Corynebacterineae

Corynebacterineae is a suborder of the class Actinobacteria, comprising a diverse group of Gram-positive, high G+C-content bacteria within the phylum Actinobacteria. Members are typically non-sporulating, aerobic or facultatively anaerobic, and exhibit a range of morphologies, from rods to filamentous forms; many occur in irregular, club-shaped cells that can align in palisades.

The suborder includes several prominent genera, most notably Corynebacterium, Mycobacterium, and Nocardia, as well as related genera such as Dietzia and Rhodococcus. These bacteria are commonly found in soil and water and can be commensals on skin and mucous membranes, with some species adapted to plant or animal associations.

Although lifestyle varies, many Corynebacterineae share a thick cell envelope with high lipid content. Some members possess mycolic acids, which is characteristic of the mycobacterial lineage, and may be acid-fast-positive, as seen in Mycobacterium and Nocardia. Others, such as Corynebacterium, are not acid-fast but still have the high G+C content characteristic of Actinobacteria.

Medical and industrial relevance is significant. Pathogenic species include Corynebacterium diphtheriae, the agent of diphtheria; pathogenic Mycobacterium species (e.g., M. tuberculosis complex) cause tuberculosis; and Nocardia species can cause nocardiosis. On the industrial side, Corynebacterium glutamicum is widely used in amino acid production, and other members contribute to biotechnological processes.

Taxonomy is based on phylogenetic analyses of 16S rRNA genes and chemotaxonomic characteristics, and the circumscription of Corynebacterineae has undergone revisions as new data emerge.