Antibiotic treatment (Terramycin)

Apply oxytetracycline (Terramycin/OTC) to suppress active American Foulbrood bacterial growth. Mix the prescribed dose with powdered sugar and dust it across the top bars of brood frames. In the US, a veterinary prescription (VFD) has been required since 2017. This treatment suppresses symptoms but does not kill AFB spores.

Why It Works

Oxytetracycline inhibits protein synthesis in the vegetative form of Paenibacillus larvae, preventing bacterial multiplication and allowing the colony to recover visually. However, dormant spores remain viable in contaminated comb indefinitely. Once treatment stops, spores can re-germinate and the disease often returns.

Tips

• Use only under veterinary guidance — improper dosing accelerates antibiotic resistance, and many countries have banned OTC use in beekeeping entirely
• Never harvest honey from treated hives during or shortly after treatment to avoid antibiotic residues in the food supply
• Treat this as a temporary suppression tool, not a cure — plan to requeen and replace contaminated comb while the colony is symptom-free
• Monitor treated colonies closely for recurrence after the treatment period ends