Antibacterial effects of propolis and brood comb extracts on the causative agent of European Foulbrood (<i>Melissococcus plutonius</i>) in honey bees (<i>Apis mellifera</i>)

Among a long list of parasites and pathogens that threaten the European honey bee (Apis mellifera), Foulbrood (EFB) has become an urgent apiary disease, as epidemic outbreaks are becoming increasingly common. EFB is bacterial disease larval bees, caused by gram-positive, anaerobic bacterium, Melissococcus plutonius. The most effective current treatment for EFB, oxytetracycline hydrochloride, can disrupt microbiome, cause mortality residues may persist in harvested human consumption. In this study, we explore efficacy more sustainable bee-derived solutions, including propolis, comb, brood comb ethanol extracts. Propolis been shown to successfully inhibit growth similar American (AFB). Using series dilutions these extracts, determined minimum inhibitory concertation (MIC) each product on M. plutonius, well two model species, Staphylococcus saprophyticus (gram-positive) Escherichia coli (gram-negative). Overall, found propolis extract was at inhibiting gram-positive bacteria, plutonius also susceptible (MIC = 16.00 mg/mL) 45.33 but much higher concentrations than 1.14 mg/mL). As previously demonstrated AFB, promising natural defense against which could have important implications hive management.