Which term describes spiral- or corkscrew-shaped bacteria?

The term that accurately describes spiral- or corkscrew-shaped bacteria is "spirochetes." This classification pertains specifically to a group of bacteria that have a distinctive helical shape, enabling them to move in a unique manner, often resembling a corkscrew motion, which can be beneficial for their motility in viscous environments, such as tissues or fluids.

Spirochetes are notable not just for their shape but also for their length and flexibility, which distinguishes them from other forms of bacteria. Understanding this classification is essential for recognizing the morphology and behavior of various bacterial strains, particularly in the context of infectious diseases where spirochetes may play a crucial role, such as in Lyme disease (Borrelia burgdorferi) and syphilis (Treponema pallidum).

In contrast, cocci refer to spherical-shaped bacteria, bacilli are rod-shaped, and streptococci indicate a type of cocci that are arranged in chains. While these other forms are significant in microbiology, they do not capture the distinct characteristics of spirochetes, making the latter the correct term for spiral- or corkscrew-shaped bacteria.