The Prevotella intermedia group organisms in young children and their mothers as related to maternal periodontal status

Currently, the Prevotella intermedia group includes three biochemically and phylogenetically related species: Prevotella intermedia, Prevotella nigres cens, and the newly described Prevotella pallens. The two first-named speci es are mentioned with varying emphasis in connection with periodontal disea ses, while such a connection of P. pallens is not known. Mothers serve as a plausible source of bacteria to their children, and conceivably, a mother with periodontitis as a recurrent reservoir of periodontally infecting orga nisms. In the present study, 23 mothers and their young children were exami ned for the presence of the P. intermedia group organisms in relation to ma ternal periodontal status (I: periodontal health, II: initial periodontitis , and III: advanced periodontitis). Species differentiation was based on es tablished biochemical methods, electrophoretic mobility patterns, SDS-PAGE, and DNA hybridization. P. intel media was not recovered from children but nearly exclusively from mothers in group III, thus confirming its associati on with periodontitis. P. nigrescens and P. pallens were frequently found i n mothers and children. To determine bacterial transmission between a mothe r and her child, 72 isolates from 13 mother-child pairs were analyzed by ar bitrarily primed PCR (AP-PCR). Similar AP-PCR types of P. nigrescens and/or P. pallens were recovered from 3/4 pairs in group I, 2/5 pairs in group II , and none in group III. Our results indicate that different species within the P. intermedia group have a different colonization pattern in childhood and that the periodontal status reflects qualitatively their presence in m aternal saliva. Intra-familial transmission of P. nigrescens and P. pallens can occur in early childhood, however similar AP-PCR types were most obvio us within periodontally healthy mother-child pairs.