Which mechanism explains the development of methicillin-resistant Staphylococcus aureus (MRSA) resistance to beta-lactam antibiotics?
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A
Overproduction of beta-lactamase enzymes that destroy all penicillins
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B
Acquisition of mecA gene encoding an altered penicillin-binding protein (PBP2a) with low affinity for beta-lactams
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C
Efflux pump upregulation that removes beta-lactams from the bacterial cell
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D
Mutation of porins that prevents beta-lactam entry into the bacterial cell