For the first time, researchers have analyzed the impact of antibiotic use on the rise of treatment-resistant bacteria over the last 20 years in the UK and Norway. They show that while the increase in drug use has amplified the spread of superbugs, it is not the only driver.

Researchers from the Wellcome Sanger Institute, the University of Oslo, the University of Cambridge, and collaborators conducted a high-resolution genetic comparison of bacteria. They compared over 700 new blood samples with nearly 5,000 previously sequenced bacterial samples to answer questions about what factors influence the spread of antibiotic-resistant Escherichia coli (E. coli).

The study, published in The Lancet Microbe, shows that greater antibiotic use does drive an increase in treatment-resistant bacteria in some instances. However, researchers have confirmed that this varies depending on the type of broad-spectrum antibiotic used. They also found that the success of antibiotic-resistance genes depends on the genetic makeup of the bacteria carrying them.