Antibiotic treatment (Oxytetracycline)

Apply oxytetracycline (OTC) to treat active European Foulbrood infections by dusting medicated powdered sugar over the top bars or mixing it into a sugar patty. OTC targets the vegetative cells of Melissococcus plutonius, halting an active EFB outbreak when administered correctly.

Why It Works

The EFB pathogen exists primarily in vegetative form rather than as resistant spores. Oxytetracycline is bacteriostatic against these cells, suppressing bacterial growth and giving the colony's hygienic behavior time to clear infected larvae from the brood nest.

Tips

• Follow your country's regulations strictly; OTC requires a veterinary prescription in many jurisdictions (e.g., the US since 2017 under the Veterinary Feed Directive).
• Administer the correct dosage -- typically 200 mg active OTC per hive mixed with powdered sugar -- applied in three treatments at 4-5 day intervals.
• Never treat during a honey flow; observe the mandatory withdrawal period before adding honey supers.
• Address underlying stressors such as poor nutrition or overcrowding, as OTC alone will not prevent recurrence.
• Combine treatment with requeening from hygienic stock to improve long-term colony resistance.