TABLE 1.
Definitions of the I group
| Interpretive category (abbreviation) | Status | Definition |
|---|---|---|
| Intermediate (I) | EUCAST previous definition (in common with CLSI) | A microorganism is defined as intermediate by a level of antimicrobial agent activity associated with uncertain therapeutic effect. It implies that an infection due to the isolate may be appropriately treated in body sites where the drugs are physically concentrated or when a high dosage of the drug can be used; it also indicates a buffer zone that should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations. |
| Susceptible, increased exposurea (I) | EUCAST new definition (not shared with CLSI) | A microorganism is categorized as “susceptible, increased exposure” when there is a high likelihood of therapeutic success because exposure to the agent is increased by adjusting the dosing regimen or by its concentration at the site of infection. |
a
Exposure is a function of how the mode of administration, dose, dosing interval, and infusion time as well as the distribution and excretion of the antimicrobial agent will influence the infecting organism at the site of infection.