The highest rates of some types of cancer in countries like the United Kingdom may be closely related to two specific strains of Escherichia coli (E. coli) so treatment or vaccines against them could help reduce the risk of colorectal, bladder and prostate canceraccording to researchers from the Wellcome Sanger Institute in the United Kingdom and the University of Helsinki in Finland.
In depth
To carry out this research, published in the journal ‘Lancet Microbe‘, the experts analyzed the two dominant strains of ‘E. coli’ that produce a substance that has previously been identified as a risk factor for colorectal cancer and have been observed to be found more frequently in industrialized countrieswhere they cause high rates of urinary tract infections (UTI) and bloodstream infections.
Furthermore, according to the researchers, the increase in the rate of certain types of cancer in these countries could be related to these two strains of ‘E. coli’ that produce a substance known as colibactin, but stress that it needs more research.
Regarding this substance, the ability to produce it is uAn unusual characteristic in some bacteria ‘E. coli’ and is found primarily in two strains that are estimated to have at least 300 years old. Therefore, interventions that target these two strains, such as a vaccine or probiotic, could prevent these bacterial strains from circulating and, in turn, reduce the risk of cancer.
More details
Similarly, as these strains of ‘E. coli’ are also the main causes of urinary tract infections and infections from the bloodstream in industrialized countries, an intervention to eliminate them would also reduce the burden of infection and the use of antibiotics.
The bacteria ‘E. coli’ is commonly found in the human intestine. Most strains of this bacteria are harmless; However, if it enters the bloodstream due to a weakened immune system, it can cause infections, ranging from mild to life-threatening.
Researchers have been using genomic surveillance pto track the different strains of ‘E. coli’ in different countries, including the United Kingdom, Norway, Pakistan and Bangladesh so that they have been able to identify the factors that cause the spread of certain strains and highlight new possible ways to stop disease-causing strains.
On the other hand, a research, developed in 2020discovered that colibactin causes DNA breaks in human cells. Furthermore, the research team also found evidence of harm caused by colibactin in tumor samples from colorectal cancer patients.
Preliminary evidence suggests that strains of ‘E. colibactin-producing coli also play a role in the development of urinary tract cancers, such as bladder and prostate cancersince this is a common site of infection for this same bacterium.
In this study, the researchers compared cancer incidence rates with E. coli genomic surveillance data and found that the two strains of E. coli that produce colibactin are observed in industrialized countries that also have higher levels of bowel, bladder and prostate cancer.
In comparison, in countries with limited resources, such as Bangladesh and Pakistanthe two colibactin-producing strains are much rarer and the incidence of bowel, bladder and prostate cancers is also lower.
For this reason, the researchers hypothesize that geographic variation in cancer incidence is affected by different levels of population exposure to these two strains of ‘E. coli’. Nevertheless, More long-range research is needed, including large-scale tumor sampling, to clarify the role of colibactin in cancer.
To take into account
The production of colibactin is a process energetically expensive for ‘E. coli’ and requires a genetic adaptation that ensures that the process is not too costly for the bacteria. This adaptation is difficult to acquire through horizontal gene transfer, which is the way bacteria share traits. Because of this, only two successful strains of ‘E. coli’, of the hundreds of strains of ‘E. coli’ that circulate globally, have managed to establish an stable maintenance of colibactin-producing genes during the last centuries.
Therefore, interventions that focus on eradicating these two strains, such as a vaccine, could be enormously effective. Another way could be the development of therapeutic probiotic products that help displace these two strains of ‘E. coli’ from the human intestine, with the objective of eliminating them from the population.
The study’s first author, from the University of Helsinki and the Wellcome Sanger Institute, Dr. Tommi Maklinassures that “‘E. coli’ can be found all over the world, in many different shapesand understanding how strains of this bacteria affect humans differently can provide a more complete picture of health and disease“.
Finally, the doctor continues stating that “having access Global genomic data on what strains are found in an area can uncover new trends and possibilities, such as possible linkage of strains in industrialized countries with the risk of certain types of cancer“.
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