Microcosm inside and around us

The human body contains a huge number of bacteria that are essential for the normal functioning of the body. The collection of microorganisms that live on the surface of the body and inside it is called the microbiome.

Our inner world

How many bacteria live in the body? It is widely believed that there are 10 times more of them than cells in the human body. A recent study by scientists at the Weizmann Institute suggests that this belief is wrong and there are actually fewer bacteria. The authors argue that the human body consists of about 30 trillion cells, and the bacteria that inhabit it, there are "only" about 40 trillion.

By the way, newborn babies receive their first "portion" of bacteria by passing through the maternal birth canal during childbirth. Thus, colonization of their sterile intestines begins. It is because of the difference in the way babies born naturally and those born by caesarean section are born have different microbiomes. These differences may be the reason why babies born by caesarean section are more likely to suffer from allergies and are more prone to obesity.

Most of these microorganisms are concentrated in the gastrointestinal tract. For example, more than 20 billion bacteria live in the oral cavity alone, which is almost 3 times more than the number of people living on the planet. The total weight of all bacteria inhabiting the human body is approximately comparable to the weight of the brain and amounts to 1.5–2 kg.

An impressive example is the bacterial diversity that scientists found in the navels of 60 volunteers who participated in the experiment. Researchers from Oxford, having analyzed what types of bacteria live in the navels of the experiment participants, found more than 2, 000 different species, almost 1, 458 of which were previously unknown to science or little studied. So, in the navel of one of the volunteers, the authors found a soil bacterium, found only in Japan, while the participant himself had never been to Japan.

Violation of the species and quantitative composition of the microbiome can lead to health problems, reduce immunity, increase the risk of depression, and affect the digestion process.

The enemy is at the gate

We can encounter microbes almost anywhere, and indeed we do encounter them on a daily basis.

For example, a kitchen that is completely safe at first glance is fraught with several dangers. Perhaps the worst thing in this regard is the kitchen sponge. Scientists estimate that more than 50 billion bacteria are present on a cube the size of a lump of sugar cut from a sponge. This concentration is acceptable in feces, but not where you prepare food.

German researchers from the University of Furtwangen (Furtwangen University), having studied 14 kitchen sponges, found that they contain bacteria belonging to 118 genera.

It was not possible to get rid of microbes by heating the sponge in the microwave or washing it in the dishwasher - even after such treatment, a lot of bacteria remained on the surface of the sponges, which continued to multiply with great intensity (some microbes divide every 4-5 hours!). Researchers have found that the only way to prevent bacterial attack in your kitchen is to replace the sponge regularly with a new one every week.

Kitchen towels are no less dangerous, the very ones with which we wipe our hands and dishes. The same bacteria grow on towels as on sponges, but their number is about 25% higher.

The best solution may be to use disposable towels. If for some reason this method is not suitable for you, then do not forget to regularly wash cloth kitchen towels, it is better to do this every two days.

Another familiar object teeming with bacteria is a smartphone. Still, many of us do not part with the phone in transport, on the street and even in the toilet. This means that a lot of bacteria get on the device - much more than if it was in your pocket or bag.

A recent study found that the surface of a smartphone can be 20 times dirtier than the surface of a toilet. Bacteriology students at the University of Surrey took and placed their cell phones on a nutrient medium. A quarter of the devices studied in this way showed a 10-fold excess of the permissible number of bacteria. And one of the smartphones turned out to be so dirty that its owner, who regularly applied it to his face, had every chance of getting an intestinal infection.

From this it follows that it is better to try to keep phones in a case, and not to constantly twirl them in your hands. And, of course, do not forget about regular disinfection, the simplest option of which is to use an alcohol wipe.

A lot of bacteria live on money too. Banknotes and coins pass through dozens of hands per day, carrying a huge number of microorganisms on their surface. Older banknotes are expected to have more bacteria than new ones, and the higher the denomination of the banknote, the cleaner it is. This is understandable: old bills are in circulation longer, and larger ones are used less often.

Some countries regularly disinfect banknotes, for example, in Japan, they are heated at high temperatures. This allows you to destroy, if not all, then at least part of the microorganisms.

Perhaps the easiest way to protect yourself from harmful germs is to regularly wash your hands, follow other hygiene rules, and properly heat your food.

Elena Bezrukova