Bacterie-fylum Actinobacteria

Actinobacteria are a diverse group of Gram-positive bacteria, including coryneform, propionic acid bacteria, mycobacteria, and actinomycetes, and are distinguished by their high G+C DNA content.

The coryneform bacteria are aerobic, nonmotile rods with irregular, club-shaped, or V-shaped arrangements due to snapping division.

The main species include pathogenic Corynebacterium diphtheriae, and Arthrobacter — a genus of soil bacteria capable of switching between rod and coccus forms.

Propionic acid bacteria, such as Propionibacterium, are anaerobes that ferment lactic acid, producing carbon dioxide and propionic acid.

Mycobacteria are commonly found in soils; most are harmless, but some, like Mycobacterium tuberculosis, are significant human pathogens.

Mycobacterium tuberculosis is a slow-growing species, but the genus Mycobacterium also includes fast-growing species like Mycobacterium smegmatis.

Their unique features include mycolic acids in their cell walls and the ability to undergo branching or filamentous growth.

Actinomycetes are filamentous and aerobic bacteria, forming mycelia and desiccation-resistant spores.

A diverse genus, Streptomyces, is well-known for its antibiotic production.