Symbionts as modulators of honeybee health: Lactic acid bacteria and foulbroods
Eva Forsgren
Department of Ecology, Swedish University of Agricultural Sciences, PO Box 7044, SE-75007 Uppsala, Sweden
Lactic acid bacteria (LAB) are recognized beneficial host-associated members of the microbiota of humans and animals. Yet, LAB-associations of invertebrates have been poorly characterized and their functions remain obscure. It has recently been shown that honeybees possess an abundant, diverse and ancient LAB microbiota in their honey crop, defending them against microbial threats, such as the bacterial brood diseases American (AFB) and European foulbrood (EFB). We used inhibition assays on agar plates to investigate the effects from honey bee LAB on the growth of the causative agents of the two foulbrood diseases, Paenibacillus larvae and Melissococcus plutonius. Furthermore, we used honey bee larval bioassays to investigate the effect from LAB supplemented feed on AFB and EFB infection in vivo. We could conclude that the honeybee LAB microbiota has an inhibitory effect on both foulbroods preventing individual larvae from fully developed and lethal infections. Work to identify the active inhibitory compounds involved is in progress and will be discussed.
