The Comparison of Proteins Elaborated by Streptococcus mutans Strains Isolated from Caries Free and Susceptible Subjects

Objective(s): The oral streptococci especially mutans Streptococci are related with the development of caries in humans. However, they are commonly distributed not only in populations with moderate or high caries incidence but also in populations having no or low caries experience. So, in this study, the differences between protein profiles of Streptococcus mutans from different sources were compared. Materials and Methods: Twelve S. mutans strains were isolated from caries-susceptible, caries-free subjects and also S. mutansATCC35668. Total proteins of the strains were extracted, and were analyzed through SDS-PAGE technique with coomassie staining. Results: The protein profiles of caries-susceptible subjects were different from those of caries-free subjects. The major protein bands of SDS-PAGE analysis were observed 26-100kDa and 45-57kDa in caries-susceptible and caries-free subjects, respectively. The major protein bands of SDS-PAGE analysis of S.mutans ATCC35668 were between 35-100kDa. Major significant differences between the protein patterns of two subject groups and interestingly, non-significant differences between the strains of each group were also found. The significant differences between the protein band number of S.mutansATCC35668 and caries-free isolates were also observed; while, there were no significant differences between S.mutansATCC35668 and caries-susceptible subject isolates. The analysis of clusters by Hierarchical cluster method confirmed the clear distinction between S.mutans strains of two groups. Also, there was a clear distinction between the strain of S.mutansATCC35668 and caries free strains Conclusion: The less protein bands and diversity in caries-free rather than caries-susceptible isolates may be the less cariogenicity it may cause. It is also revealed that the protein pattern analysis of S.mutans strains can be the suitable way for differentiation of them.