An ongoing dialogue on HIV/AIDS, infectious diseases,
March 5th, 2010
Test Question on MRSA Bacteremia
I just happened to be taking a test the other day — something I do for fun every now and then, say every 10 years or so — and I came across this question (slightly condensed/changed to protect the innocent):
Man with history of IDU admitted with fever, has bacteremia due to MRSA (MIC 2 mcg/mL confirmed by E-test). Found to have mycotic aneurysm of superficial femoral artery. Aneurysm is resected surgically on hospital day 3. On vancomycin 1 gm IV q12 hours, vancomycin trough is 15 μg/mL. Blood cultures drawn on hospital day 4 turn positive the next day; patient is subjectively improved but still febrile. WBC has declined from 16k to 11K.
What is the best next step?
1. Continue current rx
2. Increase vancomycin dose to achieve trough of 20 mcg/mL
3. Change vancomycin to daptomycin
4. Change vancomycin to linezolid
So what’s the answer?
Does anyone really know what the best thing to do here is? For the record, I got it “wrong.”