title: Development of resistance of mutans streptococci and Porphyromonas gingivalis to chlorhexidine digluconate and amine fluoride/stannous fluoride-containing mouthrinses, in vitro.
abstract: OBJECTIVE
  The aim if this study was to determine the minimal inhibitory concentrations of chlorhexidine digluconate and an amine fluoride/stannous fluoride-containing mouthrinse against Porphyromonas gingivalis and mutans streptococci during an experimental long-term subinhibitory exposition.
  
  
  METHODS
  Five P. gingivalis strains and four mutans streptococci were subcultivated for 20-30 passages in subinhibitory concentrations of chlorhexidine digluconate or an amine fluoride/stannous fluoride-containing mouthrinse.
  
  
  RESULTS
  Pre-passaging minimal inhibitory concentrations for chlorhexidine ranged from 0.5 to 2 mg/l for mutans streptococci and from 2 to 4 mg/l for the P. gingivalis isolates. For the amine fluoride/stannous fluoride-containing mouthrinse minimal inhibitory values from 0.125 to 0.25% for the mutans streptococci and from 0.063 to 0.125% for the P. gingivalis isolates were determined. Two- to fourfold increased minimal inhibitory concentrations against chlorhexidine were detected for two of the five P. gingivalis isolates, whereas no increase in minimal inhibitory concentrations was found for the mutans streptococci after repeated passaging through subinhibitory concentrations. Repeated exposure to subinhibitory concentrations of the amine fluoride/stannous fluoride-containing mouthrinse did not alter the minimally inhibitory concentrations of the bacterial isolates tested.
  
  
  CONCLUSIONS
  Chlorhexidine and the amine fluoride/stannous fluoride-containing mouthrinse are effective inhibitory agents against the oral bacterial isolates tested. No general development of resistance against chlorhexidine or the amine fluoride/stannous fluoride-containing mouthrinse was detected. However, some strains showed potential to develop resistance against chlorhexidine after prolonged exposure.
  
  
  CONCLUSIONS
  The use of chlorhexidine should be limited to short periods of time. The amine fluoride/stannous fluoride-containing mouthrinse appears to have the potential to be used on a long-term basis.
authors.affiliation: Department of Preventive Dentistry and Oral Microbiology, School of Dental Medicine, University of Basel, Hebelstrasse 3, 4056, Basel, Switzerland.
authors.forename: Eva M
authors.initials: EM
authors.lastname: Kulik
authors.forename: Tuomas
authors.initials: T
authors.lastname: Waltimo
authors.forename: Roland
authors.initials: R
authors.lastname: Weiger
authors.forename: Irene
authors.initials: I
authors.lastname: Schweizer
authors.forename: Krystyna
authors.initials: K
authors.lastname: Lenkeit
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Filipuzzi-Jenny
authors.forename: Clemens
authors.initials: C
authors.lastname: Walter
mesh_terms: D000588:Amines / Q000494:pharmacology*; D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D066298:In Vitro Techniques; D008826:Microbial Sensitivity Tests; D009067:Mouthwashes / Q000494:pharmacology*; D016966:Porphyromonas gingivalis / Q000187:drug effects*; D013295:Streptococcus mutans / Q000187:drug effects*; D014002:Tin Fluorides / Q000494:pharmacology*
chemical_list: D000588:Amines; D000891:Anti-Infective Agents, Local; D009067:Mouthwashes; D014002:Tin Fluorides; C010882:chlorhexidine gluconate; D002710:Chlorhexidine