Inhibition of the growth of Streptococcus mutans, Streptococcus sobrinus and Lactobacillus casei by oral peroxidase systems in human saliva.
Streptococcus mutans, Strep. sobrinus and Lactobacillus casei were grown in glucose-supplemented, sterilized, human whole saliva, adjusted to pH 5, 6 or 7. Components of the antibacterial peroxidase system--hypothiocyanous acid (HOSCN) and hypothiocyanite ions (OSCN-)--were generated by adding exogenous H2O2 to sterilized saliva containing endogenous peroxidases and thiocyanate (SCN-) ions. HOSCN/OSCN- generation was proportional to the amount of H2O2 added, and more HOSCN/OSCN- was detected in saliva at pH 7 than at pH 5. However, the growth of mutans streptococci and L. casei was inhibited at pH 5 by HOSCN/OSCN-, whereas no inhibition was found at pH 7. The findings show that (a) sufficient amount of HOSCN/OSCN- will inhibit the growth of cariogenic bacteria in human saliva at pH 5; (b) this amount of HOSCN/OSCN- can be generated in saliva by exogenously added H2O2; and (c) peroxidase systems have stronger antistreptococcal effects in human whole saliva than in phosphate buffer.
Lumikari
M
M
Department of Cariology, University of Turku, Finland.
Soukka
T
T
Nurmio
S
S
Tenovuo
J
J
D000900:Anti-Bacterial Agents; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007780:Lacticaseibacillus casei / Q000187:drug effects* / Q000254:growth & development; D010544:Peroxidases / Q000032:analysis / Q000494:pharmacology*; D012463:Saliva / Q000737:chemistry / Q000201:enzymology*; D013291:Streptococcus / Q000187:drug effects* / Q000254:growth & development; D013295:Streptococcus mutans / Q000187:drug effects* / Q000254:growth & development; D013861:Thiocyanates / Q000032:analysis / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D013861:Thiocyanates; C014607:hypothiocyanite ion; D010544:Peroxidases; C031760:thiocyanate