Bacillus (shape)



Although Bacillus, capitalized and italicized, specifically refers to the genus, the word bacillus may also be used to describe any rod-shaped bacterium, and in this sense, bacilli are found in many different taxonomic groups of bacteria.

It should be noted that the cell morphology term bacillus does not necessarily indicate Gram-positive staining, as E. coli is a Gram-negative, rod-shaped bacteria.

Enterobacteriaceae is also Gram-negative, and rod-shaped.

Bacillus are usually solitary, but can combine to form diplobacilli, streptobacilli, and palisades.

MacConkey agar can be used to distinguish among Gram negative bacilli.