이하선 타액의 세균응괴 및 알칼린 포스퍼타제의 수준에 의한 Streptococcus sanguis 균주의 유형화에 관한 연구

Abstract

Streptococcus sanguis displays considerable phenotypic and genotypic diversity, which makes it difficult to classify within a taxonomic framework. The two phenotyic properties of these organisms, the alkaline phosphatase production and parotid saliva-induced aggregation were reported useful in grouping certain strains of this species. Handley et al. reported that the ability or inability to produce alkaline phosphatase corresponds respectively with the presence or absence of aggregation property of the strains studied. In the present investigation, we studied on the grouping of S. sanguis which includes either the laboratory strains or the strains isolated from dental caries lesions and classified as S. sanguis based on the scheme of Hardie and Bowden. A spectrophotometric measurement of sedimentation was used to estimate the size of clumps formed after incubation of S. sanguis with parotid saliva. The alkaline phosphatase activity was determined spectrophotometrically by measuring the p-nitrophenol released when bacterial cells were incubated with the enzyme substrate, p-nitrophenyl phosphate. To check whether or not the use of intact bacterial cells were adequate for the enzyme detection disruptive cells were also used. The following results were obtained. S. sanguis strains exhibited characteristic sedimentation patterns when the cells were aggregated by parotid saliva. According to the level of alkaline phosphatase determined, S. sanguis strains could largely be divided into three groups: strong producer, poor producer, and non-producer. The bacterial strains showing no alkaline phosphatase activity when assayed with intact cells neither exhibited the activity when broken cells were used as an enzyme source. Coykendall`s Group I and III strains of S. sanguis were aggregated by parotid saliva. According to the report of Handley, the Group III strain of Coykendall should show ``+ +`` or ``- -`` pattern in alkaline phosphatase production and aggregation. However the present study showed that the corresponding pattern was ``- +``. The laboratory strains 10557 and 9811 belonging to Group II of Coykendall were positive and negative respectively in alkaline phosphatase production and both negative in aggregation.