치태형성과 혐기성 세균의 황화합물 생성에 대한 Lactobacillus salivarius의 억제효과 및 동정

Identification and inhibiting effect of Lactobacillus salivarius the formation of plaque and the production of volatile sulfur compounds by anaerobic bacteria

There are normal inhabitants doing medically useful functions in the body. There are many kinds of bacteria performing specific functions in the oral cavity. Two strains of lactic add bacteria were isolated from normal inhabitants of children's oral cavity, which inhibited the production of volatile sulfur compounds by anaerobic bacteria. The authors identified the isolates by 16S rDNA partial sequencing. 1. Two isolates were Gram-positive bacilli and produced hydrogen peroxide. 2. When Streptococcus mutans was cultured in the media, the mean weight of formed artificial plaque on the orthodontic wires was $124.4{\pm}30.4$ mg, whereas being reduced to $5.2{\pm}2.0$ mg and $10.6{\pm}6.6$ mg in the media cultured with Streptococcus mutans and each isolate, respectively(p<0.05). 3. The number of viable cells of Streptococcus mutans was $3.4{\times}10^9$ per ml in the cultured solution, whereas those of Streptococcus mutans in the combined culture with each of isolates were $4.6{\times}10^8$ and $2.4{\times}10^8$ per ml. 4. The optical density was 1.286 in the supernatant of Fusoacterium nucleatum after vortexing for 30 minutes, whereas in the supernatant of combined Fusoacterium nucleatum and each isolate, they were reduced to 0.628 and 00497, which the percentages of coaggregation between them were 2904% and 57.8%, respectively. 5. The optical density of Fusoacterium nucleatum precipitate was 1.794 in the culture media containing cysteine and $FeSO_4$ being reduced to 1.144 and 0.915 in the coaggregated precipitates of Fusoacterium nucleatum and each isolate. 6. The similarity values of 16S rDNA sequence between each of isolates and Lactobacillus salivarius subsp. salicinius were 99.60% and 99.73%, respectively, meaning that isolates were Lactobacillus salivarius subsp. salicinius. These results indicated that two strains isolated from children's saliva, which inhibited the formation of plaque and the production of volatile sulfur compounds, were identified as Lactobacillus salivarius subsp. salicinius.