Spiral-shaped bacteria are called spiral bacteria. These types of microorganisms come in three various forms, which include vibrio, spirillum and spirochete.
Bacteria are prokaryotic unicellular microscopic organisms, although some species have been known to grow in sizes that can be perceived by the naked eye. Bacteria are generally classified according to their shapes. The three primary bacterial shapes are spherical, rod-shaped and spiral, or twisted. Spiral bacteria contain one or several twists or waves. Vibrios appear like curved rods, while both spirilla and spirochetes are helical in shape. Spirilla are typically rigid in structure, whereas spirochetes have pliant bodies. Other known bacterial shapes include sheathed, stalked, star-shaped, square, lobed, rectangular and spindle-shaped.