MICROFLORA AND SANITARY-INDICATIVE BACTERIA OF SOIL, WATER, AIR.

MICROFLORA AND SANITARY-INDICATIVE BACTERIA OF SOIL, WATER, AIR.

THE METHODS OF STUDYING.

 

Microorganisms are widespread. Microbes are distributed everywhere in the environment surrounding us. They are found in the soil, water, air, in plants, animals, food products, various utensils, in the human body, and on the surface of the human body.

Potentially pathogenic bacteria can get to environment, for example, from patients, carriers and survive there for some time. From soil, water and air, microorganisms can enter the human body and cause diseases. So, the environment is a transmission factor of infectious diseases. Potentially pathogenic and pathogenic microorganisms get to environment  mainly, in 2 ways:

Fecal (with excrement from the intestine);

Airborne (with droplets of mucus from the respiratory tract).

Thus sanitary-microbiological investigations are performed for study and evaluation of different objects for determination of their epidemic potential.

Sanitary microbiology is a science that studies the microflora of the environment and its harmful effect on the human body.

Methods for sanitary-microbiological investigation include:

1) determination of a total microbial contamination;

2)detection and titration of sanitary-indicative microorganisms;

3)detection of pathogenic microorganisms and/or their metabolites. 

Direct detection of pathogenic microorganisms in the different objects of environment, in general, is complicated because of their small quantity, their temporarily staying in the environment and the d uration and laboriousness of methods for their determination.

 Thus indirect methods of detection of microbial contamination are used:

1) total microbial contamination as indicator of intensity of contamination by organic substances;

2) contamination by sanitary- indicative microorganisms.

 А total microbial number (TMN) is used for evaluation of total microbial contamination.

TMN - t he number of microbes in 1 ml of water , 1 g of soil , in 1 m3 of air .

Sanitary-indicative microorganisms - SIMs (or sanitary-indicative bacteria) are those, which are used for indirect evaluation of possible presence of pathogens in the environment.

 SIMs are representatives of normal human microflora and homoiothermal animals.

- get to environment the same ways (fecal and airdrop ways), as pathogenic m/o;

- the same terms are maintained, as pathogenic m/o;

- do not have other habitats;

- the number is constant (they do not multiply in the environment);

- methods for determining them are easy and affordable;

- have stable and typical properties, so they are easily identified and are quantifiable.

For example, presence of Escherichia coli and Enterococcus faecalis on environmental objects is indicative of fecal contamination. Simultaneous isolation of Staphylococcus aureus and hemolytic streptococci indicates possible contamination by oral droplets.

If the amount of SIMs increases in environmental objects, the probability of the presence of pathogenic and opportunistic microbes in them increases. For different objects there are specific SIMs.

Presence of sanitary-indicative microorganisms is measured by titer
and index.

The titer - min mass (in g) or volume (in ml), where else are detected SIMs.

The index is the amount of SIMs contained in a   1Lof water, 1g of soil, 1 m3 of air.

Microflora of the Water

Pseudomonasfluorescens , Micrococcus roseus, etc., are among the specific aquatic aerobic microorganisms. Anaerobic bacteria are very rarely found in water.

The microflora of rivers depends on the degree of pollution and the quality of purification of sewage waters flowing into river beds. Microorganisms are widespread in the waters of the seas and oceans. They have been found at different depths (3700-9000 m).

Determination of water TMN.

1. Sampling: 500 ml (tap water and purified water), 20 ml (water for injection), 100 ml (river water).

2. 1 ml of water is seeded in at least 2 Petri dishes according to Koch's deep method on MPA.

3. Incubation: 37 ° C, 24 hours.

4. Calculation: count the number of colonies on both plates, add up and divide by

 The result is expressed in CFU(colony forming units) / ml.

Take into account only those Petri dishes, where no more than 300 colonies have grown.

If more than 300 - do 10-fold dilutions (1: 10; 1: 100, etc.). When calculating, multiply by the dilution rate.

Standards .

Soil Microflora

Soil fertility depends not only on the presence of inorganic and organic substances, but also on the presence of various species of microorganisms which influence the qualitative composition of the soil. Due to nutrients and moisture in the soil the number of microbes in 1 g of soil reaches a colossal number — from 200 million bacteria in clayey soil to 5 thousand million in black soil.

Soil microflora consists bacteria (nitrifying, nitrogen-fixing, denitrifying), cellulose-splitting and sulfur bacteria, pigmented microbes fungi, protozoa, etc.

The greatest amount of microbes (1 000000 per cu cm) is found in the top layer of soil at a depth of 5-15 cm. In deeper layers (1.5-5 m) individual microbes are found. However, they have been discovered at a depth of 17.5 m in artesian water.

The number of microorganisms in the soil depends on the extent of contamination with faeces and urine, and also on the nature of treating and fertilizing the soil. Saprophytic spores (B. cereus. B, meguterium, etc.) survive for long periods in the soil. Pathogenic bacteria which do not produce spores due to lack of essential nutrients, and also as a result of the lethal activity of light, drying, antagonistic microbes, and phages do not live long in the soil (from a few days to a few months).

Usually the soil is an unfavourable habitat for most pathogenic species of bacteria, rickettsiae, viruses, fungi, and protozoa. However, the soil can act as a factor in the transmission of a number of pathogens of infectious diseases.  Thus, for example, anthrax bacilli after falling on the soil produce spores which can remain viable for many years. As is known, the spores of Clostridia causing tetanus, anaerobic infections, and botulism, and of many soil microbes survive for long periods in the soil. The cysts of intestinal protozoa (amoeba, balantidium, etc.) spend a certain stage in the soil. The soil plays an important role in transmitting worm invasions (ascarids, hook-worms, nematode worms, etc.). Some fungi live in the soil. Entering the body they cause fusariotoxicosis, ergotism, aspergillosis, penicilliosis mucormycosis, etc.

Taking into consideration the definite epidemiological role played by the soil in spreading some infectious diseases of animals and man, sanitary-microbiological evaluation of soil is performed.

Microbiological investigation of soil. The sanitary - bacteriological investigation of soil includes:

1) a total quantity of saprophytes bacteria in 1 g of soil - a total microbial number (TMN);

 2) contents of sanitary-indicative bacteria as indicator of  fecal contamination.

The sanitary-indicative bacteria of the soil are

1) E. coli/Enterococcus faecalis;

2) Citrobacter spp. /Enterobacter spp.;

3)  Clostridium perfringens.

Presence of E. coli/E. faecalis, Citrobacter spp. /Enterobacter spp.
and Clostridium perfringens in the soil indicates the presence of recent, non-
recent and bygone (old) fecal contamination, respectively.

More accurate evaluation is performed using coli-index — number of Enterobacteriaceae (so called coliform bacteria) found in 1 g of soil; perfringens -titer - mass of soil in which 1 cell C.
perfringens is found.

Determination of soil TMN . For this purpose it is necessary to select most typical area not more then 25 m². The samples are taken from different places of the field along the diagonal, the angles and the center 10 — 20 cm deep. The weight of each sample must be 100 - 200 g. The total weight of the soil 0,5 - 1 kg.

After careful mixing take an average sample of weight 100 - 200 g. Put the samples of soil in the sterile banks, mark and deliver to the laboratory.

1. Prepare 10-fold dilutions (1:10, 1: 100, etc.) in an isotonic sterile solution of sodium chloride.

2. Make seeding of the soil dilutions on MPA (for bacteria) and on Saburo medium (for fungi): 1 ml in the depth of agar or 0.1 ml on the surface of agar.

3. Incubation: at 24 ° C (for fungi) and 37 ° C (for bacteria).

After incubation at optimal temperature count the colonies on the plates (1 colony=1 cell). The number of cells in 1 g of soil is calculated, taking into account:

- the weight of each sample;

 - the rate of dilution;

-  the volume of seeding.

Determination of perfringens -titer:  seeding onto the Wilson-Blair medium: black colonies are formed and the gas breaks up the medium; Calculation: maximal dilution, where there are signs of growth of Clostridium perfringens.

Microflora of the Air

The composition of the microbes of the air is quite variable. Then more dust, smoke, and soot in the air, the greater the number of microbes. Each particle of dust or smoke is able to adsorb on its surface numerous microbes. The number of microbes in the air varies from a few specimens to many tens of thousands per 1 m³. Depending on the time of the year, the composition and the amount of microflora change. If the total amount of microbes in winter is accepted as 1, then in spring it will be 1.7, in summer— 2 and in autumn — 1.2.

The number of microbes in factories and homes is associated closely with the sanitary hygienic conditions of the building. At poor ventilation and natural lighting and if the premises are not properly cleaned, the number of microbes increases.

Pathogenic species of microbes (pyogenic cocci, tubercle bacilli, anthrax bacilli, bacteria of tularaemia, rickettsiac of Q-fever, etc.) may be found in the surroundings of sick animals and humans, infected arthropods and insects, and in dust. The causative agents of influenza, measles, scarlet fever, diphtheria, whooping cough, meningococcal infections, tonsillitis, acute catarrhs of the respiratory tract, tuberculosis, smallpox, pneumatic plague, and other diseases can be transmitted through the air together with droplets of mucus and sputum during sneezing, coughing, and talking.

The air is an unfavourable medium for microbes. The absence of nutrient substances, the presence of moisture, optimal temperature, the lethal activity of sunlight, and desiccation do not create conditions for keeping microbes viable and most of them perish. However, the relatively short period during which the microbes are in air is quite enough to bring about the transmission of pathogenic bacteria and viruses from sick to healthy persons, and to cause extensive epidemics of diseases such as influenza.

The laboratory investigation of air is carried out to determine the qualitative and quantitative composition of its microflora. This is achieved by using simple and complex methods. For a more accurate investigation of microbial contents of the air special apparatus are used.

At present Streptococcus viridans serves as sanitary indices for the air of closed buildings, and haemolytic streptococci and pathogenic staphylococci are a direct epidemiological hazard.  

So, sanitary-indicative bacteria of air of closed buildings are

1)Streptococcus viridans,

2)Streptococcus haemolyticus,

3) Staphylococcus aureus.

These bacteria are indicators of contamination by oral droplets.

Microbiological investigation of the air. The sanitary - bacteriological investigation of air includes:
1) determination the total number of microbes in 1 m³ of the air - a total microbial number (TMN);
2) presence of sanitary-indicative bacteria — Str. viridans, Str. haemolyticus , S. aureus.

For taking the samples sedimentation and aspiration methods are used.

Plate method (sedimentation method). The Petri’s dishes with meat-peptone agar or another special nutrient media for staphylococci and streptococci, for example blood agar, yolk- salt agar are used. They are opened and are stayed in investigated room. Term of exposition depends on prospective quantity of microbes in the air. With a plenty of microorganisms a plate is opened for 5-10 minutes to detect a total microbial number, with a little - for 20 — 40 minutes for detection of cocci.

Then the dishes put into thermostat at 37 °C for 24 hrs. After incubation all colonies are accounted (for determination of total number of microorganisms). Number of grown colonies
indicates degree of air contamination.

According to Omeliansky’s data in 5 minutes on a surface of 100 cm² so many microbes sedimentate, as they present in 10 L of air. For example, on the dish surface with MPA after 5 minute exposure 32 colonies have grown. It is necessary to calculate amount of microbes which are present in 1 nr³ of the air, applying the Omeliansky’s formula. The plate has 100 cm² . 32 colonies of microbes contain in 10 L of the air, and in 1 m³ (1000 л) there will be (32 • 1000): 10 = 3200.

Aspiration method. Krotov’s apparatus is used for this purpose. It give us the possibility to let pass 50 -100 L of air with a speed of 25 L per minute through clinoid chink in the special glass above the open dish with MPA. The rotation of Petry’s dish (1 rotation/sec) provides uniform dispersion of microorganisms on all surface of a medium. Then dish is incubated in a thermostat at 37 °C for 18-24 hrs.

For example, 250 colonies are revealed on the surface of dish after 2-minutes exposure with a 25 1/min speed. Thus the number of microbes (x) in 1 m³  of the air is: x = (250 • 1000): 50 = 5000.

 

Determination of staphylococci and streptococci. Using Krotov’s apparatus 250 L of air are seeded on the surface of open Petri dish with yolk- salt agar for staphylococci and with blood agar for streptococci. Then dishes are incubated in a thermostat at 37 °C for 18-24 hrs. After incubation growing up colonies are accounted and the number of staphylococci or streptococci in 1 m³  of the air is calculated.

To the air environment of pharmacies strict hygienic requirements are imposed, which is reflected in normative documents. Sources of air pollution pharmacies: • - visitors; • -employees; • -infected material (recipes, dishes, packaging material); • - poor-quality medicinal plant raw materials.

The permissible standards of the microbial number of air in various pharmacy premises have also been developed.

 

Normal microflora of the human body and its meaning. The concept of gnotobiology. Disbiosis. Preparations used to restore normal microflora.

In a healthy animal, the internal tissues, e. g. blood, brain, muscle, etc., are normally free of microorganisms. On the other hand, the surface tissues, e. g. skin and mucous membranes, are constantly in contact with environmental organisms and become readily colonized by certain microbial species.

The mixture of organisms regularly found at any anatomical site is referred to as the normal flora.

The normal flora of humans is exceedingly complex and consists of more than 200 species of bacteria. The makeup of the normal flora depends upon various factors, including genetics, age, sex, stress, nutrition and diet of the individual.

The normal flora of humans consists of a few eukaryotic fungi and protists, and some methanogenic Archaea that colonize the lower intestinal tract, but the Bacteria are the most numerous and obvious microbial components of the normal flora.

Very little is known about the nature of the associations between humans and their normal flora, but they are thought to be dynamic interactions rather than associations of mutual indifference. Both host and bacteria are thought to derive benefit from each other, and the associations are, for the most part, mutualistic.

The normal flora derives from the host a supply of nutrients, a stable environment and constant temperature, protection, and transport.

The host obtains from the normal flora certain nutritional benefits, stimulation of the immune system, and colonization strategies that exclude potential pathogens at the site.

The composition of the normal flora

The normal flora of corresponding anatomical sites in different animal species varies widely. Within a single species (e. g. humans) there is additional variation in the normal flora that is related to factors such as age, sex, diet and nutrition. Some bacteria are found regularly at particular anatomical locales; others are present only occasionally, or at certain times during life. Developmental changes in humans such as weaning, the eruptions of the teeth, and the onset and cessation of ovarian functions, invariably affect the composition of the normal flora in the intestinal tract, the oral cavity, and the vagina, respectively. However, within the limits of these fluctuations, the bacterial flora of humans is sufficiently constant to a give general description of the situation.

It has been calculated that the normal human houses about 10¹² bacteria on the skin, 10¹⁰ in the mouth, and 10¹⁴ in the gastrointestinal tract. The latter number is far in excess of the number of eukaryotic cells in all organs which comprise the human host.

Normal flora of the skin. The adult human is covered with approxima­tely 2 square meters of skin. The density and composition of the normal flora of the skin vary with anatomical locale. The high moisture content of the axilla, groin, and areas between the toes supports the activity and growth of relatively high densities of bacterial cells, but the density of bacterial populations at most other sites is fairly low, generally in 100s or 1000s per square cm. Qualitatively, the bacteria on the skin near any body orifice may be similar to those in the orifice.

The majority of skin microorganisms are found in the most superficial layers of the epidermis and the upper parts of the hair follicles. They consist largely of micrococci (S. epidermidis and Micrococcus spp. ) and corynebacteria. These are generally nonpathogenic and considered to be commensal, although mutualistic and parasitic roles have been assigned to them. Sometimes potentially pathogenic Staphylococcus aureus is found on the face and hands, particularly in individuals who are nasal carriers.

The skin has a bactericidal action (destruction of microbes). The bactericidal effect is due to the content of antimicrobial agents in the sweat: a-globulins, immunoglobulins A, transferrin, lysozyme, etc. This action is more effective if the skin is clean. On dirty skin, there is an increase in the growth of microorganisms, which determine the smell of the body.

The microflora of the skin is of great importance in air pollution by microorganisms. This happens when the skin is peeling, as microorganisms are on the scales. Through dirty hands:

1) contamination of medicinal products by microorganisms can occur, which cause their spoilage;

2) transmission of infections (gastrointestinal tract, skin) by contact way can occur.

The sanitary-indicative bacteria of the skin are:

 1) E. coli;

2) Streptococcus faecalis;

3) Staphylococcus aureus.

Microbiological investigation of the skin is inoculation of the washing  from the skin.

Normal flora of the respiratory tract. The nares (nostrils) are always heavily colonized, predominantly with S. epidermidis and corynebacteria, and often (about 20% of the general population) with S. aureus, this being the main carrier site of this important pathogen. The healthy sinuses, in contrast are sterile. A large number of bacterial species colonize the upper respiratory tract (nasopharynx). The predominant species are non-hemolytic and alpha- hemolytic streptococci and Neisseria spp., but sometimes pathogens such as S. pneumoniae, S. pyogenes, H. influenzae and N. meningitidis colonize the pharynx.

The lower respiratory tract (trachea, bronchi, and pulmonary tissues) are virtually free of microorganisms, mainly because of the efficient cleansing action of the ciliated epithelium which lines the tract. Any bacteria reaching the lower respiratory tract are swept upward by the action of the mucociliary blanket that lines the bronchi, to be removed subsequently by coughing, sneezing, swallowing, etc. If the respiratory tract epithelium becomes damaged, as in bronchitis or viral pneumonia, the individual may become susceptible to infection by pathogens descending from the nasopharynx (e. g. H. influenzae or S. pneumoniae). The pathogen Bordetella pertussis is specifically able to colonize the tracheal epithelium of humans, allowing it to produce the disease, pertussis (whooping cough).

Normal flora of the human oral cavity. The presence of nutrients, epithelial debris, and secretions makes the mouth a favorable habitat for a great variety of bacteria. Oral bacteria include streptococci, lactobacilli, staphylococci and corynebacteria, with a great number of anaerobes, especially Bacteroides.

The mouth presents a succession of different ecological situations with age, and this corresponds with changes in the composition of the normal flora. At birth the oral cavity is sterile but rapidly becomes colonized from the environment, particularly from the mother in the first feeding. S. salivarius is dominant and may make up 98% of the total oral flora until the appearance of the teeth (6-9 months in humans). The eruption of the teeth during the first year leads to colonization by S. mutans and S. sanguis. These bacteria require a nonepithelial surface in order to colonize. They will persist as long as teeth remain. Other strains of streptococci adhere strongly to the gums and cheeks but not to the teeth. The creation of the gingival crevice area (supporting structures of the teeth) increases the habitat for the variety of anaerobic species found. The complexity of the oral flora continues to increase with time, and Bacteroides spp. and spirochetes colonize around puberty.

The main role in the formation of microflora is played by saliva, which has bactericidal properties (lysozyme, lactoferrin, peroxidase, nuclease, Ig A).

Clearly, the normal bacterial flora of the oral cavity benefit from their associations with their host. Are there benefits as well to the host? Perhaps. The normal flora occupies available colonization sites which makes it more difficult for other microorganisms (nonindigenous species) to become established. Also, the oral flora contributes to host nutrition through the synthesis of vitamins, and they contribute to immunity by inducing low levels of circulating and secretory antibodies that may cross react with pathogens. Finally, the oral bacteria exert microbial antagonism against nonindigenous species by production of inhibitory fatty acids, peroxides, bacteriocins, etc.

The oral flora of humans may harm their host since some of these bacteria are parasites or opportunistic pathogens. The microflora of the oral cavity is one of the reasons of caries.

 If certain oral bacteria are able to invade tissues not normally accessible to them, characteristic diseases result. For example, oral organisms gaining entrance into tissues (e. g. via surgical wounds) may cause abscesses of alveolar bone, lung, brain or the extremities. Such infections usually contain mixtures of bacteria with Prevotella spp. and Porphyromonas spp. often playing a dominant role. Also, oral streptococci may be introduced into wounds created by dental manipulation or treatment. If this occurs in an individual with damaged heart valves due to rheumatic fever (previously induced by streptococci), the oral streptococci may adhere to the damaged heart valves and initiate subacute bacterial endocarditis.

Normal flora of the gastrointestinal (GI) tract

The bacterial flora of the GI tract of animals has been studied more extensively than that of any other site. The composition differs between various animal species, and within an animal species. In humans, there are differences in the composition of the flora which are influenced by age, diet, cultural conditions, and the use of antibiotics. The latter greatly perturbs the composition of the intestinal flora.

In the upper Gl tract of adult humans, the esophagus contains only the bacteria swallowed with saliva and food. Because of the high acidity of the gastric juice very few bacteria (mainly acid-tolerant lactobacilli) can be cultured from the normal stomach. However, a substantial proportion of population is colonized by a pathogenic bacterium, Helicobacter pylori. Since the 1980s, this bacterium has been known to be the cause of gastric ulcers, and it is a cause of gastric and duodenal cancer as well.

The proximal small intestine has a relatively sparse Gram-positive flora, consisting mainly of Iactobacilli and Enterococcus faecalis. This region has about 10⁵-10⁷ bacteria per ml of fluid. The distal part of the small intestine contains greater numbers of bacteria (10⁸/ml) and additional species including coliforms and Bacteroides spp., in addition to lactobacilli and enterococci.

The flora of the large intestine (colon) is qualitatively similar to that found in feces. Populations of bacteria in the colon reach levels of 10¹¹/ml feces. Coliforms become more prominent, and enterococci, clostridia and lactobacilli can be regularly found, but the predominant species are anaerobic Bacteroides spp. and anaerobic lactic acid bacteria in the genus Bifidobacterium (Bifidobacterium bifidum). These organisms may outnumber E. coli by 1, 000: 1 to 10, 000: 1. It is now known that significant numbers of anaerobic methanogenic bacteria (up to 10¹⁰/g) also reside in the colon of humans.

At birth the entire intestinal tract is sterile, but bacteria enter with the first feed. The initial colonizing bacteria vary with the food source of the infant. In breast-fed infants bifidobacteria account for more than 90% of the total intestinal bacteria. Enterobacteriaceae and enterococci are regularly present, but in low proportions, while bacteroides, staphylococci, lactobacilli and clostridia are practically absent. In bottle-fed infants, bifidobacteria are not predominant. When breast-fed infants are switched to a diet of cow’s milk or solid food, bifidobacteria are progressively joined by enterics, bacteroides, enterococci lactobacilli and clostridia. Apparently, human milk contains a growth factor that enriches for growth of bifidobacteria, and these bacteria play an important role in preventing colonization of the infant intestinal tract by non indigenous or pathogenic species.

The composition of the flora of the GI tract varies along the tract (at longitudinal levels) and across the tract (at horizontal levels) where certain bacteria attach to the gastrointestinal epithelium and others occurs in the lumen. There is frequently a very close association between specific bacteria in the intestinal ecosystem and specific gut tissues or cells (evidence of tissue tropism). Many bacteria adhere specifically to the gastrointestinal epithelial surfaces, and this has been shown in many animal species including humans, cows, dogs, pigs, mice and chickens. Gram-positive bacteria, such as the streptococci and lactobacilli, are thought to adhere to the gastrointestinal epithelium using polysaccharide capsules or wall lipoteichoic acids to attach to specific receptors on the epithelial cells. Likewise, Gram-negative bacteria such as the enterics may attach by means of specific fimbriae on the bacterial cell which bind to glycoproteins on the epithelial cell surface.

The benefits of the normal flora

The indigenous bacteria of the gastrointestinal tract of an animal, perhaps mainly as a consequence of their great numbers, seem to have the greatest overall impact on their host. The nature of the interactions between an animal host and its normal flora has been inferred from the study of germ-free animals (animals which lack any bacterial flora) compared to conventional animals (animals which have a typical normal flora).  The science of the non-microbial life of animals is called gnotobiology .

Following are the primary beneficial effects of the normal flora that are derived from this science.

1.        The normal flora synthesizes and excretes vitamins in excess of their own needs, which can be absorbed as nutrients by the host. For example, enteric bacteria secrete vitamin К and vitamin B_]2, and lactic acid bacteria produce certain В vitamins. Germ-free animals may be deficient in vitamin К to the extent that it is necessary to supplement their diets.

2. The normal flora prevents colonization by pathogens  (c olonization resistance) by competing for attachment sites or for essential nutrients. This is thought to be their most important beneficial effect, which has been demonstrated in the oral cavity, the intestine, the skin, and the vaginal epithelium. In some experiments, germ-free animals can be infected by 10 Salmonella, while the infectious dose for conventional animals is near 10⁶ cells.

3. The normal flora may antagonize other bacteria through the production of substances which inhibit or kill nonindigenous species. The intestinal bacteria produce a variety of substances ranging from relatively nonspecific fatty acids and peroxides to highly specific bacteriocins, which inhibit or kill other bacteria.

4.        The normal flora stimulates the development of certain tissues, i. e.. the caecum and certain lymphatic tissues (Peyer’s patches) in the GI tract. The caecum of germ-free animals is enlarged, thin-walled, and fluid- filled, compared to that organ in conventional animals. Also, based on the ability to undergo immunological stimulation, the intestinal lymphatic tissues of germ-free animals are poorly-developed compared to conventional animals.

5.        The normal flora stimulates the production of cross-reactive antibodies. Since the normal flora behaves as antigens in an animal, they induce an immunological response, in particular, an antibody-mediated immune (AMI) response. Low levels of antibodies produced against components of the normal flora are known to cross react with certain related pathogens, and thereby prevent infection or invasion. Antibodies produced against antigenic components of the normal flora are sometimes referred to as "natural" antibodies, and such antibodies are lacking in germ-free animals.

What is Dysbiosis?

- Quantitative and qualitative changes in the composition of normal microflora (bacteria and other groups of microbe). There is a loss of normal functions of the microflora.

Dysbiosis is a term for a microbial imbalance that most often affects a person’s digestive tract. That being said, dysbiosis can also affect the skin, eyes, lungs, ears, nose, sinuses, nails, and vagina.

Dysbiosis is also sometimes called dysbacteriosis or bacterial dysbiosis. That is because the gastrointestinal tract (GI tract) contains both “good” and “bad” bacteria to form the gut flora—also called the gut microbe. But, other tiny organisms also reside in the gastrointestinal tract, including yeast, fungus, viruses, and parasites.

The dysbiosis pronunciation is “diss-bi-osis.” Russian-born microbiologist and zoologist, Dr. Elie Metchnikoff, would first coin the term in the 20th century. Dr. Metchnikoff is the first scientist to discover the impact of the properties of probiotics—also known as that “good bacteria.” The terms “dys” and “symbiosis” translate to “not living in harmony.”

When the gut flora is balanced, it is called “orthobiosis,” which again is a term introduced by Dr. Metchnikoff in the early 1900s. He considered dysbiosis so serious that is also said, “death begins in the gut.” The issue here is that not all of the friendly organisms in the gut flora are “friendly.” In fact, when there is an overgrowth of bacteria, parasites, fungus, yeast, or other organisms, it can lead to dysbiosis.

Complications of Dysbiosis

There are various complications of gut dysbiosis. Here is a deeper look at some of the complications and conditions that may result from dysbiosis:

§ Atopic eczema: Skin conditions are a common result of dysbiosis, but especially atopic eczema. Most atopic eczema patients have malabsorption and intestinal dysbiosis.

§ Candida: Candida is the condition where fungus and yeast will grow out of control, and lead to certain debilitating symptoms like persistent fatigue, muscle pain, constipation, and rectal itching.

§ Irritable bowel syndrome: Various studies have found that IBS patients have a greater likelihood of abnormal fecal flora.

§ Other possible dysbiosis complications: When dysbiosis is left untreated it can lead to severe fungal infections, and even increase the risk of cancer.

Prevention of Dysbiosis

It is always better to prevent a disease or condition from starting in the first place. The following are a few gut dysbiosis prevention methods:

§ Eat an overall healthy and clean diet that contains lots of green leafy vegetables, organic meats, and totally avoid processed foods.

§ Avoid alcohol or extremely limit your intake to once every few months. All forms of alcohol contain acetaldehyde, yeast, and other ingredients that harm the balance of bacteria and other organisms in the GI tract.

§ Avoid antibiotics, and other drugs like proton-pump inhibitors, antacids, non-steroidal anti-inflammatory drugs (NSAIDs). All of these drugs inhibit the growth of “good” bacteria in the GI tract and rest of the body.

MICROFLORA AND SANITARY-INDICATIVE BACTERIA OF SOIL, WATER, AIR.

THE METHODS OF STUDYING.

 

Microorganisms are widespread. Microbes are distributed everywhere in the environment surrounding us. They are found in the soil, water, air, in plants, animals, food products, various utensils, in the human body, and on the surface of the human body.

Potentially pathogenic bacteria can get to environment, for example, from patients, carriers and survive there for some time. From soil, water and air, microorganisms can enter the human body and cause diseases. So, the environment is a transmission factor of infectious diseases. Potentially pathogenic and pathogenic microorganisms get to environment  mainly, in 2 ways:

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