SUMMARY
Actinomyces israelii
has long been recognized as a causative agent of actinomycosis. During the past 3 decades, a large number of novel
Actinomyces
species have been described. Their detection and identification in clinical microbiology laboratories and recognition as pathogens in clinical settings can be challenging. With the introduction of advanced molecular methods, knowledge about their clinical relevance is gradually increasing, and the spectrum of diseases associated with
Actinomyces
and
Actinomyces
-like organisms is widening accordingly; for example,
Actinomyces meyeri
,
Actinomyces neuii
, and
Actinomyces turicensis
as well as
Actinotignum
(formerly
Actinobaculum
)
schaalii
are emerging as important causes of specific infections at various body sites. In the present review, we have gathered this information to provide a comprehensive and microbiologically consistent overview of the significance of
Actinomyces
and some closely related taxa in human infections.