If the combined threats of climate change and nuclear war were not enough for humanity to deal with, scientists have warned about the looming threat of antibiotic resistance. The persistent overuse of drugs like penicillin and colistin in medicine and agriculture has given rise to antibiotic-resistant strains of bacteria. This means that we could be on course for some kind of antibiotic apocalypse unless we seriously change our ways or find an alternative – and soon.
Maybe we could learn something from the beewolves, who have been using the same antibiotics to fight pathogens since the Cretaceous period. A study, published in the Proceedings of the National Academy of Sciences, found that the antibiotic cocktails in the guts of beewolves has barely changed since evolving 68 million years ago. In contrast to humans, antibiotic resistance just doesn’t seem to be an issue.
"We had expected that some beewolf symbionts evolved new antibiotics to complement their arsenal over the course of evolution in order to help their hosts combat new or resistant mold fungi," first author Tobias Engl from Johannes Gutenberg University in Mainz, said in a statement.
Beewolves are hermits, spending most of their lives in underground brood cells where they munch on bees, nurture their young, and hibernate.
To protect her young from fast-growing mold, the mother wasp breeds a type of bacteria called Streptomyces in her antennae, which she then deposits into the brood cell walls. Later, when the larva spins a cocoon, the Streptomyces are braided into the cocoon silk, protecting the youngster from any mold spores lurking in the soil.
The researchers believe that the antibiotic mixture is effective against a wide variety of mold fungi because of the high number of substances produced by the symbiotic Streptomyces. They found that the enzymes of the Streptomyces are less selective than those of free-living bacteria, which essentially means the enzymes can bind to many different chemical precursors. Hence, the large number of antibiotic products in beewolves’ guts.
Surprisingly, the researchers discovered a similar combination of antibiotics in each of the 25 different species of beewolves studied, despite the fact that some lived continents apart. There were, however, different amounts of the various antibiotic substances, suggesting the wasps have adapted to local environments.
The complexity of the mixture likely helps prevent antibiotic resistance but, ultimately, the scientists believe their long-term success is a product of their solitary lifestyle. This is bad news for us humans who live in an evermore interconnected world.
"Beewolves, in contrast, are usually found in small populations and frequently relocate, because they rely on open sandy grounds to build their burrows," co-author Martin Kaltenpoth added. "Hence resistant pathogens have little opportunity to spread within or between populations."