RESUMO
Streptococcus mutans strongly influences the development of pathogenic biofilms associated with dental caries. Our understanding of S. mutans behaviour in biofilms is based on a few well-characterized laboratory strains; however, individual isolates vary widely in genome content and virulence-associated phenotypes, such as biofilm formation and environmental stress sensitivity. Using an ecological biofilm model, we assessed the impact of co-cultivation of several S. mutans isolates with Streptococcus oralis and Actinomyces naeslundii on biofilm composition following exposure to sucrose. The laboratory reference strain S. mutans UA159 and clinical isolates Smu44 (most aciduric), Smu56 (altered biofilm formation) and Smu81 (more sensitive to oxidative stress) were used. Our data revealed S. mutans isolates varied in their ability to compete and become dominant in the biofilm after the addition of sucrose, and this difference correlated with sensitivity to H2 O2 produced by S. oralis. Smu81 was particularly sensitive to H2 O2 and could not compete with S. oralis in mixed-species biofilm, despite forming robust biofilms on its own. Thus, diminished oxidative stress tolerance in S. mutans isolates can impair their ability to compete in complex biofilms, even in the presence of sucrose, which could influence the progression of a healthy biofilm community to one capable of causing disease.
Assuntos
Biofilmes/crescimento & desenvolvimento , Cárie Dentária/microbiologia , Interações Microbianas , Estresse Oxidativo/fisiologia , Streptococcus mutans/fisiologia , Actinomyces/fisiologia , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Peróxido de Hidrogênio/farmacologia , Concentração de Íons de Hidrogênio , Interações Microbianas/fisiologia , Complexos Multienzimáticos/genética , NADH NADPH Oxirredutases/genética , Streptococcus mutans/patogenicidade , Streptococcus oralis/fisiologia , Sacarose/metabolismo , Virulência/fisiologiaRESUMO
The fungus Candida albicans is carried orally and causes a range of superficial infections that may become systemic. Oral bacteria Actinomyces oris and Streptococcus oralis are abundant in early dental plaque and on oral mucosa. The aims of this study were to determine the mechanisms by which S. oralis and A. oris interact with each other and with C. albicans in biofilm development. Spatial distribution of microorganisms was visualized by confocal laser scanning microscopy of biofilms labeled by differential fluorescence or by fluorescence in situ hybridization (FISH). Actinomyces oris and S. oralis formed robust dual-species biofilms, or three-species biofilms with C. albicans. The bacterial components tended to dominate the lower levels of the biofilms while C. albicans occupied the upper levels. Non-fimbriated A. oris was compromised in biofilm formation in the absence or presence of streptococci, but was incorporated into upper biofilm layers through binding to C. albicans. Biofilm growth and hyphal filament production by C. albicans was enhanced by S. oralis. It is suggested that the interkingdom biofilms are metabolically coordinated to house all three components, and this study demonstrates that adhesive interactions between them determine spatial distribution and biofilm architecture. The physical and chemical communication processes occurring in these communities potentially augment C. albicans persistence at multiple oral cavity sites.
Assuntos
Actinomyces/fisiologia , Biofilmes/crescimento & desenvolvimento , Candida albicans/fisiologia , Película Dentária/microbiologia , Streptococcus oralis/fisiologia , Actinomyces/crescimento & desenvolvimento , Actinomyces/metabolismo , Aderência Bacteriana , Biofilmes/classificação , Candida albicans/crescimento & desenvolvimento , Candida albicans/metabolismo , Película Dentária/diagnóstico por imagem , Placa Dentária/microbiologia , Humanos , Hibridização in Situ Fluorescente/métodos , Interações Microbianas , Microscopia Confocal , Boca/microbiologia , Mucosa Bucal/microbiologia , Streptococcus oralis/crescimento & desenvolvimento , Streptococcus oralis/metabolismoRESUMO
OBJECTIVE: The aim of this study was to examine in vivo the initial bacterial adhesion on titanium implants with different surface treatments. DESIGN: Ten subjects wore oral splints containing machined pure titanium disks (Ti-M), acid-etched titanium (Ti-AE) and anodized and laser irradiated disks (Ti-AL) for 24h. After this period, disks were removed from the splints and adherent bacteria were quantified by an enzymatic assay to assess total viable bacteria and by Real Time PCR to evaluate total bacteria and Streptococcus oralis levels. Additionally, the initial adherent microorganisms were visualized by scanning electron microscopy (SEM). Titanium surface morphology was verified using SEM, and roughness was evaluated by profilometer analysis. RESULTS: Regarding titanium surface roughness, Ti-AL (1.423±0.397) showed significantly higher Ra values than did Ti-M (0.771±0.182) and Ti-AE (0.735±0.196) (p<0.05, ANOVA - Tahame). Ti-AE and Ti-AL presented roughened micro-structure surfaces characterized by open pores, whereas Ti-M showed long grooves alternating with planed areas. Comparing the Ti-M, Ti-AE and Ti-AL groups for viable bacteria (MTT assay), total bacteria and S. oralis quantification (qPCR), no significant differences were observed among these three groups (p>0.05, ANOVA - Tahame). SEM images showed similar bacterial adhesion on the three titanium surfaces, predominantly characterized by cocci and several bacilli, indicating an initial colonization of the oral biofilm. CONCLUSION: In conclusion, roughness and microtopography did not stimulate initial biofilm formation on titanium surfaces with different surface treatments.
Assuntos
Biofilmes/crescimento & desenvolvimento , Implantes Dentários/microbiologia , Titânio , Condicionamento Ácido do Dente/métodos , Aderência Bacteriana , Técnicas Eletroquímicas , Humanos , Lasers , Teste de Materiais , Microscopia Eletrônica de Varredura , Reação em Cadeia da Polimerase em Tempo Real , Streptococcus oralis/fisiologia , Propriedades de SuperfícieRESUMO
AIM: To assess the effect of the daily ingestion of a mixture of probiotics on the amount of Streptococcus mutans in the oral cavity of preschool-age patients with a high risk of caries. MATERIALS AND METHODS: Forty patients, aged between 4 and 6 years, with a high risk of dental caries were included in this pilot study. Patients were randomly assigned to two study groups: the Experimental Group (A) included patients who brushed their teeth and used fluoridated toothpaste in addition to consuming probiotics daily, and the Control Group (B) inclused patients who brushed their teeth and used fluoridated toothpaste but did not consume probiotics. Using the CariScreen, the microorganism count was determined at different times: baseline, 7, 14, 21 and 30 days. To identify the differences between both groups, a Mann-Whitney U test was performed, with a significance level of 0.05. RESULTS: It was observed that both groups showed similar microbial counts at the beginning of the trial (p>0.05), and a significant decrease in the count at the end of the study was found in the experimental group (p<0.05) 15 days after suspending ingestion. CONCLUSION: We found a significant reduction of RLU values in preschool children who ingested the tested probiotics in relation to the baseline values and 15 days after ceasing consumption.