Actinomycetes

Actinomycetales
Scanning electron micrograph of Actinomyces israelii.
Scientific classification
Domain:	Bacteria
Phylum:	Actinobacteria
Class:	Actinobacteria
Subclass:	Actinobacteridae
Order:	Actinomycetales Buchanan, 1917
Suborders/Families
Actinomycineae Actinomycetaceae Actinopolysporineae Actinopolysporaceae Catenulisporineae Catenulisporaceae Actinospicaceae Corynebacterineae  ?Tomitella  ?Hoyosella Corynebacteriaceae Dietziaceae Gordoniaceae Mycobacteriaceae Nocardiaceae Segniliparaceae Tsukamurellaceae Frankineae Acidothermaceae Cryptosporangiaceae Frankiaceae Geodermatophilaceae Nakamurellaceae Sporichthyaceae Glycomycineae Glycomycetaceae Jiangellineae Jiangellaceae Kineosporiineae Kineosporiaceae Micrococcineae  ?Koreibacter  ?Luteimicrobium Beutenbergiaceae Bogoriellaceae Brevibacteriaceae Cellulomonadaceae Demequinaceae Dermabacteraceae Dermatophilaceae Dermacoccaceae Intrasporangiaceae Jonesiaceae Microbacteriaceae Micrococcaceae Promicromonosporaceae Rarobacteraceae Ruaniaceae Sanguibacteraceae Micromonosporineae Micromonosporaceae Propionibacterineae Nocardioidaceae Propionibacteriaceae Pseudonocardineae Pseudonocardiaceae Streptomycineae Streptomycetaceae Streptosporangineae  ?Sinosporangium Nocardiopsaceae Streptosporangiaceae Thermomonosporaceae

The Actinomycetales are an order of Actinobacteria. A member of the order is often called an actinomycete. The actinomycetes are very diverse and contain a variety of subdivisions, as well as yet-unclassified isolates, mainly because some genera are very difficult to classify because of a highly niche-dependent phenotype. For example, Nocardia contains several phenotypes first believed to be distinct species before their differences were shown to be entirely dependent on their growth conditions.

Actinomycetales are Gram-positive, but several species have complex cell wall structures that make the Gram staining unsuitable (e.g. Mycobacteriaceae).

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Wikipedia