title: Dynamics of mono- and dual-species biofilm formation and interactions between Staphylococcus aureus and Gram-negative bacteria.
abstract: Microorganisms are not commonly found in the planktonic state but predominantly form dual- and multispecies biofilms in almost all natural environments. Bacteria in multispecies biofilms cooperate, compete or have neutral interactions according to the involved species. Here, the development of mono- and dual-species biofilms formed by Staphylococcus aureus and other foodborne pathogens such as Salmonella enterica subsp. enterica serovar Enteritidis, potentially pathogenic Raoultella planticola and non-pathogenic Escherichia coli over the course of 24, 48 and 72 h was studied. Biofilm formation was evaluated by the crystal violet assay (CV), enumeration of colony-forming units (CFU cm-2) and visualization using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). In general, Gram-negative bacterial species and S. aureus interacted in a competitive manner. The tested Gram-negative bacteria grew better in mixed dual-species biofilms than in their mono-species biofilms as determined using the CV assay, CFU ml-2enumeration, and CLSM and SEM visualization. In contrast, the growth of S. aureus biofilms was reduced when cultured in dual-species biofilms. CLSM images revealed grape-like clusters of S. aureus and monolayers of Gram-negative bacteria in both mono- and dual-species biofilms. S. aureus clusters in dual-species biofilms were significantly smaller than clusters in S. aureus mono-species biofilms.
authors.affiliation: Department of Food and Feed Safety, Veterinary Research Institute, Brno, Czech Republic.
authors.forename: Jitka
authors.initials: J
authors.lastname: Makovcova
authors.affiliation: Department of Food and Feed Safety, Veterinary Research Institute, Brno, Czech Republic.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Babak
authors.affiliation: Department of Chemistry and Toxicology, Veterinary Research Institute, Brno, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Kulich
authors.affiliation: Department of Pharmacology and Immunotherapy, Veterinary Research Institute, Brno, Czech Republic.
authors.forename: Josef
authors.initials: J
authors.lastname: Masek
authors.affiliation: Department of Food and Feed Safety, Veterinary Research Institute, Brno, Czech Republic.
authors.forename: Michal
authors.initials: M
authors.lastname: Slany
authors.affiliation: Department of Food and Feed Safety, Veterinary Research Institute, Brno, Czech Republic.
authors.forename: Lenka
authors.initials: L
authors.lastname: Cincarova
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D015169:Colony Count, Microbial; D004755:Enterobacteriaceae / Q000254:growth & development / Q000502:physiology*; D005840:Gentian Violet / Q000032:analysis; D056265:Microbial Interactions; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D013194:Staining and Labeling; D013211:Staphylococcus aureus / Q000254:growth & development / Q000502:physiology*
chemical_list: D005840:Gentian Violet