Which of the following third generation cephalosporin has activity against MRSA (Methicillin Resistant Staphylococcus Aureus)?
**Core Concept**
Third-generation cephalosporins are a class of beta-lactam antibiotics that have a broad spectrum of activity against both Gram-positive and Gram-negative bacteria. They work by inhibiting cell wall synthesis through the inhibition of penicillin-binding proteins (PBPs). However, their activity against MRSA is limited.
**Why the Correct Answer is Right**
Framycetin is not the correct answer, but we'll get to that in a moment. MRSA is resistant to methicillin and other beta-lactam antibiotics due to the acquisition of the mecA gene, which encodes for an altered PBP2a. This altered PBP has a low affinity for beta-lactams, rendering them ineffective against MRSA. However, some third-generation cephalosporins, such as ceftaroline, have a higher affinity for PBP2a and can inhibit cell wall synthesis in MRSA.
**Why Each Wrong Option is Incorrect**
* **Option A:** Ceftriaxone is a third-generation cephalosporin, but it does not have activity against MRSA. It is primarily used to treat infections caused by Gram-negative bacteria.
* **Option B:** Cefotaxime is another third-generation cephalosporin, but it is also not effective against MRSA. It is often used to treat infections caused by Gram-negative bacteria, particularly in the treatment of meningitis.
* **Option C:** Ceftaroline is a fourth-generation cephalosporin, not a third-generation cephalosporin. However, it is the correct answer, as it has activity against MRSA.
**Clinical Pearl / High-Yield Fact**
When treating infections caused by MRSA, it's essential to use antibiotics that have been specifically shown to be effective against this pathogen. Ceftaroline is a valuable option in the treatment of complicated skin and skin structure infections caused by MRSA.
**Correct Answer:** C. Ceftaroline.