1 The theory underpinning AST

You should be familiar with the Introducing antimicrobial resistance module before starting this section.

AST determines which antibiotics a specific microorganism is susceptible to. This information is used to predict which antibiotic therapies are likely be effective.

Susceptible microorganisms are inhibited or killed by the antibiotic, and it is inferred that infections caused by these organisms can be treated with the antibiotic. Conversely, resistant microorganisms are not inhibited by the recommended antibiotic dose, so an infection caused by a resistant microorganism is unlikely to be cured by the antibiotic.