A Study of the Overall Similarity of Certain Actinomycetes Mainly of Oral Origin

Abstract

Computer techniques were applied to the study of 71 isolates of branching or diphtheroid bacteria from human and bovine sources. Features including morphological and colonial characteristics, nutri-tional and environmental growth requirements, fermentative abilities and end-products and cell-wall composition were used to determine the relationships between these organisms. The features were deter-mined with aerobic or anaerobic growth conditions or both, according to the nature of the individual bacteria. Relationships between facultatively anaerobic micro-organisms were very similar whether the features were determined aerobically or anaerobically; some apparently close relationships were shown between preferentially aerobic and preferentially anaerobic bacteria when they were compared with facultatively anaerobic micro-organisms. The analysis separated groups of organisms corresponding to Actinomyces naeslundii, A. bovis, Nocardia salivae, Bacterionema matruchotii (Leptotrichia dentium) and Coryne-bacterium spp. The members of the various genera showed little af-finity to each other. A. naeslundii and A. bovis were fairly closely related and some unplaced isolates, including typical A. israelii strains, showed a lesser relationship to either or both of these species. Isolates of A. odontolyticus showed high similarity to A. bovis and were included in this species despite their better aerobic growth. Several isolates of A. naeslundii grew well aerobically and produced catalase; production of this enzyme is not, by itself, sufficient to remove an organism from the genus Actinomyces.