Concordance of Treponema denticola Colonization in Families

Objectives:The purpose of this study was to investigate the transmission of the anaerobic periodontitis associated bacterium Treponema denticola among family members. Colonization concordance for Treponema denticola was examined among the members of 100 extended families. Methods:The colonization status of 565 members of 100 multigeneration families was determined. Plaque samples were collected from each family member by placing paper points in the mesial sulcus of every tooth. The DNA was isolated from the combined paper points. A PCR assay was used for detection of Treponema denticola. A universal amplification was performed on each sample followed by a species-specific amplification targeting the 16S and intergenic spacer region between the 16S and 23S ribosomal genes. The samples were analyzed for the presence of the target bacteria by gel electrophoresis on a 1% agarose gel. All samples were amplified and scored a second time. If results were not in agreement, the assay was repeated. Results: Overall extended families were more likely (chisquare P=0.004) to be concordant for Td than would be expected by random distribution. Children with both parents positive were more likely (relative risk 5.4) to be colonized with T. denticola than those whose parents were not colonized. Among married couples from the parent generation, if the father was colonized, the mother had a 2.4 relative risk of being colonized. For the grandparent generation, having a colonized spouse did not confer extra risk of colonization. Conclusion: Contact with a family member infected with Treponema denticola increases the risk of colonization for both children and spouses. It appears Td may be commonly transmitted by contact with an infected family member. Supported by NIH Grant DE10467.