VRSA is best defined as vancomycin-resistant what organism?

VRSA is best defined as vancomycin-resistant what organism?

• A. Escherichia coli
• B. Staphylococcus aureus
• C. Streptococcus pneumoniae
• D. Pseudomonas aeruginosa

Answer: (B)

VRSA stands for vancomycin-resistant Staphylococcus aureus. Vancomycin is a last-resort antibiotic used to treat serious Staphylococcus aureus infections, including MRSA. When this organism gains resistance to vancomycin, it is labeled VRSA, signaling that the infection is much harder to treat. This resistance typically arises when S. aureus acquires resistance genes (such as vanA) from other bacteria, altering the cell wall target so vancomycin can no longer bind effectively. The other bacteria listed don’t fit the term. Escherichia coli and Pseudomonas aeruginosa are Gram-negative and vancomycin isn’t effective against Gram-negatives because of their outer membrane barriers. Streptococcus pneumoniae is a Gram-positive organism, but the designation VRSA specifically refers to Staphylococcus aureus, not pneumococcus.

VRSA stands for vancomycin-resistant Staphylococcus aureus. Vancomycin is a last-resort antibiotic used to treat serious Staphylococcus aureus infections, including MRSA. When this organism gains resistance to vancomycin, it is labeled VRSA, signaling that the infection is much harder to treat. This resistance typically arises when S. aureus acquires resistance genes (such as vanA) from other bacteria, altering the cell wall target so vancomycin can no longer bind effectively.

The other bacteria listed don’t fit the term. Escherichia coli and Pseudomonas aeruginosa are Gram-negative and vancomycin isn’t effective against Gram-negatives because of their outer membrane barriers. Streptococcus pneumoniae is a Gram-positive organism, but the designation VRSA specifically refers to Staphylococcus aureus, not pneumococcus.