What toxins can E Coli produce

Urinary tract infection pathogens produce carcinogenic toxin

Toulouse (France) - Not only tobacco consumption and frequent contact with toxic solvents lead to an increased risk of bladder cancer. Repeated or long-lasting urinary tract infections could also increase the likelihood of such a disease, as French researchers report in the journal “PLoS Pathogens”. The vast majority of urinary tract infections are caused by so-called uropathogenic E. coli bacteria (UPEC). Many of them release the toxin colibactin. The scientists found evidence of colibactin production by analyzing urine samples in almost every fourth patient. In animal experiments, they were able to prove that this toxin can damage the DNA of cells in the bladder wall and thus trigger the development of cancerous growth. The pathogens causing urinary tract infections enter the lower urinary tract from the intestines. A preventive treatment that removes the pathogen reservoir of UPEC bacteria in the intestine would therefore be helpful.

"Our results show that patients suffering from urinary tract infections should be systematically examined for evidence of colibactin production," say Jean-Philippe Nougayrède and Eric Oswald from the Université de Toulouse. It is predominantly women who develop urinary tract infections. More than 60 percent are affected at least once in a lifetime. The infection can be symptom-free, confined to the lower urinary tract, or affect the kidneys. If the pathogens even enter the bloodstream, life-threatening urosepsis can develop.

The researchers collected urine samples from 223 patients suffering from E. coli infection of the upper or lower urinary tract. By detecting a by-product that is produced during colibactin production, they identified a release of the toxin by UPEC bacteria in 55 patients. Experiments with mice have shown that urinary tract infections with these pathogens damaged the DNA of cells in the bladder wall to such an extent that mutations could develop that favor cancer growth. The researchers conclude that persistent - even symptom-free - urinary tract infections caused by colibactin-forming UPEC bacteria can damage the cells of the lower urinary tract in humans in the same way and thus increase the likelihood of cancer. It is known from previous studies that the detection of such pathogens in the intestine is associated with an increased risk of colon cancer. Targeted elimination in the intestine would reduce the risk of developing colon and bladder cancer. However, this connection would first have to be confirmed by further studies.

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