I Contain Multitudes: The Microbes Within Us and a Grander View of Life

by Ed Yong

the 1860s, when Joseph Lister instigated sterile techniques in his hospital, cleaning regimes have helped to curb the spread of pathogens. Simple measures like hand-washing have undoubtedly saved countless lives. But just as we have gone overboard in taking unnecessary antibiotics or lathering ourselves in antibacterial sanitisers, we have also gone too far in cleaning our buildings – even our hospitals. As an example, one US hospital recently spent around $700,000 to install flooring that had been impregnated with antibacterial substances, despite having no evidence that such measures work. They might even make things worse. As in the dolphin enclosure and the human gut, perhaps the quest to sterilise our hospitals has created dysbiosis in the microbiomes of our buildings. By removing harmless bacteria that would otherwise impede the growth of pathogens, perhaps we have inadvertently constructed a more dangerous ecosystem.

thoroughly scrubbed toilets are first colonised by faecal microbes, which are launched into the air by roiling, flushed water. Those species are eventually outcompeted by a diverse range of skin microbes, but once the toilet gets scrubbed again, the communities go back to square one. So, here’s the irony: toilets that are cleaned too often are more likely to be covered in faecal bacteria.