title: Intraspecies Variability Affects Heterotypic Biofilms of Porphyromonas gingivalis and Prevotella intermedia: Evidences of Strain-Dependence Biofilm Modulation by Physical Contact and by Released Soluble Factors.
abstract: It is well known that strain and virulence diversity exist within the population structure of Porphyromonas gingivalis. In the present study we investigate intra- and inter-species variability in biofilm formation of Porphyromonas gingivalis and partners Prevotella intermedia and Prevotella nigrescens. All strains tested showed similar hydrophobicity, except for P. gingivalis W83 which has roughly half of the hydrophobicity of P. gingivalis ATCC33277. An intraspecies variability in coaggregation of P. gingivalis with P. intermedia was also found. The association P. gingivalis W83/P. intermedia 17 produced the thickest biofilm and strain 17 was prevalent. In a two-compartment system P. gingivalis W83 stimulates an increase in biomass of strain 17 and the latter did not stimulate the growth of P. gingivalis W83. In addition, P. gingivalis W83 also stimulates the growth of P. intermedia ATCC25611 although strain W83 was prevalent in the association with P. intermedia ATCC25611. P. gingivalis ATCC33277 was prevalent in both associations with P. intermedia and both strains of P. intermedia stimulate the growth of P. gingivalis ATCC33277. FISH images also showed variability in biofilm structure. Thus, the outcome of the association P. gingivalis/P. intermedia seems to be strain-dependent, and both soluble factors and physical contact are relevant. The association P. gingivalis-P. nigrescens ATCC33563 produced larger biomass than each monotypic biofilm, and P. gingivalis was favored in consortia, while no differences were found in the two-compartment system. Therefore, in consortia P. gingivalis-P. nigrescens physical contact seems to favor P. gingivalis growth. The intraspecies variability found in our study suggests strain-dependence in ability of microorganisms to recognize molecules in other bacteria which may further elucidate the dysbiosis event during periodontitis development giving additional explanation for periodontal bacteria, such as P. gingivalis and P. intermedia, among others, to persist and establish chronic infections in the host.
authors.affiliation: Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, São Paulo, Brazil.
authors.forename: Graziela Murta
authors.initials: GM
authors.lastname: Barbosa
authors.affiliation: Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, São Paulo, Brazil.
authors.forename: Andrea Vieira
authors.initials: AV
authors.lastname: Colombo
authors.affiliation: Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, São Paulo, Brazil.
authors.forename: Paulo Henrique
authors.initials: PH
authors.lastname: Rodrigues
authors.affiliation: Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, São Paulo, Brazil.
authors.forename: Maria Regina Lorenzetti
authors.initials: MR
authors.lastname: Simionato
mesh_terms: D001422:Bacterial Adhesion; D018441:Biofilms / Q000254:growth & development*; D018533:Biomass; D064806:Dysbiosis / Q000382:microbiology; D006801:Humans; D010518:Periodontitis / Q000382:microbiology; D016966:Porphyromonas gingivalis / Q000145:classification / Q000502:physiology*; D018713:Prevotella intermedia / Q000145:classification / Q000235:genetics / Q000502:physiology*