Ants may offer new insights into the development of effective antibiotics, according to research led by Auburn University Assistant Professor of Entomology Clint Penick. The study, published in the Biological Journal of the Linnean Society, examined how ants use antibiotic compounds to fight pathogens and explored why their chemical defenses remain effective over long periods.
"In our study, we tested how ants use antibiotic compounds to fight off pathogens and asked why their chemical defenses remain effective over evolutionary time," Penick said.
He added, "Humans have relied on antibiotics for less than a century, yet many pathogens have already evolved resistance, giving rise to 'superbugs.' Ants, by contrast, have been using antibiotics for tens of millions of years, and they might hold the key to using these powerful drugs more wisely."
The research team focused on six ant species commonly found in the Southeastern United States. They investigated two main ideas about how ants might avoid promoting antibiotic resistance. The first was whether ants produce multiple types of antibiotics from different chemical compounds.
"It's just like when you go to the doctor, and they try one antibiotic. If it's not working, they're going to try another one," Penick explained.
Their findings indicated that ant extracts made with different solvents showed antimicrobial activity. "Just like us, ants seem to have different medicines in their medicine cabinet that they can try if the first one doesn't work," he said.
The second idea tested was whether ants create compounds targeted at specific microbes—an ongoing challenge in human medicine.
"If we just dump antibiotics into systems to kill everything, we're not only killing our target pathogen but also killing all these other microbes that aren't harming us," Penick said. "By doing that, we're helping breed resistant genes in non-target populations that can lead to drug resistance down the line."
The team discovered evidence suggesting that ants produce specialized compounds for different pathogens: some aimed at fungi, others at gram-negative bacteria or gram-positive bacteria.
"This is something that people are really interested in within human medicine - figuring out more targeted antibiotics," Penick noted. "And it looks like ants have been doing this for millions of years."
Although not a central focus of their research paper, nearly all ant species tested were found to be able to kill Candida auris—a dangerous superbug spreading in hospitals with limited treatment options—using their extracts.
The project received funding from the Alabama Agricultural Experiment Station and included contributions from Katy Chon of Kennesaw State University and Darmon Kahvazadeh from Auburn's entomology and plant pathology program.
Looking ahead, Penick said further investigation will examine what kinds of compounds ants are producing and how these are used.
"It could help inform our own practices or potentially we could discover new compounds that have medical importance," he stated. "Our findings suggest that ants could represent a vast and largely untapped source of new antibiotics, including ones capable of combating today's most dangerous drug-resistant infections."
