Antibacterial activity of fungus comb extracts from Senegalese fungus-farming termites

Fungus-farming termites (Macrotermitinae), predominantly found in Africa, are eusocial insects with significant ecological roles. Historically, they have been valued in traditional medicine, human diets, and livestock feed. These termites share a long-standing symbiotic relationship with Termitomyces fungi, which has evolved over millions of years and is critical to their survival and ecological impact. This mutualism promotes a unique monoculture of Termitomyces in the fungus comb while suppressing fungal and bacterial antagonists, likely due to the comb's structural or chemical properties, sparking interest among researchers. In this study, we conducted an extensive examination of 11 fungus combs associated with five termite species collected in Senegal. Our analysis revealed significant antibacterial properties in the crude extracts of the combs, notably against multidrug-resistant strains. Chemical analyses led to the identification of dicrotalic acid (Meglutol) in the active fractions of two combs from agricultural areas. This compound, likely of plant origin, suggests a link between termite feeding habits and the antimicrobial potential of the combs. Although the exact bioactive compounds responsible for the antimicrobial activity have not yet been fully identified, the presence of various metabolites may explain the maintenance of Termitomyces monocultures and the suppression of pathogens. This also illustrates the complex ecological relationship between Termitomyces and termites, which may work together to produce natural bioactive compounds that suppress pathogens.