Endosymbiotic interactions of actinobacteria with the insects

To stop the antimicrobial resistance crisis, there is an urgent need for increased investment in antimicrobial research and development. Currently, many researchers are focusing on insects and their microbiota in the search for new antimicrobials. This chapter summarizes recent literature dedicated to the antimicrobial screening of insect actinobacterial symbionts and/or their metabolites to uncover their value in early drug discovery. Small molecules frequently mediate symbiotic interactions between microorganisms and their hosts. Social insects have been prioritized in the studies, fungi-farming ants and stingless bees, leading to the identification of natural products involved in defensive and nutritional symbioses. Interaction between actinobacteria and insects produce novel compounds, which have potential pharmaceutical applications as antimicrobials. Microbial symbioses in termites and wasps are suggested promising sources of biologically active small molecules. The microbiota of many insect genera and orders remains untargeted so far, which leaves much room for future research. The antimicrobial screening of insect symbionts has led to the discovery of a diverse array of new active biomolecules, mainly peptides, and polyketides. Overall, insect actinobacterial symbiotic relationship appears to be a promising search area to discover new antimicrobial drug candidates.