Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Streptococcus mitis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 739 records · Page 41Linked to original sources
PubMed1999

The effect of nicotine on growth of Streptococcus mutans.

There is little information available concerning the effects of nicotine on oral bacteria; and in particular, Streptococcus mutans, an important microbe in the etiology of dental caries. To test the effects of nicotine, Streptococcus mutans were incubated in either 0 or 10(-1)-10(-7) M concentrations of nicotine and then plated onto mitis-salivarius-bacitracin agar. Colonies were counted and treatment groups compared. Both 10(-1) and 10(-2) M nicotine caused total inhibition of bacterial growth, while 10(-3) and 10(-4) M produced significantly more colonies than control. Also, 10(-6) and 10(-7) M nicotine produced a significant reduction in the mean number of colonies. These results suggest a biphasic, dosage-dependent effect of nicotine on the growth of Streptococcus mutans. Since 10(-3) M nicotine has been reported within the saliva of smokeless tobacco users, use of these products could stimulate growth of Streptococcus mutans and possibly place the user at increased risk for dental caries.

Dental Caries↗
PubMed2001

Caries risk assessment from dental plaque and salivary Streptococcus mutans counts on two culture media.

This study attempted to determine which combination of plaque or saliva, and tryptic soy agar, bacitracin (TSY20B) or mitis salivarius, bacitracin media, yielded the highest caries-predictive values for mutans counts in children with different caries prevalence. Sixty children were divided into three equally sized groups: caries free, low caries and high caries. Eighteen months later, their caries incidence and initial mutans count were compared. Fissure plaque on TSY20B yielded a high correlation between mutans counts and caries prevalence (P<0.009, r=3346) and incidence (P<0.003, r=4521). The caries-predictive values obtained demonstrate that the coefficient of variation of mutans counts from lower first-molar fissure plaque on TSY20B accounts for 20.4% of the variation in final caries index. This strong correlation provides a valuable tool for the identification of caries-prone individuals.

Agar↗
PubMed2003

Comparison of different techniques of quantitative PCR for determination of Streptococcus mutans counts in saliva samples.

Saliva samples from 16 children with current caries activity were investigated for Streptococcus mutans using three different PCR techniques, and the results were compared with those of selective cultivation on mitis salivarius agar with bacitracin (MSB) (I, II: LightCycler - competitive PCR end-point analysis; III: LightCycler - kinetic real-time analysis; IV, V: block cycler - competitive PCR end-point analysis; VI: cultivation on MSB agar). In groups I, III, IV and VI the saliva samples were analyzed directly. A DNA preparation before PCR with added competitors was carried out in groups II and V to exclude the influence of PCR inhibitors. The coefficients of correlation ranged from 0.97 to 0.98 among the competitive PCR methods, 0.8 to 0.85 for competitive vs. real-time PCR and 0.5 to 0.65 for PCR vs. cultivation methods. Competitive PCR on the real-time instrument was found to be more rapid than, comparably sensitive to, but less reproducible than competitive PCR on a block cycler.

Bacteriological Techniques↗
PubMed1991

[The antimicrobial efficiency of aqueous solutions of calcium hydroxide on Streptococcus mutans, Streptococcus faecalis and Candida albicans, in vitro].

Calcium hydroxide preparations Ca(OH)2 are used as water solutions, putly, liner, cement or artificial material. The therapeutic effect of each medicaments depends on physical and chemical characteristic of additional components. The aim of the paper is to research the sensitivity of Streptococcus faecalis and Candida albicans to different water solution concentrations of calcium hydroxide. As solid plates, Bacto-Mitis-Salivarius agar was used for S. mutans, Torlak blood agar for S. faecalis and Sabourand agar "Torlak" for C. albicans. The holes were drilled in solid plates and were filled by 0.2 ml of water solutions of Ca(OH)2. Preparations, created as described were incubated aerobically at 37 degrees C in the period of 48 hrs. Results were read after 24 as well as after 48 hrs. The examined solutions of Ca(OH)2, revealed the highest antimicrobic effect after 24 hrs. The result remained unchanged even after 48 hrs. The inhibition of S. mutans growth on the solid plate occurred with the concentration of Ca(OH)2 solution from 271.18 x 10(-2) mol/dm3 and pH 12.76. The growth of S. faecalis at the solid plate was inhibited with the concentration of 3335.21 x 10(-3) mol/dm3 and pH 12.82. The inhibition of C. albicans growth on solid plate occurred with the concentration of Ca(OH)2 solution from 1023.20 x 10(-3) mol/dm3 and pH 12.84. The difference in the sensitivity of the examined microorganisms at the same concentrations of Ca(OH)2 solution was observed.

Calcium Hydroxide↗
PubMedDate not supplied

Strain-related acid production by oral streptococci.

Acid production, in particular at low pH, is thought to be an important ecological determinant in dental caries. The aim of the present study was to determine the acid producing capability at different pH levels of 47 streptococcal strains, representing 9 species, isolated from human dental plaque. The bacteria were grown until mid log-phase under anaerobic conditions and acid production was measured in a pH-stat system at pH 7.0, 6.0, 5.5 and 5.0. At all pH values, the mean velocity of acid production (V(ap)) by Streptococcus mutans and S. sobrinus was significantly higher (p<0.01; ANOVA) than that of the other oral streptococci, including S. mitis, S. oralis, S. gordonii, S. sanguis, S. intermedius, S. anginosus, S. constellatus, and S. vestibularis. However, the V(ap) of some strains of S. mitis biovar 1 and S. oralis, particularly at pH values of 7.0 and 6.0, exceeded that of some strains of S. mutans. The V(ap) decreased with pH for all strains, but some strains of S. mitis biovar 1 and strains of the mutans streptococci maintained a relatively high rate of acid production. The results suggest that some strains of S. mitis biovar 1 and S. oralis may play an important role in caries development by modifying the environment in dental plaque to become favourable for the succession of aciduric species. The study furthermore emphasises the need for detailed species and biovar identification of oral streptococci and for recognition of the significant physiological differences that occur within single species.

Acids↗
PubMed2005

Early acquisition of Streptococcus mutans for children.

Existing evidence reveals that in Early Oral Infection the main route of transmission of Streptococcus mutans is mother-child saliva contacts and that initial acquisition takes place during a specific period of time denominated "Window of Infectivity" that lapses between 6 and 30 months of the child's life, with a higher risk between 18 and 30 months of age. The aim of the present study was to analyze Early Oral Infection. The levels of Streptococcus mutans in saliva and bacterial plaque in the binomial mother-child 6 to 18 months after childbirth were evaluated. Twenty-four mother-child binomials that attended the University Hospital of Maternity and Neonatology of Córdoba participated in the study. Samples of saliva and dental plaque were taken from mother and child and seeded in selective Agar Mitis Salivarius Bacitracin medium (0.28 mg/ml) and cultured for 48 hours at 37 degrees C and in 5% CO2 to allow for the growth of Streptococcus mutans. The colonies were identified morphologically and biochemically. At 6 months after childbirth: 58.33% of the samples of the mother's saliva were positive, while the presence of the microorganism was not detected in 100% of the samples of the infants' saliva. At 18 months of after childbirth: 79.16% of the samples of saliva and 100% of the samples of the mothers' dental plaque were positive, whereas the samples of saliva and dental plaque of the infants were positive for Streptococcus mutans in 20.83% and 70.83% of the cases respectively. The initial acquisition of Streptococcus mutans would have occurred in 20.8% of the children at the age of 18 months. Eruption of primary molars occurs at this age.

Age Factors↗
PubMed2003

Prevalence of Csh-like fibrillar surface proteins among mitis group oral streptococci.

The prevalence of Csh-like fibrillar surface proteins among oral streptococci was investigated by ELISA and by immunoelectron microscopy using antiserum raised to recombinant fragments of CshA of Streptococcus gordonii DL1. The majority of S. gordonii, Streptococcus sanguis and Streptococcus oralis strains tested elaborated short (ca. 50-80 nm long) surface fibrils and reacted with antiserum to the amino acid repeat region of CshA, demonstrating the widespread nature of Csh-like proteins among these species. In contrast, reactivity with antiserum raised to the adhesion-mediating non-repetitive region of CshA was more restricted. On the basis of the ELISA results, several isolates were selected for immunogold analysis using CshA antisera. Immunogold-negative staining showed a surface distribution of 10 nm gold particles consistent with antibody binding to short fibrils. Long fibrils (>150 nm long), where present, were not significantly labelled with gold. The results suggest that some of the short peritrichous fibrils on many mitis group streptococci comprise Csh-like fibrillar protein. Further, the data are consistent with our hypothesis that the antigenically conserved amino acid repeat region of Csh-like proteins forms a scaffold for cell-distal presentation of the amino-terminal non-repetitive region that, at least in S. gordonii DL1, functions as an adhesin.

Adhesins, Bacterial↗
PubMed1990

[Oral Streptococci - a scheme for the identification of Streptococcus mutans].

A reliable simple scheme for the rapid identification of certain species of oral streptococci has been developed and compared with biochemical and physiological results of 45 well known clinical isolates and stock strains. Moreover, a method for the determination of H2O2 production was tested. With selected reactions as for instance acid formation in mannitol and raffinose broth, hydrolysis of arginine and esculin, the production of peroxidase, and the resistance of bacitracin the species S. rattus, S. sobrinus, S. mutans, S. cricetus, S. ferus, S. milleri, S. mitis, S. sanguis, S. mitior, and S. salivarius were differentiated.

Animals↗
PubMedDate not supplied

Cariogenic potential of lactosylfructoside as determined by acidogenicity of oral streptococci in vitro and human dental plaque in situ.

The cariogenic potential of lactosylfructoside [O-beta-D-galactopyranosyl-(1-->4)-O-alpha-D-glucopyranosyl-(1<-->2)-beta-D-fructofuranoside] was estimated by experiments on oral streptococci in vitro and human dental plaque in situ. Lactosylfructoside was unable to support growth of the strains of Streptococcus mutans and S. sobrinus used in this study. However, it was able to support growth of strains of S. sanguis, S. mitis and S. oralis. Acid was produced rapidly by cell suspensions of S. oralis ATCC 10557 incubated with lactosylfructoside. Application of 5% w/v solution decreased the pH of human dental plaque. The minimum pH value was below 5.3. The results suggest that lactosylfructoside is as acidogenic as lactose and could be cariogenic if it is consumed frequently and retained for a long period in the mouth.

Acids↗
PubMed1984

Slide-scoring method for estimation of Streptococcus mutans levels in saliva.

A method was developed to facilitate the estimation of S. mutans levels in saliva. Paraffin-stimulated saliva was poured on a special slide coated with mitis-salivarius-sucrose agar. Two discs containing bacitracin (5 micrograms) were placed on the inoculated slide and the growth density of S. mutans around the bacitracin discs was scored after incubation in candle jars at 37 degrees C for 48 h. The obtained score values correlated well with the numbers of CFU of S. mutans per 1 ml of saliva estimated by a conventional method using mitis-salivarius-bacitracin agar. The experimental method was further tested by incubating the slides in an atmosphere created by CO2-generating tables that were placed into the cover tubes of the slides. These score values were similar to those after conventional incubation. The method is suggested for epidemiologic studies and in selecting persons at high risk for caries and in controlling the effectiveness of prophylactic measures of these patients.

Adolescent↗
PubMed1996

Identification and classification of species within the Streptococcus sanguis group.

A biochemical identification scheme has been produced that allows for the differentiation of nine distinct species within the Streptococcus sanguis group. The species are S. sanguis, S. gordonii, S. crista, S. oralis, S. parasanguis, S. defectivus, S. adjacens and S. mitis, which have been previously described, and a new species, S. australis; in addition two distinct subspecies, S. oralis subsp. corona and S. oralis subsp. mitior, have been identified. DNA-DNA hybridization confirmed the separation of strains into the species. A new type of peptidoglycan peptide linkage, lys-ala-gly was also found within the species S. parasanguis and S. australis that has not been observed within the streptococci previously. DNA fingerprinting was shown to be a useful method for discriminating between strains within species, but did not allow discrimination between species.

Alanine↗
PubMed1984

Comparison of two screening tests for Streptococcus mutans and evaluation of their suitability for mass screenings and private practice.

Two simple microbiological tests for quantitating salivary Streptococcus mutans levels were compared with each other and evaluated for suitability for mass screenings and private practice. Both tests use mitis salivarius medium with bacitracin (MSB) and are selective for S. mutans. One test estimates colonies grown on agar (MSBA) and the other estimates colonies grown in broth that adhere to glass (MSBB). Both are scored from 1 (lowest) to 5 (highest). Children (293) in grades 5 and 6 in Tallahassee, Florida (nonfluoridated) were tested for S. mutans levels. Scores of children by both tests were significantly similar (chi 2, regression and Kappa statistical analysis). Correlation coefficients (regression) between scores and DMFS increments of the previous 4 yr were 0.35 (MSBA) and 0.26 (MSBB). Both tests were very good in identifying children with low caries increments, but positive scores did not correlate well with high caries increments. Sampling and interpreting took 2 min (MSBA) and 1 min (MSBB). Cost of MSBA/child was $1.15, and MSBB/child $1.25. These tests are economical and suitable for mass screenings to identify low risk populations who do not require preventive treatment.

Bacteriological Techniques↗
PubMed2003

Identification of mutans streptococci by restriction fragment length polymorphism analysis of polymerase chain reaction-amplified 16S ribosomal RNA genes.

Mutans streptococci are frequently isolated from dental plaque and carious lesions. These bacteria have been identified by conventional methods such as biochemical and serologic tests followed by the isolation of colonies on the mitis-salivarius agar, which are sometimes inconsistent. Recently, species-specific polymerase chain reaction (PCR) has been reported to rapidly identify Streptococcus mutans and Streptococcus sobrinus. However, in the case of identification and classification into several species, e.g. within the group of mutans streptococci consisting of seven species, the identification using species-specific PCR seems somewhat inefficient because of need for the development and preparation of specific primers for each species. Therefore, in this study we developed a simple method using restriction fragment length polymorphism analysis of PCR-amplified 16S ribosomal RNA genes (16S rRNA genes PCR-RFLP) for the identification of seven different species included in the group of mutans streptococci. We amplified 16S rRNA gene sequences from genomic DNA samples by PCR using universal primers and digested the PCR products with the restriction endonucleases, HpaII and HaeIII. HpaII produced six RFLP patterns for eight reference strains, since the patterns for S. sobrinus, Streptococcus downei and Streptococcus ferus were similar. RFLP patterns produced with HaeIII could separate these three species. Furthermore, the RFLP patterns predicted from the 16S rRNA gene sequences in the GenBank database agreed with the actual RFLP patterns produced in the present study. The 16S rRNA sequence comparisons can be used to identify oral mutans streptococci; however, the identification by sequencing is sometimes difficult in large-scale studies and for small laboratories. Therefore, 16S rRNA genes PCR-RFLP, using HpaII and HaeIII, could be an alternative method for the identification of mutans streptococci, and may be applicable for large-scale studies on the cariogenicity of mutans streptococci.

DNA Primers↗
PubMed1999

[Phenotypes of macrolide, lincosamide, and streptogramin resistant Streptococcus viridans isolated from blood].

Macrolide resistance has been widely studied in Streptococcus pyogenes and Streptococcus pneumoniae although not in viridans group streptococci (VGS). We studied 30 blood culture isolates of viridans group streptococci (25 resistant to erythromycin: 10 S. mitis, 8 S. milleri, 6 S. sanguis and 1 S. salivarius; and 5 susceptible: 2 S. mitis, 2 S. milleri and 1 S. sanguis). We carried out a double-disk test and determined MICs. The susceptibility testing was carried out by agar dilution for 14-, 15- and 16-member lactone ring macrolides, as well as for clindamycin and quinupristin-dalfopristin. Fifty-six percent of the erithromycin-resistant strains (6 S. mitis, 6 S. milleri and 2 S. sanguis) showed an MLS(B) phenotype, with a high level of intrinsic resistance to all the macrolides studied and clindomycin; 28% were of the M phenotype (4 S. sanguis, 2 S. mitis and 1 S. salivarius). We found a third resistance phenotype, which was present in 4 strains with MICs of 2-8 microg/ml, with resistance to macrolides and different degrees of resistance to clindamycin. All isolates were fully susceptible to quinupristin-dalfopristin. The MLS(B) and M phenotypes initially described in S. pyogenes and S. pneumoniae are also observed in VGS.

Anti-Bacterial Agents↗
PubMed1999

Meningitis caused by streptococci other than Streptococcus pneumoniae: a retrospective clinical study.

We reviewed the medical records of 26 patients (median age 62 years, range 5-76 years) admitted to our institution during 1978-98 with acute bacterial meningitis (ABM) caused by streptococci other than Streptococcus pneumoniae (comprising 1.9% of all patients with ABM). 19 cases were community-acquired and 7 were nosocomial. 73% had comorbid or predisposing conditions and 73% had an identifiable extracerebral focus; only in 2 patients no comorbid disease, primary focus or predisposing condition was present. Five patients had cerebral abscesses, and 5 had endocarditis. Beta-haemolytic streptococci were grown in 14 cases (serotype A: 4, B: 5, C: 1, G: 4) and were predominant among patients with endocarditis, whereas alpha- or non-haemolytic strains grew in 12 cases (S. mitis: 4, S. constellatus: 2, E. faecalis: 2, S. bovis: 1, unspecified: 3) and were predominant in patients with a brain abscess. Staphylococcus aureus grew together with a streptococcus in 2 cases. Blood culture was positive in 9 cases (35%). Neurologic complications occurred in 11 patients (42%) and extraneurologic complications in 18 patients (69%). Adverse outcomes occurred in 10 patients (38%), including 3 patients who died. Occurrence of seizures at any time of disease was significantly associated with an adverse outcome; no other clinical or paraclinical features appeared to affect outcome.

Acute Disease↗
PubMed1997

Variations in the predominant cultivable microflora of dental plaque at defined subsites on approximal tooth surfaces in children.

The distribution and composition of the resident microflora were determined in approximal gingival margin plaque from 21 premolars extracted from schoolchildren (mean age 12.0 +/- 1.8 yr). Indigo carmine (5% w v) was used to visualize plaque to facilitate sampling. About 1 mm2 of plaque was removed from sites away from (A), to the side of (S), and below (B) the contact area. Plaque samples were dispersed, serially diluted, and cultured on selective and non-selective agar media. An average of seven to nine species was found at each subsite. Streptococcus and Actinomyces were subdivided on the basis of a range of biochemical tests. The predominant Actinomyces and streptococcal species at most subsites were A. naeslundii and Strep. mitis biovar I. A. naeslundii and A. odontolyticus were isolated more often at subsite B (90.5 and 57.1%, respectively), and A. israelii at subsite S (66.7%) Strep. mitis 1 and Strep. sanguis were found more frequently at subsite S (76.2 and 66.7% respectively), whereas Strep mutans, Strep. sobrinus, Strep. gordonii and Veillonella spp. were recovered most commonly from subsite B (85.7, 33.3, 38.1 and 76.2%, respectively). The isolation frequencies of Strep. mutans and Strep. sobrinus were significantly higher at subsite B (A B p < 0.01 and p < 0.05, respectively). Veillonella spp. were significantly higher at subsites B and S (A < B, p > 0.01; B > S, p < 0.05), while Neisseria spp. were most common at subsite A (A > B. p > 0.03). IgAl protease-producing species were found at each subsite, but they formed only a small proportion of the total Streptococcus population. This study has shown that local variations were evident at different subsites, both with respect to species prevalence and to proportions of each species within each subsite. The population shifts in gingival margin plaque appear to relate to the location of plaque in relation to the most caries-prone site below the contact area B.

Analysis of Variance↗
PubMed2002

Antimicrobial susceptibility patterns of beta-hemolytic and viridans group streptococci: report from the SENTRY Antimicrobial Surveillance Program (1997-2000).

Susceptibility patterns of 15 antimicrobial agents were assessed for 3,400 isolates of beta-hemolytic (betahS) and viridans group (VgS) streptococci in the four regions of the SENTRY Antimicrobial Surveillance Program: Asia-Pacific (APAC), Europe (EU), Latin America (LA) and North America (NA). In 1997 through 2000, SENTRY Program monitors tested strains by reference broth microdilution methods and results were interpreted using National Committee for Clinical Laboratory Standards criteria. Among the betahS processed, 81.9% of strains were either Streptococcus pyogenes (n = 650) or S. agalactiae (n = 1,190). The VgS were generally classified as unspeciated alpha-hemolytic streptococci (n = 512; 44%) or S. mitis (n = 254; 22%). Seven quinolones, two beta-lactams, erythromycin (ER), clindamycin (CM), quinupristin/dalfopristin (Q/D), vancomycin (VA), teicoplanin (TP) and linezolid (LZ) were tested. Rank order of susceptibility for betahS isolates was: ceftriaxone (CTX) = Q/D = VA = TP = LZ (100.0%) > gatifloxacin (GATI) = trovafloxacin (TROV, 99.8%) > levofloxacin (LEVO; 99.7%) > penicillin (PEN; 99.3%) > grepafloxacin (GREPA; 97.4%) > CM (94.4%) > ER (85.5%). ER versus betahS had the highest MIC(90) values (2 microg/ml) and the lowest susceptibility rates across all regions (range, 81.4% in NA to 97.3% in LA). Among the VgS, susceptibility rank order was: VA = TP = LZ (100.0%) > Q/D (99.1%) > GATI = LEVO = TROVA (98.0%) > GREPA (96.5%) > CTX (92.8%) > CM (90.3%) > PEN (68.6%) > ER (64.5%). Macrolide resistance in both streptococcal species groups of the M-phenotype was highest in the Americas, with erm-patterns predominating in EU and APAC regions. BMS284756 among the monitored new agents showed a four- to eight-fold greater potency versus these streptococcal isolates when compared to the other six tested quinolones. Like Streptococcus pneumoniae, these other streptococci appear to have acquired numerous resistances and require continued surveillance to direct adequate therapies.

Anti-Bacterial Agents↗
PubMed1983

A selective medium for the two major subgroups of the bacterium Streptococcus mutans isolated from human dental plaque and saliva.

A selective medium was developed on which both major subgroups of Strep. mutans (c/e/f and d/g) can be cultured and recognized on the basis of colonial morphology, Trypticase, yeast, cystine (TYC) agar was modified by adding separately autoclaved sucrose to a final concentration of 20 per cent and 0.1 unit/ml bacitracin (TYCSB). This medium yielded significantly higher counts of Strep. mutans than the widely used mitis-salivarius bacitracin (MSB) medium.

Bacitracin↗