title: Antimicrobial effect of acidified nitrite on periodontal bacteria.
abstract: The antimicrobial agent nitric oxide (NO) is formed in the mouth and its concentration is directly related to salivary nitrite, which in turn is related to dietary nitrate intake. The aim of this study was to determine whether nitrite under acidic conditions will have an inhibitory effect, possibly occurring through NO production, on the periodontal disease pathogens Fusobacterium nucleatum, Eikenella corrodens and Porphyromonas gingivalis. Whereas the growth of these organisms was inhibited by a more acid pH, the addition of nitrite caused a marked, further dose-dependent reduction in bacterial numbers after exposure. The ability of these bacteria to recover from nitrite exposure was also affected by pH and nitrite concentration. At acidity levels below pH 5.0, low concentrations of nitrite (0.2 mM) caused effective complete killing of the periodontal bacteria. Addition of sodium thiocyanate did not increase the bacteriostatic or bacteriocidal activity of acidified nitrite against any of the 3 bacteria. These results demonstrate the possibility that nitrite in saliva, under appropriate conditions, may have an effect on the growth and survival of the bacteria implicated in periodontal disease.
authors.affiliation: Department of Oral Microbiology, St Bartholomew's and the Royal London School of Medicine and Dentistry, London, United Kingdom.
authors.forename: R P
authors.initials: RP
authors.lastname: Allaker
authors.forename: L S
authors.initials: LS
authors.lastname: Silva Mendez
authors.forename: J M
authors.initials: JM
authors.lastname: Hardie
authors.forename: N
authors.initials: N
authors.lastname: Benjamin
mesh_terms: D000143:Acids; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D016124:Eikenella corrodens / Q000187:drug effects* / Q000254:growth & development; D016967:Fusobacterium nucleatum / Q000187:drug effects* / Q000254:growth & development; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D010510:Periodontal Diseases / Q000382:microbiology; D016966:Porphyromonas gingivalis / Q000187:drug effects* / Q000254:growth & development; D012463:Saliva / Q000378:metabolism; D013861:Thiocyanates / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D000143:Acids; D000891:Anti-Infective Agents, Local; D009573:Nitrites; D013861:Thiocyanates; D009569:Nitric Oxide; C024553:sodium thiocyanate