role of the laboratory

Question 1

What are the two main reasons for monitoring serum levels of an antimicrobial?

Answer 1

1. to ensure that therapeutic levels have been achieved

2. to ensure levels are not so high as to be toxic

Question 2

Which two antibiotics are most commonly measured in serum?

Answer 2

gentamicin and vancomycin

Question 3

what is measured in an automated test?

Answer 3

the growth of individual isolates in the presence of different concentrations of each antibiotic and the likely MIC (minimum inhibitory concentration) of the antibiotic for that organism calculated

Question 4

Despite being able to predict the sensitivity of antibiotics, which factors influence the outcome in practice?

Answer 4

route of admission
dosing schedule
penetration of antibiotic to target site
interactions with other drugs

Question 5

What is the simplest way to measure the MIC of one antibiotic against one organism?

Answer 5

E test

Question 6

Describe how an E test works?

Answer 6

A paper strip with a gradient of antibiotic concentration absorbed into it is used. The MIC can be read at the point where the organism growth intercepts the strip.