Investigation of clinical outbreaks of American foulbrood in honey-bee operations in Saskatchewan.

Four outbreaks of American foulbrood were investigated in honey-bee operations in Saskatchewan during the summer of 2019. Clinical signs were confirmed by the Saskatchewan Provincial Specialist in Apiculture and the causative agent was cultured and identified through matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Evaluation of management practices revealed off-label metaphylactic use of oxytetracycline in 3 of 4 operations and a discontinuation of antibiotic use in the fourth. Recent regulatory changes regarding access to medically important antimicrobials has provided an opportunity for veterinarians to promote evidence-based use of antimicrobials in apiculture while safe-guarding the health of commercial honeybee populations and the economic viability of their producers.