This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Staphylococci, Subject name: Microbiology
True statement regarding MRSA is: 
Select and explain. 
A. Ceftriaxone is preferred for treatment of superficial MRSA infections, B. MRSA isolates produce (3-lactamase, C. The mecA gene of MRS A encodes for penicillin- binding protein 2a (PBP2a), which has high affinity for (3-lactam antibiotics, D. Pulsed gel field electrophoresis is used for typing
D: Pulsed gel field electrophoresis is used for typing
Answer: D: Pulsed gel field electrophoresis is used for typing 
Explanation: Ref: Ananthanarayan, Paniker CJ. Textbook of Microbiology. 8th Edition. London: John Wiley & Sons: 2009. Pg. 20)Explanation:Methiciliin resistant strains of Staph aureus (MRSa) possess meca gene.The mecA gene encodes penicillin-binding protein 2a (PBP2a), which differs from other penicillin-binding proteins as it has reduced affinity for (3-lactam antibiotics.MRSA isolates are resistant not merely to penicillin, but also to all other beta lactam antibiotics including cephalosporins, carba- penems.For life-threatening MRSA infections, vancomycin is the drug of choice.For mild superficial lesions, systemic antibiotics may not be necessary.Topical applications of drugs not used systemic ally, such as bacitracin, cblorhexidine or mupirocin, may be sufficient.