Unveiling superbug drivers beyond antibiotic

Longitudinal study of multidrug-resistant E. coli across countries.


Researchers recently studied how antibiotic use affects the rise of drug-resistant bacteria in the UK and Norway over the past 20 years. They found that while more antibiotic use contributes to the spread of superbugs, it’s not the only factor.

Researchers from the Wellcome Sanger Institute, the University of Oslo, the University of Cambridge, and collaborators compared the genes of bacteria in over 700 new blood samples with 5,000 previously analyzed bacterial samples. This helped them understand what influences the spread of antibiotic-resistant E. coli.

Their findings, published in Lancet Microbe on January 11, reveal that increased antibiotic use does lead to more treatment-resistant bacteria in some cases. However, the impact varies depending on the type of antibiotic. Additionally, the success of antibiotic-resistant genes depends on the genetic makeup of the bacteria carrying them.

Understanding all the factors contributing to antibiotic resistance is crucial for gaining a deeper insight into how these bacteria spread and what hinders their control. This knowledge can then guide more effective public health interventions that consider the entire environment, helping prevent the spread of drug-resistant infections.

E. coli, a bacterium commonly found in the gut, is a frequent cause of bloodstream infections worldwide. While harmless in the heart, it can lead to severe and life-threatening conditions if it enters the bloodstream, especially in individuals with weakened immune systems.

Healthcare providers face an additional challenge as antibiotic resistance, particularly multi-drug resistance (MDR), is increasingly common in such infections. Over 40% of E. coli bloodstream infections in the UK resist a critical antibiotic used in severe hospital infections.

Globally, rates of antibiotic resistance in E. coli vary. For instance, opposition to a different antibiotic, commonly used for treating urinary tract infections caused by E. coli, ranges from 8.4% to 92.9%, depending on the country.

Antibiotic resistance has been a focus of research for many years, consistently revealing a connection between antibiotic use and the rise of multi-drug resistant (MDR) bacteria worldwide, including in the UK.

Previous studies hinted at a balanced coexistence of resistant and non-resistant E. coli strains, with non-resistant ones sometimes proving more successful. However, the lack of comprehensive long-term data made it challenging to understand the genetic drivers of this phenomenon.

In a recent study by the Wellcome Sanger Institute, the University of Oslo, and collaborators, researchers compared the success of different E. coli strains in Norway and the UK. Analyzing data spanning almost two decades, they found that antibiotic use was linked to increased resistance in some cases, depending on the type of antibiotic.

For instance, the UK’s higher usage of non-penicillin beta-lactams led to more infections by a specific multi-drug resistant E. coli strain. However, despite the more frequent use of the antibiotic trimethoprim in the UK, there was no evidence of higher resistance levels when comparing common E. coli strains in both countries.

The study discovered that the survival of multi-drug resistant (MDR) bacteria depends on the types of E. coli strains in the environment. Because of this and other influences in a specific area, researchers concluded that it’s not safe to assume that widely using a particular antibiotic will have the same impact on the spread of antibiotic-resistant bacteria in different countries.

The scientists emphasize the need for ongoing research to uncover other factors influencing the spread of E. coli and other vital bacteria in various environments. Further investigation is necessary to fully grasp how antibiotics, travel, food production systems, and other elements collectively shape drug resistance levels in a country.

Learning more about strains that can outcompete antibiotic-resistant E. coli could lead to new ways to prevent their spread. For instance, efforts to increase the presence of non-resistant, harmless bacteria in an area could be beneficial.

This study contributes valuable insights into the nuanced dynamics of antibiotic use and its impact on the prevalence of superbugs. Recognizing the multifaceted drivers of antibiotic resistance is crucial for developing informed public health interventions and strategies to curb the spread of treatment-resistant infections.

Journal reference:

  1. Anna K Pöntinen, Rebecca A Gladstone et al., Modulation of multidrug-resistant clone success in Escherichia coli populations: a longitudinal, multi-country, genomic and antibiotic usage cohort study. The Lancet. DOI: 10.1016/S2666-5247(23)00292-6.


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