Do the same laws of biodiversity which apply in nature also apply to our own bodies and homes? If so, current hygiene measures to combat aggressive germs could be, to some extent, counterproductive. So writes an interdisciplinary team of researchers from iDiv in the journal Nature Ecology & Evolution. They propose that examination of the role diversity of microorganisms plays in the ecosystems of our bodies and homes should be intensified.

Ecosystems like high-biodiversity grasslands and forests are more resistant to disturbances, such as invasive species, climate fluctuations and pathogens, than lower-diversity ecosystems. If this diversity is reduced, basic ecosystem functions are lost. This so-called stability hypothesis has been proven in hundreds of biological studies.

This research mainly deals with the world of animals and plants, but when looking at our own body or home through a microscope, an equally diverse community of microorganisms is revealed. Potentially, similar laws could apply to these communities as to the 'big' ecosystems, and this could have far-reaching consequences for our health care.

"We influence this micro-biodiversity on a daily basis, especially by combatting it with, for example disinfectants and antibiotics – actually with the aim of promoting good health," says ecologist Robert Dunn. "This interference in microbial species compositions could impede the natural containment of pathogens," says Eisenhauer.

Microorganisms also form their own ecosystems

Microorganisms also form their own ecosystems. So far, more than two hundred thousand species are known to live in human dwellings as well as on and in human bodies. Bacteria in human dwellings account for half of these, and thousands of bacteria live on our bodies. In addition, there are around forty thousand species of fungi in our homes, although these are less likely to be found on human bodies.

"Pathogens in our environment are comparable to invasive species in nature," says ecologist Nico Eisenhauer. "If you transfer the findings from large habitats to the world of microbes, you have to expect that our habitual use of disinfectants and antibiotics actually increases the dispersal of dangerous germs because it interferes with the natural species composition."

NTMs form a biofilm and can cause diseases

As an example, this has been documented for rod bacteria of the species Clostridium difficile, which causes intestinal inflammation with diarrhoea. The use of antibiotics enabled these to spread faster. So-called non-tuberculous mycobacteria (NTMs), which form a biofilm primarily on shower heads and can cause diseases, are predominant in chlorinated water.

Our fear of 'Bacteria & Co.' unfounded and our knee-jerk reaction to fight them actually dangerous? "We are not physician," says Eisenhauer. "I would certainly not recommend a surgeon to work non-sterile on the open body. Having said that, as far as surfaces are concerned, targeted inoculations with a selected microbial community could possibly prevent the spread and establishment of dangerous pathogens."