title: Effects of chelating agent and environmental stresses on microbial biofilms: relevance to clinical microbiology.
abstract: OBJECTIVE
  To determine the effect of pH, temperature, desiccation, ethylenediaminetetraacetic acid (EDTA) and desferrioxamine B (DFO) on Panton-Valentine leukocidin-positive community acquired methicillin-susceptible Staphylococcus aureus (PVL +ve CA-MSSA) biofilm formation.
  
  
  RESULTS
  Biofilms from PVL +ve CA-MSSA (clinical isolate) were subjected to pH, temperature, desiccation, EDTA and DFO. PVL +ve CA-MSSA were more resistant to pH and heat than their planktonic equivalents. Desiccation studies demonstrated that PVL +ve CA-MSSA biofilms were more refractory to the treatment than planktonic cells. Significant inhibition of PVL +ve CA-MSSA biofilm formation was observed in the presence of 1 mmol l(-1) EDTA. Low concentrations (2·5 μmol l(-1) ) of DFO enhanced the growth of PVL +ve CA-MSSA biofilms. At higher concentrations (1 mmol l(-1) ), DFO did inhibit the growth but not as much as EDTA. A combination of EDTA and DFO inhibited PVL +ve CA-MSSA biofilm formation at lower concentrations than either alone.
  
  
  CONCLUSIONS
  This study demonstrates that PVL +ve CA-MSSA biofilms are resistant to environmental stress but their growth can inhibited effectively by a mixture of EDTA and DFO.
  
  
  CONCLUSIONS
  The inhibition of biofilm formation by PVL +ve CA-MSSA using chelating agents has not been previously reported and provides a practical approach to achieve the disruption of these potentially important biofilms formed by an emerging pathogen.
authors.affiliation: School of Biomedical Sciences, King's College, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Al-Azemi
authors.forename: M D
authors.initials: MD
authors.lastname: Fielder
authors.forename: R A
authors.initials: RA
authors.lastname: Abuknesha
authors.forename: R G
authors.initials: RG
authors.lastname: Price
mesh_terms: D001427:Bacterial Toxins / Q000235:genetics; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D002614:Chelating Agents / Q000494:pharmacology*; D003676:Deferoxamine / Q000494:pharmacology; D003890:Desiccation; D004492:Edetic Acid / Q000494:pharmacology; D005098:Exotoxins / Q000235:genetics; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007956:Leukocidins / Q000235:genetics; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D013312:Stress, Physiological
chemical_list: D001427:Bacterial Toxins; D002614:Chelating Agents; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; D004492:Edetic Acid; D003676:Deferoxamine