The bandage turns a flourescent green if you're about to get an infection. University of Bath The growing threat of antibiotic resistance because of unnecessary prescribing is a “ticking time bomb” that should be ranked alongside terrorism in terms of risk, England’s chief medical officer, Sally Davis, has said.

The drugs are often administered to patients with wounds as a precautionary measure to prevent a bacterial infection from developing. However, not all patients will need antibiotics and the problem for doctors is identifying which ones are susceptible to infection.

Researchers at the University of Bath, led by Dr Toby Jenkins, have developed a type of dressing that can alert doctors when a wound becomes infected, avoiding the precautionary use of antibiotics.

The dressing releases a fluorescent dye in small dots when a wound, such as a burn, becomes infected, allowing medics to treat it quickly.

Jenkins recalls visiting a burns unit six years ago with Dr Amber Young, his clinical collaborator on the project, who heads the burns research center at Bristol children’s hospital. The sight of a child suffering from severe burns after acc

identally pouring boiling water over herself was a powerful motivation, he says.

While the primary trauma injury could be treated, there was a real risk of infection. “Knowing that because there was no rapid way to diagnose the infection and that she could die the next day as a result is highly motivational,” Jenkins said.

Colour-changing burns dressing will help in the fight against infection and antibiotic resistance from University of Bath on Vimeo.

Typically, if a doctor is concerned about a wound, they can use swabs to take samples and send them off to a lab where results will be returned in one or two days, during which time an infection can become full blown and result in septicemia, sepsis, shock or even death, he said.

To be on the safe side, clinicians may prescribe antibiotics if symptoms such as a raised temperature or redness occur. In one study, it was found that 25% of patients in a burns group were treated with antibiotics when the proportion with infections was just 7%.

As well as being costly, this adds to the growing threat of antibiotic resistance. Having to remove the dressing to assess whether the burn is infected is a painful process and can cause scarring or severe trauma in children.

In an infected wound, bacteria live in a biofilm, a group of micro-organisms where cells stick to each other. The dressing developed by Jenkins switches to its fluorescent color when it comes into contact with these wound biofilms. This happens when the build-up of bacteria on the wound reaches a stage where the body’s immune system can no longer deal with it – the critical colonization threshold (CCT).

“What we think happens here is that we get a rapid increase in the bacterial density of the wound surface so you go from perhaps a low density film of bacteria to a really high density bacteria,” Jenkins said. It is not easy to measure, he said, so clinicians and nurses may prescribe antibiotics as a precautionary measure.

When the dressing detects infection, the fluorescent dots will be visible in 10-20 minutes. This will be before the bacteria gets into the bloodstream and gives doctors time to act, said Jenkins.

The bacteria that the dressing can detect are staphylococcus aureus, of which MRSA is a form, pseudomonas, which was linked to the deaths of three babies in 2012, and enterococcus faecalis, which comes from the gut.

“What we really want to do is send the patient home but the big worry is that maybe there is an infection so the current advice is that you tell the parent to check the temperature every few hours. But temperature is not a great guide for infection. So you would use this in addition, in part to give parental reassurance that things are OK.”

The prototype of the dressing is being tested by the university. It is likely to be trialed on patients in three years and it is hoped that it will be on the market by 2020. The early version does not detect which type of infection has formed, but the aim in future is to have different infections represented by different colors.

The threat of antibiotics resistance

Warnings about the threat of antibiotic-resistant bacteria are stark. Davis said that if tough measures were not taken to restrict the use of antibiotics and no new ones were sourced, the health system risked returning to standards last seen in the early 19th century.

Research indicates that routine surgery and chemotherapy may become all but impossible unless action is taken to halt the waning effect of antibiotics. If the drugs lose just 30% of their efficacy there could be 120,000 more infections and 6,300 infection-related deaths each year in the US alone, according to a study in the journal Lancet Infectious Diseases.

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This article originally appeared on guardian.co.uk