Bioactive molecule optimized for biofilm reduction related to childhood caries.

Aim: To evaluate antimicrobial activity of a new nitrochalcone (NC-E08) against Candida albicans and Streptococcus mutans, and its toxicity. Materials & methods: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration/minimum fungicidal concentration (MFC) were determined against C. albicans and S. mutans, as well as antibiofilm potential and toxicity (human gingival fibroblast and Galleria mellonella). Infection and treatment were performed in G. mellonella. Results & conclusion: NC-E08 showed antimicrobial activity in C. albicans (MIC: 0.054 mM) and S. mutans (MIC: 0.013 mM); 10xMIC treatment reduced 4.0 log10 biofilms for both strains and there was a reduction in survival of mixed biofilms of C. albicans and S. mutans (6.0 and 4.0 log10, respectively). NC-E08 showed no cytotoxicity in human gingival fibroblast cells and G. mellonella. NC-E08 after larval infection protected them 90% (p < 0.05). Thus, is a promising one for the prevention and treatment of S. mutans and C. albicans infections.

Self-ligating versus conventional metallic brackets on Streptococcus mutans retention: A systematic review.

OBJECTIVE: The present study aimed to review the literature systematically and assess comparatively whether self-ligating metallic brackets accumulate less Streptococcus mutans biofilm than conventional metallic brackets. MATERIAL AND METHODS: The systematic search was performed following PRISMA guidelines and registration in PROSPERO. Seven electronic databases (Google Scholar, LILACS, Open Grey, PubMed, SciELO, ScienceDirect, and Scopus) were consulted until April 2016, with no restriction of language and time of publication. Only randomized clinical studies verifying S. mutans colonization in metallic brackets (self-ligating and conventional) were included. All steps were performed independently by two operators. RESULTS: The search resulted in 546 records obtained from the electronic databases. Additionally, 216 references obtained from the manual search of eligible articles were assessed. Finally, a total of 5 studies were included in the qualitative synthesis. In 1 study, the total bacterial count was not different among self-ligating and conventional brackets, whereas in 2 studies the amount was lower for self-ligating brackets. Regarding the specific count of S. mutans, 2 studies showed less accumulation in self-ligating than in conventional brackets. CONCLUSION: Based on the limited evidence, self-ligating metallic brackets accumulate less S. mutans than conventional ones. However, these findings must be interpreted in conjunction with particularities individual for each patient - such as hygiene and dietary habits, which are components of the multifactorial environment that enables S. Mutans to proliferate and keep retained in the oral cavity.

Antimicrobial and Antiproliferative Activity of Bauhinia forficata Link and Cnidoscolus quercifolius Extracts commonly Used in Folk Medicine.

BACKGROUND: Bauhinia forficata and Cnidoscolus quercifolius plants are commonly used in folk medicine. However, few studies have investigated their therapeutic potential. AIM: Herein, we evaluated the antimicrobial activity of B. forficata and C. quercifolius extracts against microorganisms of clinical relevance and their antiproliferative potential against tumor cells. MATERIALS AND METHODS: The following tests were performed: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)/minimum fungicidal concentration (MFC), inhibition of biofilm adhesion, and effects on cell morphology. Antiproliferative tests were carried out with human keratinocytes and six tumor lines. RESULTS: Bauhinia forficata showed antimicrobial activity only against C. albicans with MIC of 15.62 ug/mL and MFC higher than 2000 ug/mL. It also inhibited biofilm adhesion and caused alterations in cell morphology. Cnidoscolus quercifolius showed no significant activity (MIC > 2.0 mg/mL) against the strains. Bauhinia forficata and C. quercifolius extracts showed cytostatic activity against the tumor cells. CONCLUSION: Bauhinia forficata has promising anti-Cand/da activity and should be further investigated for its therapeutic potential. CLINICAL SIGNIFICANCE: The use of medicinal plants in the treatment of infectious processes has an important function nowadays, due to the limitations of the use of synthetic antibiotics available, related specifically to the microbial resistance emergence.

Heterologous expression of Streptococcus mutans Cnm in Lactococcus lactis promotes intracellular invasion, adhesion to human cardiac tissues and virulence.

In S. mutans, the expression of the surface glycoprotein Cnm mediates binding to extracellular matrix proteins, endothelial cell invasion and virulence in the Galleria mellonella invertebrate model. To further characterize Cnm as a virulence factor, the cnm gene from S. mutans strain OMZ175 was expressed in the non-pathogenic Lactococcus lactis NZ9800 using a nisin-inducible system. Despite the absence of the machinery necessary for Cnm glycosylation, Western blot and immunofluorescence microscopy analyses demonstrated that Cnm was effectively expressed and translocated to the cell wall of L. lactis. Similar to S. mutans, expression of Cnm in L. lactis enabled robust binding to collagen and laminin, invasion of human coronary artery endothelial cells and increased virulence in G. mellonella. Using an ex vivo human heart tissue colonization model, we showed that Cnm-positive strains of either S. mutans or L. lactis outcompete their Cnm-negative counterparts for tissue colonization. Finally, Cnm expression facilitated L. lactis adhesion and colonization in a rabbit model of infective endocarditis. Collectively, our results provide unequivocal evidence that binding to extracellular matrices mediated by Cnm is an important virulence attribute of S. mutans and confirm the usefulness of the L. lactis heterologous system for further characterization of bacterial virulence factors.

Transcriptional and Phenotypic Characterization of Novel Spx-Regulated Genes in Streptococcus mutans.

In oral biofilms, two of the major environmental challenges encountered by the dental pathogen Streptococcus mutans are acid and oxidative stresses. Previously, we showed that the S. mutans transcriptional regulators SpxA1 and SpxA2 (formerly SpxA and SpxB, respectively) are involved in stress survival by activating the expression of classic oxidative stress genes such as dpr, nox, sodA and tpx. We reasoned that some of the uncharacterized genes under SpxA1/A2 control are potentially involved in oxidative stress management. Therefore, the goal of this study was to use Spx-regulated genes as a tool to identify novel oxidative stress genes in S. mutans. Quantitative real-time PCR was used to evaluate the responses of ten Spx-regulated genes during H2O2 stress in the parent and Δspx strains. Transcription activation of the H2O2-induced genes (8 out of 10) was strongly dependent on SpxA1 and, to a lesser extent, SpxA2. In vitro transcription assays revealed that one or both Spx proteins directly regulate three of these genes. The gene encoding the FeoB ferrous permease was slightly repressed by H2O2 but constitutively induced in strains lacking SpxA1. Nine genes were selected for downstream mutational analysis but inactivation of smu127, encoding a subunit of the acetoin dehydrogenase was apparently lethal. In vitro and in vivo characterization of the viable mutants indicated that, in addition to the transcriptional activation of reducing and antioxidant pathways, Spx performs an important role in iron homeostasis by regulating the intracellular availability of free iron. In particular, inactivation of the genes encoding the Fe-S biogenesis SUF system and the previously characterized iron-binding protein Dpr resulted in impaired growth under different oxidative stress conditions, increased sensitivity to iron and lower infectivity in rats. These results serve as an entryway into the characterization of novel genes and pathways that allow S. mutans to cope with oxidative stress.

Activity of in vitro forms of dentifrices containing the hydroalcoholic extract of the ripe fruit of Eugenia uniflora L. (Surinam cherry) on cariogenic bacteria.

The aim of this study was to evaluate the in vitro activity of dentifrices containing the hydroalcoholic extract of the ripe fruit of Eugenia uniflora L. (Surinam cherry) on Streptococcus oralis (ATCC 10557) and Lactobacillus casei (ATCC 7469). Five dentifrices were used: D1: containing hydroalcoholic extract of Eugenia uniflora L.; D2: containing fluoride and hydroalcoholic extract of Eugenia uniflora L.; D3: containing triclosan and hydroalcoholic extract of Eugenia uniflora L; D4: containing triclosan, fluoride and hydroalcoholic extract of Eugenia uniflora L.; D5: positive control (Colgate Total 12). To determine the antibacterial activity, the technique used was the minimum inhibitory concentration by the diffusion method in solid culture medium. At the concentration 0.05 g/mL, the best results were achieved with D1 (18 mm) and D4 (24 mm) on L.casei, and with D3 (19 mm) on S. oralis. The dentifrices D3 and D4 were found to have greater activity on the Streptococcus oralis, while D4 and D1 were found to have greater activity on Lactobaccilus casei. It is concluded that dentifrices with Eugenia uniflora L. have antimicrobial activity, suggesting that clinical trials should be conducted.

Atividade antifúngica de schinus terebinthifolius (Aroeira) sobrecepas do gênero candida / Antifungal activity of schinus terebinthifolius (aroeira) on candida strains

Objetivo: avaliar a atividade antifúngica de Schinus terebinthifolius (aroeira) frente à Candida albicans (ATCC289065), C. tropicalis (ATCC40147) e C. krusei (ATCC40042). Material e Método: o ensaio de atividade antifúngica foi realizado pela técnica de difusão em meio sólido. Em meio de cultura Agar Sabouraud Dextrose (HIMEDIA®, São Paulo, Brasil) foram semeadas as linhagens fúngicas utilizando-se swabs. Em seguida, foram inseridos sobre a superfície do meio, discos absorventes estéreis previamente imersos em 50?L da tintura de Aroeira (10%). Como controle positivo, foram utilizados discos imersos em 50?L de Nistatina (1:100.000UI). As placas foram conduzidas à estufa, à 37º C, por 48 horas. O estudo foi feito em triplicata e analisado estatisticamente através do teste Mann Whitney. Resultados: a aroeira foi responsável pela formação de halos de inibição de crescimento das três cepas em estudo e não houve diferença estatisticamente significante entre o produto e o controle. Sobre C. albicans encontraram-se os maiores halos de inibição de 16 mm para aroeira e 18 mm para o controle (p=0,1642). Frente à C. tropicalis, os maiores halos foram de 16 mm para aroeira e 18 mm para o controle (p=0,8248). Sobre C. krusei, verificaramse halos de 14 mm para o produto e controle (p=0,6193). Conclusão: aroeira apresentou atividade antifúngica equivalente ao controle frente às cepas de Candida avaliadas. Destarte, sugerese a realização de outros estudos microbiológicos, toxicológicos e clínicos para verificar a viabilidade de uso na odontologia.

Objective: To evaluate the antifungal activity of Schinus terebinthifolius (aroeira) on Candida albicans (ATCC289065), C. tropicalis (ATCC40147) and C. krusei (ATCC40042). Materials and Methods: The antifungal activity test was performed through the diffusion technique on solid medium. In culture medium Sabouraud Dextrose Agar (HIMEDIA®,São Paulo,Brazil) were seeded the fungal strains by using swabs. Then, sterilized absorbent discs previously immersed in 50?L of Aroeira (10%) were inserted on the agar surface. As positive control, the disks were immersed in 50?L of Nystatin (1:100,000IU). Then, plates were conducted to an incubator at 37°C for 48 hours. The study was done in triplicate and statistically analyzed by Mann Whitney test. Results: Aroeira was responsible for the formation of halos of growth inhibition of the three strains under study and no statistically significant difference has been found between the product and the control. In relation to C. albicans, were found the largest inhibition zones of 16mm for aroeira and 18mm for the control (p=0.1642). Against C. tropicalis, the largest halos were of 16mm for aroeira and 18mm for the control (p=0.8248). On C. krusei, were verified halos of 14mm for both the product and control (p=0.6193). Conclusion: Aroeira has showed antifungal activity equivalent to the control on the Candida strains evaluated. Thus, it is suggested to carry out further microbiological, toxicological and clinical studies to verify the feasibility of its use in dentistry.