Question #1 Explanation:
Vancomycin lacks activity versus which of the following bacteria?
A. Staphylococcus aureus
- Vancomycin has activity versus both methicillin-sensitive Staph. aureus (MSSA) and methicillin-resistant Staph. aureus (MRSA)
B. Pseudomonas aeruginosa CORRECT
- This is a Gram negative bacterium, vancomycin only has activity versus Gram positive bacteria
C. Enterococcus faecium
- Vancomycin has activity against this Gram positive bacteria, however it can become resistant, in which case it would be called “VRE” for vancomycin-resistant Enterococcus
D. Clostridium difficile
- The oral formulation of vancomycin is considered a go-to drug for this Gram positive anaerobic organism
