A genomic analysis of Escherichia coli isolated from infected diabetic foot ulcers across 10 countries found no single dominant strain, instead revealing wide genetic diversity and a subset of isolates with markers of multidrug or extensive drug resistance, researchers from King’s College London and the University of Westminster report.
Diabetic foot infections are a serious complication of diabetes and are a leading cause of lower-limb amputation worldwide, often becoming difficult to manage when wounds involve multiple microbes and resistance to antibiotics.
New research led by King’s College London, in collaboration with the University of Westminster, adds detail on one organism frequently detected in these infections: Escherichia coli. The study, published in Microbiology Spectrum, analyzed whole-genome sequences from 42 E. coli strains isolated from infected diabetic foot ulcers in patients from 10 countries—Nigeria, the UK, Ghana, Sweden, Malaysia, China, South Korea, Brazil, India and the United States.
The genomic data showed that the isolates fell into many different genetic groups and carried a broad mix of genes associated with virulence and antimicrobial resistance. The results indicate there is not a single “diabetic-foot” E. coli strain responsible for these infections; rather, multiple unrelated lineages appear capable of adapting to the diabetic foot environment.
The researchers also reported that about 8% of the strains were classified as multidrug-resistant or extensively drug-resistant, a finding that could complicate treatment by limiting effective antibiotic options.
“Understanding these bacteria at a genomic level is a crucial step towards improving diagnosis and enabling more targeted treatments for people with diabetes,” said Dr. Vincenzo Torraca, a Lecturer in Infectious Disease at King’s College London and senior author of the paper. He added that identifying which strains are present and which antibiotics they are likely to resist could help clinicians choose therapies more likely to work, potentially reducing prolonged infection, hospitalisation and the risk of amputation.
Victor Ajumobi, the study’s first author and a PhD student at King’s College London and the University of Westminster, said the findings could be particularly useful in low-resource settings, where E. coli infections of diabetic foot ulcers are reported to be more common and where rapid tools to detect antimicrobial resistance may be limited.
The team said future work will focus on how specific virulence factors identified in the genomes—such as genes linked to tissue attachment or immune evasion—contribute to disease progression, with the aim of identifying potential therapeutic targets.
The study is titled “Population structure, antimicrobial resistance, and virulence factors of diabetic foot-associated Escherichia coli” and appears in Microbiology Spectrum (DOI: 10.1128/spectrum.02837-25).
