Today is Global Handwashing Day. Like many international days of X (Oceans, Refugees, Migratory Birds, AIDS, Jazz) it can be easy to dismiss this as just a feel-good marketing fad to temporarily give social media trending status to very important issues, until the next breaking headline comes along. But cynicism aside, handwashing is worth thinking about for a moment (and doing!) and I would argue it is one of the easiest, cheapest, most ordinary massive public health interventions we have at our disposal.

According to various leading sources, including popular science book The Drugs Don’t Work by Chief Medical Officer for England Dame Sally Davies, who is also co-chair of our Longitude Prize’s Advisory Panel and member of its Committee, the appropriate amount of time we should spend washing our hands each time is about as long as it takes us to sing the birthday song twice (or the time it took you to read this sentence, sorry). Evidently, many of us are not doing this, judging by our photography experiment at Kings College last year.

Students led by Dr Paul Long used glow gel to highlight remaining bacteria after handwashing in the college facilities. The photos below show presence of a few nasties, most worryingly E.Coli, which lives innocently in the gut but has strains that lead to intense stomach pains and all that that entails, and cause painful urinary tract infections (UTIs). E. Coli is not usually a resident of our skin bacteria metropolis, so finding it on hands is a classic sign of poor handwashing. These show up as the intense blue spots in the images below.

In the photo of the petri dish below, this is what the colours mean:

• Apple green - likely Staphylococci or Streptococci - very common bacteria found on our skin. They rarely lead to infections, but can cause gastroenteritis, skin abscesses, and other soft-tissue diseases such as cellulitis.
• White with pale blue - enteric bacteria that should be in your gut, not on your skin
• Dark, small, very intense blue – likely E. coli.
• Coral, pink, orange – possibly coryneforms or other actinobacteria. Usually harmless but a cause of acne.

So while hand bacteria might make for cool visual effects, and are usually harmless, handwashing is our first line of defence against bugs that also reach our hands and can turn deadly.

In addition to causing endless kinds of infectious ailments, ranging from a stomach ache to ebola, lack of good hand hygiene also leads to increased demand for antibiotics, the abuse of which is making drugs less efficient at an alarming rate. Conservative estimates place the yearly death toll from resistance to antimicrobial drugs (antibiotics, antivirals and antifungals) at 700,000, with this exploding to 10million in 2050 if current trends continue. No new class of antibiotics has been discovered since 1987, and WHO has reported that the bacteria and viruses responsible for malaria, HIV and TB, among many more, have shown resistance to the drugs commonly used against them.

The Longitude Prize, our £10million prize fund to combat rising antimicrobial resistance (AMR), will reward an innovator who comes up with a successful diagnostic tool to identify whether an infection requires antibiotics, and if so, which ones. It’s an important piece of the superbug puzzle, but a difficult one, requiring new ideas and specialist knowledge. Handwashing, however, couldn’t be easier and is also the most elusive of pieces: a good prevention strategy.

We hope these photos illustrate that whilst we’re all covered in crawling bugs, there is a very simple measure we can all take to make sure the bad ones don’t continue to spread, causing disease now and depleting medicines for the future.

Deputy Chief Nurse for Public Health England Joanne Bosanquet also wrote about handwashing and AMR, and what PHE is doing about it.