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Fusobacterium nucleatum, a Gram-negative anaerobic rod associated with periodontal disease, is also found in healthy individuals and is considered part of the indigenous oral microflora. Although intra-familial transmission of periodontal pathogens has been documented, there are no data relating transmission of F. nucleatum. This study investigated the distribution of F. nucleatum strains in 4 strictly healthy families. 32 F. nucleatum strains were isolated from 19 individuals (8 parents and 11 children aged 1-13 years). DNA was extracted and digested with the restriction endonucleases EcoRI, TaqI and HindIII. The digests were separated by electrophoresis through 0.8% agarose gels at 40 V overnight, in TBE buffer containing 1 microg/ml ethidium bromide, and photographed. The DNA was transferred to nylon filters by Southern blotting and hybridized with a digoxigenin labelled E. coli rRNA probe (Kit Dig DNA Labelling mixture - Boehringer). Probed DNA was visualized colorimetrically (CSPD Luminescent Detection Kit Boehringer) and photographed (Amersham). We found that 10/11 children shared identical ribotypes with at least one of their respective parents. Some of the children also harbored a unique additional ribotype. On the basis of indistinguishable restriction endonuclease and ribotype patterns these results support the hypothesis that intra-familial transmission of F. nucleatum is possible.

A rapid and simple method for lysing anerobic Gram‐positive rods is described. It is based on the simultaneous action of lysozyme and achromopeptidase (each at 5 mg/g wet weight of cells), followed by the action of SDS (0.2%). The efficiency of the bacterial lysis is measured by the yield of DNA obtained with Marmur's modified procedure. This method permits effective lysis of small amounts of anaerobic rods (200 mg wet weight) independent of their growth phase, and extraction of DNA for further analysis. It is particularly useful for strains with low growth such as certain species of Actinomyces and Bifidobacterium and it saves considerable time.

Synthesis of a new model of the Zn-based complex with two complementary antibiotics (sulfonamide and quinolone).

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