Microbiology 3 - Antimicrobial Agents 2

Question 1

What mnemonic can be used to help decide which antibiotic to use?

Answer 1

CHAOS
Choice depends on the: 
Host charcteristics 
Antimicrobial susceptibilities of the
Organism itself, as well as the
Site of infection

Question 2

What is the Minimum Inhibitory Concentration and Breakpoint of an antibiotic useful for?

Answer 2

Working out sensitivity
MIC > breakpoint = resistant
MIC < breakpoint = sensitive

Question 3

What antibiotic should be given for gram pos cocci in clusters?

Answer 3

Flucloxacillin

Question 4

What antibiotic should be given empirically for gram neg cocci?

Answer 4

Ceftriaxone (could be meningococcus)

Question 5

What is the “eagle effect”?

Answer 5

Increasing penicillin dose –> decreasing antibacterial activity after a point

Question 6

How does the choice of antibiotic to treat UTI differ between community and hospital?

Answer 6

Community: nitrofurantoin/ trimethoprim
Hospital: cephalexin/ augmentin