No abstract

Oral colonization of hamsters by Actinomyces species of human origin was studied. Strains of A. viscosus and A. naeslundii became implanted while strains of A. israelii, A. odontolyticus and Arachnia propionica did not. A glucose diet was superior to a sucrose diet for A. viscosus and A. naeslundii implantation. A. naeslundii appeared to colonize the animals at a slower rate. Suppression of the oral-intestinal flora by a short-term pretreatment of 3-7 days or continuous exposure to dietary streptomycin sulphate also improved implantation of streptomycin-resistant strains of these 2 species. An experimental period of 3-6 months was required for development of gross deposits of cervical plaque and periodontal pathology.Address:

Reference strains of A. israelii were orally implanted in germ-free rats after multiple inoculations. Early colonization was associated with areas of interdental hair and bedding impactions. Largest populations of organisms were isolated from teeth, as compared to the tongue, cheek, or palate. Examination of molar teeth with the scanning electron microscope revealed bacterial accumulations in the occlusal fissures, but not on smooth or approximal surfaces. Extensive plaque formation after 100-150 d was accompanied by root-surface caries and bacterial invasion of the pulp. There was no evidence of bacterial penetration of the dentin underlying surface enamel.

A simple and convenient method for culturing anaerobic bacteria is described. Cultures can be grown in commercially available flasks normally used for preparation of sterile external solutions. A special disposable rubber flask closure maintains anaerobic conditions in the flask after autoclaving. Growth of a variety of anaerobic oral bacteria was comparable to that obtained after anaerobic incubation of broth cultures in Brewer Anaerobic Jars.