**Core Concept**
Methicillin-resistant Staphylococcus aureus (MRSA) is a type of bacteria that has developed resistance to methicillin and other beta-lactam antibiotics. This resistance is due to the acquisition of the mecA gene, which encodes for an altered penicillin-binding protein (PBP2a) that has a low affinity for beta-lactam antibiotics.

**Why the Correct Answer is Right**
The mecA gene is located on a mobile genetic element called the staphylococcal cassette chromosome mec (SCCmec), which can be transferred between Staphylococcus aureus strains. This transfer of resistance genes is a major concern in hospitals and healthcare settings, where MRSA can spread and cause severe infections. The altered PBP2a protein produced by MRSA is responsible for its resistance to beta-lactam antibiotics, including methicillin, oxacillin, and nafcillin.

**Why Each Wrong Option is Incorrect**
**Option A:** MRSA is susceptible to all beta-lactam antibiotics. This is incorrect because MRSA has developed resistance to most beta-lactam antibiotics, including methicillin, oxacillin, and nafcillin.

**Option B:** MRSA is caused by a mutation in the mecA gene. This is incorrect because the mecA gene is not mutated in MRSA, but rather is acquired through the transfer of the SCCmec element.

**Option C:** MRSA is only found in hospitals. This is incorrect because MRSA can be found in both hospital and community settings, and can cause a range of infections from mild to severe.

**Clinical Pearl / High-Yield Fact**
To prevent the spread of MRSA, hospitals and healthcare settings should implement strict infection control measures, including hand hygiene, use of personal protective equipment, and thorough cleaning and disinfection of surfaces and equipment.

**Correct Answer:** C. MRSA can be found in both hospital and community settings.