Three Efficacy of Ligilactobacillus plantarum WB21 Against Halitosis Induced by Porphyromonas gingivalis

Halitosis is caused by volatile sulfur compounds (VSCs) produced by periodontopathogens. The aim of this study is to examine the mechanism by which Ligilactobacillus salivarius WB21 inhibits halitosis. A susceptibility assay for Porphyromonas gingivalis was conducted using spent culture media (SCM) from L. salivarius WB21, and VSCs from the suspension of P. gingivalis were analyzed in the presence or absence of the SCM. After co-cultivating P. gingivalis and L. salivarius, P. gingivalis growth and VSC levels were measured using a spectrophotometer and a gas chromatograph, respectively. Additionally, levels of methyl mercaptan in the suspension and in the mgl gene of P. gingivalis were investigated. The SCM from L. salivarius WB21 significantly inhibited growth of P. gingivalis (p < 0.05) and significantly reduced emission of VSCs from the suspension of P. gingivalis (p < 0.05). When L. salivarius WB21 was present in a co-culture condition, P. gingivalis growth was significantly inhibited, and levels of methyl mercaptan in the culture medium were also reduced (p < 0.05). Finally, expression of the mgl gene of P. gingivalis was significantly reduced under co-cultivation with L. salivarius WB21 (p < 0.05). L. salivarius WB21 may inhibit colonization of periodontopathogens in the oral cavity and suppress production and emission of VSCs. Therefore, L. salivarius WB21 may be effective in treating halitosis when applied to the oral cavity.