As bacterial pathogens evolve, the common antibiotics used to treat bacterial infections have become less effective. Bacteria are increasingly finding ways to evade the effects of these drugs, and bacterial infections are becoming more dangerous and deadly. As such, experts are warning that we need to develop novel antibiotics. And while researchers are making many efforts to find and develop those drugs, it’s a challenging prospect.
To address this problem, some researchers have begun to study other microorganisms. Since bacteria have to compete with other bacteria for space and resources, they often produce antimicrobial drugs. Investigators wanted to know if archaea, single-celled organisms that are similar to bacteria but occupy a different branch of the tree of life, could also be producing antibacterial compounds.
Two new studies have suggested that archaea do in fact generate antibiotics, and they could be a source of new drugs. One study was reported in PLOS Biology, and another in Nature Microbiology.
There are at least 20,000 species of archaea, and researchers scoured the genomes of 3,700 archaeal species to look for proteins that could degrade peptidoglycan. This molecule is a critical component of bacterial cell walls, and if a compound can digest it, that compound can likely kill bacteria.
The researchers found that about 5% of the archaea they studied carried the genetic sequences to produce peptidoglycan cutters. The investigators tested some of these compounds in the lab to confirm that they could break up peptidoglycan; and they were able to destroy bacteria. Some archaea also appeared to carry injection systems that could get these destructive compounds into bacterial targets.
"Our work sheds new light on the social lives or archaea and has implications for how we understand microbial communities. It also suggests that archaea might be a large, untapped reservoir for discovering novel antimicrobials in the future,” said the corresponding author of the P{LOS study, Tobias Warnecke of the University of Oxford, among other appointments.
Another recent study used computational tools to identify antimicrobial compounds in archaea. This study, reported in Nature Microbiology, found a range of potential antibiotics by searching through the proteins generated by 233 different species of archaea. This work revealed over 12,000 drug candidates worthy of additional investigation.
More research will be needed before these candidates could be developed into potential drugs, but the work shows that archaea could be a valuable and untapped resource for new antibiotics.
Sources: PLOS Biology, Nature Microbiology