Abstract:

Objective: The purpose of this study was to investigate the relationship between genetic diversity within A-region of surface protein of Streptococcus~(serotype c) and their binding abilities. Methods: The clinical isolates of S. mumps (serotype c) included two groups with different binding abilities (cpm > 2000, cpm<1000)，which were derived from former work in our ex- perimental lab. The bacterial DNA~extracted, and the spaP-a (473一1571饰)~amplified using polymerase chain reaction (PCR)。Genetic diversity of spaP-a~assessed场using restriction fragment-length polymorphism (RFLP) with restriction endo- nuclease Hae.Results: Four different patterns of the spaP-a PCR-RFLP among strains were revealed when digested with Hae皿. The proportions of four genotypes of strains with different binding abilities were different(P<0.05).Conclusion: The genetic di- versity exists within the spaP-a(盯3一1571 bp) of the clinical isolates of S.~( serotype C ).The diversity of strains with higher binding ability was~apparent than those with lower one.

Key words: Streptococcus mutans, A-region of surface proteingenotypebinding ability