Oral strains of Actinomyces.

Bergey (1907) is generally credited with the fir'st isolation of Actinomyces from the normal human mouth. Since then there have been a few reports of the recovery from the normal oral cavity of organisms which appear to have been identical, or nearly so, with strains isolated from clinical actinomycosis (Emmons, 1935, 1936, 1938; Ennever et al., 1951; Miller and Drake, 1951; Morris, 1954; Rosebury et al., 1944; Slack, 1942; Sullivan and Goldsworthy, 1940). In addition there have been numerous reports of the isolation from the mouth of one or more strains of organisms designated as Actinomyces. However, the data given in many of these reports were inadequate for the determination of the identity of the organisms described (Bartels, 1952; Bibby and Knighton, 1941; Bjerrum and Hansen, 1932; Citron, 1945; Crowley, 1941; Ennever and W7arner, 1952; Garrod, 1952a, b; Geister and .\Jeyer, 1951; Grythe, 1938; Harrison, 1948; Hemmens et al., 1941; Hemmens et al., 1946; Kay, 1947; Lord, 1933; Lord and Trevett, 1936; MNeyer and Verges, 1950; Naeslund, 1925, 1926). Mlore recently, Thoinpson and Lovestedt (1951) isolated organisms from the normal human mouth which differed significantly from those isolated fromllesions of actinomvcosis and suggested that these strains be designated as Actinomyces naeslundii. Garrod (1952b) has confirmed these findings. However, A. naeslundii has not yet been generally accepted as a valid species (Conant et al., 1954; Breed et al., 1957). In order to characterize further oral strains of Actinomyces and to compare them with available strains isolated from lesions, approximately 200 of the former, and 11 of the latter have been studied critically, especially with respect to their morphological and cultural characteristics.