title: Biofilm formation ability of Salmonella enterica serovar Typhimurium acrAB mutants.
abstract: Recent studies offer contradictory findings about the role of multidrug efflux pumps in bacterial biofilm development. Thus, the aim of this study was to investigate the involvement of the AcrAB efflux pump in biofilm formation by investigating the ability of AcrB and AcrAB null mutants of Salmonella enterica serovar Typhimurium to produce biofilms. Three models were used to compare the ability of S. Typhimurium wild-type and its mutants to form biofilms: formation of biofilm on polystyrene surfaces; production of biofilm (mat model) on the air/liquid interface; and expression of curli and cellulose on Congo red-supplemented agar plates. All three investigated genotypes formed biofilms with similar characteristics. However, upon exposure to chloramphenicol, formation of biofilms on solid surfaces as well as the production of curli were either reduced or were delayed more significantly in both mutants, whilst there was no visible effect on pellicle formation. It can be concluded that when no selective pressure is applied, S. Typhimurium is able to produce biofilms even when the AcrAB efflux pumps are inactivated, implying that the use of efflux pump inhibitors to prevent biofilm formation is not a general solution and that combined treatments might be more efficient. Other factors that affect the ability to produce biofilms depending on efflux pump activity are yet to be identified.
authors.affiliation: Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Dov B
authors.initials: DB
authors.lastname: Schlisselberg
authors.affiliation: Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Edna
authors.initials: E
authors.lastname: Kler
authors.affiliation: Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Guy
authors.initials: G
authors.lastname: Kisluk
authors.affiliation: Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Dina
authors.initials: D
authors.lastname: Shachar
authors.affiliation: Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel. Electronic address: simay@tx.technion.ac.il.
authors.forename: Sima
authors.initials: S
authors.lastname: Yaron
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D002352:Carrier Proteins / Q000235:genetics*; D002482:Cellulose / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D004783:Environmental Microbiology; D017353:Gene Deletion; D011137:Polystyrenes; D012486:Salmonella typhimurium / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*
chemical_list: C493251:AcrAB-TolC protein, Salmonella enterica; D001426:Bacterial Proteins; D002352:Carrier Proteins; D003470:Culture Media; D011137:Polystyrenes; C077481:Crl protein, Bacteria; D002482:Cellulose
keywords: Biofilm; Foodborne pathogens; Pellicle