The genus Bacterium was a taxon described in 1828 by Christian Gottfried Ehrenberg.
[2] In 1951 and then in 1954 it was recognised as a nomen generum rejiciendum, which means a generic name to be rejected; this also applied to its family Bacteriaceae.
[3][4] This genus included non-spore forming rods whose relation to other species was obscure (a "taxonomy dumping group").
This is different from the genus Bacillus, whose members were spore forming rods (sensu Cohn 1872[5]).
Given that the genus was abolished in the process of forming the Bacteriological Code there is no such thing as an official list of species present.