensus appeared between the 11 European reference laboratories. Of 735 serotypings, 39 erroneous serotypings were made (5% of all). Most serotyping errors included a wrong serotype within the correct serogroup, where especially types 9N, 18C and 19F were mistyped. Furthermore, misidentification of noncapsular pneumococci like S. mitis and S. oralis was also a frequent error. For 22 strains (30%) of pneumococci, serotyping mistakes were made. The erroneous serotypings were neither correlated to the use of other methods than the Neufeld test, nor to the serotyping routine of the laboratories. A number of errors may be due to a serotyping result based on a negative reaction with a specific factor serum, instead of a positive reaction with another factor serum. This may be chosen in order to simplify the serotyping procedure. Thus, all the necessary factor sera must be used in order to assure correct serotyping. CONCLUSIONS: Overall, the quality of serotyping of pneumococci was high, and a high degree of consensus was found between the eleven laboratories. It is important to use all the necessary factor sera for serotyping, to perform all the necessary tests and to base a serotyping result always on one or more positive reactions and not on a negative reaction alone. More focus on serotyping of serotypes within groups seems to be warranted.

Europe↗

PubMed1985

Longitudinal microbiological investigation of a hospitalized population of older adults with a high root surface caries risk.

Intact root surfaces of chronically hospitalized subjects were sampled periodically to enumerate bacterial species believed to be associated with root caries. Bacteria were cultivated and enumerated using a series of selective and enriched media. Microbial counts, isolation frequencies, and percent cultivable flora data were analyzed for caries-active and caries-free surfaces and subjects. S. mutans, S. sanguis, A. viscosus, A. naeslundii, total lactobacilli, and Veillonella accounted for a mean of less than 20% of the cultivated flora, with mitis salivarius agar cultivable streptococci averaging less than 5%. The microbial count data were highly variable, precluding the finding of significant differences in caries association for either subjects or sites. Streptococci, especially S. mutans, correlated highly with lactobacilli in the samples.

Actinomyces↗

PubMed2001

Automated fluorescent in situ hybridization for the specific detection and quantification of oral streptococci in dental plaque.

Our aim was to develop a rapid fluorescent in situ hybridization (FISH) assay for the identification of different oral groups of streptococci in dental plaque and to combine it with digital image analysis for the automated enumeration of target cells. Cy3-labeled oligonucleotide probes specific for 16S rRNA gene sequences of the anginosus, mitis, mutans, and salivarius groups of streptococci were hybridized under stringent conditions with bacterial cultures or supragingival plaque samples that had been permeabilized with lysozyme. Probe specificity was determined with strains from 30 different species, mainly of oral origin. Results showed that probes ANG541, MIT447, SSP001, and SAL090 with specificity for the anginosus, mitis, mutans, and salivarius groups, respectively, the pan-reactive streptococcal probe STR405, the S. mutans specific probe MUT590, and the S. sobrinus specific probe SOB174 were well-suited for the identification of cultured streptococci. Probes STR405, MIT447 and SSP001 were then successfully applied to enumerate automatically bacteria of the recognized taxa in 144 supragingival plaque samples. On the average, total streptococci accounted for 8.2%, streptococci of the mitis and mutans groups for 3.9 and 1.7%, respectively, of the plaques. The combined application of FISH and automated image analysis provides an objective time-saving alternative to culture or PCR for the enumeration of selected oral streptococci in dental plaque.

Colony Count, Microbial↗

PubMed1991

A modified mitis salivarius medium for a caries diagnostic test.

A new medium, MSKB, composed of mitis salivarius agar base, sorbitol, kanamycin sulfate and bacitracin, has been developed that is more selective for recovery of mutans streptococci (mutans) than the so called mitis salivarius bacitracin (MSB) medium. MSB and MSKB were compared for recovery and selectivity of mutans by plating saliva samples as well as pure cultures on both media. Sixty saliva samples were plated and counted for mutans and non-mutans colonies. Thirty-six samples had greater numbers of non-mutans on MSB than on MSKB, and 14 of the 36 had non-mutans colonies that could be visually confused with mutants. The recovery of mutans on MSKB was approximately 13% less than on MSB. The selectivity and recovery of MSB and MSKB were evaluated over 1-5 months of storage at 4 degrees C. Streptococcus anginosus grew on MSB after 1 month, but not on MSKB. Streptococcus milleri type 2 grew on both media after 4 months.

Bacitracin↗

PubMed2001

[Susceptibility to penicillin and 13 antimicrobial agents in erythromycin-resistant viridans group streptococci isolated from blood cultures].

From March 1998 to June 1999, we studied 63 sequential blood culture isolates of viridans group streptococci which showed a 49% resistance to erythromycin. A high level of resistance to penicillin (46%) was also found. A statistically significant correlation was detected between the two types of resistance. The erythromycin-resistant strains were phenotypically and genotypically characterized, and no differences were found between the resistance to penicillin and the M or MLS(B) phenotypes. The penicillin-erythromycin-resistant strains included: 16 S. mitis, five S. sanguis and one S. salivarius. The rank order of activity (% of susceptibility) for all 14 agents against 31 erythromycin- resistant isolates was the following: vancomycin = rifampicin (100) > chloramphenicol (98) > meropenem (65) > cefotaxime (61) > amoxicillin- clavulanic acid (42) > cefepime = ciprofloxacin (39) > tetracycline = trimethoprim-sulfamethoxazole (36) > cefuroxime (32) > penicillin = ampicillin = cefaclor (29). The species S. milleri and S. bovis were the most susceptible. The most resistant strains were two S. mitis and one S. sanguis and showed multiresistance to six different groups of antimicrobial agents. The frequent association between macrolide resistance and resistance to other antimicrobial agents suggests that the susceptibility of all clinically significant isolates needs to be evaluated and alternative agents for the prevention and treatment of viridans group streptococci infections should be identified.

Drug Resistance↗

PubMed1999

The pattern of change in salivary immunoglobulins and antibodies to S. mitis and S. oralis in children undergoing bone marrow transplantation: use of an indirect method of assessment.

The objective of this study was to assess the pattern of change in salivary immunoglobulins and antibodies to S. mitis and S. oralis in 23 children following allogeneic bone marrow transplantation and their matched controls. To overcome the difficulty of obtaining a sufficient quantity of whole saliva from very young, sick children saliva was collected in a 5-ml oral rinse of sterile normal saline. It was not possible to measure the volume of whole saliva in each rinse and the concentration of the salivary immunoglobulins and bacterial antibodies were estimated from 1 ml of oral rinse. Despite these shortcomings a pattern of change in the mean concentrations of total salivary IgA, secretory IgA, antibodies to S. mitis and S. oralis and total IgG at specific event- related times during the transplantation period has been demonstrated. There was a significant increase in the concentration of salivary IgG 7 days post-transplantation, followed by significant decreases in total salivary IgA, secretory IgA and antibodies to S. mitis after recovery of the peripheral neutrophil count above 0.5 x 10(9). The concentrations of total IgA and antibodies to S. oralis was significantly greater in the transplant group 119 days post-transplantation.

Antibodies, Bacterial↗

PubMed1983

The clinical significance of streptococcal species isolated from cerebrospinal fluid.

Alpha-hemolytic (viridans) streptococci are often isolated from cerebrospinal fluid (CSF); however, the significance of such isolates is poorly understood. In order to clarify the clinical significance of isolating these organisms from CSF, we did a retrospective analysis of 43 patients, from whom eight different species of alpha-hemolytic streptococci were recovered. Eight patients (19%) had significant infections based on bacteriologic, laboratory, and clinical findings. Significant infections were associated with S. sanguis, S. salivarius, S. intermedius, S. faecalis, and S. bovis. Thirty-five patient isolates (81%) from CSF were considered as contaminants, with S. mitis being the most frequently isolated organism (49%). Direct gram stain of CSF sediment, CSF glucose concentration, and CSF cell differential were clearly abnormal in most patients with significant infections, in contrast to patients with streptococci isolated as contaminants. Cultures of the lumbar puncture skin site yielded streptococci and other bacteria, suggesting a possible reservoir for contaminants.

Cerebrospinal Fluid↗

PubMed1984

Antibiotic susceptibility of streptococcal strains associated with infective endocarditis.

Seventy-six strains of various species of streptococci isolated from patients with infective endocarditis were tested for their susceptibility to 13 antibiotics by an agar dilution method. The antibiotics tested were: benzyl-penicillin, ampicillin, cefotaxime, vancomycin, erythromycin, rifampicin, pristinamycin, gentamicin, netilmicin, tobramycin, amikacin, dibekacin and streptomycin. Excluding enterococci, 91% of strains were sensitive to benzylpenicillin. Resistance to benzylpenicillin was only found in some strains of S. sanguis I, S. sanguis II and S. mitis. Enterococci were more sensitive to ampicillin. Cefotaxime was highly active against all strains, except enterococci. Vancomycin was active against all strains. Resistance to erythromycin was found in 16% of isolates. Rifampicin and pristinamycin were highly active against all strains, except some enterococci. Gentamicin and netilmicin were the most active of the six aminoglycosides tested. High level resistance to streptomycin was seen in six strains. Overall, S. agalactiae was more resistant to the aminoglycosides than the other species. Among the non-groupable streptococci, strains of S. mitis, S. sanguis I and S. sanguis II were the least sensitive to many antibiotics. Benzylpenicillin remains the antibiotic of choice for the treatment of IE caused by streptococci. If the MIC exceeds 0.1 mg l-1, an aminoglycoside (netilmicin or gentamicin) should be added and the duration of treatment increased from 4 to 6 weeks.

Aminoglycosides↗

PubMed1987

[Bacteriological investigation of the cariogenic effects of sugar alcohols and sucrose].

Considerable evidence indicates that the disaccharide, sucrose is probably the major dietary factor in dental caries formation and much subsequent research has gone into the search for another sweetener to replace sucrose. Currently, there is much interest in the development of new sweeteners and the cariogenic properties of sugar alcohols. The present study aimed to examine the cariogenic properties of sugar alcohols (xylitol, sorbitol, mannitol) and sucrose on growth pattern and acid production of S. mutans, S. mitis, S. salivarius, S. sanguis, S. faecalis, S. viridans, L. casei and L. acidophilus in vitro by using Photo Electrical Colorimeter and pH meter. In conclusion the results in this study showed that out of sugar alcohols, xylitol is the only compound which, depending on its concentration, significantly did not affect the growth and acid production of all tested micro organisms.

Cariogenic Agents↗

PubMed1987

Microbiology of the early colonization of human enamel and root surfaces in vivo.

This study describes the predominant early microflora on human teeth on the basis of microbiologic identification of 1742 fresh isolates. The isolates were obtained from four dental students who carried test pieces of enamel and root surface in the oral cavity for 4, 8, 12, and 24 h. During the experimental periods oral hygiene was discontinued. Under equal conditions root surfaces were more heavily colonized than were enamel surfaces. However, the composition of the microbiota was the same. Within the first 24 h the microflora was dominated by streptococci and Gram-positive pleomorphic rods. S. sanguis contributed only 6-18% of the early colonizers whereas S. mitis and S. oralis varied between 24-42% and 1-27% (mean values), respectively. The relative proportion of S. oralis increased significantly within the observation period while the proportion of S. salivarius and arginine-positive S. mitis showed a declining tendency. Actinomyces species adsorbed to the tooth surfaces within the first 4 h but did not increase their relative proportions until after 8-12 h, possibly due to a long doubling time. In one individual, encapsulated bacteria resembling Stomatococcus mucilaginosus were observed among the early colonizers. The time-dependent shifts in the bacterial populations within 24 h corroborate parallel ultrastructural findings.

Bacteria↗

PubMed1980

Virulence-related physiological changes and antigenic variation in populations of Streptococcus mutans colonizing gnotobiotic rats.

The purpose of this study was to determine if populations of Streptococcus mutans which were undergoing antigenic variation while colonizing gnotobiotic rats concomitantly became altered in physiological characteristics which affected their virulence. S. mutans strain JBP (serotype c), which was freshly isolated from a carious lesion in a 6-year old child, was used to inoculate gnotobiotic rats; uninfected animals served as controls. Substrains were isolated from animals 1, 2, 3, 4, and 12 weeks after infection; samples of pilocarpine-stimulated saliva were also obtained from representative animals for antibody analyses. Isolates derived from stock cultures of strain JBP proved to be homogeneous with respect to all of the physiological characteristics monitored. However, substrains isolated from the animals within 4 weeks after infection were altered with respect to their ability to agglutinate in the presence of sucrose, their ability to form adherent growth in sucrose broth, and the terminal pH attained in glucose broth. Some isolates obtained 12 weeks after infection no longer synthesized detectable levels of c antigen or intracellular glycogen, and they formed atypical smooth colonies on mitis salivarius agar. With an enzyme-linked immunosorbent assay, low levels of immunoglobulin A (IgA) antibodies reactive with whole JBP cells were detected in saliva samples of uninfected control animals at each sampling period; these evidently were induced to antigens contained in the diet of the animals. Significantly higher levels of IgA antibodies were present in saliva samples from animals infected with strain JBP for 3 weeks or longer. Thus, the emergence of antigenic and physiological variants of S. mutans in the animals was paralleled by increased levels of salivary IgA antibodies. The reactivity of salivary IgG with JBP cells was low, and it fluctuated in both groups of animals. No antibodies of the IgM class were detected. When tested in gnotobiotic rats, several variants, including strains which no longer formed typical rough colonies or adherent growth in sucrose broth, proved much less virulent than parental strain JBP in inducing carious lesions. Prior oral immunization, which resulted in higher levels of salivary and serum IgA antibodies reactive with strain JBP, was found to accelerate the emergence of smooth-colony variants in the animals; it was also associated with decreased streptococcal population levels on the teeth and in feces of the rats. It is suggested that part of the mechanism by which artificial immunization leads to a reduction in dental caries development in experimental animals is due to the earlier selection of less virulent streptococcal populations.

Animals↗

PubMed2005

In vitro and in vivo antimicrobial effects of mastic chewing gum against Streptococcus mutans and mutans streptococci.

BACKGROUND AND OBJECTIVE: Dental caries is associated with oral pathogens and Streptococcus mutans (S. mutans) is one of the primary cariogenic organisms. Mastic gum, from Pistacia lentiscus, has been shown to have antibacterial properties. The objective of this study was to determine antibacterial activity of mastic chewing gum against S. mutans and mutans streptococci in vitro and in vivo conditions. SETTING: Cukurova University, Dental School, in 2002. MATERIALS AND METHODS: Antimicrobial activity of mastic gum was evaluated using standard S. mutans strain by disc diffusion method in vitro. Cytotoxicity effect of mastic gum on HEp-2 cells was evaluated by conventional haemocytometer using the trypan blue exclusion method. Clinical studies were then performed on 25 periodontally healthy volunteers. The inhibitory effect of chewing mastic gum against mutans streptococci in saliva was compared to a placebo gum. Saliva samples were taken from the subjects immediately before and after chewing the mastic gum and the placebo gum for 15 min. Additional saliva samples were collected every 30 min. The samples were inoculated onto mitis salivarius-bacitracin agar and incubated for 48 h anaerobically at 37 degrees C. The total number of viable bacteria was then counted. RESULTS: Among tested solvents (chloroform, acetone, petrolium ether and ethanol), it was found that the acetone was found to be more convenient than the others to dissolve the mastic gum. In the cytotoxicity assay, concentrations up to 75 mg/ml of the mastic gum were not toxic for the replication of HEp-2 cells. Thus, lower concentrations of mastic gum (20 and 50 mg/ml) were used for the experiments. In vitro experiments, the diameters of growth inhibition zones of mastic gum were in the range 9.0-27.0 mm. In the clinical trials, the mean number of bacteria in samples taken after chewing the mastic gum and placebo gum were following; at minute 15 was 112 x 10(4)+/-268 x 10(3) and 175 x 10(4)+/-417 x 10(3)cfu/ml, for minute 45 was 85 x 10(4)+/-219 x 10(3) and 165 x 10(4)+/-329 x 10(3)cfu/ml, at minute 75 was 65 x 10(4)+/-100 x 10(3) and 160 x 10(4)+/-216 x 10(3)cfu/ml, at minute 105 was 60 x 10(4)+/-127 x 10(3) and 150 x 10(4)+/-138 x 10(3)cfu/ml, and at minute 135 was 55 x 10(4)+/-65 x 10(3) and 145 x 10(4)+/-354 x 10(3)cfu/ml, respectively. Significantly fewer bacteria was found in saliva samples collected after chewing mastic gum compared to those after chewing paraffin (p<0.001). CONCLUSIONS: This preliminary study showed that mastic gum had significant antibacterial activity against S. mutans and mutans streptococci and it may be a useful adjunct in the prevention of caries.

Adult↗

PubMed1988

Relationship of subgingival microbial complexes to clinical features at the sampled sites.

Subgingival plaque samples from 100 active destructive periodontal lesions and 150 inactive subgingival sites in 33 subjects were analyzed by predominant cultivable microbiota techniques. 50 isolates were characterized from each sample and where possible, the isolate was placed in 1 of 134 microbial species or groups. The sites were clustered on the basis of the proportions of all of the species detected in each sample using a minimum similarity matching coefficient and an average unweighted linkage sort. 10 clusters containing 166 sites were formed which exhibited greater than 35% minimum similarities. All clusters were made up of sites from multiple subjects and were formed on the basis of different combinations of micro-organisms. Certain complexes of micro-organisms appeared to relate to the severity of periodontal destruction and the activity of the sampled site. The combination of F. nucleatum, B. forsyth and W. recta (cluster VII) or B. gingivalis, B. intermedius and S. intermedius (cluster VIII) distinguished clusters made up of sites which on average had the most attachment loss and the deepest pockets. These clusters contained the highest proportions of active sites and sites which lost greater than 3 mm of attachment after therapy. Clusters dominated by V. parvula (cluster III), the Actinomyces sp. (cluster X) or the combination of S. sanguis II, S. mitis, V. parvula and S. intermedius (cluster II) were made up of sites which exhibited less active disease and responded more favorably to therapy. Sites in other clusters exhibited moderate levels of prior destructive disease and disease activity status closer to the mean values for all 250 sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1989

Zeta potential and the adhesion of oral streptococci to polymethylmethacrylate.

Adhesion of Candida albicans to the acrylic fitting surface of dentures can lead to the development of denture induced stomatitis and is suggested to be preceeded by the adhesion of indegeneous oral bacteria. Bacterial adhesion can be considered as a result of attractive van der Waals and repulsive electrostatic forces. In this paper we investigate the role of electrostatic interactions in the adhesion of oral streptococci to polymethylmethacrylate (PMMA), the most commonly employed denture-base material. Zeta potentials of the bacterial strains as well as of PMMA fillings were reduced by increasing the ionic strength in the buffer suspension, causing an elevated number of adhering S. mitis, S. sanguis and S. mutans. As streptococcal adhesion is suggested to be a prerequisite for the subsequent adhesion of Candida albicans, the use of more negatively charged denture-base materials can be recommended in order to prevent streptococcal adhesion and therewith adhesion of candidae, and the occurrence of denture-induced stomatitis.

Bacterial Adhesion↗