Actinomyces naeslundii as an agent of human actinomycosis.

The repeated isolation of Actinomyces naeslundii from clinical materials associated with disease led to a comparison of isolates from the normal mouth with isolates from pathological clinical materials not from the mouth area. No important differences were observed between the isolates from these two sources. A human case of empyema of the gall bladder, apparently due to A. naeslundii, is described.