What type of bacteria is responsible for causing syphilis?

The type of bacteria responsible for causing syphilis is classified as spirilla. These bacteria are characterized by their spiral or corkscrew shape. In the case of syphilis, the specific bacterium is called Treponema pallidum, which falls under the category of spirilla due to its unique, twisty structure. This shape allows the bacteria to move in a corkscrew motion, which can be advantageous for penetrating host tissues and evading the immune response.

In contrast, cocci are round-shaped bacteria, bacilli are rod-shaped, and staphylococci refer to clusters of round bacteria. While these other types of bacteria can cause different infections, they are not involved in syphilis, making spirilla the correct classification for the causative agent of this disease. Understanding the shapes and classifications of bacteria is crucial in microbiology and helps in identifying the types of infections they may cause.