Anaerobic infections cause a lot of trouble for the patient, since their manifestations are acute and aesthetically unpleasant. The provocateurs of this group of diseases are spore-forming or non-spore-forming microorganisms that find themselves in conditions favorable for life.

Infections caused by anaerobic bacteria develop rapidly and can affect vital tissues and organs, so their treatment must begin immediately after diagnosis to avoid complications or death.

What it is?

Anaerobic infection is a pathology caused by bacteria that can grow and multiply in the complete absence of oxygen or its low voltage. Their toxins are highly penetrating and are considered extremely aggressive.

To this group infectious diseases relate severe forms pathologies characterized by damage to vital organs and a high mortality rate. In patients, manifestations of intoxication syndrome usually predominate over local clinical signs. This pathology is different predominant defeat connective tissue and muscle fibers.

Causes of anaerobic infection

An aerobic bacteria classified as opportunistic and included in normal microflora mucous membranes, digestive and genitourinary systems and skin. Under conditions that provoke their uncontrolled reproduction, an endogenous anaerobic infection develops. Anaerobic bacteria that live in decaying organic matter and soil, when released into open wounds cause exogenous anaerobic infection.

Development anaerobic infection contribute to tissue damage, creating the possibility of penetration of the pathogen into the body, a state of immunodeficiency, massive bleeding, necrotic processes, ischemia, and some chronic diseases. Invasive manipulations (tooth extraction, biopsy, etc.) and surgical interventions pose a potential danger. Anaerobic infections can develop due to contamination of wounds with soil or the entry of other substances into the wound. foreign bodies, against the background of traumatic and hypovolemic shock, irrational antibiotic therapy, suppressing the development of normal microflora.

In relation to oxygen anaerobic bacteria are divided into facultative, microaerophilic and obligate. Facultative anaerobes can develop both under normal conditions and in the absence of oxygen. This group includes staphylococci, E. coli, streptococci, Shigella and a number of others. Microaerophilic bacteria are an intermediate link between aerobic and anaerobic; oxygen is necessary for their life, but in small quantities.

Among obligate anaerobes, clostridial and non-clostridial microorganisms are distinguished. Clostridial infections are exogenous (external). This is botulism gas gangrene, tetanus, foodborne diseases. Representatives of non-clostridial anaerobes are causative agents of endogenous purulent-inflammatory processes, such as peritonitis, abscesses, sepsis, phlegmon, etc.

Symptoms

The incubation period lasts about three days. Anaerobic infection begins suddenly. In patients, symptoms of general intoxication prevail over local inflammation. Their health deteriorates sharply until the appearance of local symptoms, the wounds become black in color.

Patients experience fever and chills, they experience severe weakness and weakness, dyspepsia, lethargy, drowsiness, apathy, blood pressure drops, heart rate increases, and turns blue. nasolabial triangle. Gradually, inhibition is replaced by excitement, restlessness, and confusion. Their breathing and heart rate increase.

The condition of the gastrointestinal tract also changes: patients' tongue is dry, coated, they experience thirst and dry mouth. The skin of the face turns pale, acquires an earthy tint, and the eyes become sunken. The so-called “Hippocratic mask” - “fades Hippocratica” - appears. Patients become inhibited or sharply agitated, apathetic, and depressed. They cease to navigate space and their own feelings.

Local symptoms of pathology:

Swelling of the tissues of the limb progresses quickly and is manifested by sensations of fullness and distension of the limb.
Severe, unbearable, increasing pain of a bursting nature, not relieved by analgesics.
Distal sections lower limbs become inactive and practically insensitive.
Purulent-necrotic inflammation develops rapidly and even malignantly. Without treatment soft fabrics are quickly destroyed, which makes the prognosis of the pathology unfavorable.
Gas in affected tissues can be detected using palpation, percussion and other diagnostic techniques. Emphysema, soft tissue crepitus, tympanitis, slight crackling, box sound are signs of gas gangrene.

The course of anaerobic infection can be fulminant (within 1 day from the moment of surgery or injury), acute (within 3-4 days), subacute (more than 4 days). Anaerobic infection is often accompanied by the development of multiple organ failure (renal, liver, cardiopulmonary), infectious-toxic shock, severe sepsis, causing death.

Diagnosis of anaerobic infection

Before starting treatment, it is important to determine exactly whether an anaerobic or aerobic microorganism caused the infection, and for this, only an external assessment of symptoms is not enough. Methods for determining an infectious agent can be different:

enzyme immunoassay of blood (the effectiveness and speed of this method is high, as is the price);
radiography (this method is most effective in diagnosing infections of bones and joints);
bacterial culture of pleural fluid, exudate, blood or purulent discharge;
Gram staining of smears taken;

Treatment of anaerobic infection

For anaerobic infection A complex approach treatment involves radical surgical treatment purulent focus, intensive detoxification and antibacterial therapy. Surgical stage must be performed as early as possible - the patient’s life depends on it.

As a rule, it consists of a wide dissection of the lesion with removal of necrotic tissue, decompression of surrounding tissue, open drainage with washing of cavities and wounds with antiseptic solutions. Features of the course of anaerobic infection often require repeated necrectomies, opening of purulent pockets, wound treatment with ultrasound and laser, ozone therapy, etc. With extensive tissue destruction, amputation or disarticulation of a limb may be indicated.

The most important components of the treatment of anaerobic infection are intensive infusion therapy and antibiotic therapy with drugs wide range actions, highly tropic to anaerobes. Within complex treatment For anaerobic infections, hyperbaric oxygenation, ultraviolet oxygen therapy, extracorporeal hemocorrection (hemosorption, plasmapheresis, etc.) are used. If necessary, the patient is administered antitoxic anti-gangrenous serum.

Forecast

The outcome of anaerobic infection largely depends on clinical form pathological process, premorbid background, timeliness of diagnosis and initiation of treatment. The mortality rate for some forms of anaerobic infection exceeds 20%.

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

Depending on the need for oxygen in the nutrient medium to carry out life activities, microorganisms are classified into the following types.

Obligate aerobic bacteria, which gather in the upper part of the nutrient medium, contained the maximum amount of oxygen in the flora.
Obligate anaerobic bacteria, which are found in the lower part of the environment, are as far away from oxygen as possible.
Facultative bacteria mainly live in the upper part, but can be distributed throughout the environment, since they do not depend on oxygen.
Microaerophiles prefer low concentrations of oxygen, although they accumulate in the upper part of the medium.
Aerotolerant anaerobes are evenly distributed in the nutrient medium and are 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 species.

The most significant anaerobes are bacteroides

The most significant aerobes are bacteroides. Approximately fifty percent of all purulent-inflammatory processes, the causative agents of which can be anaerobic bacteria, account for bacteroides.

Bacteroides are a genus of gram-negative obligate anaerobic bacteria. These are rods with bipolar stainability, the size of which does not exceed 0.5-1.5 by 15 microns. Produce toxins and enzymes that can cause virulence. Different bacteroides have different resistance to antibiotics: both resistant and sensitive to antibiotics are found.

Energy production in human tissues

Some tissues of living organisms have increased resistance to low oxygen levels. Under standard conditions, adenosine triphosphate synthesis occurs aerobically, but at elevated physical activity and during inflammatory reactions, the anaerobic mechanism comes to the fore.

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

Anaerobic mechanisms for ATP synthesis include:

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

Cultivation of anaerobic organisms

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

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

Nutrient media for anaerobic organisms

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

The base for Wilson-Blair medium is agar-agar with the addition of glucose, sodium sulfite and ferrous chloride. Black colonies of anaerobes form mainly in the depths of the agar column.

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

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

The main purpose of bismuth sulfite agar is to isolate salmonella in its pure form. This environment is based on the ability of Salmonella to produce hydrogen sulfide. This environment is similar to the Wilson-Blair environment in terms of the methodology 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 disruption of the general microflora of the body. There is also a possibility of pathogens entering from external environment, especially in late autumn and winter.

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

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

People of any age are susceptible to anaerobic infections. At the same time, children have a higher rate of infectious diseases.

Anaerobic bacteria can cause various intracranial diseases (meningitis, abscesses and others). Spread usually occurs through the bloodstream. In chronic diseases, anaerobes can cause pathologies in the head and neck area: otitis, lymphadenitis, abscesses. These bacteria are dangerous and gastrointestinal tract, and easy. For various genitourinary diseases female system There is also a risk of developing anaerobic infections. Various diseases joints and skin may be due to the development of anaerobic bacteria.

Causes of anaerobic infections and their signs

All processes during which active anaerobic bacteria enter tissues lead to infections. Also, the development of infections can be caused by impaired blood supply and tissue necrosis ( various injuries, tumors, edema, vascular diseases). Oral infections, animal bites, pulmonary diseases, inflammatory diseases pelvic organs and many other diseases can also be caused by anaerobes.

IN different organisms the infection develops in different ways. This is influenced by both 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 guesswork. Infections caused by non-clostridial anaerobes.

The first signs of tissue infection by aerobes are suppuration, thrombophlebitis, and gas formation. Some tumors and neoplasms (intestinal, uterine and others) are also accompanied by the development of anaerobic microorganisms. In anaerobic infections it may appear bad smell however, its absence does not exclude anaerobes as the causative agent of infection.

Features of obtaining and transporting samples

The very first test in identifying infections caused by anaerobes is a visual examination. 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 accurate diagnosis, first of all, you need to competently get a sample of matter from the affected area. To do this, they use a special technique, thanks to which normal flora does not get into the samples. Best Method- This is aspiration with a straight needle. Obtaining laboratory material using the smear method is not recommended, but is possible.

Samples that are not suitable for further analysis include:

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

The following can be used for research:

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

Transport samples it is necessary as quickly as possible in a special container or plastic bag with anaerobic conditions, since even 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 tubes with carbon dioxide or pre-prepared media.

If an anaerobic infection is diagnosed, adequate treatment The following principles must be followed:

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. Agents that are active against anaerobic pathogens include: penicillins, cephalosporins, clapamphenicol, fluoroquinolo, metronidazole, carbapenems and others. Some drugs have limited effect.

To control the habitat of bacteria, in most cases they use surgical intervention, which is expressed in the treatment of affected tissues, drainage of abscesses, and ensuring normal blood circulation. Ignore surgical methods not worth it due to the risk of life-threatening complications.

Sometimes used auxiliary treatment methods, and also because of the difficulties associated with accurately identifying the causative agent of the infection, empirical treatment is used.

When anaerobic infections develop in the oral cavity, it is also recommended to add as many fresh fruits and vegetables to the diet as possible. The most useful for this are apples and oranges. Meat foods and fast food are subject to restrictions.

1.Genetic and biochemical mechanisms of drug resistance. A way to overcome drug resistance in bacteria.
2. Use “infection”, “infectious process”, “infectious disease”. Conditions for the occurrence of infectious disease.
1. Rational antibiotic therapy. Side effects of antibiotics on the human body and microorganisms. Formation of antibiotic-resistant and antibiotic-dependent forms of bacteria.
2. Precipitation reaction and its varieties. Mechanism and methods of installation, practical application.
1. Methods for determining the sensitivity of bacteria to antibiotics. Determination of the concentration of antibiotics in urine and blood.
2. The main cells of the immune system: t, b-lymphocytes, macrophages, subpopulations of t-cells, their characteristics and functions.
1. Mechanisms of action of antibiotics on microbial cells. Bactericidal effect and bacteriostatic effect of antibiotics. Units for measuring the antimicrobial activity of an antibiotic.
2. The immune lysis reaction as one of the mechanisms for destroying microbes, components of the reaction, practical use.
3. The causative agent of syphilis, taxonomy, characteristics of biological properties, pathogenicity factors. Epidemology and pathogenesis. Microbiological diagnostics.
1. Methods for cultivating bacteriophages, their titration (according to Gracia and Appelman).
2. Cellular cooperation between T, B-lymphocytes and macrophages in the process of humoral and cellular immune response.
1. Respiration of bacteria. Aerobic and anaerobic types of biological oxidation. Aerobes, anaerobes, facultative anaerobes, microaerophiles.
1. The effect of biological factors on microorganisms. Antagonism in microbial biocenoses, bacteriocins.
3. Bordetella. Taxonomy, characteristics of biological properties, pathogenicity factors. Diseases caused by Bordetella. Pathogenesis of whooping cough. Laboratory diagnostics, specific prevention.
1. The concept of bacteria. Autotrophs and heterotrophs. Holophytic way of feeding bacteria. Mechanisms of nutrient transfer into the bacterial cell.
2. Antigenic structure of a bacterial cell. The main properties of microbial antigens are localization, chemical composition and specificity of bacterial antigens, toxins, enzymes.
1. Antibiotics. History of discovery. Classification of antibiotics by production methods, origin, chemical structure, mechanism of action, spectrum of antimicrobial action.
3. Influenza viruses, taxonomy, general characteristics, antigens, types of variability. Epidemiology and pathogenesis of influenza, laboratory diagnostics. Specific prevention and therapy of influenza.
2. Serological method for diagnosing infectious diseases, its evaluation.
3. Diarrheagenic Escherichia, their varieties, pathogenicity factors, diseases caused by them, laboratory diagnostics.
1. General characteristics of mushrooms, their classification. Role in human pathology. Applied aspects of study.
3. Escherichia, their role as a normal inhabitant of the intestine. Sanitary indicative values of Escherichia for water and soil. Escherichia as an etiological factor in human purulent-inflammatory diseases.
1. The use of bacteriophages in microbiology and medicine for the diagnosis, prevention and therapy of infectious diseases.
2. Bacterial toxins: endotoxin and exotoxins. Classification of exotoxins, chemical composition, properties, mechanism of action. Differences between endotoxins and exotoxins.
3. Mycoplasmas, taxonomy, species pathogenic to humans. Characteristics of their biological properties, pathogenicity factors. Pathogenesis and immunity. Laboratory diagnostics. Prevention and therapy.
1. Laboratory diagnosis of dysbacteriosis. Drugs used for the prevention and treatment of dysbacteriosis.
2. Immunofluorescence in the diagnosis of infectious diseases. Direct and indirect methods. Necessary medications.
3. Tick-borne encephalitis virus, taxonomy, general characteristics. Epidemiology and pathogenesis, laboratory diagnostics, specific prevention of tick-borne encephalitis.
1. Structural features of rickettsia, mycoplasma and chlamydia. Methods of their cultivation.
2. Biological products used for specific prevention and treatment of infectious diseases: vaccines.
3. Salmonella, taxonomy. The causative agent of typhoid fever and paratyphoid fever. Epidemiology of the pathogenesis of typhoid fever. Laboratory diagnostics. Specific prevention.
2. Antigenic structure of toxins, viruses, enzymes: their localization, chemical composition and specificity. Anatoxins.
3. Viruses that cause acute respiratory diseases. Paramyxoviruses, general characteristics of the family, diseases caused. Pathogenesis of measles, specific prevention.
1. Reproduction of viruses (disjunctive reproduction). The main stages of interaction between a virus and a host cell during a productive type of infection. Features of the reproduction of DNA and RNA-containing viruses.
2. The concept of wound, respiratory, intestinal, blood and urogenital infections. Anthroponoses and zoonoses. Mechanisms of transmission of infection.
3. Tetanus clostridia, taxonomy, characteristics of biological properties, pathogenicity factors. Epidemiology and pathogenesis of tetanus. Laboratory diagnostics, specific therapy and prevention.
1. Microflora of the skin and oral cavity of a healthy person. Microflora of the mucous membranes of the respiratory tract, genitourinary tract and eyes. Their meanings in life.
2. Intrauterine infections. Etiology, routes of transmission of infection to the fetus. Laboratory diagnostics, preventive measures.
1. Types of interaction between viruses and cells: integrative and autonomous.
2. Complement system, classical and alternative pathway of complement activation. Methods for determining complement in blood serum.
3. Food bacterial intoxication of staphylococcal nature. Pathogenesis, features of laboratory diagnostics.
1. The effect of chemical factors on microorganisms. Asepsis and disinfection. The mechanism of action of various groups of antiseptics.
2. Live killed, chemical, toxoid, synthetic, modern vaccines. Principles of obtaining, mechanisms of created immunity. Adjuvants in vaccines.
3. Klebsiella, taxonomy, characteristics of biological properties, pathogenicity factors, role in human pathology. Laboratory diagnostics.
1. Dysbacteriosis, causes, factors of its formation. Stages of dysbacteriosis. Laboratory diagnostics, specific prevention and therapy.
2. The role of neutralization of the toxin by toxoid. Practical use.
3. Picornoviruses, classification, characteristics of polio viruses. Epidemiology and pathogenesis, immunity. Laboratory diagnostics, specific prevention.
1. Types of variability in bacteria: modification and genotypic variability. Mutations, types of mutations, mechanisms of mutations, mutagens.
2. Local anti-infective immunity. The role of secretory antibodies.
3. Food bacterial toxic infections caused by Eschirichia, Proteus, staphylococci, anaerobic bacteria. Pathogenesis, laboratory diagnostics.
2. Central and peripheral organs of the immune system. Age-related characteristics of the immune system.
1. Cytoplasmic membrane of bacteria, its structure, functions.
2. Nonspecific factors of antiviral immunity: antiviral inhibitors, interferons (types, mechanism of action).
1. Protoplasts, spheroplasts, L-forms of bacteria.
2. Cellular immune response in anti-infective defense. Interaction between T-lymphocytes and macrophages during the immune response. Ways to identify it. Allergic diagnostic method.
3. Hepatitis A virus, taxonomy, characteristics of biological properties. Epidemiology and pathogenesis of Botkin's disease. Laboratory diagnostics. Specific prevention.
2. Antibodies, main classes of immunoglobulins, their structural and functional features. The protective role of antibodies in anti-infective immunity.
3. Hepatitis viruses C and E, taxonomy, characteristics of biological properties. Epidemiology and pathogenesis, laboratory diagnostics.
1. Spores, capsules, villi, flagella. Their structure, chemical composition, functions, detection methods.
2. Complete and incomplete antibodies, autoantibodies. The concept of monoclonal antibodies, hybrid.
1. Morphology of bacteria. Basic forms of bacteria. The structure and chemical composition of various structures of a bacterial cell: nucleotide, mesosomes, ribosomes, cytoplasmic inclusions, their functions.
2. Pathogenetic features of viral infections. Infectious properties of viruses. Acute and persistent viral infection.
1. Prokaryotes and eukaryotes, their differences in structure, chemical composition and function.
3. Togaviruses, their classification. Rubella virus, its characteristics, pathogenesis of the disease in pregnant women. Laboratory diagnostics.
1. Bacterial plasmids, types of plasmids, their role in the determination of pathogenic characteristics and drug resistance of bacteria.
2. Dynamics of antibody formation, primary and secondary immune response.
3. Yeast-like Candida fungi, their properties, differentiating characteristics, types of Candida fungi. Role in human pathology. Conditions conducive to the occurrence of candidiasis. Laboratory diagnostics.
1. Basic principles of taxonomy of microorganisms. Taxonomic criteria: kingdom, division, family, genus species. The concept of strain, clone, population.
2. The concept of immunity. Classification of various forms of immunity.
3. Proteus, taxonomy, properties of Proteus, pathogenicity factors. Role in human pathology. Laboratory diagnostics. Specific immunotherapy, phage therapy.
1. Microflora of newborns, its formation during the first year of life. The influence of breast and artificial feeding on the composition of the child's microflora.
2. Interferons as factors of antiviral immunity. Types of interferons, methods of obtaining interferons and practical application.
3. Streptococcus pneumoniae (pneumococci), taxonomy, biological properties, pathogenicity factors, role in human pathology. Laboratory diagnostics.
1. Structural features of actinomycetes and spirochetes. Methods for their identification.
2. Features of antiviral immunity. Congenital and acquired immunity. Cellular and humoral mechanisms of innate and acquired immunity.
3. Enterobacteriaceae, classification, general characteristics of biological properties. Antigenic structure, ecology.
1. Methods for cultivating viruses: in cell cultures, chicken embryos, in animals. Their assessment.
2. The aglutination reaction in the diagnosis of infections. Mechanisms, diagnostic value. Agglutinating sera (complex and monoreceptor), diagnosticums. Load reactions of the immune system.
3. Campylobacter, taxonomy, general characteristics, diseases caused, their pathogenesis, epidemiology, laboratory diagnostics, prevention.
1. Bacteriological method for diagnosing infectious diseases, stages.
3. Oncogenic DNA viruses. General characteristics. Virogenetic theory of the occurrence of tumors L.A. Zilbera. Modern theory of carcinogenesis.
1. Basic principles and methods of bacterial cultivation. Nutrient media and their classification. Colonies of various types of bacteria, cultural properties.
2. Enzyme immunoassay. Components of the reaction, options for its use in the laboratory diagnosis of infectious diseases.
3. HIV viruses. History of discovery. General characteristics of viruses. Epidemiology and pathogenesis of the disease, clinic. Laboratory diagnostic methods. The problem is specific prevention.
1. Organization of the genetic material of a bacterial cell: bacterial chromosome, plasmids, transposons. Genotype and phenotype of bacteria.
2. Virus neutralization reaction. Viral neutralization options, scope.
3. Yersinia, taxonomy. Characteristics of the plague pathogen, pathogenicity factors. Epidemiology and pathogenesis of plague. Laboratory diagnostic methods, specific prevention and therapy.
1. Growth and reproduction of bacteria. Phases of reproduction of bacterial populations in a liquid nutrient medium under stationary conditions.
2. Serotherapy and seroprophylaxis. Characteristics of anatoxic and antimicrobial sera, immunoglobulins. Their preparation and titration.
3. Rotaviruses, classification, general characteristics of the family. The role of rotaviruses in intestinal pathology of adults and children. Pathogenesis, laboratory diagnostics.
2. Complement fixation reaction in the diagnosis of infectious diseases. Components of the reaction, practical application.
3. Hepatitis B and D virus, delta viruses, taxonomy. General characteristics of viruses. Epidemiology and pathogenesis of hepatitis B, etc. Laboratory diagnostics, specific prevention.
1. Genetic recombinations: transformation, transduction, conjugation. From types and mechanism.
2. Paths of penetration of microbes into the body. Critical doses of microbes that cause infectious disease. Entrance gate of infection. Ways of distribution of microbes and toxins in the body.
3. Rabies virus. Taxonomy, general characteristics. Epidemiology and pathogenesis of rabies virus.
1. Microflora of the human body. Its role in normal physiological processes and pathology. Intestinal microflora.
2. Indication of microbial antigens in pathological material using immunological reactions.
3. Picornaviruses, taxonomy, general characteristics of the family. Diseases caused by Coxsackie and Echo viruses. Laboratory diagnostics.
1. Microflora of atmospheric air, residential premises and hospital institutions. Sanitary-indicative air microorganisms. Pathways for microbes to enter and survive in the air.
2. Cellular nonspecific protective factors: unreactivity of cells and tissues, phagocytosis, natural killer cells.
3. Yersinia pseudotuberculosis and enterocolitis, taxonomy, characteristics of biological properties, pathogenicity factors. Epidemiology and pathogenesis of pseudotube
1. Viruses: morphology and structure of viruses, their chemical composition. Principles of classification of viruses, significance in human pathology.
3. Leptospira, taxonomy, characteristics of biological properties, pathogenicity factors. Pathogenesis of leptospirosis. Laboratory diagnostics.
1. Temperate bacteriophages, their interaction with the bacterial cell. The phenomenon of lysogeny, phage conversion, the meaning of these phenomena.

1. Respiration of bacteria. Aerobic and anaerobic types of biological oxidation. Aerobes, anaerobes, facultative anaerobes, microaerophiles.

Based on breathing types, they are divided into several groups.

1) aerobes, which require molecular oxygen

2) obligate aerobes are not able to grow in the absence of oxygen, because they use it as an electron acceptor.

3).microaerophiles are capable of growing in the presence of small concentrations of O2 (up to 2%) 4)anaerobes do not need free oxygen; they obtain the necessary E by breaking down substances containing a large supply of hidden E

5) obligate anaerobes - cannot tolerate even small amounts of oxygen (clostridial)

6) facultative anaerobes - adapted to existence in both oxygen-containing and oxygen-free conditions. The process of respiration in microbes is substrate phosphorylation or fermentation: glycolysis, phosphoglyconate pathway and ketodeoxyphosphoglyconate pathway. Types of fermentation: lactic acid (bifidobacteria), formic acid (enterobacteria), butyric acid (clostridia), propionic acid (propionobacteria),

2. Antigens, definition, conditions of antigenicity. Antigenic determinants, their structure. Immunochemical specificity of antigens: species, group, type, organ, heterospecific. Complete antigens, haptens, their properties.

Antigens are high molecular weight compounds.

When entering the body, they cause an immune reaction and interact with the products of this reaction.

Classification of antigens. 1. By origin:

natural (proteins, carbohydrates, nucleic acids, bacterial exo- and endotoxins, antigens of tissue and blood cells);

artificial (dinitrophenylated proteins and carbohydrates);

synthetic (synthesized polyamino acids).

2. By chemical nature:

proteins (hormones, enzymes, etc.);

carbohydrates (dextran);

nucleic acids (DNA, RNA);

conjugated antigens;

polypeptides (polymers of a-amino acids);

lipids (cholesterol, lecithin).

3. By genetic relation:

autoantigens (from tissues of one’s own body);

isoantigens (from a genetically identical donor);

alloantigens from an unrelated donor of the same species)

4. By the nature of the immune response:

1) xenoantigens (from a donor of another species). thymus-dependent antigens;

2) thymus-independent antigens.

Also distinguished:

external antigens (enter the body from the outside);

internal antigens; arise from damaged molecules of the body that are recognized as foreign

hidden antigens - specific antigens

(eg, nerve tissue, lens proteins and sperm); anatomically separated from the immune system by histohematic barriers during embryogenesis.

Haptens are low molecular weight substances that under normal conditions do not cause an immune reaction, but when bound to high molecular weight molecules they become immunogenic.

Infectious antigens are antigens of bacteria, viruses, fungi, and proteas.

Types of bacterial antigens:

group-specific;

species-specific;

type-specific.

Based on localization in the bacterial cell, they are distinguished:

O - AG - polysaccharide (part of the bacterial cell wall);

lipidA - heterodimer; contains glucosamine and fatty acids;

N - AG; part of bacterial flagella;

K - AG - a heterogeneous group of surface, capsular antigens of bacteria;

toxins, nucleoproteins, ribosomes and bacterial enzymes.

3.Streptocci, taxonomy, classification according to Lanefield. Characteristics of biological properties and pathogenicity factors of streptococci. The role of group A streptococci in human pathology. Features of immunity. Laboratory diagnostics streptococcal infection.

Family Streptococcacea

Genus Streptococcus

According to Lesfield (the class is based on different types of hemolysis): group A (Str. Pyogenes) group B (Str. Agalactiae - postpartum and urogenitis infections, mastitis, vaginitis, sepsis and meningitis in newborns.), gr. C (Str. Equisimilis), gr. D (Enterococcus, Str. Fecalis). Gr.A is an acute infectious process with an allergic component (scarlet fever, erysipelas, myocarditis), GrB is the main pathogen in animals, and causes sepsis in children. GrS-characteristic hemolysis (causes pathology of the reparative tract) GrD-possessed. all types of hemolysis, being a normal inhabitant of the human intestine. These are spherical cells, arranged in pairs.gr+, chemoorganotrophs, demanding nutrition. Wednesdays, warm up on blood or sugar. agar, small colonies form on a semi-solid medium, and on liquid ones they grow at the bottom, leaving the medium transparent. By growth characteristics on blood agar: alpha-hemolysis (small zone of hemolysis with a green-gray color), beta-heme (prozr), non-hemol. Aerobes do not form catalase, but by drops, less often by contact.

Pattern parameters 1) class wall - some have a capsule.

2) f-r adhesion-teichoi to-you

3) protein M-protective, prevents phagocytosis

4) a number of toxins: erythrogenic-scarlet fever, O-streptolysin = hemolysin, leukocidin 5) cytotoxins.

Diagnosis: 1)b/l: pus, mucus from the throat - culture on the blood. agar (presence/absence of hemolysis zone), identification by Ag St. 2) b/s - smears according to Gram 3) s/l - look for Ab to O-streptolysin in RSC or precision

Treatment: c-lactamn.a/b. Gr.A causing a purulent-inflammatory process, inflammation, accompanied by abundant pus, sepsis.

Organisms that are able to obtain energy in the absence of oxygen are called anaerobes. Moreover, the group of anaerobes includes both microorganisms (protozoa and a group of prokaryotes) and macroorganisms, which include some algae, fungi, animals and plants. In our article we will take a closer look at anaerobic bacteria that are used to treat wastewater in local wastewater treatment plants. Since aerobic microorganisms can be used along with them in wastewater treatment plants, we will compare these bacteria.

We figured out what anaerobes are. Now it’s worth understanding what types they are divided into. In microbiology, the following table for the classification of anaerobes is used:

Facultative microorganisms. Facultative anaerobic bacteria are bacteria that can change their metabolic pathway, that is, they can change respiration from anaerobic to aerobic and vice versa. It can be argued that they live optionally.
Capneistic representatives of the group are able to live only in an environment with a low oxygen content and a high carbon dioxide content.
Moderately strict organisms can survive in environments containing molecular oxygen. However, here they are not able to reproduce. Macroaerophiles can both survive and reproduce in environments with reduced partial pressure of oxygen.
Aerotolerant microorganisms differ in that they cannot live facultatively, that is, they are not able to switch from anaerobic to aerobic respiration. However, they differ from the group of facultative anaerobic microorganisms in that they do not die in an environment with molecular oxygen. This group includes most butyric acid bacteria and some types of lactic acid microorganisms.
Obligate bacteria quickly die in an environment containing molecular oxygen. They are able to live only in conditions of complete isolation from it. This group includes ciliates, flagellates, some types of bacteria and yeast.

Effect of oxygen on bacteria

Any environment containing oxygen has an aggressive effect on organic life forms. The thing is that in the process of life of various forms of life or due to the influence of certain species ionizing radiation reactive oxygen species are formed, which are more toxic than the molecular substance.

The main determining factor for the survival of a living organism in an oxygen environment is the presence of an antioxidant functional system that is capable of elimination. Usually like this protective functions are provided by one or several enzymes at once:

cytochrome;
catalase;
superoxide dismutase.

Moreover, some anaerobic bacteria of a facultative species contain only one type of enzyme - cytochrome. Aerobic microorganisms have as many as three cytochromes, so they thrive in an oxygen environment. And obligate anaerobes do not contain cytochrome at all.

However, some anaerobic organisms can influence their environment and create an appropriate redox potential. For example, before starting to reproduce, certain microorganisms reduce the acidity of the environment from 25 to 1 or 5. This allows them to protect themselves with a special barrier. And aerotolerant anaerobic organisms, which release hydrogen peroxide during their life processes, can increase the acidity of the environment.

Important: to ensure additional antioxidant protection, bacteria synthesize or accumulate low molecular weight antioxidants, which include vitamins A, E and C, as well as citric and other types of acids.

How do anaerobes get energy?

Some microorganisms obtain energy through the catabolism of various amino acid compounds, such as proteins and peptides, as well as the amino acids themselves. Typically, this process of releasing energy is called putrefaction. And the environment itself, in the energy exchange of which many processes of catabolism of amino acid compounds and amino acids themselves are observed, is called a putrefactive environment.
Other anaerobic bacteria are capable of breaking down hexoses (glucose). In this case they can be used different ways splitting:
- glycolysis After it, fermentation processes occur in the environment;
- oxidative pathway;
- Entner-Doudoroff reactions, which take place under the conditions of mannan, hexuronic or gluconic acid.

However, only anaerobic representatives can use glycolysis. It can be divided into several types of fermentation depending on the products that are formed after the reaction:

alcoholic fermentation;
lactic acid fermentation;
Enterobacterium formic acid species;
butyric acid fermentation;
propionic acid reaction;
processes with the release of molecular oxygen;
methane fermentation (used in septic tanks).

Features of anaerobes for a septic tank

Anaerobic septic tanks use microorganisms that are capable of processing wastewater without access to oxygen. As a rule, in the compartment where anaerobes are located, the processes of wastewater decay are significantly accelerated. As a result of this process, solid compounds fall to the bottom in the form of sediment. At the same time, the liquid component of the wastewater is qualitatively purified from various organic inclusions.

During the life of these bacteria, a large number of solid compounds. All of them settle at the bottom of the local treatment plant, so it needs regular cleaning. If cleaning is not carried out in a timely manner, the effective and coordinated operation of the treatment plant can be completely disrupted and put out of action.

Attention: sludge obtained after cleaning a septic tank should not be used as fertilizer, since it contains harmful microorganisms that can harm the environment.

Since anaerobic representatives of bacteria produce methane during their life processes, wastewater treatment plants that use these organisms must be equipped with effective system ventilation. Otherwise, an unpleasant odor can spoil the surrounding air.

Important: the efficiency of wastewater treatment using anaerobes is only 60-70%.

Disadvantages of using anaerobes in septic tanks

Anaerobic representatives of bacteria that are part of various biological products for septic tanks have the following disadvantages:

The waste that is generated after wastewater is processed by bacteria is not suitable for soil fertilization due to the content of harmful microorganisms in it.
Since a large amount of dense sediment is formed during the life of anaerobes, its removal must be carried out regularly. To do this, you will have to call the vacuum cleaners.
Wastewater treatment using anaerobic bacteria does not occur completely, but only to a maximum of 70 percent.
A treatment plant operating with the use of these bacteria can emit a very unpleasant odor, which is due to the fact that these microorganisms emit methane during their life processes.

Difference between anaerobes and aerobes

The main difference between aerobes and anaerobes is that the former are able to live and reproduce in conditions with high oxygen content. Therefore, such septic tanks must be equipped with a compressor and an aerator for pumping air. Typically, these on-site treatment plants do not emit such an unpleasant odor.

In contrast, anaerobic representatives (as the microbiology table described above shows) do not require oxygen. Moreover, some of their species can die when high content of this substance. Therefore, such septic tanks do not require pumping air. For them, it is only important to remove the resulting methane.

Another difference is the amount of sediment formed. In aerobic systems, the amount of sediment is much less, so the structure can be cleaned much less frequently. In addition, the septic tank can be cleaned without calling a vacuum cleaner. To remove thick sediment from the first chamber, you can take a regular net, and to pump out the activated sludge formed in the last chamber, it is enough to use a drainage pump. Moreover, activated sludge from a treatment plant using aerobes can be used to fertilize the soil.

Aerobic organisms are those organisms that are able to live and develop only in the presence of free oxygen in the environment, which they use as an oxidizing agent. Aerobic organisms include all plants, most protozoa and multicellular animals, almost all fungi, that is, the vast majority known species Living creatures.

In animals, life in the absence of oxygen (anaerobiosis) occurs as a secondary adaptation. Aerobic organisms carry out biological oxidation primarily through cellular respiration. Due to the formation of toxic products during oxidation incomplete recovery oxygen, aerobic organisms have a number of enzymes (catalase, superoxide dismutase) that ensure their decomposition and are absent or poorly functioning in obligate anaerobes, for which oxygen is therefore toxic.

The most diverse respiratory chain is found in bacteria that possess not only cytochrome oxidase, but also other terminal oxidases.

Special place Among aerobic organisms, there are organisms capable of photosynthesis - cyanobacteria, algae, and vascular plants. The oxygen released by these organisms ensures the development of all other aerobic organisms.

Organisms that can develop at low oxygen concentrations (≤ 1 mg/l) are called microaerophiles.

Anaerobic organisms are able to live and develop in the absence of free oxygen in the environment. The term “anaerobes” was introduced by Louis Pasteur, who discovered butyric acid fermentation bacteria in 1861. They are distributed mainly among prokaryotes. Their metabolism is determined by the need to use oxidizing agents other than oxygen.

Many anaerobic organisms that use organic matter(all eukaryotes that obtain energy as a result of glycolysis) carry out Various types fermentation, during which reduced compounds are formed - alcohols, fatty acids.

Other anaerobic organisms - denitrifying (some of them reduce iron oxide), sulfate-reducing, methane-forming bacteria - use inorganic oxidizing agents: nitrate, sulfur compounds, CO 2.

Anaerobic bacteria are divided into butyric acid groups, etc. in accordance with the main product of exchange. A special group of anaerobes are phototrophic bacteria.

In relation to O2, anaerobic bacteria are divided into obligate, who are unable to use it in exchange, and optional(for example, denitrifying), which can transition from anaerobiosis to growth in an environment with O 2.

Per unit of biomass, anaerobic organisms produce many reduced compounds, of which they are the main producers in the biosphere.

The sequence of formation of reduced products (N 2 , Fe 2+, H 2 S, CH 4), observed during the transition to anaerobiosis, for example in bottom sediments, is determined by the energy output of the corresponding reactions.

Anaerobic organisms develop in conditions where O2 is completely used by aerobic organisms, for example in wastewater and sludge.

The influence of the amount of dissolved oxygen on the species composition and abundance of aquatic organisms.

The degree of oxygen saturation of water is inversely proportional to its temperature. The concentration of dissolved O2 in surface waters varies from 0 to 14 mg/l and is subject to significant seasonal and daily fluctuations, which mainly depend on the ratio of the intensity of the processes of its production and consumption.

In the case of high intensity of photosynthesis, water can be significantly oversaturated with O 2 (20 mg/l and above). In an aquatic environment, oxygen is the limiting factor. O 2 makes up 21% (by volume) in the atmosphere and about 35% of all gases dissolved in water. Its solubility in sea water is 80% of the solubility in fresh water. The distribution of oxygen in a reservoir depends on temperature, the movement of layers of water, as well as the nature and number of organisms living in it.

Endurance of aquatic animals to low content oxygen from different types not the same. Among fish, four groups have been established according to their relationship to the amount of dissolved oxygen:

1) 7 - 11 mg/l - trout, minnow, sculpin;

2) 5 - 7 mg/l - grayling, gudgeon, chub, burbot;

3) 4 mg/l - roach, ruff;

4) 0.5 mg/l - carp, tench.

Some species of organisms have adapted to seasonal rhythms in O2 consumption associated with living conditions.

Thus, in the crustacean Gammarus Linnaeus it was found that the intensity of respiratory processes increases with temperature and changes throughout the year.

Animals living in places poor in oxygen (coastal silt, bottom silt) have respiratory pigments that serve as an oxygen reserve.

These species are able to survive by switching to a slow life, to anaerobiosis, or due to the fact that they have d-hemoglobin, which has a high affinity for oxygen (daphnia, oligochaetes, polychaetes, some elasmobranch molluscs).

Other aquatic invertebrates rise to the surface for air. These are the imago of swimming beetles and water-loving beetles, smoothies, water scorpions and water bugs, pond snails and spool (gastropods). Some beetles surround themselves with an air bubble held by a hair, and insects can use air from the aerial sinuses of aquatic plants.