title: Influence of pH on inhibition of Streptococcus mutans by Streptococcus oligofermentans.
abstract: Streptococcus oligofermentans is a novel strain of oral streptococcus that can specifically inhibit the growth of Streptococcus mutans. The aims of this study were to assess the growth of S. oligofermentans and the ability of S. oligofermentans to inhibit growth of Streptococcus mutans at different pH values. Growth inhibition was investigated in vitro using an interspecies competition assay. The 4-aminoantipyine method was used to measure the initial production rate and the total yield of hydrogen peroxide in S. oligofermentans. S. oligofermentans grew best at pH 7.0 and showed the most pronounced inhibitory effect when it was inoculated earlier than S. mutans. In terms of the total yield and the initial production rate of hydrogen peroxide by S. oligofermentans, the effects of the different culture pH values were as follows: pH 7.0 > 6.5 > 6.0 > 7.5 > 5.5 = 8.0 (i.e. there was no significant difference between pH 5.5 and pH 8.0). Environmental pH and the sequence of inoculation significantly affected the ability of S. oligofermentans to inhibit the growth of S. mutans. The degree of inhibition may be attributed to the amount of hydrogen peroxide produced.
authors.affiliation: Department of Endodontics, School of Stomatology, Tianjin Medical University, Tianjin, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Lei
authors.initials: L
authors.lastname: Chu
authors.forename: Fei
authors.initials: F
authors.lastname: Wu
authors.forename: Lili
authors.initials: L
authors.lastname: Guo
authors.forename: Mengci
authors.initials: M
authors.lastname: Li
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Wang
authors.forename: Ligeng
authors.initials: L
authors.lastname: Wu
mesh_terms: D000675:Ampyrone; D000898:Antibiosis / Q000502:physiology*; D058491:Bacterial Load; D001431:Bacteriological Techniques; D018441:Biofilms; D006861:Hydrogen Peroxide / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D016877:Oxidants / Q000378:metabolism; D013045:Species Specificity; D013291:Streptococcus / Q000254:growth & development / Q000502:physiology*; D013295:Streptococcus mutans / Q000254:growth & development / Q000502:physiology*
chemical_list: D007202:Indicators and Reagents; D016877:Oxidants; D000675:Ampyrone; D006861:Hydrogen Peroxide
keywords: Streptococcus mutans; Streptococcus oligofermentans; hydrogen peroxide; interaction; pH