Modulation of mixed biofilm between Prevotella intermedia and Prevotella nigrescens with Porphyromonas gingivalis

• Grant number: 13/15977-0
• Support Opportunities: Regular Research Grants
• Start date: February 01, 2015
• End date: January 31, 2017
• Field of knowledge: Health Sciences - Dentistry - Periodontology
• Principal Investigator: Maria Regina Lorenzetti Simionato
• Grantee: Maria Regina Lorenzetti Simionato
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Christian Hoffmann ; José Silvio Govone ; Paulo Henrique Rodrigues

Abstract

The Prevotella genus is composed of Gram-negative anaerobic bacilli that develop pigmented black colonies on blood agar plates. In the oral cavity, Prevotella intermedia and Prevotella nigrescens , the most frequently isolated species, are associated with periodontitis, acute necrotizing ulcerative gingivitis, pregnancy gingivitis and endodontic lesions. P. intermedia and P. nigrescens are among the most abundant species in the subgingival biofilm and are part of the orange complex whose components are strongly associated with the red complex, composed of Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola. Ecological changes in the subgingival microbial succession result in the orange complex species favoring the components of red complex. Associations between P. intermedia and P. nigrescens with periodontal pathogens P. gingivalis is recognized as little investigated, since there are few reports in the literature describing studies of biofilms or interactions between these two genera. Results from previous studies performed in our laboratory suggest that intraspecific variability may affect the ability of P. intermedia and P. nigrescens of recognizing surface molecules of other bacteria, thus modulating biofilm formation not only quantitatively but also qualitative. Since the knowledge of the complexity of the associations of P. intermedia and P. nigrescens in the oral cavity remains incomplete and because these pathogens have clinical importance of, the general objectives of this study are to verify the effects of the combination of strains of P. intermedia and P. nigrescens with P. gingivalis in modulating the formation of the mixed biofilm developed both in vitro and in vivo (animal model), to determine the proportion of each species by testing quantitative Real Time PCR (qPCR), to verify the existence of mechanisms communication among strains of biofilm development by the co-culture system in two compartments, and to determine the effect of oral infection of the association on alveolar bone loss and production of inflammatory mediators in the gingival tissues. (AU)