title: Use of a predictive protocol to measure the antimicrobial resistance risks associated with biocidal product usage.
abstract: BACKGROUND
  In this study we assessed the propensity of biocide exposure in the development of antimicrobial resistance in bacteria.
  
  
  METHODS
  Our protocol is based on reporting changes in established antimicrobial susceptibility profiles in biocides and antibiotics after during use exposure to a product. The during use exposure reflects worse conditions of product use during application. It differs from the term low concentration, which usually reflects a concentration below the minimal inhibitory concentration, but not necessarily a concentration that occurs in practice.
  
  
  RESULTS
  Our results showed that exposure to triclosan (0.0004%) was associated with a high risk of developing resistance and cross-resistance in Staphylococcus aureus and Escherichia coli. This was not observed with exposure to chlorhexidine (0.00005%) or a hydrogen peroxide-based biocidal product (in during use conditions). Interestingly, exposure to a low concentration of hydrogen peroxide (0.001%) carried a risk of emerging resistance to antibiotics if the presence of the oxidizing agent was maintained. We observed a number of unstable clinical resistances to antibiotics after exposure to the cationic biocide and oxidizing agent, notably to tobramycin and ticarcillin-clavulanic acid.
  
  
  CONCLUSIONS
  Using a decision tree based on the change in antimicrobial susceptibility test results, we were able to provide information on the effect of biocide exposure on the development of bacterial resistance to antimicrobials. Such information should address the call from the U.S. Food and Drug Administration and European Union Biocidal Products Regulation for manufacturers to provide information on antimicrobial resistance and cross-resistance in bacteria after the use of their product.
authors.affiliation: Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Wesgate
authors.affiliation: Deb Group, Denby, UK.
authors.forename: Pierre
authors.initials: P
authors.lastname: Grasha
authors.affiliation: Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK. Electronic address: maillardj@cardiff.ac.uk.
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Maillard
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects*; D009154:Mutation; D012641:Selection, Genetic; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents
keywords: Resistance; antibiotics; biocides; predictive protocol