In their quest to understand how bacteria like E. coli and salmonella become antibiotic resistant, researchers at the University of Kansas have made a discovery that may hold important implications for future treatments.
It turns out the types of proteins that help shield some bacteria cells from antibiotics may have evolved independently rather than from a common ancestor, as has been commonly thought. And that discovery may lead to a more refined approach to the growing problem of antibiotic resistance.
Joanna Slusky, who led a team of researchers that made the discovery, told KCUR’s Central Standard on Wednesday that she hopes it will bring scientists closer to the goal of disabling the mechanisms that make bacteria resistant to antibiotics.
The team’s findings, published last month in the journal Structure, focus on efflux pump proteins, which are part of the mechanism on the surface of so-called Gram-negative bacteria that can push antibiotics out of cells.
Gram-negative bacteria, which include E. coli and the bacteria that cause gonorrhea and chlamydia, can be particularly resistant to antibiotics because of their outer membranes.
“They take energy to push out the antibiotics, so they’re not just passive channels, but they’re actually physically pushing so there can be a lower concentration inside than outside,” said Sluksy, an assistant professor of molecular biosciences and computational biology at KU.
By comparing proteins called beta barrels found on efflux pump with other beta barrel proteins, Slusky and her colleagues found enough differences to indicate they evolved separately.
Slusky said the question now becomes whether scientists can design proteins using evolutionary steps in the same way proteins evolved functions that ensured their evolutionary success.
Public health experts have raised alarm about antibiotic resistance, leaving doctors with less effective tools to treat illnesses spread by bacteria.
“Understanding evolution tells us where biology was, which is interesting to people because it tells us our own history and the Earth's history,” Slusky said in a release about her group’s findings. “But it also tells us where we could be going and what mechanisms are possible. It tells us how might life evolve and what tools can biologists use to change and diversify the molecules at our disposal.”
Alex Smith is a health reporter for KCUR. You can reach him at alexs@kcur.org.
