Demystifying interactions between micro organisms in oral candidiasis biofilm: the key to enhancing treatments

Introduction: candida albicans is a fungal pathogen that can provoke diseases ranging from oral infections to life-threatening systemic disorders. It is now recognized that oral bacteria, such as the genus Streptococcus, establish synergistic relationships with C. albicans, which could potentially increase the fungi's virulence and pathogenicity. Objective: this narrative review aimed to discuss the Candida-Streptococcus mechanisms of interactions and their contribution to increasing oral candidiasis severity. In addition, it provides a background of biofilm formation and potential therapeutical targets. Sources of Data: searches for papers in English were performed in the Pubmed database until May 2022. MeSH and free terms related to the field were used. In vitro studies were selected, tabulated, and qualitative and quantitative data were analyzed descriptively. Synthesis of Data: among the early colonizers bacteria, evidence pointed out that S. gordonnii and S. oralis have major implications in oral candidiasis, in which mixed biofilms increase the infection severity and challenge the host's defense. On the other hand, the outcomes of the interaction between C. albicans and S. mitis, S. sanguinis, or S. mutans remain little explored in the oral candidiasis scenario, albeit evidence pointed out an enhanced fungus population and virulence factors. Conclusion: overall, considering the polymicrobial profile of the infection and the potential to increase Candida-related disease severity, therapeutical strategies should also consider bacteria management.

Introdução: candida albicans é um patógeno fúngico que pode provocar doenças que variam de infecções orais a distúrbios sistêmicos com risco de vida. Hoje se reconhece que as bactérias orais, como o gênero Streptococcus, estabelecem relações sinérgicas com C. albicans, o que pode potencialmente aumentar a virulência e patogenicidade do fungo. Objetivo: esta revisão narrativa teve como objetivo discutir os mecanismos de interação Candida-Streptococcus e sua contribuição para o agravamento da candidíase oral. Além disso, fornece uma breve explanação sobre a formação do biofilme e potenciais alvos terapêuticos. Fonte dos dados: foi realizada pesquisa na base de dados Pubmed para a busca de artigos publicados em Inglês até maio de 2022. Para isso, foram utilizados descritores relacionados ao tema. Estudos in vitro foram selecionados, tabulados e seus resultados quantitativos e qualitativos analisados descritivamente. Síntese dos dados: entre as bactérias denominadas colonizadores iniciais, evidências apontam que S. gordonnii e S. oralis têm implicações importantes na candidíase oral, na qual biofilmes mistos aumentam a gravidade da infecção e desafiam a defesa do hospedeiro. Por outro lado, os desfechos das interações entre C. albicans e S. mitis, S. sanguinis ou S. mutans permanecem pouco explorados no cenário da candidíase oral, apesar de evidências apontarem um aumento dapopulação fúngica e de fatores de virulência. Conclusão: de maneira geral, considerando o perfil polimicrobiano da infecção e o potencial agravamento das doenças provocadas por Candida spp, as estratégias terapêuticas não devem estar focadas apenas no fungo, mas também devem considerar o manejo da bactéria.

Antibacterial and Antiadhesion Effects of Psidium guajava Fractions on a Multispecies Biofilm Associated with Periodontitis

Abstract Objective: To assess the antibacterial activity of Psidium guajava fractions and their effects on adhesion of a multispecies biofilm consisting of Streptococcus gordonii, Fusobacterium nucleatum, and Porphyromonas gingivalis in vitro. Material and Methods: Guava leaves were obtained from the mountains of northern Peru, where they grow wild and free of pesticides. The antimicrobial activity of 25 mg/mL petroleum ether, 25 mg/mL dichloromethane and 25 mg/mL methanol fractions of P. guajava was evaluated by measuring inhibition halos, as well as the effect on the adhesion of multispecies biofilms at 4, 7 and 10 days of growth by measuring the optical density. In addition, antimicrobial susceptibility was compared using the Kruskal-Wallis test and its multiple comparison tests, and differences in mean biofilm adhesion between each fraction were assessed by repeated measures analysis and the Tukey multiple comparison test. Results: The rank-based Kruskal-Wallis test highlighted differences in the effects of the fractions on the zone of inhibition for each oral bacterium, including S. gordonii (p=0.000), F. nucleatum (p=0.000), and P. gingivalis (p=0.000), the Tukey test showed that the group treated with 0.12% chlorhexidine exhibited the least amount of adhesion, followed by the group treated with the 1.56 mg/mL methanol fraction. Conclusion: The methanol fraction of P. guajava had an antibacterial effect on S. gordonii and P. gingivalis, and the 1.56 mg/mL methanol fraction decreased biofilm adhesion.

Aplicação do plasma de baixa temperatura sob pressão atmosférica no controle de biofilmes cariogênicos / Application of low temperature plasma under atmospheric pressure in the control cariogenic biofilms

O objetivo geral do presente estudo foi avaliar a aplicação dos jatos de plasma de baixa temperatura sob pressão atmosférica (PBTPA) produzidos por gás de argônio e hélio como gases de trabalho, no controle de biofilmes cariogênicos. Para tanto, foram estabelecidos os parâmetros físicos dos PBTPA gerados com argônio e hélio que se mostraram efetivos frente a biofilmes mono, dual e polimicrobianos compostos por combinações das espécies Streptococcus mutans, Streptococcus gordonii, Streptococcus sanguinis, Lactobacillus casei, Lactobacillus acidophilus, Candida albicans e Actinomyces naeslundii. Os biofilmes mono, dual e multi-espécies foram submetidos ao tratamento com PBTPA produzidos por dois dispositivos diferentes, um obtido comercialmente (kINPen09®) que usou argônio como gás de trabalho, e outro protótipo desenvolvido pela FEG-UNESP (Faculdade de Engenharia de Guaratinguetá) que usou hélio. Análises quantitativas e microscópicas (confocal, microscopia eletrônica de varredura) foram realizadas. Foi incluído controle negativo (sem tratamento), positivo (clorexidina 0,12%) e controle de gás, utilizando apenas fluxo de gás, sem produzir plasma. Além disso, os efeitos celulares do PBTPAargônio e hélio sobre biofilme dual e multi-espécies também foram analisados em microscopia eletrônica de varredura e microscopia de varredura a laser confocal. Todos os ensaios foram realizados em triplicata em três experimentos independentes. Os resultados foram tabulados e analisados quanto à distribuição. A seguir, os testes estatísticos mais adequados foram selecionados. O nível de significância foi de 5%. Os resultados obtidos para os tratamentos dos biofilmes mono, dual ou multi-espécies com PBTPA-argônio e hélio foram todos significativos em comparação ao controle negativo em todos os tempos analisados. Para PBTPA-argônio, não houve recuperação de S. gordonii e S. sanguinis em todos tempos analisados. Para PBTPA-hélio, os melhores resultados foram obtidos em 5 e 7 minutos de exposição dos biofilmes ao PBTPA. Finalmente, tanto o dispositivo gerador de PBTPA que trabalhou com gás argônio quanto o dispositivo que trabalhou com gás hélio, demonstraram resultados promissores e poderão contribuir para o desenvolvimento de novos protocolos de Odontologia de Intervenção Mínima. (AU) The general objective of this study was to evaluate the application of lowtemperature plasma under atmospheric pressure (PBTPA) of argon and helium flow, in the control of cariogenic biofilms. For this, the effective physical parameters of PBTPA-argon and helium in mono, dual and polymicrobial biofilms composed of combinations of the species Streptococcus mutans, Streptococcus gordonii, Streptococcus sanguinis, Lactobacillus casei, Lactobacillus acidophilus, Candida albicans and Actinomyces naeslundii were established. The multi-species biofilms were treated by different PBTPA generating devices, one obtained commercially (kINPen09®) that used argon as working gas, and another prototype developed by FEG-UNESP (Faculdade de Engenharia de Guaratinguetá) that used helium as working gas. Quantitative and microscopic analyzes (confocal, scanning electron microscopy) were performed. Negative control (no treatment), positive control (chlorhexidine 2%) and gas control (argon) were included. Besides that, cellular effects of PBTPA-argon and helium on dual and multi-species biofilms were analyzed by scanning electron microscopy (SEM) and confocal laser scanning microscopy. The results obtained for the treatments of mono, dual or multispecies biofilms with both PBTPA-argon and helium were all significant when compared to the negative control at all times analyzed. For PBTPA-argon, there was no recovery of S. gordonii and S. sanguinis at all analyzed times. For PBTPA-helium, the best results were obtained at 5 and 7 min of exposure of biofilms to PBTPA. All the tests were carried out in triplicate in three independent experiments. The results are tabulated and analyzed in terms of distribution. Next, the most suitable statistical tests were selected. The level of significance was 5%. The results obtained for the treatments of mono, dual or multi-species biofilms with PBTPA-argon and helium were all significant compared to the negative control at all analyzed times. Finally, both PBTPA generating could contribute to the development of new protocols for Minimal Intervention Dentistry (AU)

O objetivo geral do presente estudo foi avaliar a aplicação dos jatos de plasma de baixa temperatura sob pressão atmosférica (PBTPA) produzidos por gás de argônio e hélio como gases de trabalho, no controle de biofilmes cariogênicos. Para tanto, foram estabelecidos os parâmetros físicos dos PBTPA gerados com argônio e hélio que se mostraram efetivos frente a biofilmes mono, dual e polimicrobianos compostos por combinações das espécies Streptococcus mutans, Streptococcus gordonii, Streptococcus sanguinis, Lactobacillus casei, Lactobacillus acidophilus, Candida albicans e Actinomyces naeslundii. Os biofilmes mono, dual e multi-espécies foram submetidos ao tratamento com PBTPA produzidos por dois dispositivos diferentes, um obtido comercialmente (kINPen09®) que usou argônio como gás de trabalho, e outro protótipo desenvolvido pela FEG-UNESP (Faculdade de Engenharia de Guaratinguetá) que usou hélio. Análises quantitativas e microscópicas (confocal, microscopia eletrônica de varredura) foram realizadas. Foi incluído controle negativo (sem tratamento), positivo (clorexidina 0,12%) e controle de gás, utilizando apenas fluxo de gás, sem produzir plasma. Além disso, os efeitos celulares do PBTPAargônio e hélio sobre biofilme dual e multi-espécies também foram analisados em microscopia eletrônica de varredura e microscopia de varredura a laser confocal. Todos os ensaios foram realizados em triplicata em três experimentos independentes. Os resultados foram tabulados e analisados quanto à distribuição. A seguir, os testes estatísticos mais adequados foram selecionados. O nível de significância foi de 5%. Os resultados obtidos para os tratamentos dos biofilmes mono, dual ou multi-espécies com PBTPA-argônio e hélio foram todos significativos em comparação ao controle negativo em todos os tempos analisados. Para PBTPA-argônio, não houve recuperação de S. gordonii e S. sanguinis em todos tempos analisados. Para PBTPA-hélio, os melhores resultados foram obtidos em 5 e 7 minutos de exposição dos biofilmes ao PBTPA. Finalmente, tanto o dispositivo gerador de PBTPA que trabalhou com gás argônio quanto o dispositivo que trabalhou com gás hélio, demonstraram resultados promissores e poderão contribuir para o desenvolvimento de novos protocolos de Odontologia de Intervenção Mínima. (AU)

Diagnóstico de carcinoma urotelial durante estudio de bacteremia por Streptococcus gordonii / Diagnosis of uroepithelial carcinoma during bacteremia by Streptococcus gordonii

Resumen La bacteremia por Streptococcus gordonii es infrecuente. Su aislamiento en hemocultivo traduce alta significancia clínica y debe dirigir el abordaje diagnóstico hacia la búsqueda de entidades subyacentes como neoplasias hematológicas, cardiopatías valvulares, neumonía, alteraciones estructurales de cabeza y cuello, inmunosupresión, y otras condiciones asociadas. No se han identificado reportes en pacientes con neoplasia de vías urinarias como posible condicionante de bacteremia por este agente. Se describe el caso de un paciente que, durante el estudio de bacteremia por este microorganismo, fue diagnosticado de carcinoma urotelial de alto grado.

Abstract Streptococcus gordonii bacteremia is rare. Its isolation in blood culture translates into high clinical significance and the diagnostic approach should be directed towards the search for underlying entities such as hematologic malignancies, valvular heart disease, pneumonia, structural changes of the head and neck, immunosuppression and other related conditions. No reports have been identified in patients with urinary tract neoplasia as a possible condition of bacteremia by this agent. The case of a patient who was diagnosed with high-grade urothelial carcinoma during the study of bacteremia by this microorganism is described.

Identification of Proteins Associated with the Formation of Oral Biofilms

ABSTRACT Objective: To identify proteins associated with the formation of Streptococcus gordonii and Fusobacterium nucleatum biofilms. Material and Methods: Biofilms composed of two bacterial species, S. gordonii and F. nucleatum, were cultured for 1, 4, 7, and 10 days. The presence of both species was confirmed via amplification of the srtA and radD genes using real-time PCR. The concentrations of proteins associated with the biofilms and individual species were quantified using Western blotting. Results: The protein profiles of S. gordonii and F. nucleatum from individual cultures determined using one-dimensional electrophoresis revealed proteins found in S. gordonii and in F. nucleatum. Ct and reciprocal Ct values were determined for the exposed S. gordonii and F. nucleatum biofilms. Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) protein was detected in biofilms and F. nucleatum, whereas HSP40 protein was present only in biofilms after 7 and 10 days of formation. Conclusion: HSP40 was detected only in the formed biofilms; thus, HSP40 is an essential proteins for adhesion.

Antimicrobial effect of toothbrush with light emitting diode on dental biofilm attached to zirconia surface: an in vitro study

PURPOSE: The purpose of this study was to evaluate the antimicrobial effects of a toothbrush with light-emitting diodes (LEDs) on periodontitis-associated dental biofilm attached to a zirconia surface by static and dynamic methods. MATERIALS AND METHODS: Zirconia disks (12 mm diameter, 2.5 mm thickness) were inserted into a 24-well plate (static method) or inside a Center for Disease Control and Prevention (CDC) biofilm reactor (dynamic method) to form dental biofilms using Streptococcus gordonii and Fusobacterium nucleatum. The disks with biofilm were subdivided into five treatment groups-control, commercial photodynamic therapy (PDT), toothbrush alone (B), brush with LED (BL), and brush with LED+erythrosine (BLE). After treatment, the disks were agitated to detach the bacteria, and the resulting solutions were spread directly on selective agar. The number of viable bacteria and percentage of bacterial reduction were determined from colony counts. Scanning electron microscopy (SEM) was performed to visualize alterations in bacterial morphology. RESULTS: No significant difference in biofilm formation was observed between dynamic and static methods. A significant difference was observed in the number of viable bacteria between the control and all experimental groups (P < 0.05). The percentage of bacterial reduction in the BLE group was significantly higher than in the other treated groups (P < 0.05). SEM revealed damaged bacterial cell walls in the PDT, BL, and BLE groups, but intact cell walls in the control and B groups. CONCLUSION: The findings suggest that an LED toothbrush with erythrosine is more effective than other treatments in reducing the viability of periodontitis-associated bacteria attached to zirconia in vitro.

Antimicrobial activity of mouth rinses against bacteria that initially colonizes dental's surface / Atividade antimicrobiana de enxaguatórios bucais sobre bactérias que iniciam a colonização das superfícies dentais

Abstract Introduction Much advertising in mouthwash is conveyed in all media appealing to the anti-plaque effect and rendering a disservice to the community. Mouth rinses are available over-the-count and differ on their compositions and antimicrobial effectiveness. Objective In this study, we evaluated the antimicrobial activity of 35 widely available mouth rinses against bacterial species involved in initiation of dental biofilm - Streptococcus gordonii, Streptococcus mitis, Streptococcus oralis, Streptococcus salivarius, and Streptococcus sanguinis. Material and method The Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) of the evaluated mouth rinses were determined according to the Clinical & Laboratory Standards Institute protocols. Data were submitted to Kruskal-Wallis test and Mann-Whitney post hoc (α=0.05). Result About 70% of the mouth rinses achieved high antibacterial activity and 30%, a low antibacterial activity against all the species tested. The most ineffective mouth rinse showed antibacterial activity (MIC) at 1:1 dilution, while the most effective showed activity even at 1:2048 dilution, which may imply prolonged effect in the mouth. About 51% of mouth rinses showed bactericidal activity, and it was verified that cetylpyridinium chloride or chlorhexidine digluconate containing in the formulation were associated with the highest activity. Conclusion Most - but not all - mouth rinses commercially available are effective in inhibiting in vitro initial colonizers of dental surfaces.

Resumo Introdução Muita publicidade sobre enxaguatórios bucais é veiculada em todos os meios de comunicação apelando para o efeito anti-placa e prestando um desserviço à comunidade. Grande quantidade de enxaguatórios bucais está disponível no mercado e estes diferem em suas composições e eficácia antimicrobiana. Objetivo Neste estudo, avaliamos a atividade antimicrobiana de 35 enxaguatórios bucais amplamente disponíveis contra espécies bacterianas envolvidas na iniciação do biofilme dental - Streptococcus gordonii, Streptococcus mitis, Streptococcus oralis, Streptococcus salivarius e Streptococcus sanguinis. Material e método A Concentração Inibitória Mínima (CIM) e a Concentração Bactericida Mínima (CBM) dos enxaguatórios avaliados foram determinadas de acordo com os protocolos do Clinical & Laboratory Standards Institute. Os dados foram submetidos ao teste Kruskal-Wallis e Mann-Whitney post hoc (α=0,05). Resultado Aproximadamente 70% dos enxaguatórios bucais alcançaram alta atividade antibacteriana e 30%, baixa atividade antibacteriana contra todas as espécies testadas. O enxaguatório bucal mais ineficaz mostrou atividade antibacteriana (CIM) na diluição de 1:1, enquanto a mais eficaz mostrou atividade mesmo na diluição de 1:2048, o que pode implicar em efeito prolongado na boca. Cerca de 51% dos enxaguatórios bucais apresentaram atividade bactericida, e verificou-se que formulações contendo cloreto de cetilpiridíneo ou digluconato de clorexidina estavam associados à maior atividade. Conclusão A maior parte - mas não todos - dos enxaguatórios bucais comercialmente disponíveis são eficazes na inibição de colonizadores iniciais de superfícies dentárias in vitro.

Endocarditis infecciosa secundaria a Streptococcus gordonii, complicada con aneurisma y fístula en válvula mitral: Reporte de caso / Infective endocarditis due to Streptococcus gordonii complicated with an aneurism and mitral valve fistula.: Case report

Entre las bacterias poco comunes que causan Endocarditis infecciosa (EI), se encuentran el Streptococcus gordonii, conocido por su habilidad de colonizar y dañar las válvulas cardiacas. Asimismo, se conoce que el hallazgo de aneurisma complicado con fístula intracardiaca es infrecuente en EI, sólo se presenta en el 1,6% de pacientes. Se reporta el caso de un varón de 58 años con EI por Streptococcus gordonii complicada con aneurisma y fístula en la válvula mitral. (AU)

Streptococcus gordonii is a rare cause of infective endocarditis (IE) known for its ability to colonize and damage cardiac valves. Moreover, it is known that complicated aneurism with intracardiac fistula is an infrequent finding in IE, reported in1.6% of patients. We report the case of a 58 year old male patient with IE infected with Streptococcus gordonii and complicated with an aneurism and mitral valve fistula. (AU)

Biofilm formation on denture base resin including ZnO, CaO, and TiO₂ nanoparticles

PURPOSE: This laboratory study aimed to investigate the effect of doping an acrylic denture base resin material with nanoparticles of ZnO, CaO, and TiO₂ on biofilm formation. MATERIALS AND METHODS: Standardized specimens of a commercially available cold-curing acrylic denture base resin material were doped with 0.1, 0.2, 0.4, or 0.8 wt% commercially available ZnO, CaO, and TiO₂ nanopowder. Energy dispersive X-ray spectroscopy (EDX) was used to identify the availability of the nanoparticles on the surface of the modified specimens. Surface roughness was determined by employing a profilometric approach; biofilm formation was simulated using a monospecies Candida albicans biofilm model and a multispecies biofilm model including C. albicans, Actinomyces naeslundii, and Streptococcus gordonii. Relative viable biomass was determined after 20 hours and 44 hours using a MTT-based approach. RESULTS: No statistically significant disparities were identified among the various materials regarding surface roughness and relative viable biomass. CONCLUSION: The results indicate that doping denture base resin materials with commercially available ZnO, CaO, or TiO₂ nanopowders do not inhibit biofilm formation on their surface. Further studies might address the impact of varying particle sizes as well as increasing the fraction of nanoparticles mixed into the acrylic resin matrix.

Effect of Sub-minimal Inhibitory Concentration of Chlorhexidine on Biofilm Formation and Coaggregation of Early Colonizers, Streptococci and Actinomycetes

Chlorhexidine has long been used in mouth washes for the control of dental caries, gingivitis and dental plaque. Minimal inhibitory concentration (MIC) is the lowest concentration of an antimicrobial substance to inhibit the growth of bacteria. Concentrations lower than the MIC are called sub minimal inhibitory concentrations (sub-MICs). Many studies have reported that sub-MICs of antimicrobial substances can affect the virulence of bacteria. The aim of this study was to investigate the effect of sub-MIC chlorhexidine on biofilm formation and coaggregation of oral early colonizers, such as Streptococcus gordonii, Actinomyces naeslundii and Actinomyces odontolyticus. The biofilm formation of S. gordonii, A. naeslundii and A. odontolyticus was not affected by sub-MIC chlorhexidine. However, the biofilm formation of S. mutans increased after incubation with sub-MIC chlorhexidine. In addition, cell surface hydrophobicity of S. mutans treated with sub-MIC of chlorhexidine, decreased when compared with the group not treated with chlorhexidine. However, significant differences were seen with other bacteria. Coaggregation of A. naeslundii with A. odontolyticus reduced by sub-MIC chlorhexidine, whereas the coaggreagation of A. naeslundii with S. gordonii remained unaffected. These results indicate that sub-MIC chlorhexidine could influence the binding properties, such as biofilm formation, hydrophobicity and coaggregation, in early colonizing streptococci and actinomycetes.

Evaluation of Swallowing in Infants with Congenital Heart Defect

Introduction Surgical repair of congenital heart disease in the first years of life compromises the coordination of the suction, breathing, and swallowing functions. Objective To describe the alterations in swallowing found in infants with congenital heart defect during their hospitalization. Methods Prospective, cross-sectional study in a reference hospital for heart disease. The sample consisted of 19 postsurgical patients who underwent an evaluation of swallowing. The infants included were younger than 7 months and had a diagnosis of congenital heart defect and suspected swallowing difficulties. Results Of the 19 infants with congenital heart defect, the median age was 3.2 months. A significant association was found between suction rhythm and dysphagia (p = 0.036) and between oral-motor oral feeding readiness and dysphagia (p = 0.014). Conclusions The data suggest that dysphagia often occurs after surgery in infants with congenital heart defect. Infants with congenital heart defect had very similar behavior to preterm infants in terms of oral feeding readiness. .

Effects of growth stages and pH value on the expression of autolytic enzyme atIS gene of Streptococcus gordonii / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aimed to detect the difference in the expression levels of autolysin atIS gene of Streptococcus gordonii (S. gordonii) at different growth stages and pH values, as well as to analyze the factors regulating atlS gene expression in S. gordonii.</p><p><b>METHODS</b>S. gordonii wild strains (ATCC 35105) were collected at different growth stages (early exponential phase, mid-exponential phase, late exponential stage, and platform stage) and pH values (pH 7 and pH 5.5), and total RNA was extracted by using a conventional method. Fluorescence quantitative polymerase chain reaction (FQ-PCR) was used to measure the relative mRNA expression of atlS gene, with bacterial 16S rRNA as internal reference, for a comparison of the mRNA levels of atlS gene expression in S.gordonii at different growth stages and pH values.</p><p><b>RESULTS</b>FQ-PCR results showed that atlS gene expression increased with gradually increasing growth stage under neutral conditions and was higher than that under acidic conditions (P < 0.05).</p><p><b>CONCLUSION</b>The atlS gene expression in S. gordonii is influenced by growth stage and pH value factors.</p>

A Case of Piriform Sinus Fistula Complicated with Suppurative Thyroiditis Treated with Chemocauterization Using Trichloroacetic Acid / 계명의대학술지

A 23 months-old girl visited the hospital because of fever and left neck mass. She was diagnosed as acute suppurative thyroiditis with piriform sinus fistula. Thyroid sonography showed perithyroidal abscess formation and thyroid scan showed decreased uptake of Tc-99m pertechnate of both thyroid glands. Magnetic resonance imaging of neck showed abscess cavity extending to the swollen left thyroid gland. And there was tiny fistula between thyroid and piriform sinus in the barium esophagogram. Streptococcus gordonii was isolated on needle aspiration culture. We report a case of piriform sinus fistula of the neck complicated with suppurative thyroiditis. The fistula was treated with chemocauterization using trichloroacetic acid.

Effect of Sub-Minimal Inhibitory Concentrations of Antibiotics on Biofilm Formation and Coaggregation of Streptococci and Actinomycetes

Minimal inhibitory concentration (MIC) is the lowest antibiotic concentration that inhibits the visible growth of bacteria. Sub-minimal inhibitory concentration (Sub-MIC) is defined as the concentration of an antimicrobial agent that does not have an effect on bacterial growth but can alter bacterial biochemistry, thus reducing bacterial virulence. Many studies have confirmed that sub-MICs of antibiotics can inhibit bacterial virulence factors. However, most studies were focused on Gram-negative bacteria, while few studies on the effect of sub-MICs of antibiotics on Gram-positive bacteria. In this study, we examined the influence of sub-MICs of doxycycline, tetracycline, penicillin and amoxicillin on biofilm formation and coaggregation of Streptococcus gordonii, Streptococcus mutans, Actinomyces naeslundii, and Actinomyces odontolyticus. In this study, incubation with sub-MIC of antibiotics had no effect on the biofilm formation of S. gordonii and A. naeslundii. However, S. mutans showed increased biofilm formation after incubation with sub-MIC amoxicillin and penicillin. Also, the biofilm formation of A. odontolyticus was increased after incubating with sub-MIC penicillin. Coaggregation of A. naeslundii with S. gordonii and A. odontolyticus was diminished by sub-MIC amoxicillin. These observations indicated that sub-MICs of antibiotics could affect variable virulence properties such as biofilm formation and coaggregation in Gram-positive oral bacteria.

A periodontitis-associated multispecies model of an oral biofilm

PURPOSE: While single-species biofilms have been studied extensively, we know notably little regarding multispecies biofilms and their interactions. The purpose of this study was to develop and evaluate an in vitro multispecies dental biofilm model that aimed to mimic the environment of chronic periodontitis. METHODS: Streptococcus gordonii KN1, Fusobacterium nucleatum ATCC23726, Aggregatibacter actinomycetemcomitans ATCC33384, and Porphyromonas gingivalis ATCC33277 were used for this experiment. The biofilms were grown on 12-well plates with a round glass slip (12 mm in diameter) with a supply of fresh medium. Four different single-species biofilms and multispecies biofilms with the four bacterial strains listed above were prepared. The biofilms were examined with a confocal laser scanning microscope (CLSM) and scanning electron microscopy (SEM). The minimum inhibitory concentrations (MIC) for four different planktonic single-species and multispecies bacteria were determined. The MICs of doxycycline and chlorhexidine for four different single-species biofilms and a multispecies biofilm were also determined. RESULTS: The CLSM and SEM examination revealed that the growth pattern of the multispecies biofilm was similar to those of single-species biofilms. However, the multispecies biofilm became thicker than the single-species biofilms, and networks between bacteria were formed. The MICs of doxycycline and chlorhexidine were higher in the biofilm state than in the planktonic bacteria. The MIC of doxycycline for the multispecies biofilm was higher than were those for the single-species biofilms of P. gingivalis, F. nucleatum, or A. actinomycetemcomitans. The MIC of chlorhexidine for the multispecies biofilm was higher than were those for the single-species biofilms of P. gingivalis or F. nucleatum. CONCLUSIONS: To mimic the natural dental biofilm, a multispecies biofilm composed of four bacterial species was grown. The 24-hour multispecies biofilm may be useful as a laboratory dental biofilm model system.

Identification of Antimicrobial Peptide Hexamers against Oral Pathogens through Rapid Screening of a Synthetic Combinatorial Peptide Library

A positional scanning synthetic peptide combinatorial library (PS-SCL) was screened in order to identify antimicrobial peptides against the cariogenic oral bacteria, Streptococcus mutans. Activity against Streptococcus gordonii and Aggregatibacter actinomycetemcomitans was also examined. The library was comprised of six sub-libraries with the format O(1-6)XXXXX-NH2, where O represents one of 19 amino acids (excluding cysteine) and X represents equimolar mixture of these. Each sub-library was tested for antimicrobial activity against S. mutans and evaluated for antimicrobial activity against S. gordonii and A. actinomycetemcomitans. The effect of peptides was observed using transmission electron microscopy (TEM). Two semi-mixture peptides, RXXXXN-NH2 (pep-1) and WXXXXN-NH2 (pep-2), and one positioned peptide, RRRWRN-NH2 (pep-3), were identified. Pep-1 and pep-2 showed significant antimicrobial activity against Gram positive bacteria (S. mutans and S. gordonii), but not against Gram negative bacteria (A. actinomycetemcomitans). However, pep-3 showed very low antimicrobial activity against all three bacteria. Pep-3 did not form an amphiphilic alpha-helix, which is a required structure for most antimicrobial peptides. Pep-1 and pep-2 were able to disrupt the membrane of S. mutans. Small libraries of biochemically-constrained peptides can be used to generate antimicrobial peptides against S. mutans and other oral microbes. Peptides derived from such libraries may be candidate antimicrobial agents for the treatment of oral microorganisms.

Binding of the Streptococcus gordonii Surface Glycoprotein Hsa to alpha(2-3) Linked Sialic Acid Residues on Fibronectin

The binding of microorganisms to platelets is a critical step in the development of infective endocarditis. In Streptococcus gordonii, this binding is mediated in part by serine-rich repeat proteins, which interact directly with sialic acid residues located on GPIIb receptors in the platelet membrane. In this study, we found that S. gordonii DL1 strain binds to platelets through bridging between sialic acid residue of fibronectin and serine-rich repeat protein (Hsa). Pretreatment of fibronectin with sialidases specific for alpha(2-3)-linked sialic acids was shown to significantly inhibit binding of the DL1 strain and the binding region(BR) of Hsa protein. Similarly, pre-incubation of bacteria or BR of Hsa with alpha(2-3)-sialyl-N-acetyllactosamine blocked fibronectin binding in the DL1 strain, but not the M99 strain. Together, these data show that the alpha(2-3)-sialic acid residues of fibronectin play an important role in the binding of S. gordonii DL1 to fibronectin through interactions with the Hsa receptor. This interaction is thought to play an important role in the development of pathogenic endocarditis, and may represent an important therapeutic target for the treatment of infective endocarditis.

Streptococcus Gordonii Endophthalmitis after Pneumaic Retinopexy

PURPOSE: To report a case of streptoococcus gordonii endophthalmitis after pneumaic retinopexy in a patient with rhegmatogenous retinal detachment. CASE SUMMARY: A 40-year-old man presented with a right eye macula-on retinal detachment extending from 9 to 1 o'clock with one-clock-hour hole at 11 o'clock. After sterilizing with a Betadine solution, 0.6 cc 100% SF6 gas was injected into the vitreous through the pars plana at 11 o'clock. Two days after the injection, eyeball pain, cell and flare, and pupillary membrane developed. Under the diagnosis of endophthalmitis, vitreous tap and intravitreous vancomycin (1.0 mg/0.1 cc) and ceftazime (2.0 mg/0.1 cc) were administered. However the symptoms and signs worsened, so vitrectomy was performed, and intravitrous injections of silicone, vancomycin and ceftazime were administered. Streptococcus gordonii was identified from the excised vitreous. Visual acuity was light perception due to severe retinal necrosis. CONCLUSIONS: In cases of endophthalmitis after pneumatic retinopexy even with meticulous sterilization, a prompt operation is necessary to prevent extensive retinal damage and visual loss due to the possibility of pathogen growth other than conjunctival normal flora.

Development of Streptococcus sanguinis-, Streptococcus parasanguinis-, and Streptococcus gordonii-PCR Primers Based on the Nucleotide Sequences of Species-specific DNA Probes Screened by Inverted Dot Blot Hybridization

The objective of this study was to develop PCR primers that are specific for Streptococcus sanguinis, Streptococcus parasanguinis, and Streptococcus gordonii. We designed the S. sanguinis-, S. parasanguinis-, and S. gordonii-specific primers, Ssa21-F3/Ssa21-R2, Spa17-F/Spa17-R, and Sgo41-F1/Sgo41-R1 respectively, based on the nucleotide sequences of the Ssa21, Spa17, and Sgo41 DNA probes that were screened using inverted dot blot hybridization (IDBH). The species-specificity of these primers was assessed against 43 strains of mitis group streptococci, including clinical strains of S. sanguinis, S. parasanguinis, and S. gordonii. The resulting PCR data revealed that species-specific amplicons had been obtained from all strains of the target species tested, and that none of these amplicons occurred in any other strains from other species. These results suggest that the Ssa21-F3/Ssa21-R2, Spa17-F/Spa17-R, and Sgo41-F1/Sgo41-R1 primers may be useful in detecting S. sanguinis, S. parasanguinis, and S. gordonii at the species level, respectively.

Tyrosine phosphorylation and bacterial virulence / 国际口腔科学杂志·英文版

Protein phosphorylation on tyrosine has emerged as a key device in the control of numerous cellular functions in bacteria. In this article, we review the structure and function of bacterial tyrosine kinases and phosphatases. Phosphorylation is catalyzed by autophosphorylating adenosine triphosphate-dependent enzymes (bacterial tyrosine (BY) kinases) that are characterized by the presence of Walker motifs. The reverse reaction is catalyzed by three classes of enzymes: the eukaryotic-like phosphatases (PTPs) and dual-specific phosphatases; the low molecular weight protein-tyrosine phosphatases (LMW-PTPs); and the polymerase-histidinol phosphatases (PHP). Many BY kinases and tyrosine phosphatases can utilize host cell proteins as substrates, thereby contributing to bacterial pathogenicity. Bacterial tyrosine phosphorylation/dephosphorylation is also involved in biofilm formation and community development. The Porphyromonas gingivalis tyrosine phosphatase Ltp1 is involved in a restraint pathway that regulates heterotypic community development with Streptococcus gordonii. Ltp1 is upregulated by contact with S. gordonii and Ltp1 activity controls adhesin expression and levels of the interspecies signal AI-2.