Abstract: Experiment research of antagonistic effects of two probiotics on halitosis pathogens YANG Wenjie，Ye Wei.(Department of Prevention Dentistry，Ninth People’s Hospital，College of Stomatology, Shanghai Jiao Tong University School of Medicine，Shanghai Key Laboratory of Stomatology，Shanghai 200011，China) Abstract: Objective To evaluate the possible antagonistic effects of two probiotics Lactobacillus delbrueckii subsp. bulgaricus（Lb）and Streptococcus salivarius（Ss）on halitosis pathogens Porphyromonas gingivalis （Pg） and Fusobacteriurn nuclearum （Fn）.Methods 1ml suspensions of Lb and Ss were mixed with equal volume and concentration of Pg or Fn respectively. All mixtures were cultured under anaerobic conditions at 37 ℃for 6h，12 h, 24 h and 48 h respectively. Two probiotic bacterial species Lb、Ss were used to rate the competitive exclusion between probiotics and halitosis pathogens Fn and Pg.Result The amounts of Fn and Pg cultured with Lb and Ss significantly decreased compared with those cultured alone (P<0.05 or P<0.01).The competition between probiotics and pathogens depended on the sequence of inoculation. Conclusion The results demonstrated that Lb and Ss all strongly inhibited the growth of Fn and Pg,especially the growth of Pg by their metabolites.

Key words: halitosis, probiotics, halitosis pathogens