Site-specific oral colonization of mutans streptococci detected by arbitrarily primed PCR fingerprinting.

The clonal diversity and colonization pattern of mutans streptococci within an individual were studied by using a total of 50 tooth site samples obtained from seven 3- to 7-year-old children. Five children contributed saliva samples. From the 7 subjects, 90, 74, 81, 53, 83, 103, and 114 isolates (a total of 598) representing Streptococcus mutans and Streptococcus sobrinus were included for arbitrarily primed polymerase chain reaction (AP-PCR) fingerprinting. The children harbored one to four different AP-PCR types of mutans streptococci. In 3 of the 7 children, the distribution of AP-PCR types of S. mutans differed depending on tooth site (chi-square test for heterogeneity, p<0.001), suggesting that mutans streptococcal clones may selectively colonize specific hard-tissue sites.