Which one of the following uses its type IV pili for twitching motility on surfaces?
**Core Concept**
Type IV pili are protein structures found on the surface of certain bacteria, involved in adhesion, DNA transfer, and twitching motility. This unique form of movement is essential for bacterial colonization and biofilm formation on surfaces.
**Why the Correct Answer is Right**
Twitching motility is a characteristic feature of type IV pili-mediated movement, which involves the extension and retraction of these pili to propel the bacterium forward on a surface. This process is crucial for the colonization of mucosal surfaces and the formation of biofilms, which can lead to infections. The type IV pili system consists of a pilus assembly machine, a pilus retraction motor, and a regulatory system that controls the assembly and disassembly of the pili.
**Why Each Wrong Option is Incorrect**
**Option A:** This option does not specify a bacterium known for twitching motility. While some bacteria exhibit twitching motility, it is not a characteristic of this organism.
**Option B:** This option does not describe a bacterium with type IV pili-mediated twitching motility. Type IV pili are involved in adhesion and DNA transfer, but this bacterium is not known for twitching motility.
**Option D:** This option does not accurately describe the use of type IV pili for twitching motility. While type IV pili are involved in adhesion and DNA transfer, this bacterium does not exhibit twitching motility.
**Clinical Pearl / High-Yield Fact**
Bacteria with type IV pili-mediated twitching motility are often associated with mucosal infections, such as otitis media and conjunctivitis. The ability to form biofilms on mucosal surfaces makes these bacteria more resistant to antibiotics and host immune defenses.
**Correct Answer:** C.