Streptococcus mutans의 선택성 향상을 위한 방법 고찰: 원심분리법과 선택 배지의 활용

Abstract

Objectives: The first purpose of this study was to evaluate differences in selective ability for S. mutans between existing MSB and MS-MUT which was recently developed by Hirasawa and Takada. The second purpose was to verify whether centrifugal forces were able to enhance selective ability in S. mutans selective media and to find out the optimized centrifugal force in vitro culture. Methods: Salivary samples were collected from twenty five adults (Males: 13, Females: 12) and one milliliter of paraffin-stimulated saliva was collected for 5 minutes. MSB and MS-MUT media were used for S. mutans culture. All centrifugal conditions were in 4℃ and 15 minutes and centrifugal forces were 1000, 5000, 13000, and 20000 ×g. After the centrifugal process, we used with substratum layer for next procedure. The colony forming units (CFUs) of S. mutans and non-S. mutans in salivary samples were calculated by one experiened microbiologist. The t-test was used to compare CFUs between MSB and MS-MUT. The ANOVA test was used for evaluating of statistical significance in each centrifugal step. Results: The CFUs of S. mutans in MSB media were similar to MS-MUT meida in non centrifugal salivary samples. However, CFUs of non-S. mutans in MSB were significantly lower than MS-MUT (P<0.05). The lower stratum of centrigugal salivary sample with 13000 ×g showed the maximum CFUs of S.mutans and minimum CFUs of non-S. mutans. Conclusions: This results showed that existing MSB media was superior to new MS-MUT in selective culture of S. mutans. The centrifugal forces played an efficient role for S. mutans selective culture and the optimized centrifugal force was considered as 13,000 ×g.