Ectobacillus is a genus of Gram-positive (with the exception of Ectobacillus funiculus, which is Gram-negative), rod-shaped bacteria in the family Bacillaceae within the order Bacillales.[1][2] The type species for this genus is Ectobacillus panaciterrae.[3]
Ectobacillus is composed of species originally belonging to the genus Bacillus. The genus Bacillus comprises a large number of phylogenetically unrelated bacteria species with a diverse range of biochemical characteristics.[4][5] The polyphyletic nature of the genus is partly due to the vague criteria used to assign species to this genus (ie. accepting all species that are able to form endospores in aerobic conditions).[6] Comparative genomic analyses and phylogenetic studies have set out to clarify the complex taxonomic relationship of this genus, resulting in the transfer of many species into novel genera such as Virgibacillus, Solibacillus, Brevibacillus and Alteribacter.[7][8][9][1] In addition, the genus Bacillus has been restricted to include only species closely related to Bacillus subtilis and Bacillus cereus.[10][1]
The name Ectobacillus is derived from its taxonomic position in relation to Bacillus. The prefix "ecto-" (which comes from the Greek preposition ecto, and translates to "outside") and the suffix "-bacillus" (which comes from the Latin noun Bacillus, referring to a rod or small staff, as well as Bacillus, a bacterial genus) come together to form the name Ectobacillus, meaning "outside of Bacillus".[1]