[A new definition of the I-category in the antibiogram: I-category antibiotics no longer an option to avoid]

Currently, the meaning of the I-category of the antibiogram in culture results is changing in The Netherlands. Before, the I-category was called 'intermediate' and included combinations of antibiotics and micro-organisms in which the chance of therapeutic success was doubtful. Therefore, in clinical practice this category was mostly avoided and considered as 'in this case not clear'. From now on, the definition of I has changed to 'susceptible, increased exposure' and can be considered as a valid treatment option when adequate (higher) dosing is applied. Because of the large-scale implementation, not all microbiological laboratories may be able to implement the new I at the same moment and the way they may execute this may differ in detail. When considering treating a patient with 'susceptible, increased exposure' and you are in doubt whether your microbiological laboratory already has implemented the new definition of I or about the correct dosage, consult your clinical microbiologist or Antimicrobial Stewardship Team.