Evaluation of the capacity of oral streptococci to produce hydrogen peroxide

The capacity of 11 strains of oral streptococcal species (Streptococcus sanguis, S. oralis, S. mitis and S. sobrinus) to produce hydrogen peroxide (H2O2) was studied in vitro. Detection of this property in solid media, particularly with trypticase soy agar-benzidine-peroxidase, was more sensitive than in liquid media. The addition of carbohydrates (arabinose, xylose, mannose, sorbose and lactose), sorbitol and saccharine to buffered trypticase soy broth increased H2O2 production in S. oralis NCTC 11427, although the concentrations obtained with some substrates (glucose, galactose, mannitol and xylitol) were lower than those obtained in controls. In S. sanguis NCTC 7863, H2O2 production was detected only with galactose, sorbitol, lactose and saccharin.