Combining medications could be key to slowing antibiotic resistance

Scientists across the world are struggling to find ways to combat the spread of antibiotic resistance among bacteria, but rather than make something new, UCLA biologists say the solution could be in combining four or five existing medications.

The UCLA study starkly contrasts the traditionally accepted belief among the scientific community that a combination of more than two drugs would bring only diminishing returns in the fight against harmful bacteria.

“There is a tradition of using just one drug, maybe two,” said Pamela Yeh, one of the study’s senior authors and 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.”

In all, scientists played with 18,278 combinations of eight different antibiotics, and the efficacy against E. coli proved to have a good bit of variance. More than 8,000 combinations were more effective than predicted, while more than 7,500 combinations were less effective than researchers expected. The success rate tended to be tied to unique mechanisms for targeting E. coli in each.

“Some drugs attack the cell walls, others attack the DNA inside,” said Van Savage, a senior author and a UCLA professor of ecology, evolutionary biology and of biomathematics. “It’s like attacking a castle or fortress. Combining different methods of attacking may be more effective than just a single approach.”

While the results are still years from being evaluated for use on humans, they do herald an acceleration of combinations testing. The researchers intend to move into open-access software based on their work, which they will share with other scientists in days to come. In this way, scientists will be able to analyze different antibiotic combinations, input their own, and share results across the world.