Urethane Dimethacrylate Influences the Cariogenic Properties of Streptococcus Mutans

Concerns regarding unbound monomers in dental composites have increased with the increased usage of these materials. This study assessed the biological effects of urethane dimethacrylate (UDMA), a common monomer component of dental composite resins, on the cariogenic properties of Streptococcus mutans. Changes in the growth rate, biofilm formation, interaction with saliva, surface hydrophobicity, adhesion, glucan synthesis, sugar transport, glycolytic profiles, and oxidative- and acid-stress tolerances of S. mutans were evaluated after growing the cells in the presence and absence of UDMA. The results indicated that UDMA promotes the adhesion of S. mutans to the underlying surfaces and extracellular polysaccharide synthesis, leading to enhanced biofilm formation. Furthermore, UDMA reduced the acid tolerance of S. mutans, but enhanced its tolerance to oxidative stress, thus favoring the early stage of biofilm development. UDMA did not significantly affect the viability or planktonic growth of cells, but diminished the ability of S. mutans to metabolize carbohydrates and thus maintain the level of intracellular polysaccharides, although the tendency for sugar transport increased. Notably, UDMA did not significantly alter the interactions of bacterial cells with saliva. This study suggests that UDMA may potentially contribute to the development of secondary caries around UDMA-containing dental materials by prompting biofilm formation, enhancing oxidative tolerance, and modulating carbon flow.     

Antimicrobial activity of Hibiscus sabdariffa extract against uropathogenic strains isolated from recurrent urinary tract infections

ObjectiveTo report the antimicrobial effect and biofilm forming capacity of the uropathogenic strains that have been isolated from recurrent urinary tract infections (UTIs) in the presence of Hibiscus sabdariffa (H. sabdariffa) extract.MethodsSix Escherichia coli and two Klebsiella pneumoniae isolates were collected from patients with recurrent UTIs. The susceptibility of bacterial isolates to H. sabdariffa extracts were tested by determining their minimum inhibitory concentrations (MICs), and minimum bactericidal concentration (MBC) by using the broth microdilution method in accordance to Clinical and Laboratory Standards Institute guidelines. Time-kill curves were plotted against the eight isolates based on the MIC results. The biofilm forming capacity of the isolates were evaluated using the microtiter plate assay. Detection of biofilms was done using the crystal violet staining method.ResultsVarious levels of the extracts MIC were observed against all the uropathogenic isolates. MIC values ranged from 0.5 to 4 mg/mL, and MBC values ranged from 8 to 64 mg/mL. Both the time-kill experiment and MBC-MIC ratio demonstrated that the extracts' effect was in general, bacteriostatic. The biofilm capacity inhibition assay results showed that extracts inhibited biofilm production of all the isolates. The level of biofilm inhibition however, had varied among the bacterial strains and ranged from 8%–60% reduction in optical density.ConclusionsThe results of the study support the effective potential of H. sabdariffa extract to prevent recurrent UTIs and to emphasize the significance of the plant extract, in order to approach it as a potential antimicrobial agent.     

Novel Coatings to Minimize Corrosion of Titanium in Oral Biofilm

The aim of this work is to investigate the effects produced by polymicrobial biofilm (Porphyromonas gingivalis, Streptococcus mutans, Streptococcus sanguinis, and Streptococcus salivarius) on the corrosion behavior of titanium dental implants. Pure titanium disks were polished and coated with titanium nitride (TiN) and silicon carbide (SiC) along with their quarternized versions. Next, the disks were cultivated in culture medium (BHI) with P. gingivalis, S. mutans, S. sanguinis, and S. salivarius and incubated anaerobically at 37 °C for 30 days. Titanium corrosion was evaluated through surface observation using Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM). Furthermore, the Ti release in the medium was evaluated by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). SEM images showed that coated Ti disks exhibited lower corrosion compared to non-coated disks, except for the quartenized TiN. This was confirmed by AFM, where the roughness was higher in non-coated Ti disks. ICP showed that Ti levels were low in all coating disks. These results indicate that these SiC and TiN-based coatings could be a useful tool to reduce surface corrosion on titanium implant surfaces.     

Surface Roughness and Streptococcus mutans Adhesion on Metallic and Ceramic Fixed Prosthodontic Materials after Scaling

The aim of this study was to evaluate the surface roughness of fixed prosthodontic materials after polishing or roughening with a stainless steel curette or ultrasonic scaler and to examine the effect of these on Streptococcus mutans adhesion and biofilm accumulation. Thirty specimens (10 × 10 × 3 mm³) of zirconia (Zr), pressed lithium disilicate (LDS-Press), milled lithium disilicate glazed (LDS-Glaze), titanium grade V (Ti) and cobalt-chromium (CoCr) were divided into three groups (n = 10) according to surface treatment: polished (C), roughened with stainless steel curette (SC), roughened with ultrasonic scaler (US). Surface roughness values (Sa, Sq) were measured with a spinning disc confocal microscope, and contact angles and surface free energy (SFE) were measured with a contact angle meter. The specimens were covered with sterilized human saliva and immersed into Streptococcus mutans suspensions for bacterial adhesion. The biofilm was allowed to form for 24 h. Sa values were in the range of 0.008–0.139 µm depending on the material and surface treatment. Curette and ultrasonic scaling increased the surface roughness in LDS-Glaze (p < 0.05), Ti (p < 0.01) and CoCr (p < 0.001), however, surface roughness did not affect bacterial adhesion. Zr C and US had a higher bacterial adhesion percentage compared to LDS-Glaze C and US (p = 0.03). There were no differences between study materials in terms of biofilm accumulation.     

Real-time mapping of a hydrogen peroxide concentration profile across a polymicrobial bacterial biofilm using scanning electrochemical microscopy

Quantitative detection of hydrogen peroxide in solution above a Streptococcus gordonii (Sg) bacterial biofilm was studied in real time by scanning electrochemical microscopy (SECM). The concentration of hydrogen peroxide was determined to be 0.7 mM to 1.6 mM in the presence of 10 mM glucose over a period of 2 to 8 h. The hydrogen peroxide production measured was higher near the biofilm surface in comparison to Sg grown planktonically. Differential hydrogen peroxide production was observed both by fluorometric as well as by SECM measurements. The interaction between two different species in a bacterial biofilm of Sg and Aggregatibacter actinomycetemcomitans (Aa) in terms of hydrogen peroxide production was also studied by SECM. One-directional y-scan SECM measurements showed the unique spatial mapping of hydrogen peroxide concentration across a mixed species biofilm and revealed that hydrogen peroxide concentration varies greatly dependent upon local species composition.     

Precision-guided antimicrobial peptide as a targeted modulator of human microbial ecology

One major challenge to studying human microbiome and its associated diseases is the lack of effective tools to achieve targeted modulation of individual species and study its ecological function within multispecies communities. Here, we show that C16G2, a specifically targeted antimicrobial peptide, was able to selectively kill cariogenic pathogen Streptococcus mutans with high efficacy within a human saliva-derived in vitro oral multispecies community. Importantly, a significant shift in the overall microbial structure of the C16G2-treated community was revealed after a 24-h recovery period: several bacterial species with metabolic dependency or physical interactions with S. mutans suffered drastic reduction in their abundance, whereas S. mutans’ natural competitors, including health-associated Streptococci, became dominant. This study demonstrates the use of targeted antimicrobials to modulate the microbiome structure allowing insights into the key community role of specific bacterial species and also indicates the therapeutic potential of C16G2 to achieve a healthy oral microbiome.Human microbiome research revealed that every human body contains a variety of microbial communities on various mucosal surfaces that consist of thousands of different microbial species (1–4). Disturbance from host and environmental factors may alter the composition and abundance of these microbial species, leading to various polymicrobial diseases (5–8). With the complexity of these multispecies microbial communities, it is very difficult to determine the functions of individual species contributing to observed physiological and pathological changes, making it one of the most challenging issues in human microbiome research. This study aims to develop and validate a new tool to address this important issue.The indigenous microbial flora of the human oral cavity consists of over 700 different species of bacteria, with over 100 present in any individual (4, 9, 10). Most bacteria help promote a healthy oral environment by stimulating the immune system and preventing the invasion of pathogenic species (11–13). One pathogenic bacterium, Streptococcus mutans, is predominantly responsible for tooth decay worldwide (14). The carious lesions that S. mutans can cause are generally not considered life-threatening, but they result in an economic burden that leaves many cases in underdeveloped areas untreated, resulting in tooth extraction as the only remedy (15). Currently, there is no effective treatment for S. mutans. Broad-spectrum antibiotics administered to the oral cavity result in destruction of the entire oral bacterial flora, making it prone to reinfection by S. mutans, which reestablishes at pretreatment levels.To combat S. mutans infection, our group developed C16G2, a synthetic peptide that belongs to a new class of antimicrobials called specifically targeted antimicrobial peptides that can achieve targeted killing of selected pathogens (16). A typical targeted antimicrobial peptide molecule consists of two functionally independent moieties conjoined in a linear peptide sequence: a nonspecific antimicrobial peptide serves as the killing moiety, whereas a species-specific binding peptide comprises the targeting moiety that provides specific binding to a selected pathogen and facilitates the targeted delivery of the attached antimicrobial peptide. Previous studies showed that C16G2 was potent against S. mutans grown in liquid or biofilm states. It displays targeted killing of S. mutans within a three-species biofilm without affecting closely related noncariogenic oral streptococci, including Streptococcus sanguinis and Streptococcus gordonii (16). Additional study showed that C16G2 has a mechanism of action similar to that of traditional antimicrobial peptides and kills S. mutans through disruption of the cell membrane followed by a loss of membrane potential and cell death. Interestingly, this membrane activity is rapid and potent against S. mutans but not against other noncariogenic oral streptococci (17).In this study, we further investigated the antimicrobial specificity of C16G2 by expanding the panel of testing bacterial species to include more oral streptococci species closely related to S. mutans, nonstreptococcal oral species, and nonoral representatives. To explore its potential clinical application, a saliva-derived in vitro model containing over 100 species approaching the diversity and overall metabolic functionality of the human oral microbiome (18) was used for examining the selective antimicrobial activity of C16G2 against S. mutans within a multispecies community. The main goal of this study is to investigate the impact of targeted removal of S. mutans on the overall structure of a multispecies oral microbial community and provide proof of concept data for using targeted antimicrobials to modulate the microbiome structure and study the ecological role of specific bacterial species.     

Antibacterial activity of medicinal plant Cyclea peltata (Lam) Hooks & Thoms

ObjectiveTo investigate the antibacterial activity of Padathaali (Cyclea peltata) against three gram positive and eight gram negative bacterial strains.MethodsThe fresh whole plants were collected from Kerala, India. The dry crude nonpolar and polar extract of whole plant of C. peltata i. e. Petroleum ether, hexane, chloroform, ethyl acetate, acetone, methanol and aqueous extracts of five concentrations (1, 2, 5, 10 mg/ml) were used to investigate the antibacterial activity. NCCL standards were strictly followed to perform antibacterial disc susceptibility test using disc diffusion method.ResultsAll the extracts showed varying degree of inhibitory potential against all the tested bacteria. Methanol extract of plant had higher inhibitory action against Staphylococcus aureus, Streptococcus haemolyticus, Klebsiella pneumonia and Proteus vulgaris. Acetone extract of plant showed maximum inhibitory action against Klebsiella pneumonia and Streptococcus haemolyticus.ConclusionsThe present investigation showed the effectiveness of crude extract of this plant against tested bacterial strains. This study further suggests the use of whole plant extract in treating disease caused by tested microbial organisms.     

Effect of Surface Tooling Techniques of Medical Titanium Implants on Bacterial Biofilm Formation In Vitro

The aim of this study was to assess the biofilm formation of Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli on titanium implants with CAD-CAM tooling techniques. Twenty specimens of titanium were studied: Titanium grade 2 tooled with a Planmeca CAD-CAM milling device (TiGrade 2), Ti₆Al₄V grade 5 as it comes from CAD-DMLS device (computer aided design-direct metal laser sintering device) (TiGrade 5), Ti₆Al₄V grade 23 as it comes from a CAD-CAM milling device (TiGrade 23), and CAD-DMLS TiGrade 5 polished with an abrasive disc (TiGrade 5 polished). Bacterial adhesion on the implants was completed with and without saliva treatment to mimic both extraoral and intraoral surgical methods of implant placement. Five specimens/implant types were used in the bacterial adhesion experiments. Autoclaved implant specimens were placed in petri plates and immersed in saliva solution for 30 min at room temperature and then washed 3× with 1× PBS. Bacterial suspensions of each strain were made and added to the specimens after saliva treatment. Biofilm was allowed to form for 24 h at 37 °C and the adhered bacteria was calculated. Tooling techniques had an insignificant effect on the bacterial adhesion by all the bacterial strains studied. However, there was a significant difference in biofilm formation between the saliva-treated and non-saliva-treated implants. Saliva contamination enhanced S. mutans, S. aureus, and E. faecalis adhesion in all material types studied. S. aureus was found to be the most adherent strain in the saliva-treated group, whereas E. coli was the most adherent strain in the non-saliva-treated group. In conclusion, CAD-CAM tooling techniques have little effect on bacterial adhesion. Saliva coating enhances the biofilm formation; therefore, saliva contamination of the implant must be minimized during implant placement. Further extensive studies are needed to evaluate the effects of surface treatments of the titanium implant on soft tissue response and to prevent the factors causing implant infection and failure.     

The Effect of Liquid Rubber Addition on the Physicochemical Properties,Cytotoxicity, and Ability to Inhibit Biofilm Formation of Dental Composites

The aim of this study was to evaluate the effect of modification with liquid rubber on the adhesion to tooth tissues (enamel, dentin), wettability and ability to inhibit bacterial biofilm formation of resin-based dental composites. Two commercial composites (Flow-Art–flow type with 60% ceramic filler and Boston–packable type with 78% ceramic filler; both from Arkona Laboratorium Farmakologii Stomatologicznej, Nasutów, Poland) were modified by addition of 5% by weight (of resin) of a liquid methacrylate-terminated polybutadiene. Results showed that modification of the flow type composite significantly (p < 0.05) increased the shear bond strength values by 17% for enamel and by 33% for dentine. Addition of liquid rubber significantly (p < 0.05) reduced also hydrophilicity of the dental materials since the water contact angle was increased from 81–83° to 87–89°. Interestingly, modified packable type material showed improved antibiofilm activity against Steptococcus mutans and Streptococcus sanguinis (quantitative assay with crystal violet), but also cytotoxicity against eukaryotic cells since cell viability was reduced to 37% as proven in a direct-contact WST-8 test. Introduction of the same modification to the flow type material significantly improved its antibiofilm properties (biofilm reduction by approximately 6% compared to the unmodified material, p < 0.05) without cytotoxic effects against human fibroblasts (cell viability near 100%). Thus, modified flow type composite may be considered as a candidate to be used as restorative material since it exhibits both nontoxicity and antibiofilm properties.     

vicK基因ATP结合位点对变异链球菌生物学功能的影响

目的 构建变异链球菌UA159 vicKATP缺失突变株,研究vicK基因ATP结合位点对变异链球菌生长、产酸耐酸、细胞外多糖(exopolysaccharides,EPS)和生物膜形成等生物学功能的影响.方法 quick change法构建vicKATP缺失突变质粒,同时引入SmalI,SmalI插入kan基因盒(l...     

Evaluation of in vitro antioxidant and apoptotic activities of Cyperus rotundus

Objective:To evaluate in vitro antioxidant and apoptotic activities of Crperus rotundas(C.rotundus).Methods:The phytochemical study and the antioxidant activities of both methanol and aqueous extracts from C.rotundus aerial part were determined.In addition,these extracts were also investigated for their cytotoxic and apoptotic activities.The major compound of the methanol extract was isolated.Both metlianol and aqueous extracts(300,150,and 50μg/mL)were evaluated for their antioxidant activity by the xanthine/xanthine oxidase assay system.However,16,8,and 4 mg/mL of each extract were tested to investigate their OH.formation scavenging potential.Aqueous extract(800,400.and 200μg/mL)and melhunol extract(350,175,and 88μg/mL)were tested against lipid peroxidation,induced by 75μM H_2O_2,The cytotoxicity(by MTT assay)and cell DNA fragmentation of both extracts were evaluated Inwards K562 and L1210 cell lines.The major compound was obtained from the butanol fraction of methanol extract and its structure was determined by KMN spectroscopic analysis.Results:The methanol and aqueous extracts showed respectively,88%and 19%inhibition of xanthine oxidase activity.Vet.the same extracts inhibited lipid peroxidation by 61.5%and 42.0%.respectively.Roth extracts inhibited OH.formation by 27.1%and 25.3%,respectively.Only methanol cxtract induced DNA degradation.Orientin was determined as the major compound isolated from the butanol fraction of metlianol extract.Conclusions:It appears that C.rotundus extracts exhibit a potential use as a natural antioxidant and an apoptosis inducer.     

Biocompatibility and Antibacterial Action of Salvadora persica Extract as Intracanal Medication (In Vitro and Ex Vivo Experiment)

This study aimed to test the biocompatibility and antibacterial properties of Salvadora persica (S. persica) extract, a natural product, as an intracanal medication in comparison with calcium hydroxide (Metapaste, META BIOMED, Cheongju, Korea). The pH values of both materials were tested. The biocompatibility of S. persica extract and Metapaste was determined using light microscopy and MTT assays. The antibacterial action was tested using the zone of bacterial inhibition on four common bacterial species. In addition, intracanal medication was administered using 68 extracted single-rooted teeth contaminated with Enterococcus faecalis (E. faecalis), and the percentage reduction in colony count (% RCC) at 1, 3, and 7 days was measured. The extension of activity for both materials was assessed using histological sections and scanning electron microscopy. S. persica was found to be acidic in nature. Both materials showed significantly lower cell viability than the positive control cells on days 1 and 3 but not on day 7. S. persica showed better antibacterial effects against E. faecalis and S. mutans. S. persica extract showed 97.6%, 98.9%, and 99.3% RCC values at 1, 3, and 7 days, respectively, which are comparable to those of Metapaste. S. persica herbal extract is a promising material that can be utilized as an intracanal medication, but its use requires further research.     

Anticariogenic potentials of clove, tobacco and bitter kola

ObjectiveTo investigate three tropical plant materials – clove seeds [Syzygium aromaticum (S. aromaticum)], bitter kola fruits [Garcinia kola (G. kola)] and tobacco leaves (Nicotiana species) as potential targeted killers of Streptococcus mutans (S. mutans), a cavity-causing bacterium (gram-positive, facultative anaerobe) that resides in a multispecies microbial community (dental plaque) for the treatment of dental caries (tooth decay).MethodsThirty one (31) teeth samples were collected from patients with obvious signs of tooth decay (swollen gum, weak or fallen tooth, etc.) using sterile swab sticks. These samples were collected from two major dental clinics in Nsukka, Enugu State, Nigeria and investigated by spread inoculation onto sterile blood agar and Mueller Hinton agar (MHA) respectively and incubated at 37 °C for 24 h. The discrete colonies obtained were further re-inoculated onto sterile Mitis salivarius agar (MSA) plates and incubated as above. The isolates were characterized by gram staining and catalase test. Tobacco leaves, clove seeds and bitter kola fruits were ground into powder, extracted with three different solvents (n-hexane, hot water and ethanol), filtered, dried and stored in clean containers, corked and kept until used. The plant extracts were investigated for phytochemistry, minimum inhibitory concentration (MIC), minimum cidal concentration (MCC) and compared with some conventional antibiotics commonly used against tooth decay. Antibiotic sensitivity test was also carried out. The results were statistically analyzed.ResultsThe extracts showed varied phytochemical composition but most abundantly the flavonoids. Our result also shows that females (16) have more tooth decay than males (15) and that 16 samples were very bloody while 15 were slightly bloody. The microbial characterization showed that 18 samples were catalase-positive indicating the presence of S. mutans while 13 were catalase-negative suspected to be Staphylococcus spp. The Gram reaction confirmed 13 Gram-negative and 18 Gram-positive organisms. The n-hexane extract had the best antimicrobial activity followed by the ethanol and lastly hot water. MIC showed that n-hexane clove extract had the largest inhibition zone diameter, followed by bitter kola extract and lastly tobacco extract. The antibiotic sensitivity test credited ciprofloxacin the best because it exhibited broad spectrum of action.ConclusionsSince the n-hexane extract of clove seeds demonstrated preferential growth-inhibitory activity against the causal cariogenic pathogens (S. mutans) in dental caries, we therefore, report here that clove extract be henceforth considered as a potential ingredient in toothpaste preparation.     

In vitro antitrypanosomal activity,antioxidant property and phytochemical constituents of aqueous extracts of nine Nigerian medicinal plants

ObjectiveTo study the in vitro antitrypanosomal activity, antioxidant property and phytochemical constituents of aqueous extracts of nine Nigerian medicinal plants.MethodsIn vitro antitrypanosomal activity test was carried out on aqueous extracts of dried leaves of Acacia albida (A. albida), Artemisia absinthium, Bryophyllum pinnatum, Gongronema latifolium, Holarrhena floribunda, Leptadenia hastata, Pericopsis laxiflora (P. laxiflora) and dried stem barks of A. albida and P. laxiflora. The phytochemical constituents and composition of the extracts and the in vitro antioxidant activity of the extracts were subsequently measured using the α,α-diphenyl-β-picryl-hydrazyl (DPPH) radical scavenging assay, Ferric reducing antioxidant power (FRAP) assay, thiobarbituric acid (TBA) activity assay and H₂O₂ radical scavenging activity assay.ResultsFrom the study, it was discovered that the stem bark extracts of A. albida and P. laxiflora were most active against both Trypanosoma evansi and Trypanosoma congolense. There was complete cessation of motility in both trypanosomes within 5 min at 40 mg/mL of the stem bark extract of A. albida and complete cessation of motility within 25 min and 40 min at 40 mg/mL with P. laxiflora stem bark extract for Trypanosoma congolense and Trypanosoma evansi, respectively. Quantitative analysis of the phytochemical constituents of the aqueous extracts of the plant parts such as alkaloids, saponins, flavonoids and phenols revealed that the stem barks of A. albida, P. laxiflora and leaves of Leptadenia hastata contained relatively high amount of all the phytochemicals quantified. The stem bark extracts of A. albida, P. laxiflora and leaves of Gongronema latifolium possess more scavenging capacity when compared to other extracts in relation to vitamin C, the reference antioxidant.ConclusionsThis study provides scientific evidence for the use of A. albida, and P. laxiflora for the treatment of trypanosomosis and diseases associated with oxidative stress.     

Incorporation of Arginine to Commercial Orthodontic Light-Cured Resin Cements—Physical,Adhesive, and Antibacterial Properties

(1) Background: The amino acid arginine is now receiving great attention due to its potential anti-caries benefits. The purpose of this in vitro study was to evaluate the shear bond strength (SBS), ultimate tensile strength (UTS), and antimicrobial potential (CFU) of two arginine-containing orthodontic resin cements. (2) Methods: Forty bovine incisors were separated into four groups (n = 10): Orthocem, Orthocem + arginine (2.5 wt%), Transbond XT, and Transbond XT + arginine (2.5 wt%). The brackets were fixed to the flat surface of the enamel, and after 24 h the SBS was evaluated using the universal testing machine (Instron). For the UTS test, hourglass samples (n = 10) were made and tested in a mini-testing machine (OM-100, Odeme). For the antibacterial test (colony forming unit-CFU), six cement discs from each group were made and exposed to Streptococcus mutans UA159 biofilm for 7 days. The microbiological experiment was performed by serial and triplicate dilutions. The data from each test were statistically analyzed using a two-way ANOVA, followed by Tukey’s test (α = 0.05). (3) Results: The enamel SBS mean values of Transbond XT were statistically higher than those of Orthocem, both with and without arginine (p = 0.02033). There was no significant difference in the SBS mean values between the orthodontic resin cements, either with or without arginine (p = 0.29869). The UTS of the Transbond XT was statistically higher than the Orthocem, but the addition of arginine at 2.5 wt% did not influence the UTS for either resin cement. The Orthocem + arginine orthodontic resin cement was able to significantly reduce S. mutans growth, but no difference was observed for the Transbond XT (p = 0.03439). (4) Conclusion: The incorporation of arginine to commercial orthodontic resin cements may be an efficient preventive strategy to reduce bacterial growth without compromising their adhesive and mechanical properties.     

Isolation and Characterization of Streptococcus mutans Phage as a Possible Treatment Agent for Caries

Streptococcus mutans is a key bacterium in dental caries, one of the most prevalent chronic infectious diseases. Conventional treatment fails to specifically target the pathogenic bacteria, while tending to eradicate commensal bacteria. Thus, caries remains one of the most common and challenging diseases. Phage therapy, which involves the use of bacterial viruses as anti-bacterial agents, has been gaining interest worldwide. Nevertheless, to date, only a few phages have been isolated against S. mutans. In this study, we describe the isolation and characterization of a new S. mutans phage, termed SMHBZ8, from hundreds of human saliva samples that were collected, filtered, and screened. The SMHBZ8 genome was sequenced and analyzed, visualized by TEM, and its antibacterial properties were evaluated in various states. In addition, we tested the lytic efficacy of SMHBZ8 against S. mutans in a human cariogenic dentin model. The isolation and characterization of SMHBZ8 may be the first step towards developing a potential phage therapy for dental caries.     

Phenolic profile and antimicrobial activities to selected microorganisms of some wild medical plant from Slovakia

ObjectiveTo investigate the chemical composition and antimicrobial activity of the methanol extracts of Tussilago farfara (T. farfara), Equisetum arvense, Sambucus nigra (S. nigra) and Aesculus hippocastanum.MethodsThe antimicrobial activities of the extracts against Enterococcus raffinosus, Escherichia coli, Lactobacillus rhamnosus, Pseudomonas aeruginosa, Serratia rubidaea, Saccharomyces cerevisiae and Staphylococcus epidermis were determined by the microbroth dilution method according to Clinical and Laboratory Standards Institute, while the concentrations of main phenolic acids and flavonoids in the form of trimethylsilyl ethers were analysed using gas chromatography-mass spectrometry. The probit analysis was used for statistical evaluation.ResultsOf the 4 plant tested, all extracts showed a significant antimicrobial activity against one or more species of examined microorganisms. The most active antimicrobial plant extract was gathered from T. farfara, followed by Aesculus hippocastanum and Equisetum arvense. The extract from S. nigra showed no antimicrobial effects. The flavonoids quercetin and kaempferol, as well as several phenolic acids (p-hydroxybenzoic acid, gallic acid, ferulic acid and caffeic acid) were identified in all extracts. The highest concentrations of bioactive compounds were detected in the extracts of T. farfara (9 587.6 μg/mg quercetin and 4 875.3 μg/mg caffeic acid) as well as S. nigra (4788.8 μg/mg kaempferol).ConclusionsWe can state that the methanolic plant extract of T. farfara showed the strongest antimicrobial activity against Saccharomyces cerevisiae as well as other tested microorganisms. At the same time, a good antimicrobial activity was found in the other medical plant extracts as well. No antimicrobial effect of the S. nigra extract was found with respect to the growth of Pseudomonas aeruginosa, Enterococcus raffinosus and Saccharomyces cerevisiae.     

Estimation of total phenolic content,cytotoxicity and in–vitro antioxidant activity of stem bark of Moringa oleifera

ObjectiveTo assess the phytochemical constituents, total phenolic content, cytotoxicity and in-vitro antioxidant activity of stem bark extracts of Moringa oleifera (M. oleifera) (Moringaceae).MethodsBrine shrimp lethality (BSL) bioassay was used to investigate the cytotoxic effects. DPPH and nitric oxide radical scavenging activity was used to demonstrate antioxidant activity.ResultsPhytochemical analysis revealed the presence of tannins, flavonoids, steroids and alkaloids. The LC₅₀ values were obtained for extracts as 850 μg/mL for petroleum ether extract, 800 μg/mL for chloroform extract and 900 μg/mL for methanol extract. The total phenolic content of the methanolic extract was 50.72% w/w, equivalent to gallic acid. Petroleum ether, chloroform and methanolic extracts of M. oleifera and standard ascorbic acid were found to be scavenger of DPPH radical with an IC₅₀ of 124.75, 112.08, 54.34 and 13.86 μg/mL, respectively. Methanolic extract was found to be good scavenger of DPPH radical. Petroleum ether, chloroform, ethyl acetate soluble fraction of methanolic extracts of M. oleifera and ascorbic acid were found to be scavenger of nitric oxide radical with an IC₅₀ of 93.32, 65.12, 54.83 and 12.59 μg/mL, respectively. Ethyl acetate soluble fraction was found to be good scavenger of nitric oxide radical.ConclusionsIt can be concluded that the crude extracts of M. oleifera is a potential source of natural antioxidants, and this justifies its uses in folkloric medicines.     

Antimicrobial activity, cytotoxicity, and phytochemical screening of Voacanga globosa (Blanco) Merr. leaf extract (Apocynaceae)

ObjectiveTo determine the antibacterial, antifungal, antiprotozoal, cytotoxic, and phytochemical properties of ethanol extracts of leaves of Voacanga globosa (Blanco) Merr. (V. globosa).MethodsThe extracts were tested against bacteria and fungus through disc diffusion assay; against protozoa through growth curve determination, antiprotozoal and cytotoxicity assays.ResultsThe extract revealed antibacterial activities, inhibiting the growth of Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa, Micrococcus luteus, and Salmonella typhimurium. Antifungal assay showed that it inhibited Candida albicans. The antiprotozoal assay against Trichomonas vaginalis and Entamoeba histolytica showed that V. globosa can inhibit the parasites, wherein the action can be comparable to metronidazole. With the in situ cell death detection kit, Trichomonas vaginalis and Entamoeba histolytica exposed to V. globosa leaf extract was observed to fluoresce simultaneously in red and yellow signals signifying apoptotic-like changes. Preliminary phytochemical screening revealed the chemical composition of plant extract containing alkaloids, saponins, 2-deoxysugars, and hydrolysable tannins.ConclusionsThus, this study provides scientific evidence on the traditional use of V. globosa leaf extract in treating microbial diseases. Further, the leaf extract can possibly be used to produce alternative forms of antimicrobials.     

Antibacterial and Antibiofilm Properties of Three Resin-Based Dental Composites against Streptococcus mutans

Antibacterial and antibiofilm properties of restorative dental materials may improve restorative treatment outcomes. The aim of this in vitro study was to evaluate Streptococcus mutans capability to adhere and form biofilm on the surface of three commercially available composite resins (CRs) with different chemical compositions: GrandioSO (VOCO), Venus Diamond (VD), and Clearfil Majesty (ES-2). Disk-shaped specimens were manufactured by light-curing the CRs through two glass slides to maintain a perfectly standardized surface topography. Specimens were subjected to Planktonic OD_600nm, Planktonic CFU count, Planktonic MTT, Planktonic live/dead, Adherent Bacteria CFU count, Biomass Quantification OD_570nm, Adherent Bacteria MTT, Concanavalin A, and Scanning Electron Microscope analysis. In presence of VOCO, VD, and ES2, both Planktonic CFU count and Planktonic OD_600nm were significantly reduced compared to that of control. The amount of Adherent CFUs, biofilm Biomass, metabolic activity, and extracellular polymeric substances were significantly reduced in VOCO, compared to those of ES2 and VD. Results demonstrated that in presence of the same surface properties, chemical composition might significantly influence the in vitro bacterial adhesion/proliferation on resin composites. Additional studies seem necessary to confirm the present results.