All Bacterial Classes

Gammaproteobacteria is a class of bacteria in the phylum Pseudomonadota (synonym Proteobacteria).

Alphaproteobacteria or α-proteobacteria, also called α-Purple bacteria in earlier literature, is a class of bacteria in the phylum Pseudomonadota (also called "Proteobacteria").

Betaproteobacteria are a class of Gram-negative bacteria, and one of the six classes of the phylum Pseudomonadota (synonym Proteobacteria).

Bacilli is a taxonomic class of bacteria that includes two orders, Bacillales and Lactobacillales, which contain several well-known pathogens such as Bacillus anthracis (the cause of anthrax).

The Clostridia are a highly polyphyletic class of Bacillota, including Clostridium and other similar genera.

Actinomycetes is a class of bacteria in the phylum Actinomycetota.

Deinococcota (synonym, "Deinococcus-Thermus") is a phylum of bacteria with a single class, Deinococci (from Ancient Greek δεινός (deinós), meaning "terrible", and κόκκος (kókkos), meaning "berry"), that are highly resistant to environmental hazards, also known as extremophiles.

The class Flavobacteriia is composed of a single class of environmental bacteria.

A spirochaete () or spirochete is a member of the phylum Spirochaetota (also called Spirochaetes ), which contains distinctive diderm (double-membrane) Gram-negative bacteria, most of which have long, helically coiled (corkscrew-shaped or spiraled, hence the name) cells.