Normal commensal of skin is
**Core Concept**
The human skin is inhabited by a diverse range of microorganisms, with some being beneficial and others potentially pathogenic. **Normal skin flora** plays a crucial role in maintaining skin health and preventing infections. **Staphylococcus epidermidis** is one such commensal organism that is commonly found on the skin.
**Why the Correct Answer is Right**
**Staphylococcus epidermidis** is a type of coagulase-negative staphylococcus that is typically found on the skin and mucous membranes. It is a **gram-positive bacterium** that helps to prevent the colonization of more pathogenic organisms by competing for space and resources. This commensal relationship is essential for maintaining skin health and preventing infections.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because while other organisms may occasionally be found on the skin, they are not as commonly associated with the skin as **Staphylococcus epidermidis**.
**Option B:** Incorrect as it is not a typical commensal organism of the skin.
**Option C:** Incorrect because it is not a common skin flora.
**Option D:** Incorrect as it is not typically found on healthy skin.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that **Staphylococcus epidermidis** is a common cause of infections in patients with compromised immune systems or medical devices, such as catheters or prosthetics.
**Correct Answer:** D. Staphylococcus epidermidis