It is a rod shaped, aerobic and motile bacteria, which is able to migrate across surfaces due its “swarming” characteristic in temperatures between 20 and 37 °C.

P. vulgaris occurs naturally in the intestines of humans and a wide variety of animals, and in manure, soil, and polluted waters.

Similar to other members of the Enterobacterales order, bacteria from the Proteus genus are glucose fermenting, oxidase-negative, catalase-positive, and nitrate-positive.

Glucose fermentation in this species can be demonstrated through the triple sugar iron (TSI) test.

However, further biochemical testing is now required to speciate Proteus since the discovery of the indole positive Proteus hauseri [4] Most strains produce a powerful urease enzyme, which rapidly hydrolyzes urea to ammonia and carbon monoxide; exceptions are some Providencia strains.

This system is based on historic observations of Edmund Weil (1879–1922) and Arthur Felix (1887–1956) of a thin surface film produced by agar-grown flagellated Proteus strains, a film that resembled the mist produced by breath on a glass.

[8][9][10][11] The cell wall O-antigen of certain strains of Proteus, such as OX-2, OX-19, OX-k, crossreact with several species of Rickettsia.