Thu. Mar 28th, 2024
Pamela Yeh (left) with Elif Tekin (right). | Credit: Reed Hutchinson/UCLA

Scientists have always believed that if they combined more than two drugs to resist harmful bacteria would only yield diminishing returns. The prevailing theory says that that the additional benefits of combining three or more drugs would be too small to matter, or that the interactions among these drugs would cause their benefits to cancel each other out.

But now, a team of UCLA biologists has discovered thousands of four- and five-drug combinations of antibiotics that are more efficient at killing harmful bacteria than the prevailing views had suggested. Their findings were reported recently in the journal npj Systems Biology and Applications. This could be a major discovery for protecting public health at a time when pathogens and common infections are becoming resistant to antibiotics at an alarming rate.

“There is a tradition of using just one drug, maybe two,” said Pamela Yeh, who is one of the study’s senior authors and also a UCLA assistant professor of ecology and evolutionary biology. “We’re offering an alternative that looks very promising. We shouldn’t limit ourselves to just single drugs or two-drug combinations in our medical toolbox. We expect several of these combinations, or more, will work much better than existing antibiotics.”

The research team worked with eight antibiotics, and examined how every possible four- and five-drug combination, including many of those with varying dosages — a total of 18,278 combinations in all — worked against E. coli. Scientists did have an idea that some of these combinations would be significantly effective at killing the bacteria, but they were really surprised by how many potent combinations they had discovered.

For every combination they had tested, the researchers first decided to predict how effective they thought it would be in stopping the growth of the bacteria E. coli. Out of the four-drug combinations, there were 1,676 groupings that performed better than they expected and among the five-drug combinations, 6,443 groupings proved to be more effective than the research team had expected.

“I was blown away by how many effective combinations there are as we increased the number of drugs,” said Van Savage, another one of the study’s senior author and a UCLA professor of ecology and evolutionary biology and of biomathematics. “People may think they know how drug combinations will interact, but they really don’t.”

By Purnima

Leave a Reply

Your email address will not be published. Required fields are marked *