Disbiose supragengival e o risco de doenças orais em pacientes colonizados por Staphylococcus aureus

O biofilme é um componente essencial no desenvolvimento da cárie, das doenças periodontais e peri-implantares. O conhecimento da sua composição e a compreensão das interações microbianas presentes no biofilme oral são fundamentais para a conceção de medidas preventivas e terapêuticas eficazes. Objetivo: Investigar se a presença de Staphylococcus aureus favorece uma mudança na composição do biofilme supragengival in vitro. Materiais e métodos: Neste estudo foi utilizado um modelo padrão de biofilme supragengival com seis espécies (Actinomyces oris, Veillonella dispar, Fusobacterium nucleatum, Streptococcus mutans, Streptococcus oralis e Candida albicans). O biofilme foi suplementado com isolados clínicos de Staphylococcus aureus, Staphylococcus aureus (linhagem USA300 do tipo selvagem) e Staphylococcus aureus contendo mutações em genes que codificam para proteínas adesivas da superfície da matriz. Resultados: As estirpes de Staphylococcus aureus resistentes à meticilina (MRSA) aumentaram o número de Streptococcus mutans, Streptococcus oralis, Fusobacterium nucleatum e Veillonella dispar no biofilme supragengival. A estirpe mutante de Staphylococcus aureus, onde deletamos os genes que codificam as proteínas de adesão bacteriana, reduziu o crescimento dessas espécies para um nível normal e homeostático. Conclusão: A espécie Staphylococcus aureus na cavidade oral, por si só, pode não causar periodontite nem peri-implantite, mas promove a disbiose do biofilme, onde microrganismos potencialmente patogénicos, normalmente em baixa quatidade, se tornam predominantes. A co-presença de componentes no ambiente bucal, tais como proteínas/citocinas na saliva, microrganismos transitórios ou biomateriais, podem contribuir para a patogénese da doença e serem determinantes na etiologia multifatorial das doenças orais. Os resultados da mudança da composição do biofilme supragengival in vitro produzidas por estirpes de Staphylococcus aureus, sugerem que indivíduos portadores deste microrganismo na cavidade oral, podem apresentar uma maior suscetibilidade a doenças orais

Staphylococcus aureus Interferes with Streptococci Spatial Distribution and with Protein Expression of Species within a Polymicrobial Oral Biofilm

We asked whether transient Staphylococcus aureus in the oral environment synergistically interacts with orally associated bacterial species such as Actinomyces oris, Candida albicans, Fusobacterium nucleatum, Streptococcus oralis, Streptococcus mutans, and Veillonella dispar (six-species control biofilm 6S). For this purpose, four modified biofilms with seven species that contain either the wild type strain of the S. aureus genotype (USA300-MRSA WT), its isogenic mutant with MSCRAMM deficiency (USA300-MRSA ΔMSCRAMM), a methicillin-sensitive S. aureus (ST72-MSSA-) or a methicillin-resistant S. aureus (USA800-MRSA) grown on hydroxyapatite disks were examined. Culture analyses, confocal-laser-scanning microscopy and proteome analyses were performed. S. aureus strains affected the amount of supragingival biofilm-associated species differently. The deletion of MSCRAMM genes disrupted the growth of S. aureus and the distribution of S. mutans and S. oralis within the biofilms. In addition, S. aureus caused shifts in the number of detectable proteins of other species in the 6S biofilm. S. aureus (USA300-MRSA WT), aggregated together with early colonizers such as Actinomyces and streptococci, influenced the number of secondary colonizers such as Fusobacterium nucleatum and was involved in structuring the biofilm architecture that triggered the change from a homeostatic biofilm to a dysbiotic biofilm to the development of oral diseases

Influence of Sintering Temperature on Mechanical Properties of Glass-Ceramics Produced with Windshield Waste

In this work, glass-ceramics were produced with mechanical and physical properties, using recycled glass powder from windshields as raw material. The glass powder was formed and sintered at temperatures 600, 650, 700, 750, and 800°C. Pieces were also produced with the addition of niobium oxide to the glass powder. The flexural strength and the Archimedes density of the produced parts were determined. The reliability of the results was evaluated by the Weibull statistic. X-ray diffraction was performed. Maximum flexural strength was 77.64 MPa at 750°C, with the addition of niobium oxide at 43.86 MPa at 700°C. X-ray diffraction showed crystalline structures in the specimens with the addition of the nucleating agent, confirming the production of glass-ceramics in this composition. The pure glass powder only crystallized from 750°C. The Nb2O5 favors the formation of crystalline structures in the vitreous matrix at low temperatures and with piezoelectric structures

Staphylococcus aureus Interferes with Streptococci Spatial Distribution and with Protein Expression of Species within a Polymicrobial Oral Biofilm

We asked whether transient Staphylococcus aureus in the oral environment synergistically interacts with orally associated bacterial species such as Actinomyces oris, Candida albicans, Fusobacterium nucleatum, Streptococcus oralis, Streptococcus mutans, and Veillonella dispar (six-species control biofilm 6S). For this purpose, four modified biofilms with seven species that contain either the wild type strain of the S. aureus genotype (USA300-MRSA WT), its isogenic mutant with MSCRAMM deficiency (USA300-MRSA ΔMSCRAMM), a methicillin-sensitive S. aureus (ST72-MSSA-) or a methicillin-resistant S. aureus (USA800-MRSA) grown on hydroxyapatite disks were examined. Culture analyses, confocal-laser-scanning microscopy and proteome analyses were performed. S. aureus strains affected the amount of supragingival biofilm-associated species differently. The deletion of MSCRAMM genes disrupted the growth of S. aureus and the distribution of S. mutans and S. oralis within the biofilms. In addition, S. aureus caused shifts in the number of detectable proteins of other species in the 6S biofilm. S. aureus (USA300-MRSA WT), aggregated together with early colonizers such as Actinomyces and streptococci, influenced the number of secondary colonizers such as Fusobacterium nucleatum and was involved in structuring the biofilm architecture that triggered the change from a homeostatic biofilm to a dysbiotic biofilm to the development of oral diseases.ISSN:2079-638