title: Effects of chlorhexidine diacetate on ruminal microorganisms.
abstract: The objectives of this study were to examine the effects of chlorhexidine diacetate on growth and L-lactate production by Streptococcus bovis JB1 as well as the effects of this antimicrobial compound on the mixed ruminal microorganism fermentation. Addition of 1.8 microM chlorhexidine diacetate to glucose medium resulted in a lag in growth by S. bovis JB1, and growth was completely inhibited in the presence of 3.6, 9.0, and 18 microM chlorhexidine. When 6.2 microM chlorhexidine diacetate was added to glucose medium after 2 h of incubation, glucose utilization and L-lactate production by S. bovis JB1 were reduced. Phosphoenolpyruvate-dependent phosphorylation of 14C-glucose by toluene-treated cells of S. bovis JB1 was inhibited by increasing concentrations (1.8 to 18 microM) of chlorhexidine, whereas only the 18 microM concentration reduced the membrane potential (delta psi). Chlorhexidine diacetate was a potent inhibitor of L-lactate and methane production from glucose fermentation by mixed ruminal microorganisms. However, because chlorhexidine also decreased acetate and propionate concentrations and increased ammonia concentrations in mixed-culture incubations, this antimicrobial compound may have limited application as a ruminant feed additive.
authors.affiliation: Department of Animal and Dairy Science, University of Georgia, Athens 30602-2771, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Attia-Ismail
authors.forename: S A
authors.initials: SA
authors.lastname: Martin
authors.forename: T R
authors.initials: TR
authors.lastname: Callaway
mesh_terms: D000818:Animals; D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D002710:Chlorhexidine / Q000494:pharmacology*; D005285:Fermentation; D019344:Lactic Acid / Q000378:metabolism; D012417:Rumen / Q000382:microbiology*; D016985:Streptococcus bovis / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D000891:Anti-Infective Agents, Local; D019344:Lactic Acid; D002710:Chlorhexidine