A new study found bacteria are plentiful on virtually every bathroom surface you might imagine touching — toilet handles, stall doors, soap and towel dispensers.
Gut bacteria — the type of bugs that live in the human gastrointestinal tracts — were even found on the handles of bathroom exits, a dead giveaway that not everyone is following Mom's advice.
"That's not the ideal spot for them," lead author Gilberto Flores said in an interview Wednesday. "You'd hope that most people would wash their hands with soap and water and that you would eliminate most of those."
"You do see kind of a trail based on your activities in the restroom."
The study, done at the University of Colorado in Boulder, saw researchers test surfaces in 12 bathrooms on the university campus to look for microbes. An equal distribution of men's and women's bathrooms were tested.
The findings were published Thursday in the journal PLoS One, a publication of the U.S. Public Library of Science.
The researchers found a wide variety of bacteria, even though the facilities were well maintained, Flores said.
The microbes broke down roughly into three groups: bacteria that live on human skin, bacteria from the outdoors that people likely brought in on their shoes and bacteria that live inside humans and are passed in urine or feces.
The latter type is the one which would pose the most concern, though the work didn't find illness-causing bacteria such as Shigella.
Where the different types of bacteria were found correlated with the type of body part the surface came in contact with. Skin bacteria were the main findings on touch surfaces and floors were positive for soil bacteria.
Interestingly, some toilet handles also were positive for soil bacteria, suggesting some people were using their feet to flush the toilet, the authors said.
Toilet seats and most of the toilet handles were populated with gut microbes, "suggesting fecal contamination of these surfaces," the paper said, adding the contamination could have been the result of direct contact or water splashes when a toilet was flushed.
In many respects, what was seen was what one would expect to see from this kind of study — a fact which could explain the bemused reactions of a couple of infection control experts asked to comment on the study. Where there are people, there are bacteria, they both said.
"We know that we do not live in a sterile world," said Dr. Andrew Simor, head of microbiology at Sunnybrook Health Sciences Centre in Toronto.
"There are bacteria all around us. And in particular, we're going to find human bacteria in places where humans are."
In fact, bacteria don't just surround us, they live in us. The human gastrointestinal tract is home to a vast array of bacteria.
"We're surrounded by bugs and we're covered in bugs, both inside and out," Flores agreed. "Most of them are beneficial to our health, actually."
Dr. Michael Gardam suggested people can over-fixate on coming in contact with bacteria. For instance, he questioned the benefit of trying to disinfect one's desk.
But bathroom bugs are something one should pay attention to, suggested Gardam, who is director of infection prevention and control at Toronto's University Health Network.
Finding gut bacteria in various places in public washrooms is a reminder that bathrooms could play a role in spreading gastrointestinal ailments, he said.
"A large percentage of these things, you don't know where you got it from. And it's perfectly conceivable you got it from a washroom," said Gardam.
"If you are using the toilet after someone else, not cleaning your hands, and that other person happened to have Salmonella, you could potentially catch it. So it is appropriate to be paranoid in that setting and actually clean your hands appropriately."
Simor concurred. "The public health implications really are: Wash your hands after you go to the toilet."