A possible vaccine target against a number of cancers has been identified.
Researchers found two strains of E.coli could be linked to higher rates of colorectal, bladder and prostate cancers in countries including the UK.
Trevor Lawley Microbiotica.
The scientists at the Wellcome Sanger Institute, the University of Helsinki and collaborators say targeting these with treatments or vaccines could help to reduce the risk of these cancers.
They examined global data tracking two dominant Escherichia coli (E.coli) strains more commonly found in industrialised countries and compared it to differences in the incidence of these cancers.
These strains produce a substance called colibactin previously identified as a risk factor for colorectal cancer.
The researchers say further investigation is needed but the higher rate of certain cancers could be linked at least in part to the two E.coli strains in these countries, where they cause high rates of urinary tract infections (UTIs) and bloodstream infections. These strains do not cause food poisoning.
Estimated to be at least 300 years old, these strains are unusual in their ability to produce colibactin. Interventions to tackle them - via a vaccine or a probiotic, for example - could prevent these bacterial strains from circulating and then reduce cancer risk.
Efforts to eliminate them would also reduce the infection burden and antibiotic use to tackle the UTIs and bloodstream infections they cause.
Dr Trevor Lawley, senior author from the Wellcome Sanger Institute, said: “Our guts contain many different types of bacteria, most of which are harmless, including some strains of E.coli. As not all bacterial strains can live in your gut at the same time, they have to compete for space and resources.
“In the future, it could be possible to develop therapeutic probiotics that help to displace unwanted bacterial strains, such as the ones that release colibactin. Understanding more about the interactions between E.coli and cancer risk highlights the impact our microbiome has on our health and is a crucial avenue to explore if we want to work with our bodies to help combat certain conditions.”
Prof Jukka Corander, senior author from the Wellcome Sanger Institute, University of Oslo and the University of Helsinki, said: “We have been using large-scale genomics to track E. coli strains across multiple countries for the last five years, using data that goes back to the early 2000s.
“This has allowed us to start to see the possible connections between two E.coli strains and cancer incidence rates. Science is not a stand-alone endeavour and by working together with cancer and microbiome experts, we are hopeful that in the future this work might lead to new ways to eradicate colibactin-producing E. coli strains.
“Vaccines or other interventions that target these E.coli strains could offer huge public health benefits. Such as reducing the burden of infections and lessening the need for antibiotics to treat these, as well as reducing the risk of cancers that could be linked to the effects of colibactin exposure.”