title: The effects of chlorhexidine on the maximum specific growth rate, biomass and hydrolytic enzyme production of Bacteroides gingivalis grown in continuous culture.
abstract: Bacteroides gingivalis was grown in continuous culture in the presence of chlorhexidine. Maximum specific growth rates and biomass levels initially increased but then decreased as the chlorhexidine level increased from 0 to 30 micrograms/ml. Total inhibition of growth occurred when the chlorhexidine concentration reached 60 micrograms/ml. The steady-state levels of cell-bound, extracellular vesicle and extracellular soluble enzymes, trypsin-like protease, alkaline phosphatase and N-acetyl-beta-glucosaminidase were measured. With increasing sub-lethal concentrations of chlorhexidine, levels of alkaline phosphatase increased noticeably in all three fractions of culture, whilst cell-bound and extracellular vesicle levels of N-acetyl-beta-glucosaminidase remained approximately constant. Extracellular soluble levels of alkaline phosphatase and N-acetyl-beta-glucosaminidase increased with increasing levels of chlorhexidine. The levels of trypsin-like protease decreased significantly in all fractions of the culture when cells were grown in the presence of chlorhexidine. Thus, chlorhexidine has a differential effect on the production of B. gingivalis hydrolytic enzymes.
authors.affiliation: Department of Science, Bristol Polytechnic, Frenchay, UK.
authors.forename: T
authors.initials: T
authors.lastname: Minhas
authors.forename: J
authors.initials: J
authors.lastname: Greenman
mesh_terms: D000118:Acetylglucosaminidase / Q000096:biosynthesis; D000469:Alkaline Phosphatase / Q000096:biosynthesis; D001439:Bacteroides / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D002710:Chlorhexidine / Q000494:pharmacology*; D014357:Trypsin / Q000096:biosynthesis
chemical_list: D000469:Alkaline Phosphatase; D000118:Acetylglucosaminidase; D014357:Trypsin; D002710:Chlorhexidine