Bacterial Strains Isolated from Stingless Bee Workers Inhibit the Growth of Apis mellifera Pathogens

Abstract

Apis mellifera bees are an important resource for the local economy of various regionsin Argentina and the maintenance of natural ecosystems. In recent years, differentalternatives have been investigated to avoid the reduction or loss of colonies causedby pathogens and parasites such as Ascosphaera apis, Aspergillus flavus andPaenibacillus larvae. We focused on bacterial strains isolated from the intestine ofnative stingless bees, to elucidate their antagonistic effect on diseases of A. melliferacolonies. For this purpose, worker bees of the species Tetragonisca fiebrigi, Plebeiaspp. and Scaptotrigona jujuyensis were captured from the entrance to tree hives andtransported to the laboratory, where their intestines were extracted. Twenty bacterialcolonies were isolated from the intestines and those capable of inhibitingenterobacteria in vitro and producing organic acids, proteases and chitinases wereselected. Four genera Levilactobacillus, Acetobacter, Lactiplantibacillus and Pantoeawere selected and identified by the molecular marker that codes for the 16S rRNAgene. For inhibition assays, cell suspensions and cell-free suspensions wereperformed. All treatments showed significant antibacterial effects, in comparison withthe controls, against P. larvae and antifungal effects against A. apis and A. flavus.Although the mechanisms by which these bacteria inhibit the growth of thesepathogens were not studied.