Oral streptococci: modulators of health and disease.

Streptococci are primary colonizers of the oral cavity where they are ubiquitously present and an integral part of the commensal oral biofilm microflora. The role oral streptococci play in the interaction with the host is ambivalent. On the one hand, they function as gatekeepers of homeostasis and are a prerequisite for the maintenance of oral health - they shape the oral microbiota, modulate the immune system to enable bacterial survival, and antagonize pathogenic species. On the other hand, also recognized pathogens, such as oral Streptococcus mutans and Streptococcus sobrinus, which trigger the onset of dental caries belong to the genus Streptococcus. In the context of periodontitis, oral streptococci as excellent initial biofilm formers have an accessory function, enabling late biofilm colonizers to inhabit gingival pockets and cause disease. The pathogenic potential of oral streptococci fully unfolds when their dissemination into the bloodstream occurs; streptococcal infection can cause extra-oral diseases, such as infective endocarditis and hemorrhagic stroke. In this review, the taxonomic diversity of oral streptococci, their role and prevalence in the oral cavity and their contribution to oral health and disease will be discussed, focusing on the virulence factors these species employ for interactions at the host interface.

Tracing of Microbes in Prepared Cavity Following Different Minimally Invasive Caries Removal Protocols.

AIMS: The conventional caries removal technique has been replaced with minimally invasive (MI) techniques to preserve healthy natural teeth and to provide durable dental restorations. Each of these MI caries removal protocols is reported to be favorable in dealing with different caries conditions. The current study aimed to trace the residual bacteria that may remain in a prepared cavity following a visual-tactile (VT), caries detection dye (CDD), and chemo-mechanical caries removal (CMCR) protocol. MATERIALS AND METHODS: A total of 29 extracted human molar teeth with visible caries lesions were randomly divided into three groups. The cavity preparation and caries removal of each group was accomplished following one of the MI caries removal protocols. Swab samples (one from each specimen) were taken and inoculated onto a blood agar plate and incubated for 48 hours. The growth of the bacterial colony was observed under a microscope and the specific genome of the bacteria was identified by polymerase chain reaction (PCR) test. RESULTS: The maximum number of traceable bacteria was observed following the chemo-mechanical caries removal group followed by the caries detection dye group and the least in the visual-tactile group. The PCR test revealed the presence of Streptococcus mutans in all the observed colonies; however, Streptococcus sobrinus was absent completely. The Chi-square test reveals a statistically insignificant (p = 0.646) difference among the tested groups. CONCLUSION: All of the MI caries removal protocols used in this study showed a trace of microbes in certain teeth. The cavity prepared following a visual tactile protocol showed the least amount of traceable bacteria in the prepared cavity. CLINICAL SIGNIFICANCE: Cavity that is prepared following individual MI protocol has a risk of leaving microbes in it.

Salivary levels of five microorganisms of root caries in nursing home elderly: a preliminary investigation.

BACKGROUND: Streptococcus, Bifidobacteria, Lactobacillus and Actinomyces are acidogenic aciduria that may be associated with root caries (RC). The aim of the study was to analyze Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus), Bifidobacterium spp., Lactobacillus spp. and Actinomyces naeslundii (A. naeslundii) in the saliva of nursing home elderly, to assess the correlation between bacterial composition and RC for five putative catiogenic organisms. METHODS: In this study, we collected 43 saliva samples and divided into two groups: the root caries group (RCG, n = 21) and the caries-free group (CFG, n = 22). Bacterial DNA was extracted from the saliva samples. The presence and abundance of the five microorganisms were detected by Quantitative real-time PCR (qPCR). Spearman correlation test was performed to evaluate the relationship between the numbers of root decayed filled surfaces (RDFS) and root caries index (RCI) and salivary levels of the bacteria. RESULTS: The salivary levels of S. mutans, S. sobrinus, Bifidobacterium spp. and Lactobacillus spp. were significantly higher in RCG than in CFG (p < 0.05). RDFS and RCI (RDFS/RCI) were positively associated with salivary levels of S. mutans, S. sobrinus and Bifidobacterium spp. (r = 0.658/0.635, r = 0.465/0.420 and r = 0.407/0.406, respectively). No significant differences in presence and amounts of A. naeslundii was observed between the two groups (p > 0.05). CONCLUSION: S. mutans, S. sobrinus and Bifidobacterium spp. in saliva appear to be associated with RC in the elderly. Taken together, the findings indicate that specific salivary bacteria may be involved in the progression of RC.

Streptococcus sobrinus as a Predominant Oral Bacteria Related to the Occurrence of Dental Caries in Polish Children at 12 Years Old.

Dental caries is listed by the WHO as one of the major non-communicable diseases that need to be prevented and treated. The aim of the study was to evaluate the prevalence and severity of caries expressed as the Decayed, Missing and Filled Permanent Teeth (DMFT) index in 12-year-old Polish children and to verify bacterial species related to the occurrence of dental caries. Quantitative real-time PCR analysis of DNA isolated from saliva samples was performed to detect 8 cariogenic and periopathogenic bacterial strains. A total of 118 Polish children were enrolled in the study. They had low mean DMFT scores of 1.58 ± 1.98. The prevalence of dental caries in the children tested was low (53.4%), with a tendency to decrease compared to previous oral surveys. Bacterial abundance of other species in the dental caries and caries-free groups did not differ; however, periopathogenic Prevotella pallens, Fusobacterium nucleatum along with cariogenic Streptococcus mutans and Lactobacillus fermentum were significantly strongly correlated in the caries-active subjects. The prevalence of S. sobrinus was significantly higher in children with dental caries (p = 0.023) and correlated with higher DMFT. It may temporarily play an important role in the initiation of the cariogenic process or in its enhancement due to an ecological imbalance in dental microbiota.

Saliva sampling methods. Cariogenic streptococci count using two different methods of saliva collection in children.

The aim of this study is to compare the efficacy of two methods for collecting saliva samples from infants under 2 years of age for cariogenic streptococci (CS) count. Two collection methods were applied in 11 infants. In Method (A), saliva samples were collected by swabbing the inner cheek mucosa and floor of the mouth in figure of eight motions with a sterile cotton swab until it was soaked. In method (B), saliva samples were collected by aspiration of 1 ml of saliva with a sterile plastic syringe on the floor of the mouth, after stimulation with glove. The samples were cultured in modified Gold's broth (MSMG), and on trypticase, yeast extract, sucrose, cystine and bacitracin culture medium (TYSCB). In method (A), the swab with the sample was unloaded in situ on TYSCB and placed in PBS medium for transport. Then, 100 µl of the eluate was seeded in MSMG. In method (B) 100 µl were seeded in TYSCB and 100 µl in MSMG. Both culture media were incubatedundercapnophilicconditions for 48 hours at 37 °C. Colony forming units (CFU/ml) were counted by calibrated operators (kappa = 0.75). The presence of cariogenic streptococci (CS) (Streptococcus mutans-Streptococcus sobrinus) was determined by qPCR in the samples collected by both methods. The CFU/ml counts in MSMG differed significantly between methods (p = 0.021). In TYSCB, the recovery of CFU/ml was higher in method (A), without significant difference (p = 0.705). The molecular technique detected presence of CS, with no difference between collection methods. Collecting saliva samples by swabbing proved more effective in terms of recovery of microorganisms, and did not affect the detection of presence of CS by molecular techniques.

El objetivo de este estudio es comparar la eficacia de dos métodos de obtención de muestras salivales, en infantes menores de 2 años para el recuento de estreptococos cariogénicos (EC). Se aplicaron dos métodos de recolección en 11 infantes, el método (A), consistió en la recolección de muestras de saliva con hisopos de algodón estériles, realizando movimientos en ocho sobre la mucosa del carrillo y piso de boca, hasta embeber el hisopo. En el método (B) la recolección de las muestras se realizó por aspiración con jeringa plástica estéril en piso de boca hasta obtener 1 ml, luego de estimulación con guante. Las muestras fueron cultivadas en caldo de Gold modificado (MSMG) y medio de cultivo TYSCB (tripticasa, extracto de levadura, sacarosa, cistina y bacitracina). En (A), el hisopo con la muestra fue descargado in situ en TYSCB y colocado en medio de transporte PBS. 100 µl del eluato se sembró en MSMG. En (B) 100 µl fueron sembrados en TYSCB y 100µlen MSMG. Ambosmedios de cultivo fueron incubados en condiciones de capnofilia por 48 hs. a 37°C. El recuento de unidades formadoras de colonias (UFC/ml) se realizó por operadores calibrados (kappa= 0.75). La presencia de EC (Streptococcus mutans - Streptococcus sobrinus) fue determinada por qPCR en las muestras obtenidas por ambos métodos. Los resultados mostraron que los recuentos de UFC/ml en MSMG presentaron diferencias significativas entre ambos métodos (p=0.021) En TYSCB la recuperación de UFC/ml fue mayor en el método (A), sin observarse diferencias significativas (p=0.705). Se detectó la presencia de EC por técnica molecular, sin mostrar diferencias entre los métodos empleados. La recolección de muestra de saliva con hisopo presentó mayor eficacia en términos de recuperación de microorganismos, sin alterar la detección de presencia de EC por técnicas moleculares.

Streptococcus mutans and Streptococcus sobrinus contributions in dental caries in Iranian and Afghan children: A report from serotype distribution and novel STs.

OBJECTIVE: This study evaluated the frequency and the effects of S. mutans and S. sobrinus on Decayed, Missing, and Filled Teeth (DMFT) scores in Iranian and Afghan populations. Serotyping of S. mutans isolates and multi-locus sequence typing (MLST) were the secondary goals. DESIGN: This study was performed on 360 saliva and plaque samples from people from age groups of 4-7 and 15-17 years with Iranian and Afghan nationality who were residents of Tehran province. The DMFT index of the study population was determined, and S. mutans and S. sobrinus were identified using species-specific primers. Following the collagen-binding protein of S. mutans (cnm) gene identification, serotypes were determined, and genotyping was performed on eight selected isolates by assessing eight loci in the existing MLST scheme. RESULTS: Of 360 samples, 300 were recruited as population study. Of these, 204 (51%) harbored S. mutans alone. In 42 specimens (10.5%), both specious were detected, and 54 (13.5%) were free of both. The frequencies of c, f, e, and k serotypes were 47.5%, 17.9%, 13.8%, and 8.1%, respectively. The frequency of serotype f was significantly higher in four-year-old Iranian children. MLST showed eight different sequence types (STs), which were confirmed as novel singleton sequence types. CONCLUSIONS: The high frequency of serotypes k and f as systemic serotypes with the cnm gene among the Iranian population suggests the need for more worldwide studies on serotype distribution. Since very few studies have reported the epidemiological status of mutans streptococci (MS), the molecular properties of the isolates are unknown. Thus, the STs reported in this study should be considered as emerging strains.

Evaluation of the cariogenic potential of a probiotic candidate strain Lactobacillus gasseri YIT 12321.

OBJECTIVE: This study was designed to evaluate the cariogenic potential of Lactobacillus gasseri YIT 12321. DESIGN: L. gasseri YIT 12321 was isolated from the human oral cavity as a probiotic candidate strain. Three types of experimental biofilm formations on bovine enamel specimens were assessed using Streptococcus sobrinus ATCC 33478, L. gasseri YIT 12321, and a co-culture of S. sobrinus and L. gasseri YIT 12321 in vitro. L. gasseri YIT 12321 was analyzed for its ability to utilize seven carbohydrates. L. gasseri YIT 12321 was cultured in tryptic soy broth without dextrose and containing a test carbohydrate at 37 °C for 16 h. RESULTS: The decrease in pH in the region under the biofilm produced by L. gasseri YIT 12321 was unusually slow, and the pH was maintained above 5.5 for 16 h. The amount of biofilm and the reduction in enamel hardness were minimal in the L. gasseri YIT 12321 group among the three experimental groups. The amount of co-culture-derived biofilms was less than that of S. sobrinus biofilms. When S. sobrinus was grown using sucrose, the pH decreased to 3.98. In contrast, L. gasseri YIT 12321 cultures maintained the pH above the critical pH for dentin demineralization. CONCLUSIONS: L. gasseri YIT 12321 is suggested to have a low cariogenic potential. The application of this strain as a probiotic may contribute to oral safety.

Estudio de la actividad antimicrobiana de Xenophyllum poposum sobre microorganismos de la cavidad bucal por el método de difusión radial / Study of the antimicrobial activity of Xenophyllum poposum on microorganisms of the oral cavity by the radial diffusion method

Resumen En este estudio se evaluó la actividad antimicrobiana in vitro de extractos de Xenophyllum poposum sobre microorganismos bucales como Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, Actinomyces naeslundii, Actinomyces odontolyticus, Candida albicans y Veillonella sp. Se empleó el método de difusión radial en agar y como controles negativo y positivo de inhibición se emplearon etanol y clorhexidina al 0,12% (Plac out NF®) respectivamente. Los extractos con mayor actividad antimicrobiana fueron el etanólico y el clorofórmico. La diferencia entre ambos no fue estadísticamente significativa (p≥0,05). Tampoco se observó diferencia significativa con respecto a la clorhexidina, excepto sobre Veillonella sp., ya que el extracto etanólico presentó halos de inhibición significativamente menores sobre este microorganismo. Esto es importante ya que Veillonella se considera indicador de salud en relación a la caries dental. En base a esto, el extracto etanólico de Xenophyllum poposum podría ser usado como control químico de la biopelícula dental.

Abstract In this study, the in vitro antimicrobial activity of Xenophyllum poposum extracts on oral microorganisms such as Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, Actinomyces naeslundii, Actinomyces odontolyticus, Candida albicans, Veillonella sp. was evaluated. The radial diffusion method in agar was used and 0.12% ethanol and chlorhexidine (Plac out NF®) were used as negative and positive inhibition controls, respectively. The extracts with the highest antimicrobial activity were the ethanolic and chloroform extracts. The difference between the two was not statistically significant (p≥0.05). No significant difference was observed with respect to chlorhexidine, except on Veillonella sp., since the ethanolic extract presented significantly lower inhibition halos on this microorganism. This is important as Veillonella is considered an indicator of health in relation to dental caries. Based on this, the ethanolic extract of Xenophyllum poposum could be used as chemical control of dental biofilm.

Resumo Neste estudo, a atividade antimicrobiana de extratos de Xenophyllum poposum sobre microrganismos orais como Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, Actinomyces naeslundii, Actinomyces odontolyticus, Candida albicans e Veillonella sp. Foi utilizado o método de difusão radial em ágar e etanol 0,12% e clorexidina (Plac out NF®) como controles de inibição negativa e positiva, respectivamente. Os extratos com maior atividade antimicrobiana foram os extratos etanólico e clorofórmio. A diferença entre os dois não foi estatisticamente significativa (p≥0,05). Não foi observada diferença significativa em relação à clorexidina 0,12%, exceto em Veillonella sp., uma vez que o extrato etanólico apresentou halos de inibição significativamente menores neste microrganismo. Isso é importante, pois a Veillonella é considerada um indicador de saúde em relação à cárie dentária. Com base nisso, o extrato etanólico de Xenophyllum poposum pode ser utilizado como controle químico do biofilme dental.

Streptococcus mutans in atherosclerotic plaque: Molecular and immunohistochemical evaluations.

OBJECTIVES: To verify the presence of Streptococcus mutans (S. mutans) in atherosclerotic plaque (AP) using techniques with different sensitivities, correlating with histological changes in plaque and immunoexpression of inflammatory markers. MATERIALS AND METHODS: Thirteen AP samples were subjected to real-time polymerase chain reaction (qRT-PCR), histopathological analyses, histochemical analysis by Giemsa staining (GS), and immunohistochemical analysis for S. mutans, IL-1ß, and TNF-α (streptavidin-biotin-peroxidase method). Ten necropsy samples of healthy vessels were used as controls. RESULTS: All AP samples showed histopathological characteristics of severe atherosclerosis and were positive for S. mutans (100.0%) in qRT-PCR and immunohistochemical analyses. GS showed that Streptococcus sp. colonized the lipid-rich core regions and fibrous tissue, while the control group was negative for Streptococcus sp. IL-1ß and TNF-α were expressed in 100% and 92.3% of the AP tested, respectively. The control samples were positive for S. mutans in qRT-PCR analysis, but negative for S. mutans, IL-1ß, and TNF-α in immunohistochemical analyses. CONCLUSION: The detection of S. mutans in AP and the visualization of Streptococcus sp. suggested a possible association between S. mutans and atherosclerosis. The results obtained from the control samples suggested the presence of DNA fragments or innocuous bacteria that were not associated with tissue alteration. However, future studies are necessary to provide more information.

The Clinical Pattern and Prevalence of Streptococcus mutans and Streptococcus sobrinus among Adult and Children Patients with Dental Caries

Abstract Objective: To explore the clinical pattern, host factors, and presentation of Streptococcus mutans related to caries incidence among children and adults visiting Universitas Airlangga dental clinic. Material and Methods: This was an observational study with a cross-sectional approach with 50 patients in each group of carious children (6-12 years) and adults (18-35 years). Dental decay samples were taken by sterile excavator, put in a BHI's transport medium, and directly incubated overnight at 37 ºC. The next day, they were sub-cultured microbiologically in Tryptone Yeast Cystine Sucrose Bacitracin (TYCSB) selective medium. Bacterial species and serogroups were examined by PCR. All patient's data were collected from medical records and direct observation. Results: Caries were mostly media type in both children and adults. Oral hygiene (OHIS) in children was higher than in adults but not significantly different according to their DMFT. The highest scores for decay, missed and filled teeth were 16, 8 and 7, with an average of 6.82, 1.22 and 0.63, considered quite high. Conclusion: The prevalence of S. mutans was higher in children's caries than in adults, but among the adult patients the co-incidence of S. mutans and S. sobrinus was associated with higher DMFT. The mutans serotypes e, f, and d were more prevalent among children than adults.

Comparative Analysis of Streptococcus Mutans and Streptococcus Sobrinus from Dental Plaque Samples of Nigerian Pre-school Children with and Without Caries.

BACKGROUND: Early childhood caries (ECC), despite being a preventable disease, remains prevalent in sub-Saharan Africa. This study compared the occurrence of Streptococcus mutans and Streptococcus sobrinus in dental plaque from caries free and caries active Nigerian preschool children. METHODS: Structured questionnaire were administered to eighty (80) mothers to inquire about the sociodemographic characteristics of their children. Diagnosis of dental caries was made according to the diagnostic criteria of the World Health Organization (WHO). Supragingival plaque sample collected from caries free children and children with dental caries (cavitated and non-cavitated lesions) using wooden toothpicks were cultured anaerobically. Samples were cultured in anaerobiosis and isolates obtained were identified based on molecular characterization performed by polymerase chain reaction (PCR) analysis. Statistical package for the social sciences (SPSS 25.0) was used for analysis. RESULTS: Streptococcus mutans was detected in 26(65.0%) children with early childhood caries, and S. sobrinus in 10(25.0%) children with early childhood caries. The presence of S. mutans and S. sobrinus occurring together was associated with a higher deft score. Occurrence of S. mutans did not show significant difference between children with ECC and caries free children (p=0.099), however, the proportion of children with ECC positive for S. sobrinus was significantly higher than that of caries free children (p= 0.003). CONCLUSIONS: S. mutans and S. sobrinus had a similar frequency of occurrence in children with ECC and caries free children. The occurrence of S. mutans alongside S. sobrinus in ECC is related to its severity.

CONTEXTE: La carie de la petite enfance (CPE), bien qu'étant une maladie évitable, reste prévalente en Afrique sub-saharienne. Cette étude a comparé la présence de Streptococcus mutans et Streptococcus sobrinus dans la plaque dentaire d'enfants nigérians d'âge préscolaire avec et sans caries. MÉTHODES: Des questionnaires structurés ont été administrés à quatrevingts (80) mères pour connaître les caractéristiques sociodémographiques de leurs enfants. Le diagnostic de la carie dentaire a été établi selon les critères de diagnostic de l'Organisation mondiale de la santé (OMS). Des échantillons de plaque supragingivale prélevés sur des enfants exempts de caries et des enfants atteints de caries dentaires (lésions cavitaires et non cavitaires) à l'aide de cure-dents en bois ont été mis en culture en anaérobiose. Les échantillons ont été mis en culture en anaérobiose. Les isolats obtenus ont été identifiés sur la base d'une caractérisation moléculaire effectuée par une analyse de réaction en chaîne par polymérase (PCR). Le progiciel statistique pour les sciences sociales (SPSS 25.0) a été utilisé pour l'analyse. RÉSULTATS: Streptococcus mutans a été détecté chez 26(65,0%) enfants atteints de caries de la petite enfance, et S. sobrinus chez 10(25,0%) enfants atteints de caries de la petite enfance. La présence simultanée de S. mutans et de S. sobrinus était associée à un score de déformation plus élevé. La présence de S. mutans n'a pas montré de différence significative entre les enfants atteints de CEC et les enfants indemnes de caries (p=0,099), cependant, la proportion d'enfants atteints de CEC positifs pour S. sobrinus était significativement plus élevée que celle des enfants indemnes de caries (p= 0,003). CONCLUSIONS: S. mutans et S. sobrinus ont une fréquence d'apparition similaire chez les enfants atteints de CEC et les enfants indemnes de caries. La présence de S. mutans et de S. sobrinus dans l'ECC est liée à sa gravité. MOTS CLÉS: Streptococcus mutans, Streptococcus sobrinus, caries de lapetite enfance, plaque supragingivale.

ß-Glycyrrhetinic acid inhibits the bacterial growth and biofilm formation by supragingival plaque commensals.

ß-Glycyrrhetinic acid (BGA) is a natural antibacterial agent. Previous studies reported that BGA has antibacterial effects against several bacteria. This study evaluated the effects of BGA on the regulation of supragingival plaque bacteria. First, the minimum inhibitory concentrations (MICs) of BGA against oral bacteria were measured. Next, the minimum concentrations for inhibition of biofilm formation were evaluated against Streptococcus mutans and Streptococcus sobrinus, possessing insoluble glucan synthesis abilities. The MICs of biofilm formation by these bacteria ranged from 1/8 to 2× MIC. Furthermore, the inhibition effects of BGA against the coaggregation of Porphyromonas gingivalis and Streptococcus gordonii were evaluated. BGA at 32 or 64 µg/mL inhibited the coaggregation of these bacteria after a 30 min incubation. Lastly, the inhibition effects of BGA against human supragingival plaque bacteria were evaluated. Human supragingival plaque samples were obtained from 12 healthy donors. The inhibition effects of BGA against biofilm formation by these plaque bacteria were evaluated. Of 12 samples, the biofilm formation by 11 was significantly attenuated by 128-256 µg/mL of BGA. The number of colony forming units in these biofilms was also significantly attenuated. In conclusion, it was revealed that BGA inhibits the growth and biofilm formation of bacteria, furthermore, the same effect was confirmed with supragingival plaque bacteria. BGA is a good candidate for a natural agent that prevents the outbreak and progression of periodontal disease because it suppresses not only the growth and biofilm formation of bacteria, but also the coaggregation of P. gingivalis with plaque bacteria.

A Novel Competence Pathway in the Oral Pathogen Streptococcus sobrinus.

Streptococcus sobrinus is an etiologic cause of dental caries (tooth decay) in humans. Our knowledge of S. sobrinus is scant despite the organism's important role in oral health. It is widely believed that S. sobrinus lacks the natural competence pathways that are used by other streptococci to regulate growth, virulence, and quorum sensing. The lack of natural competence has also prevented genetic manipulation of S. sobrinus, limiting our knowledge of its pathogenicity. We discovered that most strains of S. sobrinus contain a new class of the ComRS competence system. Although S. sobrinus is typically placed among the mutans group streptococci, the S. sobrinus ComRS system is most similar to the competence pathways in the salivarius group. Unlike all other ComRS systems, the S. sobrinus pathway contains 2 copies of the transcriptional regulator ComR and has a peptide pheromone (XIP) that lacks any aromatic amino acids. Synthetic XIP enables transformation of S. sobrinus with plasmid or linear DNA, and we leverage this newfound genetic tractability to confirm that only 1 of the ComR homologs is required for induced competence while the other appears to suppress competence. Exogenous XIP increases the expression of bacteriocin gene clusters and produces an antimicrobial response that inhibits growth of S. mutans. We also identified 2 strains of S. sobrinus that appear to be "cheaters" by either not responding to or not producing XIP. We show how a recombination event in the nonresponsive strain could restore function of the ComRS pathway but delete the gene encoding XIP. Thus, the S. sobrinus ComRS pathway provides new tools for studying this pathogen and offers a lens into the evolution of ecological cheaters.

Antimicrobial Photodynamic Treatment with Mother Juices and Their Single Compounds as Photosensitizers.

The potent antimicrobial effects of antimicrobial photodynamic therapy (aPDT) with visible light plus water-filtered infrared-A irradiation and natural compounds as photosensitizers (PSs) have recently been demonstrated. The aim of this study was to obtain information on the antimicrobial effects of aPDT with mother juices against typical cariogenic oral Streptococcus pathogens in their planktonic form and determine its eradication potential on total human salivary bacteria from volunteers. Mother juices of pomegranate, bilberry, and chokeberry at different concentrations were used as PSs. The unweighted (absolute) irradiance was 200 mW cm-2, applied five minutes. Planktonic cultures of Streptococcus mutans and Streptococcus sobrinus and total mixed bacteria from pooled saliva of volunteers were treated with aPDT. Up to more than 5 log10 of S. mutans and S. sobrinus were killed by aPDT with 0.4% and 0.8% pomegranate juice, 3% and 50% chokeberry juice, and 12.5% bilberry juice (both strains). Concentrations of at least 25% (pomegranate) and >50% (chokeberry and bilberry) eradicated the mixed bacteria in saliva samples. This pilot study has shown that pomegranate mother juice is superior to the berry juices as a multicomponent PS for killing pathogenic oral bacteria with aPDT.

Multiple biosurfactant production by Aureobasidium pullulans strain YTP6-14 in aqueous and heavy oil layers.

Aureobasidium pullulans YTP6-14 was demonstrated to be an excellent multiple biosurfactant producer utilizing cheap carbon sources available in Thailand, including glycerol and cassava flour hydrolysate. A. pullulans YTP6-14 maximally produced 1.81 g/l biosurfactant in an aqueous layer (BS-AQ) in a medium containing glycerol, and 7.37 or 6.37 g/l biosurfactant in a heavy oil layer (BS-HO) in cassava flour hydrolysate or a glucose containing medium, respectively. Each BS-AQ and BS-HO had critical micelle concentration values of 41.32 mg/l and 13.51 mg/l, and both biosurfactants formed a stable food oil emulsion and reduced the amount of biofilms formed by Streptococcus sobrinus and Streptococcus mutans. BS-AQ and BS-HO were mainly composed of liamocins or exophilins and massoia lactone, respectively.

Antimicrobial activity of ginger on cariogenic bacteria: molecular networking and molecular docking analyses.

Streptococcus mutans and Streptococcus sobrinus have been implicated as the primary causative agents of dental caries in humans. This study aimed to screen the antibacterial activity of the n-hexane, ethyl acetate, methanol, and aqueous extracts of Ginger against mentioned bacteria and investigate chemical constituents of the extracts, and their activity against some drug targets in S. mutans. Antimicrobial tests including biofilm inhibition, time-kill kinetics, and adherence inhibition alongside cytotoxicity of extracts, were assessed. A molecular networking technique was used to find chemical constituents of the extracts. Molecular docking analysis on the Schrodinger package was applied to identify the binding interactions of the compounds to targeted enzymes. Methanol and ethyl acetate extracts showed the highest antibacterial activity against S. mutans and S. sobrinus. Different compounds including polyphenols, alkaloids, anthraquinones, flavonoids, terpenoids, glycosides, steroids, and reducing sugars dereplicated from Ginger extracts. The binding affinity of ligands with free hydroxyl groups was better than other ligands against all tested enzymes. This study introduces a wide range of Z. officinal extracts compounds to be used in different drug discovery studies. Some Ginger compounds with high affinity to investigated enzymes can be considered as candidate compounds for anti-caries drug development studies.Communicated by Ramaswamy H. Sarma.

Streptococcus mutans and Streptococcus sobrinus distribution in the saliva and plaque of Iranian population: Higher prevalence of S. mutans serotypes f and k.

OBJECTIVE: This study aimed to find the relation of the MS co-existence with the decayed, missing (Extracted) and filled teeth (DMFT) score and the prevalence of Streptococcus mutans serotypes in the Iranian population. METHODS: In this cross-sectional research conducted in 2018, volunteers aged 10-60< years were measured by population selection criteria. PCR technique was used to screen MS serotypes in the homogenized saliva and plaque samples. RESULTS: 499 subjects met the selection criteria of the study population. Out of 499 samples, 448 samples were finalized for serotype determination and DMFT relation evaluation. From 448, 348 (77.6%) samples harboured only S. mutans, 44 (9.8%) had both S. mutans and S. sobrinus, 6 (1.3%) were positive for S. sobrinus alone, and 94 (20.9%) were free of both specious. The mean DMFT score in people with S. mutans (6.7) was higher than S. mutans negative (4.6) participants (p < 0.05). In people with both S. mutans and S. sobrinus, the mean DMFT did not change significantly. The frequency of c, e, f and k serotypes was 47.7, 22.7, 27.5 and 22.1%, respectively. The mean DMFT score in participants with serotype e was significantly higher than others (p < .05). CONCLUSIONS: People can acquire different S. mutans serotypes over a lifetime. The high prevalence rate of serotype k, a systemic S. mutans serotype, calls worldwide studies on the prevalence of serotype k strains.

In Vitro Studies of Xylitol and Erythritol Inhibition of Streptococcus Mutans and Streptococcus Sobrinus Growth and Biofilm Production.

The aim of this study was to evaluate synergy and inhibitory effects of xylitol and erythritol on Streptococcus mutans and Streptococcus sobrinus growth and biomass production on a polystyrene plastic surface. Study design; S. mutans and sobrinus strains (American Type Culture Collection reference strains 31341, 35668, 25175, sobrinus 33478) were cultivated in media (Todd Hewitt Broth with 1% sucrose or heart-brain infusion broth with 1% sucrose) at differing concentrations of xylitol or erythritol in microtiter assay plates incubated for 48 hours. Bacterial growth was quantified and measured by optical density using a microplate reader. Experiments assessing synergy and biofilm growth were carried out also using microdilution assays. All four strains were inhibited by 30% (w/v) xylitol, and 15% erythritol at 150mg/ml erythritol, 2/4 strains had reduced growth; at 270mg/ml, 4/4 strains were inhibited. Bactericidal effects were not observed at any polyol concentration. Combinations of both polyols in a checker board array were used to determine if there were any benefits of polyol combinations. Results The combination studies yielded mixed outcomes with indifference in growth for strains 68 and 78, potential additive effect for strain 75 and possible antagonism for strain 41. Assessment of biomass formation and polyol interference were also performed post MIC assessment. Strains 41, 68 and 75 produced significant biomass in the absence of either polyol. Both polyols inhibited biomass formation in a dose-dependent fashion. Strain 75 is a poor biomass producer and could not be assessed for polyol effects in our assay. Conclusion: Our results demonstrate significant polyol influence on the oral Streptococcal strains tested in our laboratory.

Metagenomics of the modern and historical human oral microbiome with phylogenetic studies on Streptococcus mutans and Streptococcus sobrinus.

We have recently developed bioinformatic tools to accurately assign metagenomic sequence reads to microbial taxa: SPARSE for probabilistic, taxonomic classification of sequence reads; EToKi for assembling and polishing genomes from short-read sequences; and GrapeTree, a graphic visualizer of genetic distances between large numbers of genomes. Together, these methods support comparative analyses of genomes from ancient skeletons and modern humans. Here, we illustrate these capabilities with 784 samples from historical dental calculus, modern saliva and modern dental plaque. The analyses revealed 1591 microbial species within the oral microbiome. We anticipated that the oral complexes of Socransky et al., which were defined in 1998, would predominate among taxa whose frequencies differed by source. However, although some species discriminated between sources, we could not confirm the existence of the complexes. The results also illustrate further functionality of our pipelines with two species that are associated with dental caries, Streptococcus mutans and Streptococcus sobrinus. They were rare in historical dental calculus but common in modern plaque, and even more common in saliva. Reconstructed draft genomes of these two species from metagenomic samples in which they were abundant were combined with modern public genomes to provide a detailed overview of their core genomic diversity. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.

Silver nanoparticles in orthodontics, a new alternative in bacterial inhibition: in vitro study.

BACKGROUND: The purpose of the study is to assess the antiadherent and antibacterial properties of surface-modified different orthodontic brackets with silver nanoparticles against Streptococcus mutans and Streptococcus sobrinus, using radiomarker. METHODS: In this study evaluated quantitatively the adherence of Streptococci to orthodontic brackets, 300 samples of orthodontic brackets were selected and classified in to 10 groups as follow: GIn (InVu-Roth), GIIn (System-AlexanderLTS), GIIIn (Gemini-Roth), GIVn (NuEdge-Roth), GVn (Radiance plus-Roth), GVI (InVu-Roth), GVII (System-AlexanderLTS), GVIII (Gemini-Roth), GIX (NuEdge-Roth), GX (Radiance plus-Roth). All the samples were sonicated and Streptococci were cultivated by gender. A radioactive marker (3H) was used to codify the bacteria and measure them. After that, the brackets were submerged in a radiolabelled solution, and the radiation was measured. The statistical analysis was calculated with ANOVA test (Sheffè post hoc). RESULTS: The results showed significant differences were found among the groups. GIIIn shown the lowest scores for both bacteria; in contrast, GIX for Streptococcus mutans and GVI for Streptococcus sobrinus were the highest values. CONCLUSIONS: Surface modification of orthodontic brackets with silver nanoparticles can be used to prevent the accumulation of dental plaque and the development of dental caries during orthodontic treatment.