Untraditional glucose fermenting actinomycetes as human pathogens. Part I: Actinomyces naselundii as a cause of abdominal actinomycosis.

Actinomyces naeslundii was proved as a primary pathogen in the case of a fulminant abdominal infection of a 74 aged woman. The preliminary diagnosis of actinomycosis based on direct microscopical findings of microgranules in the pus was confirmed by the results of cultivation and casuistry in addition. The case was of a typical course for actinomycosis and penicillin following surgery was of life saving effect for the patient who was dismissed asymptomatic after 55 days of hospitalization. Actinomycotic microgranules were demonstrated in the pus from the natural infection and from experimentally infected mice and the causative agent Actinomyces naeslundii TR 91/67 was defined. Nevertheless it was concluded that the judgment of the pathogenicity of Actinomyces naeslundii and of the other members of the heterogenous group of etiological agents of human actinomycosis still remains a matter of delicacy in any actual case of their isolation. In practice however, the presumption of actinomycotic etiology of an actual infection may be supported in retrospect by the dramatical effect of penicillin without regard to the presence of concomitant microflora not necessarily sensitive to penicillin.