Infections due to Actinomyces neuii (former "CDC coryneform group 1" bacteria).

Sixty-seven patients with infections in which the recently proposed species Actinomyces neuii was involved were observed during a 4 1/2-year period. Microbiological as well as clinical features of the patients are presented. A. neuii does not cause typical actinomycosis and is detected most often in material from abscesses or infected atheromas. One case of a fatal septicemia caused by A. neuii in a non-immunocompromised host was seen. Antimicrobial susceptibility patterns of A. neuii isolates and results of various treatment regimens are discussed.