Using high-tech genetic sequencing, researchers from the University of Colorado in the US detected a plethora of bugs on all surfaces that can be touched in a dozen of men's and women's bathrooms on a college campus.
Bacteria commonly associated with human skin were found on all surfaces that included door, toilet and faucet handles, soap dispensers, toilet seat and various areas of the floor.
It's not a big surprise, since most of the areas sampled are routinely touched, the researchers said. Other human bugs, including some linked with the mouth, gut and urine were also found on all surfaces, Los Angeles Times reported.
Bacteria associated with the gut were common on toilet surfaces, signifying fecal contamination (and an argument for seat protectors).
The floor had the biggest bacteria party, revealing what the authors called "diverse bacterial communities" of organisms, including several typically found in soil.
Some toilet flush handles also had bacteria comparable to what was found on the floor, which suggests that some people flush the handles with their feet.
The practice, the authors said "well known to germophobes and those who have had the misfortune of using restrooms that are less than sanitary".
Finding bacteria associated with the gut and female urine at various points in the restrooms may indicate that frequent toilet use distributes those germs around and about.
This emphasises the importance of hand washing after using toilets, since surfaces could transmit human pathogens, the researchers wrote in journal PloS ONE.