Everything you need to know about bacteria

How many kilograms of bacteria are in my body? Which bacteria are good for it, and which are bad? How quickly does the bacterial flora regenerate? You’ll find answers to these and other questions about bacteria in the text below!

1. There are more bacteria in the human body than any other type of cell. Together, they weigh about two kilograms—since they are smaller and lighter than stem cells. There are about 20 trillion in the mouth alone—that’s more than the number of people living in the world!
2. Bacteria are divided into those that are good and those that are bad for our bodies. The bad ones cause diseases, while the good ones are essential for proper functioning. However, this distinction is not always clear-cut! There are also bacteria that can have a dual effect on our bodies. For example, the bacterium Helicobacter pylori contributes to the development of peptic ulcers and gastritis. According to the World Health Organization, between 30% and approximately 70% of the population carries it. Is the absence of this bacterium, then, a cause for celebration? Not necessarily—it has been proven that the absence of Helicobacter pylori may actually contribute to diseases of the esophagus and throat.
3. Our natural, so-called endogenous, bacterial flora is essential for life. So is hand sanitizing—recommended in situations where, among other things, we cannot wash our hands with soap and water or during flu season—harmful to it? After a doctor performs surgical hand disinfection before an operation—that is, after killing all microorganisms on the surface of the hands—their bacterial flora fully regenerates in about two hours. So we have nothing to fear—our native bacteria will certainly manage just fine.
4. Before birth, an infant has no bacteria on its body. It acquires its first dose of microbes in the mother’s birth canal during delivery. We then build up our bacterial flora over the next few years of life—by the third year of life, our microbiome (the totality of microorganisms in the body) typically contains most of the bacteria characteristic of it.
5. How many bacteria can live in the navel? In 2012 alone, scientists discovered 1,458 new species of bacteria living there! Interestingly, the bacterial flora in the navel is unique to every person, just like a fingerprint.
6. Bacteria appeared on Earth a very, very long time ago. Bacterial fossils found in Australia—the oldest ever discovered—predate the appearance of oxygen on our planet; they may be around three and a half trillion years old!