title: Assessment and characterization of biofilm formation among human isolates of Streptococcus dysgalactiae subsp. equisimilis.
abstract: The capacity to form biofilm is considered a protective mechanism that allows the bacteria to survive and proliferate in hostile environments, facilitating the maintenance of the infectious process. Recently, biofilm has become a topic of interest in the study of the human pathogen group A Streptococcus (GAS). Although GAS has not been associated with infection on medical implants, the presence of microcolonies embedded in an extracellular matrix on infected tissues has been reported. Despite the similarity between GAS and Streptococcus dysgalactiae subspecies equisimilis (SDSE), there are no studies in the literature describing the production of biofilm by SDSE. In this work, we assessed and characterized biofilm development among SDSE human isolates of group C. The in vitro data showed that 59.3% of the 118 isolates tested were able to form acid-induced biofilm on glass, and 28% formed it on polystyrene surfaces. More importantly, biofilm was also formed in a foreign body model in mice. The biofilm structure was analyzed by confocal laser scanning microscopy, transmission electron microscopy, and scanning electron microscopy. Long fibrillar-like structures were observed by scanning electron microscopy. Additionally, the expression of a pilus associated gene of SDSE was increased for in vitro sessile cells compared with planktonics, and when sessile cells were collected from biofilms formed in the animal model compared with that of in vitro model. Results obtained from the immunofluorescence microscopy indicated the biofilm was immunogenic. Our data also suggested a role for proteins, exopolysaccharide and extracellular DNA in the formation and accumulation of biofilm by SDSE.
authors.affiliation: Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Avenida Carlos Chaga Filho 373, Rio de Janeiro, RJ 21941-902, Brazil. Electronic address: genteluci2@hotmail.com.
authors.forename: Gabrielle Limeira
authors.initials: GL
authors.lastname: Genteluci
authors.affiliation: Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Avenida Carlos Chaga Filho 373, Rio de Janeiro, RJ 21941-902, Brazil. Electronic address: ligia.guedes@micro.ufrj.br.
authors.forename: Ligia Guedes
authors.initials: LG
authors.lastname: Silva
authors.affiliation: Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Avenida Carlos Chaga Filho 373, Rio de Janeiro, RJ 21941-902, Brazil.
authors.forename: Maria Clara
authors.initials: MC
authors.lastname: Souza
authors.affiliation: Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Avenida Carlos Chaga Filho 373, Rio de Janeiro, RJ 21941-902, Brazil. Electronic address: thixglatthardt@gmail.com.
authors.forename: Thaís
authors.initials: T
authors.lastname: Glatthardt
authors.affiliation: Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Avenida Carlos Chaga Filho 373, Rio de Janeiro, RJ 21941-902, Brazil. Electronic address: demattos@acd.ufrj.br.
authors.forename: Marcos Corrêa
authors.initials: MC
authors.lastname: de Mattos
authors.affiliation: Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Avenida Carlos Chaga Filho 373, Rio de Janeiro, RJ 21941-902, Brazil. Electronic address: ejzemberg@micro.ufrj.br.
authors.forename: Regina
authors.initials: R
authors.lastname: Ejzemberg
authors.affiliation: Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Avenida Carlos Chaga Filho 373, Rio de Janeiro, RJ 21941-902, Brazil. Electronic address: alviano@micro.ufrj.br.
authors.forename: Celuta Sales
authors.initials: CS
authors.lastname: Alviano
authors.affiliation: Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Avenida Carlos Chaga Filho 373, Rio de Janeiro, RJ 21941-902, Brazil. Electronic address: agnes@micro.ufrj.br.
authors.forename: Agnes Marie Sá
authors.initials: AM
authors.lastname: Figueiredo
authors.affiliation: Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Instituto de Microbiologia Paulo de Góes, Avenida Carlos Chaga Filho 373, Rio de Janeiro, RJ 21941-902, Brazil. Electronic address: bernadete@micro.ufrj.br.
authors.forename: Bernadete Teixeira
authors.initials: BT
authors.lastname: Ferreira-Carvalho
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis; D018441:Biofilms / Q000254:growth & development*; D004269:DNA, Bacterial / Q000032:analysis; D004195:Disease Models, Animal; D005547:Foreign Bodies / Q000150:complications; D006801:Humans; D008297:Male; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D011135:Polysaccharides, Bacterial / Q000032:analysis; D013290:Streptococcal Infections / Q000382:microbiology*; D013291:Streptococcus / Q000254:growth & development / Q000302:isolation & purification* / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D011135:Polysaccharides, Bacterial
keywords: In vitro biofilm; In vivo biofilm; Streptococcus dysgalactiae subsp. equisimilis