New research from King's College London, in partnership with the University of Westminster, has provided new insight into the diversity and characteristics of E. coli strains found in diabetic foot infections.
The study, published in Microbiology Spectrum, represents the first comprehensive genomic analysis of E. coli strains taken directly from diabetic foot ulcers across several continents. Researchers sequenced whole genomes from 42 E. coli strains isolated from patients in Nigeria, the UK, Ghana, Sweden, Malaysia, China, South Korea, Brazil, India and the USA. By examining these genomes, scientists identified genetic differences between strains and genes linked to antibiotic resistance and disease severity.
The results show that E. coli strains associated with diabetic foot infections are highly diverse. They belong to various genetic groups and carry a wide range of antibiotic resistance genes as well as traits that can increase their ability to cause disease. The research indicates there is no single strain responsible for these infections; instead, different lineages have independently adapted to thrive in the environment of diabetic foot ulcers.
By analyzing how these bacterial strains are related and identifying their resistance mechanisms and harmful traits (virulence factors), the researchers provide an explanation for why some diabetic foot infections are particularly hard to treat or can quickly progress to serious illness.
Notably, about 8 percent of the studied E. coli strains were classified as multidrug-resistant or extensively drug-resistant—meaning they do not respond to multiple or nearly all available antibiotics.
Victor Ajumobi, a second-year PhD student at King's College London and the University of Westminster who is also first author on the paper, said: "This information will be particularly valuable in low-resource settings, where E. coli infections of diabetic foot ulcers are more common and where rapid diagnostic tools for antimicrobial resistance are not always readily available."
Future studies will look into how specific virulence factors help drive disease progression. Many isolates contain genes that allow E. coli to attach to host tissues or evade immune defenses; understanding these mechanisms could lead to new treatments for diabetic foot infections.
