[Detection of the transmitted strains and non-transmitted strains of Mutans streptococci by AP-PCR].
OBJECTIVE
Dental caries is a transmissible infectious disease in which S. mutans plays the major role. The purpose of this study was to detect the S. mutans transmitted strains and non-transmitted strains by AP-PCR fingerprint for laying the foundation of study on the relation between bacterial properties of S. mutans and its transmission.


METHODS
Plaque samples were obtained from buccal surfaces of 20 3-4 years old children and their mothers. Caries experience was scored by dmft (DM-FT). Diet regime, breast feeding and care of the children were recorded. 200 Isolates of S. mutans were detected by S. mutans B medium and confirmed biochemically. DNA from each isolate was purified and AP-PCR fingerprinting was conducted. Amplicons were separated by electrophoresis in 1.5% agarose gels.


RESULTS
45 different patterns among the 200 isolates were found. There were 10 mothers (50%) and 15(75%) children owning one genotype while 10 mothers and 5 children owning more than one (2 mothers owning 5 types). The data showed that the mothers harbored a more heterogeneous population of S. mutans than their children. Comparisons in genotypes between children and their mothers discovered that 16(80%) children harbored the same genotypes as their mothers, indicating high transmission in the group of people. Detection of the S. mutans transmitted strains and non-transmitted strains in mothers demonstrated that 10 (50%) mothers harbored not only transmitted strains but also non-transmitted strains, suggesting that different strains had different ability of transmission.


CONCLUSIONS
AP-PCR was capable of detecting the S. mutans transmitted strains and non-transmitted strains. Some S. mutans genotypes had higher ability of transmission than others.
Li
Song
S
Department of Operative Dentistry and Endodontics, West China College of Stomatology, Sichuan University, Chengdu 610041, China.
Liu
Tianjia
T
Zhuang
Heng
H
D002675:Child, Preschool; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D003731:Dental Caries / Q000382:microbiology*; D003773:Dental Plaque / Q000382:microbiology*; D005192:Family Health; D005260:Female; D005838:Genotype; D006801:Humans; D018445:Infectious Disease Transmission, Vertical; D008297:Male; D009035:Mothers; D016133:Polymerase Chain Reaction / Q000379:methods; D013290:Streptococcal Infections / Q000635:transmission*; D013295:Streptococcus mutans / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*
D004269:DNA, Bacterial