title: Staphylococcus aureus and Escherichia coli dual-species biofilms on nanohydroxyapatite loaded with CHX or ZnO nanoparticles.
abstract: Implant-associated infections are caused by surface-adhering microorganisms persisting as biofilms, resistant to host defense and antimicrobial agents. Given the limited efficacy of traditional antibiotics, novel strategies may rely on the prevention of such infections through the design of new biomaterials. In this work, two antimicrobial agents applied to nanohydroxyapatite materials-namely, chlorhexidine digluconate (CHX) and zinc oxide (ZnO) nanoparticles-were compared concerning their ability to avoid single- or dual-species biofilms of Staphylococcus aureus and Escherichia coli. The resulting biofilms were quantified by the enumeration of colony-forming units and examined by confocal microscopy using both Live/Dead staining and bacterial-specific fluorescent in situ hybridization. The sessile population arrangement was also observed by scanning electron microscopy. Both biomaterials showed to be effective in impairing bacterial adhesion and proliferation for either single- or dual-species biofilms. Furthermore, a competitive interaction was observed for dual-species biofilms wherein E. coli exhibited higher proliferative capacity than S. aureus, an inverse behavior from the one observed in single-species biofilms. Therefore, either nanoHA-CHX or nanoHA-ZnO surfaces appear as promising alternatives to antibiotics for the prevention of devices-related infections avoiding the critical risk of antibiotic-resistant strains emergence. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 491-497, 2017.
authors.affiliation: FEUP - Faculdade de Engenharia, Departamento de Engenharia Metalúrgica e Materiais, Universidade do Porto, Portugal.|i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.|INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Portugal.
authors.forename: Joana
authors.identifier: 0000-0002-8205-5675
authors.initials: J
authors.lastname: Barros
authors.affiliation: FEUP - Faculdade de Engenharia, Departamento de Engenharia Metalúrgica e Materiais, Universidade do Porto, Portugal.|i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.|INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Portugal.
authors.forename: Liliana
authors.initials: L
authors.lastname: Grenho
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.|IPATIMUP - Institute of Molecular Pathology and Immunology of the University of Porto, Portugal.|LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Departamento de Engenharia Química, Universidade do Porto, Portugal.
authors.forename: Sílvia
authors.initials: S
authors.lastname: Fontenente
authors.affiliation: LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Departamento de Engenharia Química, Universidade do Porto, Portugal.|ULP-Universidade Lusófona do Porto, Portugal.
authors.forename: Cândida M
authors.initials: CM
authors.lastname: Manuel
authors.affiliation: LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Departamento de Engenharia Química, Universidade do Porto, Portugal.
authors.forename: Olga C
authors.initials: OC
authors.lastname: Nunes
authors.affiliation: LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Departamento de Engenharia Química, Universidade do Porto, Portugal.
authors.forename: Luís F
authors.initials: LF
authors.lastname: Melo
authors.affiliation: FEUP - Faculdade de Engenharia, Departamento de Engenharia Metalúrgica e Materiais, Universidade do Porto, Portugal.|i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.|INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Portugal.
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Monteiro
authors.affiliation: FP-ENAS/CEBIMED, University Fernando Pessoa Energy, Environment and Health Research Unit/Biomedical Research Center, Porto, Portugal.
authors.forename: Maria P
authors.initials: MP
authors.lastname: Ferraz
mesh_terms: D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D017886:Durapatite / Q000737:chemistry / Q000494:pharmacology; D004926:Escherichia coli / Q000502:physiology*; D053758:Nanoparticles / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000502:physiology*; D015034:Zinc Oxide / Q000737:chemistry / Q000494:pharmacology
chemical_list: D017886:Durapatite; C010882:chlorhexidine gluconate; D002710:Chlorhexidine; D015034:Zinc Oxide
keywords: FISH; chlorhexidine digluconate; dual-species biofilm; nanohydroxyapatite; single-species biofilm; zinc oxide nanoparticles