title: Propyl paraben induces potassium efflux in Escherichia coli.
abstract: OBJECTIVE
  Parabens are currently used as antibacterial preservatives in pharmaceutical, cosmetic and food products but there are no precise data concerning their activity on bacterial membranes.
  
  
  METHODS
  We analysed the cytoplasmic potassium release during propyl paraben addition by using a selective electrode. Various conditions were assayed to investigate the bacterial paraben susceptibility. We compared the activity of propyl paraben with the activities of colicin A and polymyxin B.
  
  
  RESULTS
  Propyl paraben induced potassium efflux that was related to the porin expression in the bacterial outer membrane. In addition, the presence of spermine, previously described as an efficient OmpF channel-blocker, protected susceptible cells against paraben activity.
  
  
  CONCLUSIONS
  Propyl paraben induced potassium release in susceptible Escherichia coli cells similar to that observed with polymyxin B. Moreover, this efflux depended on porin channel activity. This permeabilizing effect is probably related to antibacterial properties of paraben molecules.
authors.affiliation: Enveloppe Bactérienne, Perméabilité et Antibiotiques, IFR 48, Faculté de Médecine, Université de la Méditerranée, 27 Boulevard Jean Moulin, 13385 Marseille Cedex 05, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Bredin
authors.forename: Anne
authors.initials: A
authors.lastname: Davin-Régli
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Pagès
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism; D010226:Parabens / Q000494:pharmacology*; D018272:Porins / Q000502:physiology; D011188:Potassium / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; C109237:OmpF protein; D010226:Parabens; D018272:Porins; D011188:Potassium; C006068:propylparaben