Forget yoghurt, experts now want friendly bacteria put in your ceiling!

Could our homes, offices and hospitals soon improve our health in the way that probiotic yoghurts are meant to — by boosting ‘friendly’ bacteria? That’s the hope of scientists who are working to envelop us in healthy bacteria that both promote our well-being and elbow out diseasecausing bugs, such as E.coli. Their aim is to create an urban world of ‘probiotic buildings’.

We think our homes, workplaces and hospitals are bacteria-free. But we each send around 37 million bacteria (good and bad) an hour into the environment around us, simply by walking, breathing, sweating and sneezing, according to a study in the journal Indoor Air in 2012.

These bugs land on surfaces and make new homes there, rapidly colonising our buildings.

Within 24 hours of moving into a new home, we fill it with our own microbes, overwriting those of the previous occupants, according to a 2014 study by Professor Jack Gilbert, a British ecologist and director of the university of Chicago Microbiome Centre.

We then ingest other people’s bugs by touching surfaces and inhaling air.

If our homes, workplaces and hospitals are colonised by harmless bacteria, this isn’t a problem. But too often, they are not, with bacterial pathogens causing outbreaks of food poisoning, as well as skin infections such as contact dermatitis — and even lethal outbreaks of superbugs such as MRSA and Clostridium difficile, which haunt wards and care homes, where they are brought in by infected patients, staff and visitors.

Richard Beckett, a lecturer in architecture at university College london, is among those leading the ‘probiotic building’ movement. He aims to create places where benign bacteria stop the growth of infectious pathogens by out-competing them for territory in our homes and public buildings. This could help prevent an all too widespread problem where being overly hygienic in a bid to kill nasty bugs can actually backfire.

For example, a study in the journal Applied Environmental Biology in 2015 showed that when a loo is freshly scrubbed, it is initially colonised by potentially infectious faecal microbes spread in clouds from the flushed water.

If the loo is left uncleaned, these are out- competed by harmless skin microbes that drop off people. When the loo is scrubbed again, we are back to square one, according to researchers at the Argonne National laboratory in the u.S.

That doesn’t mean we should stop cleaning, but we want to prevent the bacterial nasties that remain. Hence dr Beckett’s hope of crowding them out by filling buildings with bacterial good guys.

He is working to ‘seed’ helpful microbes into the walls, floors and ceilings of new and existing buildings — similar to the way probiotic yoghurts contain bugs such as lactobacillus to promote a healthy bacteria balance in our guts.

‘Many people now spend 90 per cent of their time indoors, and we are not being exposed to as many beneficial microbes, which live in the outside air and soil,’ he says.

dr Beckett is working to integrate the good bacteria into porous concrete and ceramics — two materials frequently used in modern construction. ‘There is an exchange of moisture between the concrete and the air,’ he says.

‘We breathe this in and touch the concrete surfaces, and the microbes can eventually find their way into our guts.’ He describes the work as ‘very speculative’ at this stage, but Professor Gilbert seems to be closer to making this a reality. He plans to culture the interiors of new and existing homes, offices and hospital interiors with millions of tiny plastic spheres containing cultures of ‘good’ bacterial strains and hopes to launch the first projects in the u.S. within four years.

He believes there may be friendly probiotic strains of the bacterium Clostridia that could displace pathogens and help reduce inflammatory conditions such as cardiovascular disease ( these probiotics have already been shown to have this effect when ingested orally). DR

Beckett’S ideas have partly been inspired by Graham Rook, a professor of medical microbiology at university College london, who came up with the ‘old Friends’ theory — that there are hosts of microbes we should have. Without them — especially in our immune systems — our bodies don’t work properly.

‘The idea of probiotic buildings is a perfectly sensible notion,’ says Professor Rook. ‘We know that air- conditioning systems can infect people with legionnaires’ disease (caused by the bacterium legionella pneumophila).

‘ So we should be perfectly capable of putting into the indoor air organisms we do want.’

He stresses, however, that there remains much work to be done.

For now, the answer might simply be to get out more. ‘We think that much of the physical and mood-lifting benefits people get from being out in green spaces aren’t due to exercise or uplifting views,’ says Professor Rook. ‘It may well be down to the microbes to which they are exposed.’