Some people systematically take off their shoes as soon as they enter the front door so as not to contaminate their home. Others even change completely for fear of spreading germs on their bed or couch. But are these precautions justified?
Bacteria, viruses, fungi… “We can take absolutely everything home,” Bruno Périchon, a microbiology researcher at the Pasteur Institute, explains to BFMTV.com.
Remember that bacteria are microorganisms, generally single-celled, capable of reproducing on their own. Some are pathogenic and can cause infectious diseases, such as whooping cough, tuberculosis or salmonellosis.
The virus, for its part, needs a host and must penetrate a living cell to multiply. As for fungi, some are microscopic, like yeast. And some are worrying, especially for public health: this is the case of Candida auris, a single-celled fungus that persists on surfaces and is resistant to disinfectant or antifungal products.
Abundant life in our environment.
Regarding the risks of contamination, it must be recognized that there is no shortage of microorganisms of all kinds on the streets and sidewalks. A study by the National Center for Scientific Research (CNRS) showed that Parisian gutters host “a great diversity”: from microalgae to fungi, including sponges and mollusks.
From a hundred samples taken in all districts of the capital, the researchers identified some 6,900 species of eukaryotes, unicellular or multicellular organisms. “An abundant and unexpected life,” is the title of the CNRS article.
While bacteria have a half-life of a few hours to a few days, others can survive in their environment for up to several years. Shorter lifespan for viruses, especially if the neighbor’s saliva with the flu got on your coat. “Even if we touch our face an average of twenty times an hour, there is little chance of catching the flu on our coat,” the specialist reassures.
As a precaution, should we wash or bleach everything that has been in contact with the outside world? Bruno Périchon assures us: whatever our more or less rigorous hygiene practices, microorganisms will always attack us.
“Even if you wash the floor at home meticulously, an hour later you will have bacteria again,” he warns.
Especially because the human body is a “support” for bacteria, Pascal-Jean López, a CNRS researcher in the biology of aquatic organisms and ecosystems, explains to BFMTV.com. “We have billions of them on our skin, in our body even more bacteria than cells.”
“Without bacteria we could not live”
But aren’t some of these microorganisms dangerous? “The bacteria in our environment are part of our bacteria,” says microbiologist Pascal-Jean López, who points out that the vast majority are not pathogenic.
“Of course, we can find pathogenic bacteria in the gutters, but these are potential pathogenic bacteria.”
A point of view shared by Bruno Périchon, from the Pasteur Institute. “We are afraid of bacteria, but most of them are harmless and even useful.” Pascal-Jean López insists: “Without bacteria we could not live.”
As the National Museum of Natural History explains, “our body is a mosaic of microbiota.” The microbiota is all the microorganisms (bacteria, viruses, parasites and non-pathogenic fungi) that live in a specific environment, explains Inserm. There are several in the body: the intestinal microbiota, but also the oral, skin or vaginal microbiota.
“The microbiota has a symbiotic relationship with us,” continues the Museum. “That is, we provide mutual services.” That of our skin, for example, acts as a shield. “The microbial diversity it harbors protects us from many pathogenic germs, the Staphylococcus of the epidermis, for example, defends us from its cousin, Staphylococcus aureus.”
The recommendation: wash your hands
Furthermore, these microorganisms are not invited into homes and our clothes or shoes are not their only means of transportation. Banknotes, for example, are true breeding grounds for culture. “They are constantly passed from hand to hand and are full of bacteria,” says Bruno Périchon.
“As soon as we touch a table, an object or a door handle, we contract bacteria that we in turn transmit when shaking hands, kissing or touching another object,” continues the specialist.
“We have billions of bacteria in our bodies and we do quite well,” he insists.
In any case, caution with small children, the elderly or immunocompromised people. For these people, as well as during epidemic periods, additional precautions are needed.
But in the general population, the best recommendation is to simply wash your hands regularly. Unless you have walked on dirt – where there are bacteria absent in the human body – or on feces, “there is no health obligation to take off your shoes at home, unless you want the floor to shine”, assures Bruno Périchon. “Even if there is no zero risk, there is very little risk of getting a disease.”
Source: BFM TV
