Probably, you will not surprise anyone with the information that bacteria live in any organism. Everyone knows very well that this neighborhood can be safe for the time being. This also applies to anaerobic bacteria. They live and, if possible, slowly multiply in the body, waiting for the moment when they could attack.

Infections caused by anaerobic bacteria

Anaerobic bacteria differ from most other microorganisms in survivability. They are able to survive where other bacteria will not last even a few minutes - in an oxygen-free environment. Moreover, with prolonged contact with clean air, these microorganisms die.

Simply put, anaerobic bacteria have found a unique loophole for themselves - they settle in deep wounds and dying tissues, where the level of protection of the body is minimal. Thus, microorganisms get the opportunity to develop freely.

All types of anaerobic bacteria can be conditionally divided into pathogenic and conditionally pathogenic. Microorganisms that pose a real threat to the body include the following:

• peptococci;
• clostridia;
• peptostreptococci;
• some types of clostridia (anaerobic spore-forming bacteria that occur naturally and live in the gastrointestinal tracts of humans and animals).

Some anaerobic bacteria not only live in the body, but also contribute to its normal functioning. A good example is bacteroids. IN normal conditions these microorganisms are an obligatory component of the colon microflora. And varieties of anaerobic bacteria such as Fusobacteria and Prevotella provide a healthy oral flora.

In different organisms, anaerobic infection manifests itself in different ways. It all depends on the state of health of the patient, and on the type of bacteria that struck him. The most common problem is infection and suppuration of deep wounds. This is a vivid example of what the vital activity of anaerobic bacteria can lead to. In addition, microorganisms can be causative agents of such diseases:

• necrotic pneumonia;
• peritonitis;
• endometritis;
• bartholinitis;
• salpingitis;
• epiema;
• periodontitis;
• sinusitis (including its chronic form);
• infections of the lower jaw and others.

Treatment of infections caused by anaerobic bacteria

Manifestations and methods of treatment anaerobic infections also depend on the pathogen. Abscesses and suppurations are usually treated with surgery. Dead tissue must be removed very carefully. After that, the wound is disinfected no less thoroughly and regularly treated with antiseptics for several days. Otherwise, the bacteria will continue to multiply and penetrate deeper into the body.

You need to be ready for treatment with potent drugs. Often, it is not possible to effectively destroy anaerobic, as, in general, any other type of infection, without antibiotics.

Anaerobic bacteria in the mouth require special treatment. They are what cause bad breath. In order for the bacteria to stop receiving nutrients, you need to add as many fresh vegetables and fruits as possible to your diet (oranges and apples are considered the most useful in the fight against bacteria), and it is advisable to limit yourself in meat, fast food and other junk food. And of course, don't forget to brush your teeth regularly. The particles of food remaining in the gaps between the teeth are favorable soil for the growth of anaerobic bacteria.

By following these simple rules, you can not only get rid of the unpleasant, but also prevent the appearance of plaque.

Anaerobes and aerobes are two forms of existence of organisms on earth. This article is about microorganisms.

Anaerobes are microorganisms that develop and multiply in an environment that does not contain free oxygen. Anaerobic microorganisms are found in almost all human tissues from pyoinflammatory foci. They are classified as conditionally pathogenic (they exist in a person in a nome and develop only in people with a weakened immune system), but sometimes they can be pathogenic (disease-causing).

There are facultative and obligate anaerobes. Facultative anaerobes can develop and multiply both in oxygen-free and oxygen environments. These are microorganisms such as E. coli, Yersinia, staphylococcus, streptococcus, shigella and other bacteria. obligate anaerobes can exist only in an oxygen-free environment and die when free oxygen appears in the environment. Obligate anaerobes are divided into two groups:

• spore-forming bacteria, otherwise known as clostridia
• bacteria that do not form spores, or otherwise non-clostridial anaerobes.

Clostridium is the causative agent of anaerobic clostridial infections - botulism, clostridial wound infections, tetanus. Non-clostridial anaerobes are the normal microflora of humans and animals. These include rod-shaped and spherical bacteria: bacteroids, fusobacteria, peillonella, peptococci, peptostreptococci, propionibacteria, eubacteria and others.

But non-clostridial anaerobes can significantly contribute to the development of purulent-inflammatory processes (peritonitis, abscesses of the lungs and brain, pneumonia, pleural empyema, phlegmon of the maxillofacial region, sepsis, otitis, and others). Most anaerobic infections caused by non-clostridial anaerobes are endogenous (of internal origin, caused by internal causes) and develop mainly with a decrease in the body's resistance, resistance to pathogens as a result of injuries, operations, hypothermia, and reduced immunity.

The main part of the anaerobes that play a role in the development of infections are bacteroids, fusobacteria, peptostreptococci and spore bacilli. Half of purulent-inflammatory anaerobic infections are caused by bacteroids.

• Bacteroides-rods, 1-15 microns in size, non-motile or moving with the help of flagella. They secrete toxins that act as virulence factors (pathogens).
• Fusobacteria are rod-shaped obligate (surviving only in the absence of oxygen) anaerobic bacteria that live on the mucous membrane of the mouth and intestines, can be immobile or mobile, contain a strong endotoxin.
• Peptostreptococci are spherical bacteria, arranged in twos, fours, irregular clusters or chains. These are non-flagellated bacteria that do not form spores. Peptococci is a genus of spherical bacteria represented by a single species P.niger. Arranged singly, in pairs or in clusters. Peptococci do not have flagella and do not form spores.
• Veionella is a genus of diplococci (bacteria of a coccal form, the cells of which are arranged in pairs), arranged in short chains, immobile, do not form spores.
• Other non-clostridial anaerobic bacteria that are isolated from infectious foci of patients are propionic bacteria, volinella, the role of which is less studied.

Clostridium is a genus of spore-forming anaerobic bacteria. Clostridia live on the mucous membranes of the gastrointestinal tract. Clostridia are mainly pathogenic (disease-causing) for humans. They secrete highly active toxins specific to each species. The causative agent of anaerobic infection can be either one type of bacteria or several types of microorganisms: anaerobic-anaerobic (bacteroids and fusobacteria), anaerobic-aerobic (bacteroids and staphylococci, clostridia and staphylococci)

Aerobes are organisms that need free oxygen for life and reproduction. Unlike anaerobes, aerobes take part in the process of generating the energy they need. Aerobes include animals, plants and a significant part of microorganisms, among which they are isolated.

• obligate aerobes - these are "strict" or "unconditional" aerobes, they receive energy only from oxidative reactions involving oxygen; these include, for example, some species of Pseudomonas, many saprophytes, fungi, Diplococcus pneumoniae, diphtheria bacilli
• in the group of obligate aerobes, microaerophiles can be distinguished - for their vital activity they need a low oxygen content. When released into the normal environment, such microorganisms are suppressed or killed, since oxygen adversely affects the action of their enzymes. These include, for example, meningococci, streptococci, gonococci.
• facultative aerobes - microorganisms that can develop in the absence of oxygen, for example, a yeast bacillus. Most pathogenic microbes belong to this group.

Each aerobic microorganism has its own minimum, optimum and maximum oxygen concentration in its environment, which is necessary for its normal development. Increasing the oxygen content beyond the “maximum” boundary leads to the death of microbes. All microorganisms die at an oxygen concentration of 40-50%.

Bacteria are present everywhere in our world. They are everywhere and everywhere, and the number of their varieties is simply amazing.

Depending on the need for the presence of oxygen in the nutrient medium for the implementation of vital activity, microorganisms are classified into the following types.

• Obligate aerobic bacteria, which are collected in the upper part of the nutrient medium, the flora contained the maximum amount of oxygen.
• Obligate anaerobic bacteria, which are located in the lower part of the environment, as far as possible from oxygen.
• Facultative bacteria mainly live in the upper part, but can be distributed throughout the environment, as they do not depend on oxygen.
• Microaerophiles prefer a low concentration of oxygen, although they gather in the upper part of the environment.
• Aerotolerant anaerobes are evenly distributed in the nutrient medium, insensitive to the presence or absence of oxygen.

The concept of anaerobic bacteria and their classification

The term "anaerobes" appeared in 1861, thanks to the work of Louis Pasteur.

Anaerobic bacteria are microorganisms that develop regardless of the presence of oxygen in the nutrient medium. They get energy by substrate phosphorylation. There are facultative and obligate aerobes, as well as other types.

The most significant anaerobes are bacteroides

The most important aerobes are bacteroids. Approximately fifty percent of all purulent-inflammatory processes, the causative agents of which can be anaerobic bacteria, are bacteroids.

Bacteroides are a genus of Gram-negative obligate anaerobic bacteria. These are rods with bipolar coloration, the size of which does not exceed 0.5-1.5 by 15 microns. They produce toxins and enzymes that can cause virulence. Different bacteroids have different resistance to antibiotics: there are both resistant and susceptible to antibiotics.

Energy production in human tissues

Some tissues of living organisms have increased resistance to low oxygen content. Under standard conditions, the synthesis of adenosine triphosphate occurs aerobically, but with increased physical exertion and inflammatory reactions, the anaerobic mechanism comes to the fore.

Adenosine triphosphate (ATP) is an acid that plays important role in the production of energy by the body. There are several options for the synthesis of this substance: one aerobic and as many as three anaerobic.

Anaerobic mechanisms of ATP synthesis include:

• rephosphorylation between creatine phosphate and ADP;
• transphosphorylation reaction of two ADP molecules;
• anaerobic breakdown of blood glucose or glycogen stores.

Cultivation of anaerobic organisms

There are special methods for growing anaerobes. They consist in replacing air with gas mixtures in sealed thermostats.

Another way is to grow microorganisms in a nutrient medium to which reducing substances are added.

Culture media for anaerobic organisms

There are common culture media And differential diagnostic nutrient media. Common ones include the Wilson-Blair medium and the Kitt-Tarozzi medium. For differential diagnostic - Hiss medium, Ressel medium, Endo medium, Ploskirev medium and bismuth-sulfite agar.

The basis for the Wilson-Blair medium is agar-agar with the addition of glucose, sodium sulfite and iron dichloride. Black colonies of anaerobes are formed mainly in the depth of the agar column.

Ressel's (Russell's) medium is used in the study of the biochemical properties of bacteria such as Shigella and Salmonella. It also contains agar-agar and glucose.

Wednesday Ploskirev inhibits the growth of many microorganisms, so it is used for differential diagnostic purposes. In such an environment, pathogens of typhoid fever, dysentery and other pathogenic bacteria develop well.

The main purpose of bismuth sulfite agar is the isolation of salmonella in its pure form. This environment is based on the ability of Salmonella to produce hydrogen sulfide. This medium is similar to the Wilson-Blair medium in the technique used.

Anaerobic infections

Most anaerobic bacteria living in the human or animal body can cause various infections. As a rule, infection occurs during a period of weakened immunity or a violation of the general microflora of the body. There is also the possibility of infection pathogens from the external environment, especially in late autumn and winter.

Infections caused by anaerobic bacteria are usually associated with the flora of the human mucous membranes, that is, with the main habitats of anaerobes. Typically, these infections multiple triggers at once(to 10).

The exact number of diseases caused by anaerobes is almost impossible to determine due to the difficulty in collecting materials for analysis, transporting samples, and cultivating the bacteria themselves. Most often, this type of bacteria is found in chronic diseases.

Anaerobic infections affect people of all ages. At the same time, the level of infectious diseases in children is higher.

Anaerobic bacteria can cause various intracranial diseases (meningitis, abscesses, and others). Distribution, as a rule, occurs with the blood stream. In chronic diseases, anaerobes can cause pathologies in the head and neck: otitis media, lymphadenitis, abscesses. These bacteria are dangerous to both the gastrointestinal tract and the lungs. With various diseases of the urogenital female system, there is also a risk of developing anaerobic infections. Various diseases of the joints and skin can be the result of the development of anaerobic bacteria.

Causes of anaerobic infections and their symptoms

Infections are caused by all processes during which active anaerobic bacteria enter the tissues. Also, the development of infections can cause impaired blood supply and tissue necrosis (various injuries, tumors, edema, vascular disease). Mouth infections, animal bites, lung diseases, pelvic inflammatory disease and many other diseases can also be caused by anaerobes.

In different organisms, the infection develops in different ways. This is influenced by the type of pathogen, and the state of human health. Because of the difficulties associated with diagnosing anaerobic infections, the conclusion is often based on assumptions. Differ in some features of the infection caused by non-clostridial anaerobes.

The first signs of infection of tissues with aerobes are suppuration, thrombophlebitis, gas formation. Some tumors and neoplasms (intestinal, uterine and others) are also accompanied by the development of anaerobic microorganisms. With anaerobic infections, an unpleasant odor may appear, however, its absence does not exclude anaerobes as the causative agent of the infection.

Features of obtaining and transporting samples

The very first study in determining infections caused by anaerobes is a visual inspection. Various skin lesions are a common complication. Also, evidence of the vital activity of bacteria will be the presence of gas in infected tissues.

For laboratory research and establishing an accurate diagnosis, first of all, it is necessary to competently get matter sample from the affected area. For this, a special technique is used, thanks to which normal flora does not get into the samples. The best method is aspiration with a straight needle. Obtaining laboratory material by smears is not recommended, but possible.

Samples not suitable for further analysis include:

• sputum obtained by self-excretion;
• samples obtained during bronchoscopy;
• smears from the vaginal vaults;
• urine with free urination;
• feces.

For research can be used:

• blood;
• pleural fluid;
• transtracheal aspirates;
• pus obtained from the abscess cavity;
• cerebrospinal fluid;
• lung punctures.

Transport samples it is necessary as soon as possible in a special container or plastic bag with anaerobic conditions, since even a short-term interaction with oxygen can cause the death of bacteria. Liquid samples are transported in a test tube or in syringes. Swabs with samples are transported in test tubes with carbon dioxide or pre-prepared media.

In the case of diagnosing an anaerobic infection for adequate treatment, it is necessary to follow the following principles:

• toxins produced by anaerobes must be neutralized;
• the habitat of bacteria should be changed;
• the spread of anaerobes must be localized.

To comply with these principles antibiotics are used in treatment, which affect both anaerobes and aerobic organisms, since often the flora in anaerobic infections is mixed. At the same time, appointments medications, the doctor must evaluate the qualitative and quantitative composition of the microflora. The agents that are active against anaerobic pathogens include: penicillins, cephalosporins, champhenicol, fluoroquinolo, metranidazole, carbapenems and others. Some drugs have a limited effect.

To control the habitat of bacteria, in most cases, surgical intervention is used, which is expressed in the treatment of affected tissues, drainage of abscesses, and ensuring normal blood circulation. Surgical methods should not be ignored because of the risk of life-threatening complications.

Sometimes used ancillary therapies, and also because of the difficulties associated with the exact determination of the causative agent of the infection, empirical treatment is used.

With the development of anaerobic infections in the oral cavity, it is also recommended to add as many fresh fruits and vegetables to the diet as possible. The most useful are apples and oranges. The restriction is subjected to meat food and fast food.

Bacteria are present everywhere, their number is huge, the species are different. anaerobic bacteria- the same types of microorganisms. They can develop and live independently, whether there is oxygen in their feeding environments or it does not exist at all.

Anaerobic bacteria obtain energy from substrate phosphorylation. There are facultative aerobes, obligate or other varieties of anaerobic bacteria.

Facultative species of bacteria are almost everywhere. The reason for their existence is the change of one metabolic pathway to a completely different one. This species includes E. coli, staphylococci, shigella, and others. These are dangerous anaerobic bacteria.

If there is no free oxygen, then obligate bacteria die.

Arranged by class:

1. Clostridia- obligate types of aerobic bacteria, can form spores. These are the causative agents of botulism or tetanus.
2. non-clostridial anaerobic bacteria. Varieties from the microflora of living organisms. They play a significant role in the formation of various purulent and inflammatory diseases. Non-spore-forming types of bacteria live in the oral cavity, in the gastrointestinal tract. On the skin, in the genitals of women.
3. Capneistic anaerobes. They live with an exaggerated accumulation of carbon dioxide.
4. Aerotolerant bacteria. In the presence of molecular oxygen, this type of microorganisms has no respiration. But he doesn't die either.
5. Moderately strict types of anaerobes. In an environment with oxygen, they do not die, do not multiply. Bacteria of this species require a nutritional environment with reduced pressure to live.

Anaerobes - bacteroids

Considered the most important aerobic bacteria. They make up 50% of all inflammatory and purulent types. Their causative agents are anaerobic bacteria or bacteroids. These are gram-negative obligate types of bacteria.

Rods with bipolar staining and sizes from 0.5 to 1.5, in areas of approximately 15 microns. They can produce the production of enzymes, toxins, cause virulence. dependent on antibiotic resistance. They can be persistent or just sensitive. All anaerobic microorganisms are very resistant.

The formation of energy for gram-negative obligate anaerobes is carried out in human tissues. Some of the tissues of organisms have an increased resistance to a reduced oxygen value in the food environment.

Under the conditions of the standard, the synthesis of adenosine triphosphate is performed only aerobically. This occurs with increased physical effort, inflammation, where anaerobes act.

ATP is adenosine triphosphate or acid, which appears during the formation of energy in the body. There are several variations of the synthesis of this substance. One of them is aerobic, or there are three variations of anaerobes.

Anaerobic mechanisms for the synthesis of adenosine triphosphate:

• rephosphorylation, which is carried out between adenosine triphosphate and creatine phosphate;
• the formation of transphosphorylation of adenosine triphosphate molecules;
• anaerobic breakdown of blood components of glucose, glycogen.

Formation of anaerobes

The purpose of microbiologists is the cultivation of anaerobic bacteria. To do this requires a specialized microflora, and the concentration of metabolites. It is usually used in research of a different nature.

There are special methods for growing anaerobes. Occur when replacing air with a mixture of gases. There is an action in thermostats with sealing. This is how anaerobes grow. Another method is the cultivation of microorganisms with the addition of reducing agents.

Sphere of nutrition

There is a sphere of nutrition with a general view or differential diagnostic. The base - for the type of Wilson-Blair is agar-agar, which has some content of glucose, 2-x iron chloride, sodium sulfite among its components. Among them there are colonies that are called black.

The Ressel sphere is used in the study of the biochemical qualities of bacteria called Salmonella or Shigella. This medium may contain both glucose and agar-agar.

Ploskirev's environment is such that it can inhibit the growth of certain microorganisms. They make up a multitude. For this reason, it is used for the possibility of differential diagnostic. Here, dysentery pathogens, typhoid fever, and other pathogenic anaerobes can be successfully produced.

The main direction of the bismuth-sulfite agar medium is the isolation of Salmonella by this method. This is done with the ability of Salmonella to produce hydrogen sulfide.

In the body of every living individual, many anaerobes live. They cause various types of infectious diseases in them. Infection with an infection can occur only with a weakened immune system or disruption of the microflora. There is a possibility of infection getting into a living organism from the environment. It could be in autumn, in winter. Such hit of infections is saved during the listed periods. The ailment caused sometimes gives complications.

Infections caused by microorganisms - anaerobic bacteria, are directly linked to the flora of the mucous membranes of living individuals. With living places anaerobes. Each infection has several pathogens. Their number usually reaches ten. An absolutely specified number of diseases that cause anaerobe cannot be determined with accuracy.

Due to the difficult selection of materials intended for the study of the transportation of samples, the determination of bacteria. Therefore, this type of component is often found only with already chronic inflammation in humans. This is an example of a careless attitude to one's health.

Anaerobic infections are periodically exposed to absolutely all people with different ages. In small children, the degree of infectious inflammation is much greater than in people of other ages. Anaerobes often cause diseases inside the skull in humans. Abscesses, meningitis, other types of diseases. The spread of anaerobes is carried out with blood flow.

If a person has a chronic disease, then anaerobes can form anomalies in the neck or head. For example: abscesses, otitis or lymphadenitis. Bacteria are dangerous for the gastrointestinal tract, lungs of patients.

If a woman has diseases of the genitourinary system, then there is a risk of anaerobic infections. Various diseases of the skin, joints - this is also a consequence of the life of anaerobes. This method is one of the first to indicate the presence of an infection.

Reasons for the appearance of infectious diseases

Human infections are caused by those processes in which energetic anaerobe bacteria enter the body. The development of the disease may be accompanied by unstable blood supply, the appearance of tissue necrosis. These can be injuries of a different nature, swelling, tumors, vascular disorders. The appearance of infections in the oral cavity, diseases in the lungs, inflammation of the pelvic organs, other diseases.

Infection can develop in a peculiar way for each species. The development is influenced by the type of pathogen, the health of the patient. It is difficult to diagnose such infections. The seriousness of diagnosticians is often based on assumptions alone. There is a difference in the characteristics of infections that arise from non-clostridial anaerobes.

The first signs of infection are gas formation, any suppuration, the appearance of thrombophlebitis. Sometimes tumors or neoplasms can be signs as signs. They can be neoplasms of the gastrointestinal tract, uterine. Accompanied by the formation of anaerobes. At this time, an unpleasant odor may come from a person. But, even if the smell does not exist, this does not mean that there are no anaerobes as pathogens for infection in this organism.

Features for getting samples

The first examination in anaerobic infections is an external examination. general view man, his skin. Because the presence of skin diseases in humans is a complication. They indicate that the vital activity of bacteria is the presence of gases in infected tissues.

In laboratory studies, determining a refined diagnosis, it is necessary to correctly obtain a sample of infected matter. Often specialized equipment is used. The best method of obtaining samples is considered to be aspiration performed with a straight needle.

Types of samples that do not correspond to the possibility of continuing analyzes:

• sputum acquired by self-excretion;
• bronchoscopy samples;
• types of smears from the vaults of the vagina;
• urine from free urination;
• types of faeces.

Samples are subject to research:

1. blood;
2. pleural fluid;
3. transtracheal aspirates;
4. pus taken from abscesses
5. fluid from the brain back;
6. lung punctures.

Samples must be moved to their destination quickly. Work is carried out in a specialized container, sometimes in a plastic bag.

It must be designed for anaerobic conditions. Because the interaction of samples with atmospheric oxygen can cause the complete death of bacteria. Liquid types of samples are moved in test tubes, sometimes directly in syringes.

If swabs are moved for research, then they are transported only in test tubes with the presence of carbon dioxide, sometimes with pre-made substances.

A BRIEF HISTORY OF MICROBIOLOGY

The study of the history of science makes it possible to trace the processes of its origin and development, to understand the continuity of ideas, the level of the current state of science and the prospects for further progress. The course of medical microbiology mainly outlines the history of this branch of microbiology.

The first person, before whose astonished eyes the invisible mysterious world of microscopic creatures was opened, was the Dutch naturalist Anthony Leeuwenhoek (1632-1723). In September 1675, he reported to the Royal Society of London that in rainwater that stood in the air, he managed to find the smallest living animals (viva animalcula), which differed from each other in size and movement. In subsequent letters, he reported that such creatures are found in hay infusions, stool, and plaque. He wrote about living animals of dental plaque. With the greatest amazement, I saw in this material (dental plaque) a lot of the smallest animals moving very briskly. There are more of them in my mouth than there are people in the United Kingdom. Leeuwenhoek published his observations in the form of letters, which were later summarized by him in the book Secrets of Nature, discovered by Antony Leeuwenhoek.

The idea of ​​the presence in nature of invisible living beings appeared among many researchers. Back in the 6th century BC. h. Hippocrates, 16th century A.D. e. Giralamo Frakastro and at the beginning of the 17th century Athanasius Kircher suggested that invisible living beings are the cause of contagious diseases. But none of them had any evidence of this. Leeuwenhoek demonstrated microbes under a microscope, and in 1683 presented drawings of bacteria for the first time.

Leeuwenhoek's discovery attracted everyone's attention. It was the basis for the development of microbiology, the study of the forms of microbes and their distribution in the external environment. This so-called morphological period, which lasted almost two decades, was unproductive, since the optical instruments of that time did not make it possible to distinguish one type of microbe from another, and could not give an idea of ​​the role of microbes in nature.

Constructive metabolism of bacteria.

For micro-organisms to grow and reproduce, their habitat must have nutrient materials and available sources of energy.

Nutrition is the process by which bacterial cell gets out environment components necessary for the construction of its biopolymers.

According to the source of C, microorganisms are divided into:

Autotrophs (self-feeding) or lithotrophs (litho - stone) - microorganisms that are capable of synthesizing complex organic compounds from simple inorganic compounds (the only source of carbon is CO2)

Heterotrophs (feeding at the expense of others) or organotrophs - they cannot synthesize complex organic compounds from simple inorganic ones, they need ready-made organic compounds(carbon is extracted from glucose, polyhydric alcohols, less often hydrocarbons, amino acids, organic acids). Heterotrophs are divided into:

Saprophytes (rotten, plant) - get ready-made organic compounds from dead nature, decomposing organic waste, animal and human corpses (environmental orderlies)

According to the ability to absorb nitrogen, microorganisms are classified:

Aminoautotrophs - use molecular nitrogen from the air (nitrogen-fixing bacteria) or ammonium salts, nitrates, nitrites (ammonifying bacteria)

Aminoheterotrophs - get nitrogen from organic compounds (amino acids, complex proteins)

Only small molecules of amino acids, glucose, etc. can penetrate into the cytoplasm of cells. Therefore, macromolecules are pre-treated with enzymes that the cell releases into the external environment (exoenzymes). Only then are they available for use.

Nutrient pathways:

Simple diffusion - goes without energy costs, nutrients come from places with a higher concentration to places with a lower concentration

Facilitated diffusion - the transfer of nutrients from places with a higher concentration to places with a lower concentration, but with the participation of carrier molecules (permeases) without energy expenditure, but at a faster rate than with simple diffusion

active transport- the transfer is carried out with the help of permeases, but with energy costs, while the transfer can be carried out from places with a lower concentration to places with a higher concentration.

Radical transfer is accompanied by the translocation of chemical groups, resulting in chemical modification transferred substance. Radical transport is similar to active transport.

Phagocytosis and pinocytosis - enveloping solid and liquid nutrients with the cytoplasm of a microbial cell, followed by their digestion.

Metabolism or metabolism consists of the following processes: 1) assimilation (anabolism) - accompanied by an increase in the complexity of compounds (synthesis of substances with energy consumption). 2) dissimilation (catabolism) - splitting of complex compounds into simple ones, which are then used for subsequent synthesis, and part is released into the external environment, while freeing up the energy necessary for the life of the microbial cell.

4 Energy metabolism. However, the vast majority of prokaryotes receive energy through dehydrogenation. Aerobes need free oxygen for this purpose. Obligate (strict) aerobes cannot live and reproduce in the absence of molecular oxygen, since they use it as an electron acceptor. ATP molecules are formed by them during oxidative phosphorylation with the participation of cytochrome oxidases, flavin-dependent oxidases, and dehydrogenases. In this case, if the final electron acceptor is oxygen, significant amounts of energy are released

Anaerobes get energy in the absence of oxygen access by accelerated, but not complete breakdown of nutrients. Obligate anaerobes (tetanus, botulism) cannot tolerate even traces of oxygen. They can form ATP as a result of the oxidation of carbohydrates, proteins and lipids by substrate phosphorylation to pyruvate. In this case, a relatively small amount of energy is released.

There are facultative anaerobes that can grow and multiply both in the presence of atmospheric oxygen and without it. They form ATP by oxidative and substrate phosphorylation.

Aerobic and anaerobic microorganisms.

Different bacteria react differently to the presence or absence of free oxygen. On this basis, they are divided into three groups: aerobes, anaerobes and facultative anaerobes. Strict aerobes, for example, Pseudomonas aeruginosa, can develop only in the presence of free oxygen. Anaerobes, eg. causative agents of gas gangrene, tetanus, Develop without access to free oxygen, the presence of which depresses their vital activity. Finally, facultative anaerobes, for example, causative agents of intestinal infections, develop in both oxygen and anoxic environments. Aerobicity or anaerobicity of bacteria is determined by the way they receive the energy necessary to ensure vital processes. Some bacteria (photosynthetic) are able, like plants, to directly use the energy of sunlight. The rest (chemosynthetic) receive energy during various chemical reactions. There are bacteria (chemoautotrophs) that oxidize inorganic substances (ammonia, sulfur and iron compounds, etc.). But for most bacteria, transformations of organic compounds serve as an energy source: carbohydrates, proteins, fats, etc. Aerobes use biological oxidation reactions involving free oxygen (respiration), as a result of which organic compounds are oxidized to carbon dioxide and water. Anaerobes obtain energy from the breakdown of organic compounds without the participation of free oxygen. This process is called fermentation. During fermentation, in addition to carbon dioxide, various compounds are formed, for example, alcohols, lactic, butyric and other acids, acetone.

6 morphology and classification of bacteria! Bacteria (from lat. bacteria - stick) are single-celled organisms lacking chlorophyll. Biologically, they are prokaryotes. Sizes from 0.1 to 0.15 micrometers to 16-28 microns. The size and shape of bacteria are inconsistent and change with the influence of the environment.

By appearance Bacteria are divided into 4 forms: spherical (cocci), rod-shaped (bacteria, bacilli and clostridia), convoluted (vibrios, spirilla, spirochetes) and filamentous (chlamydobacteria).

1. Cocci (from lat. coccus - grain) - a spherical microorganism, it can be spherical, elliptical, bean-shaped and lanceolate. According to the location, nature of division and biological properties, cocci are divided into micrococci, diplococci, streptococci, tetracocci, sarcina, staphylococci.

Micrococci are characterized by a single, paired or random arrangement of cells. They are saprophytes, inhabitants of water, air.

Diplococci (from lat. diplodocus - double) divide in one plane and form cocci, connected in two individuals. Diplococci include meningococci - the causative agents of epidemic meningitis and gonococci - the causative agents of gonorrhea and blennorrhea.

Streptococci (from lat. streptococcus - twisted), dividing in the same plane, are arranged in chains of various lengths. There are streptococci that are pathogenic for humans and cause various diseases.

Tetracocci (from lat. tetra - four), located in 4, are divided in two mutually perpendicular planes.

Rarely found as pathogens in humans.

Sardines (from Latin saris - I bind) are coccal forms that divide in three mutually perpendicular planes and look like bales of 8-16 or more cells. Often found in the air. There are no pathogenic forms.

Staphylococci (from lat. staphylococcus) - clustered cocci, dividing in different planes; arranged in irregular clusters.

Some species cause disease in humans and animals.