Though you may not be aware of it, we’re are all chronically infected. Every bit of us, inside and out, is home to a myriad of microbes. Every nook, cranny and crease is a specific ecolological niche, colonised by species that have adapted to that particular environment.
Microbes adapt to survive in different conditions
The microbes on the outside of the nose are adapted to live on the skin; those on the inside are different in all respects and at home in the very different conditions there.
Then there’s the gut, of course, with microbes so different, so diverse and so numerous that it’s effectively as if every human is host to mini universe living within them.
Every family doctor can testify that many of what Dame Edna Everage refers to as our ‘nooks and crannies’ attract certain micro-organisms with their own, very individual characteristics that are associated with their location as well as the person who’s playing host.
A friend’s foot will smell more like yours than their own armpit, for example. You might want to put it to the test. There again, you might not…
Hand colonisation tends to vary most over time. Presumably this reflects the fact that hands, of course, have most direct (hands on) contact with the outside world.
As a result, your dominant hand will have a different set of microbes to your non-dominant one (whether this is also the case for ambidextrous people has yet to be confirmed). In addition, the resident microbes on the hands are disrupted by washing more frequently than other sites.
Symbiotic relationship between humans and microbiomes
We’re increasingly starting to recognise that microbiota have a significant role to play in our lives. It seems we meet pathogens regularly and our home guard of micro-organisms plays a part in protecting us from infection by them. Those in the bowel especially are metabolically and even genetically active. We have evolved into having a symbiotic relationship with our microbiome.
Until recently, the interaction between our microbiome and the environments in which we live had attracted limited interest from reserachers. As we come to recognise just how important they can be – and not just in acting as an important part of our body’s deference mechanism, that’s starting to change.
The movement of microbiomes through families and home
In a recent study looking at the microbial communities, seven US families from different ethnicities – and their pets (three dogs and a cat) – were tracked to see what happened to their microbiome over time.
The results showed that families tend to share many similarities of their microbiome. Not surprisingly, this is greatest when contact is more intimate. Tactile families will share more microbes than the more hands off.
It also showed that we coat our houses with our bugs rather than pick them up from them. Move into a new home and, found the researchers, which three families did during the course of the study, and the families would rapidly colonise the new home which adopted their unique microbial signature. We may never be aware of it but subconsciously, it could well be the indefinable ingredient that makes our homes ‘feel’ like home.
If one family member left, there was a decline in that individual’s contribution to the home environment. Different surfaces declined at different, but predictable, rates.
It’s a fascinating result, which raises the possibility that, at some time in the future, that rate of decline in an individual’s microbial trail could “provide a metric for assessing the time course of events related to that house and those persons”. Put simply the microbial fingerprint, as unique as the traditional kind, could be used to tell not only if someone was in the house but how long ago too.
The story of the microbiome continues to unfold. Now it seems that the bugs can reveal our secret movements, too.