Bacteria sensors 'detect diabetes and cancer'

Scientists can transform bacteria into tiny living computers capable of detecting diabetes and cancer, early studies suggest.

Published in Science Translational Medicine, researchers modified pro-biotics so they lit up in the presence of cancers in mice.

In separate research, scientists re-wired the genetics of bacteria so they changed colour when detecting sugar.

Several further studies are needed before these could be seen in clinics.

Switching colour

But a team of US scientists, including researchers from the Massachusetts Institute of Technology and the University of California, San Diego, say bacteria could one day provide a good way of making new diagnostic tools.

They have several advantages - bacteria are relatively cheap and easy to grow for example.

In the first study US researchers used E. coli bugs harvested from a readily available pro-biotic.

The bugs are able to grow on certain tumours while ignoring healthy tissue.

Exploiting this property, the researchers re-wired their genetics so the bacteria produced an enzyme that was easy to detect.

When given to mice with liver tumours, their urine changed colour or gave off light, depending on which additional substances were added to the signalling system.

In the second paper, published in the same journal, a group of researchers engineered E. coli bacteria to change colour in the presence of sugar.

The team, including scientists from Montpellier University Hospital and the company Sys2Diag, tested the modified bugs on patients' urine.

As people with untreated diabetes can have sugar in their urine, the bugs changed colour when added to their samples.

But there are several hurdles to overcome before this could be used practically.

For now the scientists say they have just proved the concept can work.

For example the bacterial systems currently take several hours to produce results.

And the researchers acknowledge the ethics of using genetically modified bacteria need to be discussed and explored further - particularly if such tests were to be used invasively in humans.

But they hope after further work, the general approach could one day be used to develop relatively cheap and easy to use home-testing kits for a range of diseases.

Richard Elliott at the charity Diabetes UK, said the research was interesting.

"But it still has a long way to go before it can compete with existing technologies, such as tests strips and glucometers, which are widely used to quickly and accurately measure the changes in blood glucose levels experienced by people living with diabetes," he added.