MRSA stands for which organism?

MRSA stands for which organism?

• A. Methicillin-resistant Staphylococcus epidermidis
• B. Methicillin-resistant Staphylococcus aureus
• C. Methicillin-sensitive Staphylococcus aureus
• D. Vancomycin-resistant Staphylococcus aureus

Answer: (B)

MRSA refers to a strain of Staphylococcus aureus that has acquired resistance to methicillin and related beta-lactam antibiotics. The key is the organism being Staphylococcus aureus and the resistance to methicillin. Among the options, the one that matches both the species (Staphylococcus aureus) and the resistance pattern (methicillin-resistant) is the correct description. Why this fits best: Staphylococcus aureus is a common cause of skin infections, pneumonia, and bloodstream infections. When it’s resistant to methicillin, it’s labeled MRSA, signaling that standard beta-lactam antibiotics won’t be effective. The other choices describe a different species (Staphylococcus epidermidis), a methicillin-susceptible strain (MSSA), or resistance to a later antibiotic (VRSA), which are not what MRSA denotes.

MRSA refers to a strain of Staphylococcus aureus that has acquired resistance to methicillin and related beta-lactam antibiotics. The key is the organism being Staphylococcus aureus and the resistance to methicillin. Among the options, the one that matches both the species (Staphylococcus aureus) and the resistance pattern (methicillin-resistant) is the correct description.

Why this fits best: Staphylococcus aureus is a common cause of skin infections, pneumonia, and bloodstream infections. When it’s resistant to methicillin, it’s labeled MRSA, signaling that standard beta-lactam antibiotics won’t be effective. The other choices describe a different species (Staphylococcus epidermidis), a methicillin-susceptible strain (MSSA), or resistance to a later antibiotic (VRSA), which are not what MRSA denotes.