principles of antimicrobial use (ic7)

Question 1

Lab tests that indicate infection (4 points)

Answer 1

High neutrophils

Increased C-reactive protein (CRP)
- acute phase reactant
- not specific to infection

Increased erythrocyte sedimentation rate (ESR)
- bone and joint infection

Increased procalcitonin
- specific to infection (more specific than CRP)
- help to determine if need to start or stop antibiotics

Question 2

Procalcitonin levels for starting and stopping antibiotics

Answer 2

Start antibiotics
- if < 0.25 ug: infection not likely, dont need to start
- if > 0.5: antibiotics encouraged

Stop antibiotics
- < 0.25: strongly encouraged
- Continue to increase and > 0.5: antibiotics not working, should consider changing

Look at trend of Procalcitonin, if decreasing = antibiotics is working

Question 3

antibiotics that should not be used in G6PD deficiency

Answer 3

Cotrimox
Nitrofurantoin
Fluoroquinolones

Question 4

Penicillin allergy (3 groups that share similar side chains)

Which drug is safe for all allergic reactions

Answer 4

If allergic to one, cannot use the rest in the grp

1) Amoxicillin, Ampicillin, cephalexin

2) Cefepime, Ceftriaxone

3) Ceftazidime, Aztreonam

Cefazolin is safe, can use in all patients with penicillin allergic reaction

Question 5

Which antibiotics should be used for ESBL and Amp-C producing enterobacterales

Answer 5

Carbapenems

Aminoglycosides

Question 6

When is an antibiotic bactericidal

Answer 6

when MBC is within 4x MIC

if MBC is more than 2x MIC, antibiotics is bacteriostatic

Question 7

Which bacteria is bacteriostatic (3 points)

Answer 7

Macrolides
Tetracyclines
Cotrimoxazole

the rest are bactericidal

Question 8

Concentration killing drugs

Time dependent

AUC dependent

Answer 8

Aminoglycosides
Fluoroquinolones

Beta lactams (penicillins, Ceph, Carbapenems)

Vancomycin, tetracyclines (TDM), 50s (Clindamycin, Macrolides, Linezolid)