Preparation of discs

  1. Prepare a stock ethanol solution containing 500 µg/ml of tetracycline as explained in section 3.6.1.
  2. Pipette 10 µl of the stock solution onto each sterile disc.
  3. Dry the discs in a sterile laminar flow cabinet.
  4. Store in sterile containers at -20°C in darkness until used.

Note: Other tetracyclines (e.g., oxytetracycline) can be tested in the same way. Discs containing antibiotics other than tetracyclines should be prepared at the concentrations suggested by CLSI or EUCAST.