title: Inhibition of Neisseria gonorrhoeae growth due to hydrogen peroxide production by urogenital streptococci.
abstract: Seven streptococci isolated from the normal urogenital flora were selected for the production of an inhibitory activity toward Neisseria gonorrhoeae on solid medium. This activity was abolished when catalase was added to the medium in the case of Streptococcus mitis isolates 22, 25, 74 and Streptococcus sanguis II isolate 70 suggesting the involvement of hydrogen peroxide. The inhibitory activities produced by the other isolates (Streptococcus faecalis) were trypsin sensitive (isolates 12 and 14) or stable (isolate 59). Hydrogen peroxide production by S. sanguis II was quantitatively evaluated by reference to a standard curve representing the inhibitory effect of various concentrations of commercial H2O2 on N. gonorrhoeae growth. After 22 h of incubation a yield of 5.3 m mol H2O2 I-1 was reached on solid medium while in liquid medium values of 2.8 and 7.3 m mol H2O2 I-1 were obtained, respectively, in non-agitated and agitated cultures after 8 h of incubation.
mesh_terms: D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000633:toxicity*; D007700:Kinetics; D009344:Neisseria gonorrhoeae / Q000187:drug effects / Q000254:growth & development*; D013045:Species Specificity; D013291:Streptococcus / Q000302:isolation & purification / Q000378:metabolism*; D014566:Urogenital System / Q000382:microbiology*
chemical_list: D006861:Hydrogen Peroxide