How a simple dye could save thousands of lives

16/04/2020

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The dye that could save lives

There’s no doubt that urinary tract infections (UTIs) are a serious issue. They are the most common infections picked up in hospital, and catheters are a major cause.

“If you are catheterised for more than two weeks then you virtually have a 100 per cent chance of getting a UTI,” says Professor Toby Jenkins from the University of Bath.

Catheterisation is very common – about 1 in 5 patients in hospital will have a small tube inserted into their urethra to collect urine in a bag attached to the leg. This may be for a short period following surgery, or, as is common after urological surgeries, or longer-term to manage urinary incontinence.

Thanks to your support, Toby is using funding from TUF to test a bright idea for detecting the most dangerous UTIs as early as possible. One in particular, called Proteus mirabilis, creates small crystals which can block the flow of urine in the tubing.

“This is very, very dangerous because it can be asymptomatic for patients, who don’t realise the catheter is blocked. The urine backs up into the kidneys, causing kidney failure, sepsis and death.”

It’s thought that 3,500 people in the UK die each year from sepsis caused by catheter-related UTIs. Toby has developed a new product that releases a brightly-coloured dye into the leg bag if the catheter is about to be blocked.

It relies on the fact the urine becomes less acidic when there is a Proteus infection. So he has wrapped a green dye in a special plastic that dissolves when this happens.

“We can see the colour change in the leg bag 12 hours before the catheter blocks,” says Toby. “We’re lucky that we have such a simple early warning system for when things go wrong.”

He and his team refer to the package of dye as a lozenge “because it looks like a lozenge sweet.”

“We might change the dye to blue as it should be easier to see – your urine really shouldn’t be blue!”

“The Urology Foundation funding has been fantastic, because it’s allowed us to set up a clinical study where we can do off-patient testing of the lozenge. We’re recruiting patients and asking them to donate their urine bags when they’re full,” he says.

Toby thinks that the main advantage of this approach is that it will be very cheap to produce, only 5p each. If this TUF-funded project goes well, then he hopes to start a large-scale clinical study in the next two years.

“It does require a commercial manufacturer to do the next step – upscaling the production of the lozenge. Once that’s done, we’d like to do a very large clinical study with potentially thousands of patients.”

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