Cohort study about transmission of cariogenic bacterium between mother and child

2005 Fiscal Year Final Research Report Summary

• Project/Area Number: 15592205
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Social dentistry
• Research Institution: Hokkaido University
• Principal Investigator: OOKUBO Ruka Hokkaido Univ Hokkaido Univ. Hospital, Inst., 北海道大学病院, 助手 (80271683)
• Co-Investigator(Kenkyū-buntansha): MORITA Manbu Hokkaido Univ., Grad. Sch. Of Dent. Med, Prof., 大学院歯学研究科, 教授 (40157904) ; HONGO Hirohisa Hokkaido Univ., Grad. Sch. Of Dent Med, Inst, 大学院歯学研究科, 助手 (00281816)
• Project Period (FY): 2003 – 2005
• Keywords: Cariogenic bacterium / DNA / transmission / breast-fed infant / Tooth caries / lifestyle / Cohort study

Research Abstract

Streptococcus mutans are considered to transmit to children from their own mothers, however, the exact time of the infection is unknown. And it has not been reported how Streptococcus mutans transform their genes.
We secured the cooperation of the day-care center for infant to collect the bacterial samples from the mouth of the infant and their mothers.
109 pairs of mother and infant agreed with the purpose of our study and 100 pairs joined the dental checkup. We collected the samples from all attendance. We incubated these samples with TYCSB agar medium for 3 days. Then we inoculate single colonies on the plate into the TYCS liquid medium and amplified the bacteria. We collected the bacterium by centrifugation and extracted DNA. The DNA were digested with restriction enzymes and analyzed by electrophoresis, however, we could not got clear electrophoretic pattern. Then we analyzed the samples by PCR by using the primer complementary to a part of 16SrRNA of S. mutans. We obtained PCR products of about 1400bp and analyzed the base sequence. We also analyzed the S.mutans by AP-PCR. We could not find the homology among the samples.