Enterobacter aerogenes is a Gram-negative bacterium with a rod-shaped morphology. This means it has a cell wall that does not retain the crystal violet stain used in Gram staining, and its cells appear as short, cylindrical rods under a microscope.

While its cellular arrangement isn't a defining characteristic, Enterobacter aerogenes typically occurs in pairs or short chains. This arrangement is not as tightly clustered as a "coccus" arrangement (spherical bacteria in clusters) or as extended as a "filamentous" arrangement (long, chain-like structures).

It's important to note that the specific arrangement can vary depending on growth conditions and the stage of the bacterial life cycle.