Antimicrobial activity in culturable gut microbial communities of springtails

Aims: The rise of antibiotic resistance pushes the pharmaceutical industry to continually search for substances with new structures and novel mechanisms of action. Many environmental niches are still to be explored as sources of antimicrobials. In this paper, we assess the antimicrobial potential of gut microbes of springtails, soil invertebrates which live in a microbe-dominated environment and are known to be tolerant to entomopathogenic micro-organisms. Methods and Results: Bacteria isolated from the guts of five springtail species were tested for inhibitory activity against different microbial pathogens. We identified 46 unique isolates belonging to 17 genera and 15 families. Thirty-five of these isolates (76%) showed inhibitory activity, and 18 inhibited both bacterial and fungal pathogens. One isolate was active against all the pathogens tested. Conclusions: We demonstrated a range of antimicrobial activities in bacteria isolated from the guts of springtails, indicative of complex interactions within the gut community, possibly relating to nutrition or defence against pathogens. Significance and Impact of the Study: Our results suggest that a large proportion of cultivatable microbes associated with Collembola have a potential for antimicrobial production. We propose that soil invertebrates and their associated microbes are interesting targets for drug discovery.