South American Leafcutter Ants, which are possibly the oldest farmers on Earth, beating humans by a cool 10 million years. (Image credit: University of East Anglia)

South American Leafcutter Ants, some of the the oldest farmers on Earth (Image credit: University of East Anglia)

Many antibiotics, antifungals and anti-cancer drugs are produced by bacteria living in the soil or in the case of penicillin, moldy bread. But, scientists have only identified a fraction of the microbes living on Earth and are looking for useful new ones in some unlikely locations.

Projects like the Small World Initiative hope to use crowdsourcing to jump-start new antibiotic discovery. In the meantime, scientists from the University of East Anglia, have to turned to bioprospecting to find undiscovered microbes that could be the foundation for new antiobiotic drugs.

Dr. Matt Hutchings, a Reader in Molecular Microbiology, University of East Anglia in the United Kingdom says most of the antibiotics we use today were discovered in the mid-20th century and disease-causing bacteria is becoming multi-drug resistant. Dr. Hutchings' research focuses on exploring new environments to uncover novel antibiotics to help in the fight against antimicrobial resistance. The team has focused its efforts on the nests of the South American leafcutter ant to look for the next generation of antibiotics.

“We are interested in identifying the environmental signals and signalling pathways that activate production of these natural products and also in finding new strains in unusual places that make novel chemical scaffolds," said Dr. Hutchings.

The ant research is focused on the discovery of novel antibiotics made by the actinomycete bacteria that live on the ants. The team is also using leafcutter ants to try and understand how animals form symbioses with beneficial bacteria.

The South American leafcutter ants chop down swathes of rainforest canopy which they carry back to their nest to feed to a fungus called Leucoagaricus gongylophorus the ants themselves eat. The ants feed the fungus and give it a safe, warm and humid place to live. The ants also use antibiotics made by bacteria they grow on their bodies, to protect their fungus against disease.

“The bacteria growing on leafcutter ants are a rich source of novel chemical diversity, we have already found new antibiotics and we are confident we will find many more," said Dr. Hutchings. "Our hope is that one day some of these will enter the clinical trials pipeline."

Here are a few examples of other environments where bioprospecting could lead to new antibiotic drugs.