Mutans Biofilm Formation Research Articles

The Inhibitory Effect of Agastache rugosa Essential Oil on the Dental Biofilm

This study aimed to identify the inhibitory effect of Agastache rugosa essential oil (AREO) on the cariogenic properties of Streptococcus mutans, which causes dental caries and dental plaque formation. After extracting the AREO, their effects on the growth and acid production of S. mutans were examined. Furthermore, S. mutans biofilm formation was observed on the resin teeth surface. The effect on the expression of biofilm-related genes of S. mutans was measured using real-time PCR. AREO components were analyzed using gas chromatography (GC) and GC-mass spectrometry (MS). The growth and acid production of S. mutans were significantly inhibited at concentrations of 0.02 mg/mL or higher of AREO. At 0.04 mg/mL, inhibition was similar to that of the positive control, 0.1% NaF. AREO suppressed the expression of virulence factors such as gtfB, gtfC, gtfD, gbpB, SpaP, brpA, relA, and vicR at concentrations of 0.02 mg/mL or higher. As a result of GC and GC-MS analyses, the main components of AREO included estragole, limonene, and β-caryophyllene. These results suggest that A. rugosa may be a useful agent for inhibiting the cariogenic properties of S. mutans.

Comparing The Antibacterial Effectiveness Of Indigenously Derived Propolis In Various Vehicles Against Streptococcus Mutans Biofilm Formation: A Study With Contemporary Pulp Capping Agents

Comparing The Antibacterial Effectiveness Of Indigenously Derived Propolis In Various Vehicles Against Streptococcus Mutans Biofilm Formation: A Study With Contemporary Pulp Capping Agents

Comparative Evaluation of Biofilm Formation on Temporization Crown Materials Used in the Rehabilitation of Primary Dentition With Different Polishing Materials: An In Vitro Study.

Introduction Advancements in dental materials have enhanced aesthetic treatments for managing dental caries and injuries in primary dentition. Bis-acryl composite-based temporization materials are now preferred for restoring primary crowns due to their superior properties. However, prolonged exposure to dietary and hygienic factors can lead to discoloration and roughness, making efficient polishing essential to prevent plaque buildup. Objective This study aims to evaluate Streptococcus mutans biofilm formation on temporization material polished with different polishing systems. Methods This study tested bis-acryl methacrylate temporization material. Thirty disk-shaped specimens were prepared and divided into three groups according to the polishing system used (n = 10 per group): Shofu Super Snap mini kit (Shofu, San Marcos, CA), aluminum oxide polishing paste, and propol polishing paste. Each group's specimens were polished according to the manufacturer's instructions. Surface roughness (SR), scanning electron microscopy (SEM) morphological analysis, and Streptococcus mutans biofilm formation were assessed for each group. Results The results showed significant differences in roughness average (Ra) values among the polishing materials, with the Shofu Super Snap mini kit having the highest roughness (Ra = 2.04), followed by propol polishing paste (Ra = 1.30)and aluminum oxide paste (Ra = 0.75). Additionally, polishing methods significantly affected mean colony-forming unit (CFU) levels, with the first group having the highest mean CFU value (0.24), with SEM images showing substantial biofilm formation by Streptococcus mutans. Conclusion Bacterial biofilm formation on the aluminum oxide paste group's surface differed from that on the propol polishing paste and aluminum oxide disc groups. The polishing techniques that we tested significantly influenced surface properties and biofilm formation. These findings suggest that selecting an appropriate polishing system can reduce the risk of gingival inflammation associated with temporization materials.

The impact of Streptococcus mutans biofilms on the color stability and topographical features of three lithium disilicate ceramics.

Secondary caries around ceramic restorations is the most common reason for the replacement of fixed dental prostheses (FDPs). Therefore, it is important to examine the susceptibility of different ceramic materials to biofilm formation. This study aimed to evaluate biofilm development and associated roughness and color alterations in three lithium disilicate ceramics: Emax CAD (EC), Emax Press (EP), and LiSi Press (LP). Streptococcus mutans biofilms were grown on the three ceramics (n = 10 per group) for 7 days. Surface roughness values and color alteration were assessed before and after the biofilm using a non-contact profilometer and spectrophotometer, respectively. Biofilm growth was evaluated using colony-forming units (CFUs) and scanning electron microscope (SEM) images. The data were analyzed using one-way ANOVA and Tukey tests. There was a significant (p≤0.001) growth of S. mutans colonies on EC (6.75 ± 0.56) and EP (6.72 ± 0.54) specimens compared to LP, which showed no biofilm growth. The change in average surface roughness (∆Ra, nm) was significantly lower (p < 0.001) in the EC specimens (0.029 ± 0.003) compared to the EP (0.055 ± 0.012) and LP (0.041 ± 0.010). When the changes in the Rv and Rt values were investigated, no significant difference was observed among the groups. Following the biofilm challenge, the change in color (∆E00) was significantly lower (p = 0.005) in the LP group (1.68 ± 1.45) compared to the EC group (3.89 ± 1.50) and no significant difference was observed between the EP group (2.74±1.01) and the other two ceramics (p ≥ 0.05). LP ceramics exhibited superior resistance to S. mutans biofilm formation and associated changes in surface roughness and color compared to the Emax CAD and Emax Press ceramics. These findings suggest that the LiSi Press material may be more favorable to mitigate the risk of secondary caries.

S. mutans Antisense vicK RNA Over-Expression Plus Antibacterial Dimethylaminohexadecyl Methacrylate Suppresses Oral Biofilms and Protects Enamel Hardness in Extracted Human Teeth.

Streptococcus mutans (S. mutans) antisense vicK RNA (ASvicK) is a non-coding RNA that regulates cariogenic virulence and metabolic activity. Dimethylaminohexadecyl methacrylate (DMAHDM), a quaternary ammonium methacrylate used in dental materials, has strong antibacterial activity. This study examined the effects of S. mutans ASvicK on DMAHDM susceptibility and their combined impact on inhibiting S. mutans biofilm formation and protecting enamel hardness. The parent S. mutans UA159 and ASvicK overexpressing S. mutans (ASvicK) were tested. The minimum inhibitory concentration (MIC) and minimum bactericidal concentrations for planktonic bacteria (MBC-P) and biofilms (MBC-B) were measured. As the ASvicK MBC-B was 175 μg/mL, live/dead staining, metabolic activity (MTT), colony-forming units (CFUs), biofilm biomass, polysaccharide, and lactic acid production were investigated at 175 μg/mL and 87.5 μg/mL. The MIC, MBC-P, and MBC-B values for DMAHDM for the ASvicK strain were half those of the UA159 strain. In addition, combining S. mutans ASvicK with DMAHDM resulted in a significant 4-log CFU reduction (p < 0.05), with notable decreases in polysaccharide levels and lactic acid production. In the in vitro cariogenic model, the combination achieved the highest enamel hardness at 67.1% of sound enamel, while UA159 without DMAHDM had the lowest at 16.4% (p < 0.05). Thus, S. mutans ASvicK enhanced DMAHDM susceptibility, and their combination effectively inhibited biofilm formation and minimized enamel demineralization. The S. mutans ASvicK + DMAHDM combination shows great potential for anti-caries dental applications.

A Strain of Streptococcus mitis Inhibits Biofilm Formation of Caries Pathogens via Abundant Hydrogen Peroxide Production.

Commensal oral streptococci that colonize supragingival biofilms deploy mechanisms to combat competitors within their niche. Here, we determined that Streptococcus mitis more effectively inhibited biofilm formation of Streptococcus mutans within a seven species panel. This phenotype was common amongst all assayed isolates of S. mutans, but was specific to a single strain of S. mitis, ATCC 49456. The growth inhibitory factor was not effectively carried in spent supernatants of S. mitis. However, we documented ATCC 49456 to accumulate 4-5 times more hydrogen peroxide (H2O2) than other species tested, and 5-18 times more than other S. mitis strains assayed. The S. mutans biofilm formation inhibitory phenotype was reduced when grown in media containing catalase or with a S. mitis mutant of pyruvate oxidase (spxB; pox), confirming that SpxB-dependent H2O2 production was the main antagonistic factor. Addition of S. mitis within hours after S. mutans inoculation was effective at reducing biofilm biomass, but not for 24 h pre-formed biofilms. Transcriptome analysis revealed responses for both S. mitis and S. mutans, with several S. mutans differentially expressed genes following a gene expression pattern previously described, while others being unique to the interaction with S. mitis. Finally, we show that S. mitis also affected coculture biofilm formation of several other commensal streptococci. Our study shows that strains with abundant H2O2 production are effective at inhibiting initial growth of caries pathogens like S. mutans, but are less effective at disrupting pre-formed biofilms and have the potential to influence the stability of other oral commensal strains.

Association between the biofilm formation of streptococcus mutans, dental caries experience, and resistance to antibiotics in adult patients

Objectives: The aim of this study was to consider the potential association between the formation of bucall mucusa streptococcus biofilms and a high DMFT index, as well as the occurrence of antibiotic resistance among adult patients in Sana'a, Yemen. Study design: A total of 100; 34-85 year old. Clinical examinations of patients were performed to estimate dental caries experience with the Silness-Loe index, as well as bucall mucusa swabs were collected to assess biofilm production by the phenotypic method, i.e., tissue culture palate methods (TCPM). Finally, the antibiogram susceptibility pattern of isolated S. mutans was done by the Kirby-Bauer disc diffusion method for L-Lactam antibiotics (as ampicillin and penicillin) and non-L-Lactam antibiotics (clindamycin, erythromycin, lincomycin, and vancomycin). Results: When isolated S. mutans were exposed to biofilm detection by the TCP method, 1 (1.2%) showed strong biofilm formation capacity, 71 (86.6%) showed moderate biofilm formation capacity, and 10 (12.2%) showed non/weak formation capacity of biofilm. There was an escalation in the rate of formation of S. mutans biofilms with an increased degree of caries index. The S. mutans biofilms positively showed a higher rate of resistance than non/weak biofilm formation, e.g., ampicillin (91.1% versus 8.9%, p &lt;0x7E&gt; 0.0001), tetracycline (87.8% versus 12.2%, p &lt;0x7E&gt; 0.0001), and co-trimoxazole (90%% versus 10%, p &lt;0x7E&gt; 0.0001), etc. Conclusion: The present study proved that S. mutans is still the major bacteria isolated from the oral cavity, but few persons might not have a significant number of S. mutans in the oral cavity. The S. mutans biofilm producers were more able to cause dental caries compared to the S. mutans biofilm non-producers. Drug-resistant factor in the S. mutans isolates was found to be associated with S. mutans biofilm formation.

Synthesis and Characterization of a Sustained Nitric Oxide-Releasing Orthodontic Elastomeric Chain for Antimicrobial Action.

The acidic byproducts of bacteria in plaque around orthodontic brackets contribute to white spot lesion (WSL) formation. Nitric oxide (NO) has antibacterial properties, hindering biofilm formation and inhibiting the growth of oral microbes. Materials that mimic NO release could prevent oral bacteria-related pathologies. This study aims to integrate S-nitroso-acetylpenicillamine (SNAP), a promising NO donor, into orthodontic elastomeric ligatures, apply an additional polymer coating, and evaluate the NO-release kinetics and antimicrobial activity against Streptococus mutans. SNAP was added to clear elastomeric chains (8 loops, 23 mm long) at three concentrations (50, 75, 100 mg/mL, and a control). Chains were then coated, via electrospinning, with additional polymer (Elastollan®) to aid in extending the NO release. NO flux was measured daily for 30 days. Samples with 75 mg/mL SNAP + Elastollan® were tested against S. mutans for inhibition of biofilm formation on and around the chain. SNAP was successfully integrated into ligatures at each concentration. Only the 75 mg/mL SNAP chains maintained their elasticity. After polymer coating, samples exhibited a significant burst of NO on the first day, exceeding the machine's reading capacity, which gradually decreased over 29 days. Ligatures also inhibited S. mutans growth and biofilm formation. Future research will assess their mechanical properties and cytotoxicity. This study presents a novel strategy to address white spot lesion (WSL) formation and bacterial-related pathologies by utilizing nitric oxide-releasing materials. Manufactured chains with antimicrobial properties provide a promising solution for orthodontic challenges, showing significant potential for academic-industrial collaboration and commercial viability.

Antibacterial and antibiofilm activity of mint leaves (Mentha piperita L) extracts against Streptococcus mutans UA159: a laboratory experiment

Introduction: Oral health is a major concern in healthcare worldwide, with dental caries being a prevalent issue among children and adults. Streptococcus mutans is a primary bacterium implicated in the development of dental caries due to its acidogenic nature. Mint leaf (Mentha piperita L.) is a unique herbal plant that has antibacterial and antibiofilm properties against S. mutans and minimal side effects. The purpose of this study was to analyze the antibacterial effectiveness of mint leaf against the growth of S. mutans UA159 and its antibiofilm effects. Methods: This study was conducted experimentally with the posttest-only control group design, using the broth microdilution method in 6 test groups, namely mint leaf extract with a concentration of 3.125, 6.25, 12.5, 25, 50, and 100% and also two control groups, namely the negative control using aquadest and the positive control using 0.2% chlorhexidine. Biofilm growth is determined by comparing Optical Density (OD) values and then calculating the percentage of eradication of S. mutans biofilm formation. Results: The results indicated that the mint leaf extract exhibited antibacterial effects against S. mutans, with the largest inhibition zone diameter observed at a 100% concentration. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)90 values using the broth microdilution method in this study were 12.5% and 100% concentrations, respectively. Mint leaf extract has been shown to significantly inhibit the growth of S. mutans (p&lt;0.05). The results of the inhibition test on biofilm formation at a concentration of 100% averaged 87.39%. Conclusion: Mint leaf extract has an antibacterial and antibiofilm effect on the growth of S. mutans. The level of inhibition of mint leaf extract on the growth of S. mutans is proportional to its concentration; the higher the concentration of the extract, the stronger the inhibitory ability.KeywordAnti-Bacterial agents, biofilms, Mentha piperita, oral health, Streptococcus mutans.

Virtual Screening of Inhibitors of Streptococcus mutans Biofilm from Lonicera japonica flos and Activity Validation.

In this study, potential inhibitors of Streptococcus mutans biofilm were screened from Lonicera japonica flos using semiflexible molecular docking. A total of 88 metabolites from L. japonica flos and 14 biofilm-related proteins of S. mutans were analyzed, and 25 compounds were initially screened out. Subsequently, 9 compounds with higher availability were subjected to experimental validation, confirming that 6 of them effectively inhibit the S. mutans biofilm formation. Notably, chlorogenic acid was found to potentially disrupt the GbpC protein, which plays a role in the sucrose-dependent adhesion pathway. Similarly, oleanolic acid appeared to impede the adhesin P1 protein involved in the sucrose-independent adhesion mechanism, corroborating the computational predictions. The results of this study provide essential insights for leveraging L. japonica flos in the creation of dental-care-related products and food items aimed at oral health.

Antimicrobial and Antibiofilm Effects of Silver-Copper Nanoparticles Obtained by Green Synthesis Against Streptococcus mutans.

Ag-Cu NPs were synthesized using a green chemical method and characterized using a scanning electron microscope (SEM), ultraviolet-visible (U-vis) spectrophotometer, and Fourier Transform Infrared Spectroscopy (FT-IR). The minimum inhibitory concentration (MIC) against S. mutans was determined using the broth microdilution method, while the antibiofilm effect was assessed by the crystal violet method. The synthesized Ag-Cu NPs demonstrated antimicrobial activity with an MIC of 128 µg/ml, significantly inhibiting S. mutans biofilm formation by up to 94% at a concentration of 256 µg/ml. Characterization studies confirmed the successful synthesis of Ag-Cu NPs with spherical morphology. These findings highlight the potential of Ag-Cu NPs as a novel approach for combating dental caries by targeting S. mutans biofilms. Further research is warranted to explore their safety and efficacy in clinical settings.

Antibacterial effect of novel dental resin composites containing rod-like zinc oxide

Abstract Dental resin composite materials are widely used as dental fillings; however, the accumulation of microbes and the resulting secondary caries often leads to filling failure. ZnO, an inorganic antibacterial material, exhibits effective antibacterial properties and is considered safe for use. In this study, rod-like ZnO was prepared by using the atmospheric-pressure hydrothermal method, and its microstructure and antibacterial effects on Streptococcus mutans were studied. Subsequently, we created modified resins by incorporating rod-like ZnO at varying mass fractions and analyzed their morphological characteristics and elemental distributions. The antibacterial effectiveness, biocompatibility, and mechanical properties of these materials were examined using in vitro experiments. The results indicated that the rod-like ZnO exhibited a complete hexagonal wurtzite structure, with columnar dimensions of approximately 2.5 μm in length, 0.8 μm in diameter, and a lattice spacing of 0.2544 nm. The growth, biofilm formation, and biofilm destruction of S. mutans were significantly inhibited at 1/4, 1/2, 3/4, and 1 times the minimum inhibitory concentration. The rod-like modified resin, with mass fractions of 2.5, 5, and 7.5 wt%, exhibited evident inhibitory effects on S. mutans biofilm formation. These modified resins demonstrated no cytotoxicity toward HGF-1 cells and exhibited enhanced compressive strength. Therefore, rod-like ZnO modified resin has promising potential for the treatment of dental caries.

Comparative evaluation of anti-biofilm and anti- adherence potential of plant extracts against Streptococcus mutans: A therapeutic approach for oral health

Dental caries predominantly attributed to the cariogenic nature of Streptococcus mutans, continue to pose a substantial global challenge to oral health. In response to this challenge, this study aimed to evaluate the effectiveness of leaf extracts (LEs) and essential oils (EOs) derived from different medicinal plants in inhibiting the growth of Streptococcus mutans biofilm. In vitro and in silico approaches were employed to identify active compounds and assess their inhibitory effects on S. mutans. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were measured to determine the anti-biofilm and anti-adherence activity against S. mutans. Biofilm viability (CFU/mL) and extracellular polymeric substance (EPS) concentration were quantified. GC-MS analysis was utilized to identify active compounds in the most effective plant extracts exhibiting anti-S. mutans activity. A high-throughput screening focused on the interaction between these compounds and the target enzyme SortaseA (SrtA) using molecular docking was performed. Results indicated that Cymbopogon citratus displayed the highest efficacy in reducing S. mutans biofilm formation and adhesion activity, achieving 90 % inhibition at an MIC value of 12 μg/mL. Among the 12 bioactive compounds identified, trans-Carvyl acetate exhibited the lowest binding energy with SrtA (-6.0 Kcal/mole). Trans-Carvyl acetate also displayed favorable pharmacokinetic properties. This study provides novel insights into the anti-S. mutans properties of C. citratus and suggests its potential as a therapeutic approach for oral health. Further research is needed to explore the combined effect of plant extracts for enhanced protection against dental caries.

Antimicrobial effect of probiotic bacteriocins on Streptococcus mutans biofilm in a dynamic oral flow chamber model – an in vitro study

ABSTRACT Aim To determine the antimicrobial activity of the bacteriocin-producing probiotic strains Streptococcus salivarius K12 and Streptococcus salivarius M18 alone or in combination against caries-associated Streptococcus mutans. Methods Antimicrobial activity of S. salivarius K12 and/or S. salivarius M18 against S. mutans ATCC 25175 growth and biofilm formation on hydroxyapatite (HA) discs was determined in a flow chamber model by recording the colony forming units (CFU/ml) after 48 h of co-cultivation. The biofilm was analyzed by scanning electron microscopy (SEM) and by confocal laser scanning microscopy (CLSM). Additionally, the simultaneous antagonism assay was used to assess the inhibitory effect of S. salivarius K12 and/or S. salivarius M18 against S. mutans ATCC 25175 and 21 clinical isolates of S. mutans. Results Co-cultivation of S. mutans and S. salivarius K12 and/or S. salivarius M18 led to the inhibition of S. mutans viability, thereby, preventing its biofilm formation on HA discs. Furthermore, S. salivarius K12 and S. salivarius M18 exhibited antimicrobial activity against most clinical isolates of S. mutans. Conclusion The in vitro flow chamber system used in this study allows the simulation of time-dependent administration of S. salivarius probiotic strains, either alone or in combination, to investigate the prevention of S. mutans biofilm formation in a standardized model.

Antibiofilm Properties and Demineralization Suppression in Early Enamel Lesions Using Dental Coating Materials.

This study aimed to investigate the effects of dental coating materials on Streptococcus mutans biofilm formation. The test materials were PRG Barrier Coat (PRG), BioCoat Ca (BioC), and FluorDental Jelly (FluorJ). Bovine enamel specimens were demineralized to mimic early enamel lesions. The biofilm was developed on a specimen treated with one of the materials by using a modified Robbins device flow-cell system. Scanning electron and fluorescence confocal laser scanning microscopy, viable and total cell counts, and gene expression assessments of the antibiofilm were performed. Ion incorporation was analyzed using a wavelength-dispersive X-ray spectroscopy electron probe microanalyzer. All materials allowed biofilm formation but reduced its volume. FluorJ was the only material that inhibited biofilm accumulation and had a bactericidal effect, revealing 0.66 log CFU in viable cells and 1.23 log copy reduction in total cells compared with the untreated group after 24 h of incubation. The ions released from PRG varied depending on the element. BioC contributed to enamel remineralization by supplying calcium ions while blocking the acid produced from the biofilm. In summary, the dental coating materials physically prevented acid attacks from the biofilm while providing ions to the enamel to improve its mechanical properties.

Inhibition of Streptococcus mutans growth and biofilm formation through protein acetylation.

Numerous cellular processes are regulated in response to the metabolic state of the cell, and one such regulatory mechanism involves lysine acetylation. Lysine acetylation has been proven to play an important role in the virulence of Streptococcus mutans, a major cariogenic bacterial species. S. mutans' glucosyltransferases (Gtfs) are responsible for synthesizing extracellular polysaccharides (EPS) and contributing to biofilm formation. One of the most common nonsteroidal anti-inflammatory drugs is acetylsalicylic acid (ASA), which can acetylate proteins through a nonenzymatic transacetylation reaction. Herein, we investigated the inhibitory effects of ASA on S. mutans. ASA treatment was observed to impede the growth of S. mutans, leading to a reduction in the production of water-insoluble EPS and the formation of biofilm. Moreover, ASA decreased the enzyme activity of Gtfs while increasing the protein acetylation level. The in vivo anticaries efficacy of ASA has further been proved using the rat caries model. In conclusion, ASA as an acetylation agent attenuated the cariogenic virulence of S. mutans, suggesting the potential value of protein acetylation on antimicrobial and anti-biofilm applications to S. mutans.

Potential Activities of Centella asiatica Leaf Extract against Pathogenic Bacteria-Associated Biofilms and Its Anti-Inflammatory Effects.

The medicinal value of Centella asiatica leaf extract was evaluated as an alternative treatment. The chemical composition of the leaf extract was analyzed, and the biological activities were determined. High-performance liquid chromatography coupled with a photodiode array detector (HPLC-PDA) was used to identify the asiatic acid, madasiatic acid, and madecassic acid/Brahmic acid isolated from the ethanolic extract. The plant extract at 25 mg/disk was found to inhibit both Gram-positive and Gram-negative pathogenic bacteria by the agar disk diffusion test. The MIC and MBC of the ethanolic extracts were better than those of the aqueous extracts. The ethanolic extracts showed antibacterial activity against Gram-positive bacteria with MICs and MBCs ranging from 1.024 to 2.048 mg/mL and 2.048 to 4.096 mg/mL, respectively. The remarkable antibacterial activities were observed against S. mutans. The ethanolic extract at a concentration of 1/2 × MIC exhibited the inhibition effect on S. mutans biofilm formation like the activity of 0.2% chlorhexidine and significantly modified hydrophobicity of the bacterial cell surface. The effects were confirmed via molecular docking analysis. The binding affinities of asiatic acid, madecassic acid, and madasiatic acid with glucosyltransferase C (GtfC) of S. mutans exhibited superior strength in comparison with alpha-acarbose and chlorhexidine. Moreover, the nitric oxide (NO) secretion of RAW247.6 cells was determined after treating the cells with concentrations of the extract. The C. asiatica ethanolic extract can inhibit the secretion of NO, which can inhibit the inflammatory process. The findings indicate the applications of the C. asiatica ethanolic extract as the alternative anti-S. mutans agent and could be used for further formulation for the treatment and prevention of dental diseases and inflammatory injury in the oral cavity.

The inhibitory effect of berberine chloride hydrate on Streptococcus mutans biofilm formation at different pH values.

Streptococcus mutans (S. mutans) is one of the major cariogenic bacteria of dental caries owing to its ability to adhere to tooth surfaces and biofilm formation. Berberine chloride hydrate (BH), a quaternary ammonium salt alkaloid, has diverse pharmacological efforts against microorganisms. However, the effect of BH on S. mutans biofilm has not been reported. Considering that berberine is a quaternary ammonium salt alkaloid, which needs to adapt to a large variation in pH values and the acid resistance of S. mutans, we employed three groups including pH 5 (acidic), pH 8 (alkaline), and unprocessed group (neutral) to examine the antibiofilm activities of BH against S. mutans during different pH values. In this study, we found BH effectively suppresses S. mutans biofilm formation as well as its cariogenic virulence including acid production and EPS synthesis significantly, and the inhibitory effort was reduced under acidic condition whereas elevated under alkaline condition. In addition, we preliminarily explored the influence of pH values on the structural stability and biosafety of BHas well as the underlying mechanism of inhibition of S. mutans biofilm formation with BH. Our study showed BH could maintain a good structural stability and low toxicity to erythrocytes at different pH values. And BH could downregulate the expression of srtA, spaP, and gbpC, which play critical roles in the adhesion process, promoting bacterial colonization and biofilm formation. Furthermore, comX and ldh expression levels were downregulated in BH-treated group, which might explain its inhibitory effect on acid production.IMPORTANCEDental caries is a common chronic detrimental disease, which could cause a series of oral problem including oral pain, difficulties in eating, and so on. Recently, many natural products have been considered as fundamental sources of therapeutic drugs to prevent caries. Berberine as a plant extract showed good antibiofilm abilities against microorganism. Our study focuses on its antibiofilm abilities against S. mutans, which was defined as major cariogenic bacterium and explored the role of pH values and possible underlying mechanisms in the inhibitory effect of BH on S. mutans biofilm formation. This study demonstrated a promising prospect for BH as an adjuvant drug in the prevention and management of dental caries.

IN VITRO ANTIBACTERIAL AND ANTIBIOFILM ACTIVITIES OF ULTRAFILTRATED-BROMELAIN AGAINST DENTAL CARIES PATHOGENS

Dental plaque on tooth surfaces significantly contributes to dental caries leading to acidic demineralization of the tooth enamel and dentin. This is mainly caused by the formation of pathogenic bacterial biofilm. Dental caries affects approximately 3.5 million people around the world. Compared to synthetic anticariogenic agents such as chlorohexidine, plant-based compounds were found to have fewer side effects and higher economic value. Pineapple (Ananas comosus) is one of the largely commercialized plants in Malaysia with beneficial attributes such as its Bromelain enzyme. This study aimed to purify Bromelain enzyme from MD2 pineapple core and to evaluate their antibacterial properties against dental caries-associate pathogens in vitro. This study evaluated the effect of Bromelain enzyme isolated from MD2 pineapple core using 50% Ammonium Sulphate precipitation incorporated with centrifugal ultrafiltration against Streptococcus mutans, Staphylococcus aureus, Lactobacillus acidophilus, and Lactobacillus casei. Bromelain enzyme showed effectivity of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) for all cariogenic organisms. Ultrafiltrate Bromelain (UFB) enzyme had significant antibacterial activity against S.mutans with a MIC value of 250 μg/ml and complete susceptibility at an MBC value of 1000 μg/ml. Biofilm inhibition against S.mutans increased from 45.98% to 57.48% with ultrafiltration. A 3.25 purification fold increase was observed in the ultrafiltrate sample. In conclusion, the ultrafiltration technique is efficient in purifying Bromelain enzyme and effectively inhibits S. mutans biofilm formation and thus possesses a potential inhibitory effect on dental caries in vitro.

Virulence factors analysis and determination of the suitable chemical agent to inhibit Streptococcus mutans growth and biofilm formation

Streptococcus mutans is one of the most important causes of tooth decay and oral diseases, and it has received wide attention from researchers worldwide. The present work aimed to investigate, evaluation and comparisons effect of the antimicrobial and anti-biofilm property of some commercial compounds (chlorhexidine, hyaluronic acid, sodium fluoride and silver nanoparticles) against oral bacteria pathogens of S. mutans. In this work, S. mutans ATCC 25175 was used and its virulence factors were analyzed using Seed Viewer and The Comprehensive Antibiotic Resistance Database (CARD). The antibacterial susceptibility testing (AST) confirms effects of chlorhexidine mouthwash on S. mutans ATCC 25175 beggar than all components. The minimum inhibitory concentration (MIC) minimum bactericidal concentration (MBC) and Minimum biofilm inhibition concentration (MBIC) of the commercial compounds were determined. The statistical analysis was performed using One-Way ANOVA (Tukey test). The VITEK2system was used to confirm the biochemical features of S. mutans ATCC 25175 and susceptibility testing was done to compare the results with Seed Viewer and CARD analysis. The findings showed that The MICs, MBCs, and MBIC means of chlorhexidine against S. mutans ATCC 25175 was 0.0079, 0.0038, and 0.0039 μg/mL respectively, where its biological activity was significantly (P < 0.05) higher compared to other commercial compounds included in this study. The S. mutans strain used in this study showed sensitivity to all tested antibiotics and the Seed Viewer and CARD reported that it has several virulence factors such as adhesion genes (hsp33, Cpa, PrtF, PrtF2, MsmRL, Nra, SOF, LepAL, Spy0135, and RofA) and antibiotic-resistant genes (vanY, vanT, and mdeA). This study concluded that chlorhexidine was the best in inhibiting S. mutans growth as well as preventing biofilm formation, and the study recommends further investigation about antibiotic resistance genes and susceptibility profile.