Clinical Isolates Of Streptococcus Mutans Research Articles

Probiotics, A New Frontier in Oral Health: Unraveling the Efficacy of Probiotic Metabolites vs. Chlorhexidine on Streptococcus mutans in Dental Plaque

The battle against dental caries has long been fought with conventional antimicrobial agents, with Chlorhexidine leading the charge. However, recent research has delved into the potential of probiotic metabolites as an alternative or adjunctive therapy in the quest for better oral health. In this editorial, we explore the emerging evidence surrounding the efficacy of probiotic metabolites compared to Chlorhexidine, specifically targetting local clinical isolates of Streptococcus mutans within dental plaque. Streptococcus mutans, a key player in the formation of dental plaque, has been a prime target for antimicrobial interventions due to its significant role in tooth decay. Chlorhexidine, a widely used antiseptic, has been a stalwart in dental care. However, its efficacy and potential side effects have prompted researchers to seek alternative approaches. Probiotic metabolites, byproducts of beneficial bacteria, have emerged as a promising avenue, with studies suggesting their ability to promote oral health by modulating the microbial balance.1 Recent studies have begun to unravel the intricate interactions between probiotic metabolites and Streptococcus mutans. These investigations have not only explored the direct antimicrobial effects but also the potential for probiotics to influence the overall microbial environment in the oral cavity. The comparison with Chlorhexidine, a gold standard in dental care, adds depth to our understanding of these alternative therapies.2 The evidence supporting the efficacy of probiotic metabolites in controlling Streptococcus mutans is not only encouraging but also challenges the status quo. A study by Gong SG et al. (2023) demonstrated that probiotic metabolites significantly reduced the growth of Streptococcus mutans in vitro, highlighting their potential as a potent antimicrobial agent.3 This finding is particularly promising given the increasing concerns about antibiotic resistance and the need for sustainable alternatives.
 Continued...

Antibiofilm Efficacy of Mimosa pudica against Clinical Isolates of Streptococcus mutans as a Mouthrinse

Antibiofilm Efficacy of Mimosa pudica against Clinical Isolates of Streptococcus mutans as a Mouthrinse

Characteristics of Clinical Isolates of Streptococcus mutans

Dental caries is an infectious disease which remains a significant health problem all over the world. The purpose of the study was to characterise a collection of 60 clinical isolates of S. mutans from adults’ and children’s dental plaque (natural biofilm). The paper describes the process of isolation, identification, analysis of biofilm formation and collection testing for the presence of 13 two-component systems (TCS) identified earlier in reference strain ATCC 700610 (UA159). In the case of S. mutans strains, plaque formation is specifically influenced by binary systems. All isolated strains of S. mutans form biofilm at high levels and possess a set of 26 genes forming TSC binary systems, which have an important role in plaque formation.

Association of sepM gene mutation with mutacin IV production by Streptococcus mutans

To investigate the types of sepM gene mutations and their distribution in clinical isolates of Streptococcus mutans (S. mutans) and explore the association of sepM gene mutation with the capacity of mutacin Ⅳ production by S. mutans. We assessed the capacity of mutacin Ⅳ production in 80 clinical isolates of S. mutans using an inhibition zone assay. The minimum spanning tree and phylogenetic tree of these isolates were constructed using core genome multilocus sequence typing and maximum likelihood method, respectively. GeneMarkS software was used to predict the coding genes of these isolates, and the predicted genes were blasted against the sepM gene sequence of the reference genome UA159 to determine sepM gene mutations and their distribution characteristics in the clinical isolates. The mutation types affecting mutacin Ⅳ production were identified by analyzing the differentially distributed mutations between mutacin Ⅳ-producing isolates and mutacin Ⅳ-free isolates and by comparing the inhibition zones between isolates with sepM gene mutations and those without mutations. Among the 80 clinical isolates of S. mutans, 25 isolates were capable of mutacin Ⅳ production and 55 did not produce mutacin Ⅳ. The minimum spanning tree showed that the allelic differences were less among the mutacin Ⅳproducing isolates than among the mutacin Ⅳ-free isolates, and the origins of the mutacin Ⅳ-producing isolates were similar. We identified a total of 34 single base mutations in the 80 clinical isolates, and among them, C31T (P=0.001), G533A (P < 0.001), C756T (P=0.025), and C1036T (P=0.003) showed significant differential distributions between the mutacin Ⅳ-producing and mutacin Ⅳ-free isolates. These differentially distributed mutations were positively correlated with the capacity of mutacin Ⅳ production of the bacteria. sepM gene mutations that affect the capacity of mutacin Ⅳ production are present in the clinical strains of S. mutans.

Green Synthesis, Characterization of Zinc Oxide Nanoparticles and their Incorporation into Glass Ionomer Cement for Inhibition of Streptococcus mutans

In present study, zinc oxide nanoparticles were synthesised using Syzygium aromaticum and characterized using UV visible spectroscopy, SEM, XRD and FTIR techniques. The characteristic hexagonal structure of the ZnO nanoparticles was confirmed through XRD analysis. The UV-Visible spectrum showed a strong absorbance at 366 nm confirming the presence of ZnO and the peak at 496 cm-1 in FTIR indicated the Zn-O stretch bond. Average size of the zinc oxide nanoparticles obtained from SEM analysis was found to be 86 nm. The zinc oxide nanoparticles exhibited better antibacterial activity than clove extract, when tested against clinical isolates of Streptococcus mutans. The nanoparticles incorporated into the dental restorative material, glass ionomer cement (GIC) were tested against S. mutans and exhibited better antibacterial activity than clove extract. Glass ionomer cement (GIC) did not exhibit antibacterial activity alone, but the incorporation of ZnO nanoparticles into GIC significantly improved antibacterial activity. Hence, ZnO embedded GIC is a promising material in restorative dentistry for preventing the recurrence of dental caries.

Antimicrobial Potential of Ethanol Extract and Fractions of Caesalpinia benthamiana (Caesalpinaceae) Root on Some Organisms Implicated in Oral Infections

This study investigated the activities of ethanol root extract of Caesalpinia benthamiana (Baill) Herend. and Zarucchi. (Caesalpiniaceae) against some microbial isolates implicated in oral infections and determined the killing rate of the most active fraction. It also investigated the phytochemical properties of the root extract. This was with a view to providing scientific basis for the use of the root in the treatment of oral infections.&#x0D; The plant root was collected from the wild, washed, air-dried, ground to powder and macerated using ethanol and water at ratio 7:3 (v/v) with constant shaking for 72 hours in a mechanical shaker. The filtrate was concentrated in-vacuo at 50°C using a rotary evaporator and freeze dried. The crude extract was screened for phytochemical and antimicrobial properties. The extract was further partitioned into fractions using different organic solvents in order of their polarity. The antimicrobial potential of the different fractions was determined using agar-well diffusion and agar dilution method respectively. Time-kill-assay of the most active fraction was carried out on each of the organisms namely, Staphylococcus aureus (NCIB 8588) clinical isolates of Streptococcus mutans, S. pyogenes, S. salivarius, Staphylococcus aureus and Candida albicans. The values obtained were subjected to inferential statistical analysis.&#x0D; Phytochemical screening revealed the presence of flavonoids, tannins, terpenes, saponins, phenolics and phenolic glycosides and anthraquinones. The root extract showed appreciable activity against all the test organisms, with the ethyl acetate fraction demonstrating highest activity and lowest MIC (0.16 mg/mL) compared with the crude extract and the other fractions. The activity was also time and concentration dependent. At triple the MIC all cells of respective organisms were killed at 5 minutes as was the case with all the standard antibiotics and anti-fungi used as positive control. &#x0D; It was concluded that C. benthamiana ethanol root extract was highly active against oral isolates with its ethyl acetate fraction being the most effective.

Analysis of glucosyltransferase gene expression of clinical isolates of Streptococcus mutans obtained from dental plaques in response to sub-lethal doses of photoactivated disinfection.

Dental caries is a disease caused by a group of oral streptococcal microorganisms, primarily Strptococcus mutans. Photoactivated disinfection (PAD) has been proposed as a conservative method for treatment of carious lesions. Therefore, the aim of this study was to assess the effectiveness of indocyanine green (ICG)- and toluidine blue O (TBO)-PAD as supplementary tools in reducing the bacterial load and expression profiling of the gene associated with the biofilm formation in S. mutans. S. mutans strains were isolated from dental plaque samples collected from 212 patients through conventional biochemical tests and molecular methods. After identification, S. mutans strains were photosensitized in vitro with TBO and ICG, which were excited at a specific light wavelength based on the photosensitizer. After evaluating doses of TBO- and ICG-PAD contributing to sub-significant reduction of CFU/mL, ROS levels were measured with DCFH-DA fluorescent probe. Eventually, TBO- and ICG-PAD effects on the gtfB gene expression were assessed using real-time quantitative reverse transcription polymerase chain reaction. S. mutans strains were isolated from 50 (23.5%) patients. In this study, maximum doses of TBO- and ICG-PAD contributing to sub-significant reduction of CFU/mL against S. mutans strains were 23.12 μM/mL TBO at fluence of 68.75 J/cm2 and 20.15 μM/mL ICG at fluence of 31.2 J/cm2. According to the results, 3.8- and 6.1-fold increases in the fluorescence were observed in ICG and TBO treated cells compared to the control, respectively. The expression of gtfB was down regulated to approximately 3.9- and 8.25-fold following treatment with TBO- and ICG-PAD, respectively. The gtfB gene expression profiling decreased in the bacterial cells, with ICG-PAD causing a greater reduction. PAD may be a promising therapy for dentinal carious lesions.

Characterization of acid‑tolerance‑associated small RNAs in clinical isolates of Streptococcus mutans: Potential biomarkers for caries prevention.

Streptococcus mutans is a cariogenic bacterium that contributes to dental caries due to its ability to produce lactic acid, which acidifies the local environment. The potential of S.mutans to respond to environmental stress and tolerate low pH is essential for its survival and predominance in caries lesions. Small noncoding RNAs (sRNAs) have been reported to be involved in bacterial stress and virulence. Few studies have investigated the sRNAs of S.mutans and the function of these sRNAs remains to be elucidated. In the present study, the association between sRNA133474 and acid tolerance, including potential underlying mechanisms, were investigated within clinical strains of S.mutans. From pediatric dental plaques, 20strains of S.mutans were isolated. An acid killing assay was performed to analyze acid tolerance of S.mutans. Expression patterns of sRNA133474 were investigated during various growth phases under various acidic conditions via reverse transcription‑quantitative polymerase chain reaction. RNA predator and Kyoto Encyclopedia of Genes and Genomes analyses were performed to predict target mRNAs of sRNA133474 and to examine the involvement of putative pathways of target mRNAs, respectively. The results of the present study demonstrated that sRNA133474 activity was growth phase‑dependent, and two distinct expression patterns were identified in 10 clinical strains. At pH5.5 and 7.5 the expression levels of sRNA133474 were significantly different, and high‑acid tolerant strains exhibited reduced expression levels of sRNA133474 compared with low‑acid tolerant strains. A correlation between sRNA133474 expression levels and acid tolerance was observed in 20 clinical isolates of S.mutans (r=‑0.6298, P<0.01). Finally, five target mRNAs (liaS, liaR, comE, covR and ciaR) involved in the two‑component system (TCS) were selected for further evaluation; the expression levels of three target mRNAs (liaR, ciaR and covR) were negatively correlated with sRNA133474 expression levels. In conclusion, the results of the present study suggested that S.mutans may utilize sRNA133474 to orchestrate TCSs for optimal adaption to acidic pH in clinical strains.

Correction to 'Reactive oxygen species drive evolution of pro-biofilm variants in pathogens by modulating cyclic-di-GMP levels'.

[ Open Biol . 6, 160162. (Published online 23 November 2016). ([doi:10.1098/rsob.160162][2])][2] A correction is required to the author list and contributions statement for ‘Reactive oxygen species drive evolution of pro-biofilm variants in pathogens by modulating cyclic-di-GMP levels’ doi:10.

Genetic polymorphism of scrA gene of Streptococcus mutans isolates is not associated with biofilm formation in severe early childhood caries

BackgroundTo explore and analyse the association between biofilm and the genetic polymorphisms of scrA gene of EnzymeIIscr found in clinical isolates of Streptococcus mutans (S. mutans) from severe early childhood caries (S-ECC) in 3 years old children.MethodsClinical strains of S. mutans were conserved from a previous study. Thirty strains of S. mutans from the S-ECC group and 30 strains of S. mutans from the caries free (CF) group were selected. Biomass and viability of biofilm formed by the strains were evaluated by crystal violet and alamar blue assay. Genomic DNA was extracted from the S. mutans isolates. PCR was conducted to amplify scrA gene. After purified and sequenced the PCR products, BioEdit sofeware was used to analyse the sequence results. A chi-square test was used to compare the results.ResultsCompared to the CF group, the biomass of S-ECC group was higher (P = 0.0424). However, the viability of the two groups showed no significant difference. All 60 clinically isolated S. mutans strains had a 1995 base pair (bp) scrA gene. Forty-nine point mutations were identified in scrA from the 60 clinical isolates. There were 17 missense point mutations at the 10, 65, 103, 284, 289, 925, 1444, 1487, 1494, 1508, 1553, 1576, 1786, 1822, 1863, 1886, and 1925 bp positions. The other 32 mutations were silent point mutations. No positions were found at active sites of ScrA. The statistic analyse showed no significant missense mutation rates between the two groups.ConclusionsThere was no association between biofilm and genetic polymorphisms of scrA from S. mutans with S-ECC in 3 years old children.

Antimicrobial Properties of Biofunctionalized Silver Nanoparticles on Clinical Isolates of Streptococcus mutans and Its Serotypes.

(1) Background: Streptococcus mutans (S. mutans) is the principal pathogen involved in the formation of dental caries. Other systemic diseases have also been associated with specific S. mutans serotypes (c, e, f, and k). Silver nanoparticles (SNP) have been demonstrated to have good antibacterial effects against S. mutans; therefore, limited studies have evaluated the antimicrobial activity of biofunctionalized SNP on S. mutans serotypes. The purpose of this work was to prepare and characterize coated SNP using two different organic components and to evaluate the antimicrobial activity of SNP in clinical isolates of S. mutans strains and serotypes; (2) Methods: SNP with bovine serum albumin (BSA) or chitosan (CS) coatings were prepared and the physical, chemical and microbiological properties of SNP were evaluated; (3) Results: Both types of coated SNP showed antimicrobial activity against S. mutans bacteria and serotypes. Better inhibition was associated with smaller particles and BSA coatings; however, no significant differences were found between the different serotypes, indicating a similar sensitivity to the coated SNP; (4) Conclusion: This study concludes that BSA and CS coated SNP had good antimicrobial activity against S. mutans strains and the four serotypes, and this study suggest the widespread use of SNP as an antimicrobial agent for the inhibition of S. mutans bacteria.

Comparative evaluation of antimicrobial and physical properties of a newer dentin bonding agent with cetylpyridinium chloride: An in vitro study

Context: Though adhesive systems in restorative dentistry possess many advantages, secondary caries is still a problem to be contended with. Addition of antibacterial agents could possibly be a potential remedy for this recurring problem. Aims: To evaluate and compare in vitro the antimicrobial property, microleakage, and shear bond strength of G-Bond (one component self-etching light cured adhesive) with different concentrations of cetylpyridinium chloride (CPC). Settings and Design: In vitro intergroup experimental randomized control trial. Subjects and Methods: The in vitro study with the study groups Group I: G-Bond, Group II: G-Bond with 1% CPC, and Group III: G-Bond with 3% CPC was tested against the clinical isolates of Streptococcus mutans through the direct contact test determining the turbidometric bacterial growth using spectrophotometer. The microleakage was tested using dye penetration method and the shear bond strength of the three groups was tested using universal testing machine. Statistical Analysis Used: The data were analyzed using paired t-test, one-way ANOVA, followed by post-hoc Tukey's test. For all the tests, a P ≤ 0.05 was considered for statistical significance. Results: G-bond with 3% CPC showed the highest rate of antibacterial activity against S. mutans than other two groups (highly significant P < 0.001). However, microleakage and shear bond strength between the groups did not show any statistically significant change. Conclusions: G-Bond with 3% CPC additive was effective against S. mutans.

Draft Genome Sequences of Two Clinical Isolates of Streptococcus mutans.

We report the draft genome sequences of PKUSS-HG01 and PKUSS-LG01, two clinical isolates of Streptococcus mutans from human dental plaque. The genomics information will facilitate the study of the mechanisms of pathogenicity and evolution of S. mutans.

Anticaries Activity of &lt;i&gt;Usnea pictoides&lt;/i&gt; G. Awasthi -A macrolichen from Western Ghats of Karnataka, India

The present study was conducted to determine anticaries activity of solvent extracts of a macrolichen Usnea pictoides G. Awasthi (Parmeliaceae) collected at Mullayanagiri, Western Ghats of Chikmagalur district, Karnataka, India. The lichen material was sequentially extracted using solvents viz., petroleum ether, ethyl acetate, chloroform and methanol in a soxhlet assembly. Anticaries activity of solvent extracts was determined against four clinical isolates of Streptococcus mutans (recovered from dental caries subjects) by Agar well diffusion assay. All solvent extracts were effective against the clinical isolates. High inhibitory potential was observed in case of chloroform extract. Thin layer chromatogram showed the presence of Usnic acid. Inhibitory effect could be ascribed to the bioactive secondary metabolites, mainly Usnic acid present in the lichen. Purification of bioactive principles and determination of their anticaries activity are to be conducted.

ANTICARIES AND ALFA-AMYLASE INHIBITORY ACTIVITY OF JASMINUM ARBORESCENS ROXB. (OLEACEAE) LEAVES EXTRACT

The aim of the present study was to determine anti caries and α - amylase inhibitory activity of leaf extract of Jasminum arborescens Roxb. (Oleaceae). Anti caries activity was determined by Aga r well diffusion assay against seven clinical isolates of Streptococcus mutans (Sm - 01 to Sm - 07) recovered from dental caries subjects. Enzyme inhibitory activity was tested against α - amylase by s pectrophometric method using starch as substrate . The extract exhibited dose dependent inhibition against cariogenic isolates . Among seven isolates, isolate Sm - 04 and Sm - 06 were inhibited to higher and least extent respectively. The extract was found to ca use inhibition of α - amylase activity in a dose dependent manner and its IC 50 value was found to be 17.45 mg/ml . The inhibitory activity could be attributed to the presence of secondary metabolites. The plant may be a potential source for development of agents which are acti ve against dental caries pathogens and for diabetes mellitus.

Anticariogenic Activity of Gnidia glauca (Fresen.) Gilg, Pothos scandens L. and Elaegnus kologa Schlecht

The present study was conducted to estimate total phenolic and flavonoid content and to determine anticariogenic efficacy of methanol extract of Gnidia glauca (Fresen.) Gilg (Thymelaeaceae), Pothos scandens L. (Araceae) and Elaegnus kologa Schlecht (Elaeagnaceae) leaves. Total phenolic and flavonoid content of leaf extracts was determined by Folin-Ciocalteau method and Aluminium chloride colorimetric estimation method respectively. Anticariogenic activity of leaf extracts was assessed against 13 clinical isolates of Streptococcus mutans by Agar well diffusion technique. The contents of total phenolics and flavonoids were higher in G. glauca followed by P. scandens and E. kologa. The extract of G. glauca showed greater inhibition of cariogenic isolates than P. scandens and E. kologa as revealed by wider inhibition zones. The study revealed a correlation between the amount of phenolics and flavonoids present in the extracts and the anticariogenic activity of the extracts. The plants used in this study could be used against dental caries.

Identification of protein differences between two clinical isolates of Streptococcus mutans by proteomic analysis

Streptococcus mutans is generally considered to be the principal etiological agent for dental caries. Different strains of S. mutans may display different virulence mechanisms, so the isolation of the differential proteins is illuminating. S. mutans strains 9-1 and 9-2, which both colonized the same oral cavity, were selected after screening for the possession of suspected virulence traits. The soluble cellular proteins were extracted from steady-state planktonic cells of strains 9-1 and 9-2 and were analyzed using high-resolution two-dimensional gel electrophoresis. Then, replicate maps of proteins from the two strains were generated. Proteins expressed only in strain 9-1 or 9-2 were excised and digested with trypsin by using an in-gel protocol. Tryptic digests were analyzed using matrix-assisted laser desorption/ionization time of flight mass spectrometry, by which peptide mass fingerprints were generated, and these were used to assign putative functions according to their homology with the translated sequences in the S. mutans genomic database. There were 12 proteins only expressed in strain 9-1 and three proteins only expressed in strain 9-2. They were involved in protein biosynthesis, protein folding, cell wall biosynthesis, fatty acid biosynthesis, nucleotide biosynthesis, repair of DNA damage, carbohydrate metabolism, signal transduction, and translation. The identification of proteins differentially expressed between strains 9-1 and 9-2 provides new information concerning the mechanisms of cariogenesis

Antimicrobial activity of Uncaria tomentosa against oral human pathogens

Uncaria tomentosa is considered a medicinal plant used over centuries by the peruvian population as an alternative treatment for several diseases. Many microorganisms usually inhabit the human oral cavity and under certain conditions can become etiologic agents of diseases. The aim of the present study was to evaluate the antimicrobial activity of different concentrations of Uncaria tomentosa on different strains of microorganisms isolated from the human oral cavity. Micropulverized Uncaria tomentosa was tested in vitro to determine the minimum inhibitory concentration (MIC) on selected microbial strains. The tested strains were oral clinical isolates of Streptococcus mutans, Staphylococcus spp., Candida albicans, Enterobacteriaceae and Pseudomonas aeruginosa. The tested concentrations of Uncaria tomentosa ranged from 0.25-5% in Müeller-Hinton agar. Three percent Uncaria tomentosa inhibited 8% of Enterobacteriaceae isolates, 52% of S. mutans and 96% of Staphylococcus spp. The tested concentrations did not present inhibitory effect on P. aeruginosa and C. albicans. It could be concluded that micropulverized Uncaria tomentosa presented antimicrobial activity on Enterobacteriaceae, S. mutans and Staphylococcus spp. isolates.

Inactivation of the ciaH Gene in Streptococcus mutans diminishes mutacin production and competence development, alters sucrose-dependent biofilm formation, and reduces stress tolerance.

Many clinical isolates of Streptococcus mutans produce peptide antibiotics called mutacins. Mutacin production may play an important role in the ecology of S. mutans in dental plaque. In this study, inactivation of a histidine kinase gene, ciaH, abolished mutacin production. Surprisingly, the same mutation also diminished competence development, stress tolerance, and sucrose-dependent biofilm formation.

Susceptibility of Streptococcus mutans and Streptococcus sobrinus to antimicrobial agents after short-term oral chlorhexidine treatments.

Effects of three different types of short-term applications (1-3 times during 1 week) of chlorhexidine (1 or 40%) on the susceptibility of 863 clinical isolates of Streptococcus mutans and 53 isolates of Streptococcus sobrinus from 58 subjects were studied. Chlorhexidine-resistant isolates were not found either before or after the treatment. The minimum inhibitory concentrations (MICs) to chlorhexidine of all isolates of S. mutans were < or = 1 microgram/ml, and of S. sobrinus < or = 2 micrograms/ml. S. mutans and S. sobrinus were also susceptible to ampicillin, penicillin, cefuroxime, and tetracycline. In conclusion, different short-term chlorhexidine regimens do not induce resistance in S. mutans or S. sobrinus and, furthermore, these species have so far retained their susceptibility to common antibiotics.