Ceftaroline differs from earlier cephalosporins in its clinical utility against MRSA because:
- A It has high binding affinity for PBP2a (the altered penicillin-binding protein encoded by mecA in MRSA) ✓
- B It is resistant to all beta-lactamases including carbapenemases
- C It inhibits transpeptidase activity via a mechanism independent of PBPs
- D It acts synergistically with vancomycin by blocking D-Ala-D-Lac-type cell wall precursors
Correct answer: A. It has high binding affinity for PBP2a (the altered penicillin-binding protein encoded by mecA in MRSA)
Explanation
MRSA resistance to beta-lactams is mediated by the mecA gene encoding PBP2a (penicillin-binding protein 2a), which has extremely low affinity for virtually all beta-lactams. Ceftaroline fosamil (a 5th-generation cephalosporin) is unique in having a rigid side-chain with high binding affinity for PBP2a, restoring bactericidal activity against MRSA. It does not affect D-Ala-D-Lac (a vancomycin resistance mechanism in VRE) and is susceptible to some extended-spectrum beta-lactamases.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.