Scientists use bacteria to detect cancer, diabetes

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WASHINGTON: Two research teams said they have used Escherichia coli (E. coli) as diagnostic tools to detect liver cancer and diabetes, Xinhua news agency reported.

In the first study, researchers at the Massachusetts Institute of Technology (MIT) and University of California at San Diego used a harmless strain of E. coli called Nissle 1917, which is marketed as a promoter of gastrointestinal health. The researchers engineered the bacteria to produce a luminescent signal when they encounter a tumour, which will then be detected with a simple urine test.

When fed to mice by mouth, the bacteria do not accumulate in tumours all over the body but predictably zero in on liver tumours because the hepatic portal vein carries them from the digestive tract to the liver.

The animals that were given the engineered bacteria did not exhibit any harmful side effects. With the E. coli test, the researchers said they were able to detect liver tumours larger than about one cubic millimetre, offering more sensitivity than existing imaging methods.

“This kind of diagnostic could be most useful for monitoring patients after they have had a colon tumour removed because they are at risk for recurrence in the liver,” said study author Sangeeta Bhatia, a professor of health sciences and electrical engineering and computer science at MIT.

In the second study, researchers engineered E. coli to detect biological signals in urine and generate a visible colour change at a specific threshold.

The researchers demonstrated their so-called bactosensors in urine samples from diabetic patients and found that they accurately and reliably detected abnormal glucose levels in urine, performing almost as well as current standard urine dipsticks. Both papers were published in the US journal Science Translational Medicine. — Bernama