Alcaligenes faecalis

Alcaligenes faecalis is a Gram-negative, rod-shaped, motile, non-nitrate-reducing, oxidase-positive, catalase-positive, alpha-hemolytic, and citrate-positive (variable) obligate aerobe commonly found in the environment. It was originally named for its first discovery in feces, but was later found to be much more common in other places, as well. Optimum growth occurs around 37°C with no pigmentation. While opportunistic infections do occur, the bacterium is generally considered nonpathogenic. When an opportunistic infection does occur, it is usually observed in the form of a urinary tract infection. The bacterium degrades urea, creating ammonia which increases the pH of the environment. Although A. faecalis is considered to be alkali-tolerant, it maintains a neutral pH in its cytosol to prevent the damaging or denaturing of its charged species and macromolecules.