In amphitrichous bacteria, flagella operate one at a time for smooth and accurate multi-directional travel. Examples of amphitrichous bacteria include alcaligenes faecalis, which causes peritonitis, meningitis, and appendicitis; and rhodospirillum rubrum, which is used for to ferment alcohol.
Bacterial flagella are helically shaped structures containing the protein flagellin. The base of the flagellum (the hook) near the cell surface is attached to the basal body enclosed in the cell envelope. The flagellum rotates in a clockwise or counterclockwise direction, in a motion similar to that of a propeller.