Assistant Professor Auburn University Auburn, Alabama
For over a decade, we have been witnessing the growth of difficult to treat infectious diseases caused by bacteria becoming resistant to antibiotics. To restore this problem, humans have turned to new sources to produce antibiotics. In this study, we focused on using ants.
Social insects encountered strong disease pressures during their evolution and have developed a range of methods to fight or slow the spread of disease. One of these mechanisms is the development of antimicrobial compounds that ants and bees secrete onto their external body surface. Previous work that used ethanol (a polar solvent) and one microbe (Staphylococcus epidermidis) has shown that many, but not all, ant species produce strong, broad-spectrum antimicrobials. Here we discuss new work testing four solvents varying in polarity from polar to non-polar: ethanol, isopropanol, dichloromethane, and hexane. We tested each extract against two different microbes: Staphylococcus epidermidis, and Escherichia coli using three species of ants representing three different ant sub-phyla: Solenopsis invicta (Myrmecinae), Brachyponera chinensis(Ponerinae), and Prenolepis imparis (Formicinae). Previous work showed that S. invicta and P. imparis produce antimicrobials effective against S. epidermidis using a polar solvent (ethanol), and we predict that we will see differences in extract activity using non-polar solvents and against different microbes. Previously we found no evidence of antimicrobial activity from extracts of B. chinensis, but predict to see antimicrobial activity when using different solvents or against different microbes. Ultimately, this work will show specificity of antimicrobial compounds in ants and could identify future antibiotics for human use.