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The human body has about 2 kg of bacteria! Most of them are harmless and even useful, although there are also groups of bacteria that may affect the risk of developing certain diseases, as well as the tendency to gain weight. What do you need to know about bacteria in the human body?
Man is colonized by approx. 2 thousand speciesbacteria . Although it is hard to imagine, the number ofmicrobesthat inhabit our body is ten times greater than the number of our own cells! This proves that they must have a huge impact on our body. And it is so. Throughout the years of evolution, the human body has entered into such close harmony with various types of bacteria that without them many life processes could not take place. The vast majority of microorganisms that live in us are good for us. Thanks to us, they live, but also work for us, effectively protecting against pathogenic bacteria. Therefore, the naturalmicroflorais an important component of the immune system. According to research, individual groups of bacteria living within the human body may also affect the risk of developing certain diseases, as well as the tendency to gain weight!
Tame bacteria
Usually, when microbes enter the body, the immune system recognizes them as foreign and tries to eliminate them. In the case of "tame" microflora does not react in this way. It is an adaptation both on the part of bacteria that are able to defend themselves against elimination, and it results from a certain "tolerance" that arises in early and constant contact with the antigen. It is believed that the immune system is formed in the first stage of life, especially in the neonate. At this time, the newborn's digestive system is also colonized by bacteria - during childbirth and later from the mother and medical staff. These bacteria, which colonize the body early in life, are already treated as their own in the digestive tract, so the immune system "cannot see" them. Each of us has our own individual microflora, unique in terms of species composition and number of bacteria, and - as it turned out recently - that does not change much over time. Recent studies have shown that flora is similarbacterial growth of people results more from genetic conditions than from close contacts.
According to an expertprof. dr hab. n. med. Grażyna Młynarczyk, head of the Chair and Department of Medical Microbiology, Medical University of WarsawWhen good becomes bad
The development of medical techniques saves lives, but also poses a threat. More and more people are exposed to infections with non-pathogenic microorganisms, especially their own flora. The development of transplantology, and hence - immunosuppression, cancer chemotherapy, implantation, catheterization - all this is conducive to infections. Infection of artificial valves or orthopedic endoprostheses can be particularly fatal. Normally, non-pathogenic microorganisms from the skin or mouth enter the blood due to some trauma. The blood should be sterile tissue and all microorganisms are eliminated from it by the own immune system. However, with an artificial implant, bacteria may or may not settle on its surface. These implants are much more susceptible to infections, because microorganisms are more difficult to eliminate from them than from living tissue that defends itself. The so-called a biofilm where bacteria are extremely difficult to eliminate, even by antibiotics. Often, in such a situation, it may be necessary to remove or replace the endoprosthesis, because it will be a serious threat to the patient's life.
Bacteria can be dangerous
"Domesticated" bacteria do their job well when they are not transferred elsewhere. If they are left where they do not normally occur, they can become infected with their own germs. It happens, for example, during injuries, when the continuity of tissues is broken. A benevolent army can fail when the body's immunity is lowered, e.g. as a result of prolonged stress, chronic diseases, taking medications (including antibiotics, cytostatics). In such cases, there is a reduction in the number of good bacteria, which paves the way for "bad competition", or the multiplication of weakly pathogenic microorganisms, a huge number of which can also cause disease. There may also be an infection with normally harmless microorganisms (e.g. for people shortly after bone marrow transplantation, even bacteria present in yoghurts can be pathogenic).
Favorite places of bacteria
Bacteria are found in almost every part of the body that comes into contact with the external environment. Most of them inhabit the digestive system, mainly the large intestine and the oral cavity. They are also on the skin, in the upper respiratory tract (nose), lower respiratory tractgenitourinary (urethra) and reproductive system (vagina).» There are over 100 bacteria per cm on the skin2 . Most of them live in symbiosis with humans, but some contribute to the development of, inter alia, eczema, acne. Bacteria reside in hair follicles and sebaceous glands, they like warm and humid places (in the armpits, in the groin). They are not harmed by solid hygiene, because they regenerate within a few hours of bathing. Recent studies have shown that by touching various surfaces (e.g. computer keyboard), we leave a unique trace of bacterial flora on them, which can last up to 2 weeks!» Most bacteria living in the mouth do not it is harmful, but some of them cause periodontitis, caries, and tartar. There are as many as 10 billion microbes in 1 ml of saliva, and the plaque is partially made up of bacteria that make up a layer 300-500 of these microbes.Streptococcus mutansandStreptococcus sanguislive in the mouth, and their amount depends on our diet. If we eat a lot of products containing sucrose, these bacteria intensively multiply and locate in the spaces between the teeth, favoring the production of acids that destroy the surface of the teeth.» Huge amounts of bacteria are found in the digestive tract - most of them are the large intestine, as many as 1012 bacteria in 1 g of stool. There are fewer of them in the small intestine (108-10), and even fewer in the stomach due to the acidic environment necessary for digestion. 99.9 percent these bacteria are obligate anaerobes. They are of two main types:FirmicutesandBacteroidetes . The first of these are mainly gram-positive bacteria, and the second are gram-negative. Recent studies have shown that obese people have moreBacteroidetesbacteria than lean people. People with anorexia have the advantage of bacteria belonging toFirmicutes(e.g.Clostridium rhamnosum ). Proper flora in the intestines (bacteria of the genusLactobacillusandBifidobacteriumlactic acid-producing bacteria predominate in it), apart from non-specific defense against pathogens, enables the decomposition of non-digestible ingredients food and mucus secreted into the intestinal lumen. In addition, it produces vitamin K, and also produces short-chain fatty acids, which are a source of energy for the cells of the colon epithelium. Microbiological analyzes have shown that people suffering from chronic bowel disease have a different composition of bacteria than he althy ones, as well as a lower number of beneficial microbes. It is suspected that the products of the metabolism of some bacteria may even be carcinogenic. Change of florabacterial, at least partially, is likely to be caused by a radical change in diet, e.g. from meat to vegetarian or vice versa.
» In the urogenital system of men, colonized by microorganisms (eg from the skin) may be the lower section of the urethra, and there are practically no bacteria closer to the bladder. Due to the close proximity of the urethra and anus, women have more bacteria than men and different types of bacteria (intestinal flora), and urinary tract infections are more common (laboratory tests show that the number of bacteria exceeds 103 in 1 ml of urine, depending on the type of bacteria).
» In the lower part of the reproductive system, i.e. in the vagina, the most important flora are lactobacilli ( Lactobacillus , the so-called Döderlein bacilli) . They create an acidic environment that effectively prevents the multiplication of pathogenic bacteria and fungi, thus protecting against infection.
ImportantThe effects of antibiotic therapy
Antibiotics wreak havoc on normal microbial flora. Their goal is to eliminate pathogenic bacteria, but they also destroy beneficial microbes. And then the gates for pathogenic microorganisms open. And although it is most often a temporary state, antibiotic therapy may be accompanied by symptoms, usually from the gastrointestinal tract, e.g. diarrhea, flatulence (in extreme cases pseudomembranous enteritis caused by the multiplication of an anaerobic bacterium Clostridium difficile). In the case of women, it is often vaginal fungal infections. To restore the balance of the bacterial flora, during antibiotic therapy, doctors recommend taking probiotics, i.e. preparations with lactic acid bacteria, and drinking yoghurt or kefir, which are rich in these beneficial microorganisms. Preparations containing the yeast Saccharomyces boulardii are also effective in post-antibiotic diarrhea.
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