Biofilm-forming lactic acid bacteria of honey bee origin intended for potential probiotic use

Scientists around the world are focusing their interest on the use of probiotics in honey bees as an alternative method of prophylaxis against causative agents of both American and European foulbrood. In our study we tested inhibitory activity against Paenibacillus larvae and the biofilm formation activity by various lactic acid bacteria isolated from honey bee guts or fresh pollen samples in the presence of different sugars added to the cultivation media. In addition, we tested the probiotic effect of a newly selected Apilactobacillus kunkeei V18 in an in situ experiment in bee colonies. We found antibacterial activity against P. larvae in four isolates. Biofilm formation activity of varying intensity was noted in six of the seven isolates in the presence of different sugars. The strongest biofilm formation (OD570 >= 1) was noted in A. kunkeei V18 in the presence of fructose; moreover, this isolate strongly inhibited the growth of P. larvae under laboratory conditions. Inhibition of P. larvae and Melissococcus plutonius by A. kunkeei V18 in situ was confirmed in a pilot study.