THE DISTRIBUTION AND TRANSMISSION OF ACTINOBACILLUS-ACTINOMYCETEMCOMITANS IN FAMILIES WITH LOCALIZED JUVENILE PERIODONTITIS

The prevalence and distribution of A. actinomycetemcomitans in familie s where at least one family member (proband) suffered from localized j uvenile periodontitis was investigated. 25 probands with localized juv enile periodontitis (LJP) and their 78 close family members were scree ned for the presence of A. actinomycetemcomitans. Among these 25 famil ies, 10 contained at least one additional family member colonized with oral A. actinomycetemcomitans. Genomic DNA from subgingival A. actino mycetemcomitans strains from each of the probands and their family mem bers were amplified and characterized by the polymerase chain reaction (PCR) using a single primer known to distinguish A. actinomycetemcomi tans strains. The PCR products from each strain were separated by elec trophoresis on a 1% submarine agarose gel containing ethidium bromide and visualized by UV light transillumination. The studies showed that 41.2% of the parents and 58% of the siblings in this LJP-based populat ion harbored the bacterium. Comparison of the PCR generated amplitypes showed that there was a wide distribution of amplitypes among the pro bands and immediate relatives. No clear transmission paths were observ ed in this specific population.