title: Detection of cell surface hydrophobicity, biofilm and fimbirae genes in salmonella isolated from tunisian clinical and poultry meat.
abstract: BACKGROUND
  The aim of this study was to evaluate the ability of 15 serotypes of Salmonella to form biofilm on polystyrene, polyvinyl chloride (PVC) and glass surfaces. .
  
  
  METHODS
  Initially slime production was assessed on CRA agar and hydrophobicity of 20 Salmonella strains isolated from poultry and human and two Salmonella enterica serovar Typhimurium references strains was achieved by microbial adhesion to n-hexadecane. In addition, biofilm formation on polystyrene, PVC and glass surfaces was also investigated by using MTT and XTT colorimetric assay. Further, distribution of Salmonella enterotoxin (stn), Salmonella Enteritidis fimbrial (sef) and plasmid encoded fimbrial (pef) genes among tested strains was achieved by PCR.
  
  
  RESULTS
  Salmonella strains developed red and white colonies on CRA and they are considered as hydrophilic with affinity values to n-hexadecane ranged between 0.29% and 29.55%. Quantitative biofilm assays showed that bacteria are able to form biofilm on polystyrene with different degrees and 54.54% of strains produce a strong biofilm on glass. In addition, all the strains form only a moderate (54.54%) and weak (40.91%) biofilm on PVC. PCR detection showed that only S. Enteritidis harbour Sef gene, whereas Pef and stn genes were detected in S. Kentucky, S. Amsterdam, S. Hadar, S. Enteritidis and S. Typhimurium.
  
  
  CONCLUSIONS
  Salmonella serotypes are able to form biofilm on hydrophobic and hydrophilic industrial surfaces. Biofilm formation of Salmonella on these surfaces has an increased potential to compromise food safety and potentiate public health risk.
authors.affiliation: 1. Laboratory of Genetic, Biodiversity and Valorization of Bio-ressources. Higher Institute of Biotechnology , Monastir, Tunisia . ; 2. Fermentation Unit, Pasteur Institute , Tunisia.
authors.forename: Fethi
authors.initials: F
authors.lastname: Ben Abdallah
authors.affiliation: 3. Laboratory of Analysis, Treatment and Valorization of Environment polluants and Product. Faculty of Pharmacy, Monastir , Tunisia.
authors.forename: Rihab
authors.initials: R
authors.lastname: Lagha
authors.affiliation: 1. Laboratory of Genetic, Biodiversity and Valorization of Bio-ressources. Higher Institute of Biotechnology , Monastir, Tunisia .
authors.forename: Khaled
authors.initials: K
authors.lastname: Said
authors.affiliation: 2. Fermentation Unit, Pasteur Institute , Tunisia.
authors.forename: Héla
authors.initials: H
authors.lastname: Kallel
authors.affiliation: 4. Sequencing and Genomic Analysis Unit. Higher Institute of Biotechnology , Monastir, Tunisia.
authors.forename: Jawhar
authors.initials: J
authors.lastname: Gharbi
keywords: Biofilm; Fimbriae genes; Hydrophilic and hydrophobic surfaces; Hydrophobocity; Salmonella