Relationship between oral gram-negative anaerobic bacteria in saliva of the mother and the colonization of her edentulous infant.

Various gram-negative anaerobic bacterial species can be detected in the oral flora of edentulous infants. However, knowledge of the initial infection source is still scarce. Thirty Caucasian mothers (mean age 30 years) and their edentulous infants (mean age 3 months) were examined for the possible similarity of the oral gram-negative anaerobic flora. Paraffin-stimulated saliva was collected from the mothers. A pooled swab sample from mucosal surfaces and unstimulated saliva were collected from the infants. The samples were inoculated on nonselective and selective media and cultured aerobically and anaerobically. All of the 30 mothers harbored Fusobacterium nucleatum and 29 mothers Prevotella melaninogenica in their saliva. The salivary levels of P. melaninogenica, F. nucleatum, nonpigmented Prevotella spp., Prevotella intermedia and Prevotella loescheii exceeded 10(4) CFU/ml in about half of the 30 mothers. At this maternal salivary level, the infants' colonization frequency of P. melaninogenica and F. nucleatum was doubled. A positive correlation between maternal salivary concentration and infant's colonization was found for P. melaninogenica. No positive association was found with nonpigmented Prevotella spp., P. intermedia and P. loescheii. It can be speculated that maternal saliva may act as a source of some gram-negative anaerobes in the oral microflora of edentulous infants as early as before tooth eruption.