Anaerobes are microbes that can grow and multiply in the absence of free oxygen. The toxic effect of oxygen on anaerobes is associated with the suppression of the activity of a number of bacterial. There are facultative anaerobes that can change the anaerobic type of respiration to aerobic, and strict (obligate) anaerobes, which have only anaerobic type of respiration.

When cultivating strict anaerobes, chemical methods are used to eliminate oxygen: substances capable of absorbing oxygen are added to the environment surrounding anaerobes (for example, alkaline solution pyrogallol, sodium hydrosulfite), or are introduced into the composition of substances capable of restoring incoming oxygen (for example, etc.). It is possible to provide anaerobes by physical methods: mechanically remove from nutrient media before sowing by boiling, followed by filling the surface of the medium with liquid, and also use an anaerostat; inoculate by injection into a tall column of nutrient agar, then pouring it with viscous vaseline oil. The biological way to provide anoxic conditions for anaerobes is the combined, joint sowing of crops and anaerobes.

Pathogenic anaerobes include rods, pathogens (see Clostridia). See also .

Anaerobes are microorganisms that can exist and develop normally without access to free oxygen.

The terms "anaerobes" and "anaerobiosis" (life without access to air; from the Greek negative prefix anaer - air and bios-life) were proposed by L. Pasteur in 1861 to characterize the conditions for the existence of butyric fermentation microbes discovered by him. Anaerobes have the ability to decompose organic compounds in an oxygen-free environment and thus obtain the necessary energy for their life.

Anaerobes are widely distributed in nature: they live in soil, pond silt, compost heaps, in the depths of wounds, in the intestines of people and animals - wherever decomposition occurs. organic matter without air access.

In relation to oxygen, anaerobes are divided into strict (obligate) anaerobes, which are not able to grow in the presence of oxygen, and conditional (facultative) anaerobes, which can grow and develop both in the presence of oxygen and without it. The first group includes most anaerobes from the genus Clostridium, bacteria of lactic and butyric fermentation; to the second group - cocci, fungi, etc. In addition, there are microorganisms that require a small concentration of oxygen for their development - microaerophiles (Clostridium histolyticum, Clostridium tertium, some representatives of the genus Fusobacterium and Actinomyces).

The genus Clostridium unites about 93 species of rod-shaped gram-positive bacteria that form terminal or subterminal spores (tsvetn. Fig. 1-6). Pathogenic clostridia include Cl. perfringens, Cl. oedema-tiens, Cl. septicum, Cl. histolyticum, Cl. sordellii, which is the causative agent of anaerobic infection (gas gangrene), pulmonary gangrene, gangrenous appendicitis, postpartum and post-abortion complications, anaerobic septicemia, and food poisoning (Cl. perfringens, types A, C, D, F).

Pathogenic anaerobes are also Cl. tetani is the causative agent of tetanus and Cl. botulinum is the causative agent of botulism.

The genus Bacteroides includes 30 species of rod-shaped, non-spore-forming, gram-negative bacteria, most of them are strict anaerobes. Representatives of this genus are found in the intestinal and genitourinary tracts of humans and animals; some species are pathogenic, causing septicemia and abscesses.

Anaerobes of the genus Fusobacterium (small sticks with a thickening at the ends, not forming spores, gram-negative), which are inhabitants of the oral cavity of humans and animals, in association with other bacteria cause necrobacillosis, Vincent's tonsillitis, gangrenous stomatitis. Anaerobic staphylococci of the genus Peptococcus and streptococci of the genus Peptostreptococcus are found in healthy people in the respiratory tract, mouth, vagina, and intestines. Anaerobic cocci cause various purulent diseases: lung abscess, mastitis, myositis, appendicitis, sepsis after childbirth and abortion, peritonitis, etc. Anaerobes from the genus Actinomyces cause actinomycosis in humans and animals.

Some anaerobes also perform useful functions: they contribute to the digestion and absorption of nutrients in the intestines of humans and animals (bacteria of butyric and lactic acid fermentation), participate in the circulation of substances in nature.

Methods for isolating anaerobes are based on creating anaerobic conditions (reducing the partial pressure of oxygen in the medium), for the creation of which the following methods are used: 1) removal of oxygen from the medium by pumping out air or displacement with an indifferent gas; 2) chemical absorption of oxygen using sodium hydrosulfite or pyrogallol; 3) combined mechanical and chemical removal of oxygen; 4) biological absorption of oxygen by obligate aerobic microorganisms seeded on one half of the Petri dish (Fortner method); 5) partial removal of air from the liquid nutrient medium by boiling it, adding reducing substances (glucose, thioglycolate, cysteine, pieces of fresh meat or liver) and filling the medium with vaseline oil; 6) mechanical protection from air oxygen, carried out by seeding anaerobes in a tall column of agar in thin glass tubes according to the Veillon method.

Methods for identifying isolated cultures of anaerobes - see Anaerobic infection (microbiological diagnostics).

A., dying in the presence of free oxygen in environment … Big Medical Dictionary

See Anaerobic Organisms. Geological dictionary: in 2 volumes. M.: Nedra. Edited by K. N. Paffengolts et al. 1978 ... Geological Encyclopedia

Modern Encyclopedia

- (anaerobic organisms) are able to live in the absence of atmospheric oxygen; some types of bacteria, yeast, protozoa, worms. Energy for life is obtained by oxidizing organic, less often inorganic substances without the participation of free ... ... Big Encyclopedic Dictionary

Anaerobes- (from the Greek an negative particle, aer air and bios life), organisms that can live and develop in the absence of free oxygen; some types of bacteria, yeast, protozoa, worms. Obligate, or strict, anaerobes develop ... ... Illustrated Encyclopedic Dictionary

Organisms (mainly prokaryotes) that can live in the absence of free oxygen in the environment. Obligate A. receive energy as a result of fermentation (butyric acid bacteria, etc.), anaerobic respiration (methanogens, sulfate-reducing bacteria ... Dictionary of microbiology

Ow, pl. (unit anaerobe, a; m.). Biol. Organisms capable of living and developing in the absence of free oxygen (cf. aerobes). ◁ Anaerobic, oh, oh. Ah, bacteria. Ah, the infection. * * * anaerobes (anaerobic organisms), able to live in the absence of ... ... encyclopedic Dictionary

I Anaerobes (Greek negative prefix an + aēr air + b life) are microorganisms that develop in the absence of free oxygen in their environment. They are found in almost all samples of pathological material with ... ... Medical Encyclopedia

Anaerobic organisms, anaerobionts, anoxybionts (from the Greek an negative particle and Aerobes), organisms that can live and develop in the absence of free oxygen and receive energy for life by splitting ... ... Great Soviet Encyclopedia

ANAEROBES- (from the Greek an negative particle, aer air and bios life), organisms that can live and reproduce in the absence of atm. oxygen. They receive energy for life by splitting Ch. arr. organic substances without the participation of free oxygen. Veterinary Encyclopedic Dictionary

Oxygen is widely distributed in nature, being both in a bound and free state. In the first case, it is part of water molecules, organic and inorganic compounds. In the second, it is present in the modern atmosphere in the form of molecular oxygen (O2), the volume fraction of which is 21%.

Oxygen is an essential chemical component of any cell. The vast majority of organisms meet their needs for this element using both forms of oxygen. When growing Pseudomonas in the presence of 18O2 and H218O, gaseous oxygen served as a source of approximately 10% of the oxygen in the cellular material, and 50–60% of cellular oxygen came from water. The rest of the oxygen was supplied to the cell by organic and inorganic components of the nutrient medium (glucose, phosphates, nitrates, sulfates, etc.).

Among prokaryotes, there are significant differences in relation to molecular oxygen. On this basis, they can be divided into several groups (Fig. 34). Prokaryotes, for the growth of which O2 is necessary, are called obligate (mandatory) aerobes. These include most prokaryotes. Among obligate aerobes, significant differences were found in relation to the level of molecular oxygen in the environment. Some representatives of this group are not able to grow at an O2 concentration equal to atmospheric, but can grow if the O2 content in the environment is significantly lower (about 2%). Such obligately aerobic prokaryotes are called microaerophiles.

The requirement of prokaryotes for a low concentration of O2 in the environment is associated with their metabolic features. Many aerobic nitrogen-fixing bacteria can grow in an environment with molecular nitrogen only at O2 concentrations below 2%, i.e. as microaerophiles, and in the presence of bound nitrogen, such as ammonium, in air. This is explained by the inhibitory effect of molecular oxygen on the activity of nitrogenase, the enzyme complex responsible for N2 fixation.

A similar pattern has been found in many hydrogen-oxidizing bacteria. On Wednesday with organic compounds as an energy source, they grow well at atmospheric O2 content. If the energy source is the oxidation of molecular hydrogen, these same bacteria require a low concentration of O2 for growth. The latter is associated with the inactivation of hydrogenase, an enzyme catalyzing the use of H2, by molecular oxygen.

Finally, among obligate aerobes, there are significant differences in resistance to high levels O2 in the environment. 100% molecular oxygen inhibits the growth of all obligate aerobes. Many aerobic bacteria can form colonies on the surface of a solid nutrient medium in an atmosphere containing 40% O2, but their growth stops when the O2 content in the atmosphere rises to 50%.

Prokaryotes are known for whose metabolism O2 is not needed, i.e., their energy and structural processes occur without the participation of molecular oxygen. Such organisms are called obligate anaerobes. These include methane-forming archaebacteria, sulfate-reducing, butyric and some other eubacteria. Until relatively recently, it was believed that obligate anaerobes can get energy only in the process of fermentation. At present, many obligate anaerobic prokaryotes are known that evolved from aerobes as a result of secondary adaptation to anaerobic conditions, which led to the loss of the ability to use O2 as the final electron acceptor during respiration. Such obligate anaerobes receive energy in the processes of anaerobic respiration, i.e. electron transfer along the chain of carriers to CO2, SO4--, fumarate and other acceptors.

Among obligate anaerobic prokaryotes that do not include O2 in metabolic reactions, there is a wide range of resistance to molecular oxygen present in the environment. Many of the obligate anaerobes cannot tolerate the presence of even small amounts of molecular oxygen in the environment and quickly die. Such organisms are called strict anaerobes. Strict anaerobes include representatives of the genera Bacteroides, Fusobacterium, Butyrivibrio, Methanobacterium, etc.

Butyric acid bacteria also belong to the group of obligate anaerobes, but among them there are species that are moderately (Clostridium tetani, Clostridium carnis, Clostridium tertium, Clostridium sporogenes) or quite high (Clostridium perfringens, Clostridium acetobutylicum) tolerant to O2.

Finally, lactic acid bacteria, which have an anaerobic-type metabolism only, can grow in the presence of air and are isolated in a separate group of aerotolerant anaerobes. (Some authors classify lactic acid bacteria of the genus Lactobacillus as microaerophiles on the grounds that their cells contain flavoproteins that catalyze the transfer of electrons from NAD * H2 to O2. However, this process is not associated with obtaining energy by the cell).

Although obligate anaerobic bacteria are generally very sensitive to O2, they can naturally occur in aerobic zones. The wide distribution of representatives of the genus Clostridium in places with a high partial pressure of O2 is explained by the presence of endospores that are insensitive to molecular oxygen. However, many strictly anaerobic prokaryotes that do not form spores have been found in nature in places where the active development of obligate aerobes is observed. Probably, joint development with obligate aerobes, actively consuming molecular oxygen, leading to the formation of zones with a low concentration of 02, creates opportunities for the development of strictly anaerobic species.

Described are prokaryotic organisms that can grow under both aerobic and anaerobic conditions. The study of this phenomenon showed that its nature is different. Bacteria that do not need O2 (the latter does not participate in their metabolic reactions), but are able to grow in its presence, are obligate anaerobes, resistant to O2 of the external environment, according to the type of metabolism they carry out. An example of such organisms are lactic acid bacteria. Many prokaryotes belonging to the same group have adapted, depending on the presence or absence of O2 in the environment, to switch from one metabolic pathway to another, for example, from respiration to fermentation, and vice versa. Such organisms are called facultative anaerobes, or facultative aerobes. Representatives of this physiological group of prokaryotes are enterobacteria. Under aerobic conditions, they obtain energy through the process of respiration. (Among the facultative anaerobes under the conditions of their aerobic metabolism, there may also be microaerophiles). Under anaerobic conditions, the source of energy for them is the processes of fermentation or anaerobic respiration.

The need for O2 in aerobes is determined by its participation in energy and structural processes. In the first case, O2 serves as an obligatory final electron acceptor; in the second case, it participates in reactions (or a single reaction) along the path of multistage transformation of cellular metabolites or exogenous substrates. In obligate aerobes most of O2 is used as the final electron acceptor in reactions catalyzed by cytochrome oxidases. A smaller part is included in molecules with the help of enzymes that have received common name oxygenases. The cells of facultative anaerobes also contain cytochrome oxidases. Obligate anaerobes do not have enzymes that catalyze interaction with O2.

The effect of temperature on the vital activity of microorganisms. Temperature Range. Psychrophiles, mesophiles, thermophiles and their distribution in nature. Mechanisms of psychro- and thermophilia. Use of high temperatures to inactivate microorganisms. The use of low temperatures for the storage of microorganisms.

Temperature: the vital activity of each microorganism is limited by certain temperature limits. This temperature dependence is usually expressed by three points: the minimum (min) temperature - below which reproduction stops, the optimal (opt) temperature - the best temperature for the growth and development of microorganisms, and the maximum (max) temperature - the temperature at which cell growth either slows down or stops. at all. For the first time in the history of science, Pasteur developed methods for the destruction of microorganisms when exposed to high temperatures.
The optimum temperature is usually equated to the ambient temperature.
All microorganisms in relation to temperature can be conditionally divided into 3 groups:
First group: psychrophiles - these are cold-loving microorganisms, they grow at low temperatures: min t - 0 °С, opt t - from 10-20 °С, max t - up to 40 °С. These microorganisms include the inhabitants of the northern seas and reservoirs. To the action of low temperatures, many microorganisms are very resistant. For example, Vibrio cholerae can be stored in ice for a long time without losing its viability. Some microorganisms can withstand temperatures down to -190°C, and bacterial spores can withstand temperatures down to -250°C. The effect of low temperatures stops putrefactive and fermentation processes, so we use refrigerators in everyday life. At low temperatures, microorganisms fall into a state of suspended animation, in which all vital processes in the cell slow down.
The second group includes mesophiles - this is the most extensive group of bacteria, which includes saprophytes and almost all pathogenic microorganisms, since the opt temperature for them is 37 °C (body temperature), min t = 10 °C, maxt = 45 °C.
The third group includes thermophiles - heat-loving bacteria, develop at t above 55 °C, min t for them = 30 °C, max t = 70-76 °C. These microorganisms live in hot springs. There are many spore forms among thermophiles. Bacterial spores are much more resistant to high temperatures than vegetative forms of bacteria. For example, spores of anthrax bacilli withstand boiling for 10-20 seconds. All microorganisms, including spores, die at a temperature of 165-170°C within an hour. The action of high temperatures on microorganisms is the basis of sterilization.

Anaerobes are organisms that obtain energy in the absence of oxygen access by substrate phosphorylation. The term "anaerobes" was introduced by Louis Pasteur, who discovered butyric fermentation bacteria in 1861.

All microorganisms according to the type of respiration are divided into aerobic and anaerobic. Anaerobic respiration is a set of biochemical reactions that occur in the cells of living organisms when other substances (for example, nitrates) are used as the final proton acceptor, and refers to energy metabolism processes (catabolism, dissimilation), which are characterized by the oxidation of carbohydrates, lipids and amino acids to low molecular weight compounds.

If an organism is able to switch from one metabolic pathway to another (for example, from anaerobic to aerobic respiration and vice versa), then it is conditionally referred to as facultative anaerobes. Until 1991, in microbiology, a class of capneistic anaerobes was distinguished that required a low concentration of oxygen and a high concentration of carbon dioxide (Brucella bovine type - B. abortus). A moderately strict anaerobic organism survives in an environment with molecular O2, but does not reproduce. Microaerophiles are able to survive and multiply in an environment with a low partial pressure of O2. If an organism is not able to "switch" from anaerobic to aerobic respiration, but does not die in the presence of molecular oxygen, then it belongs to the group of aerotolerant anaerobes. For example, lactic acid and many butyric bacteria. Obligate anaerobes die in the presence of molecular oxygen O2 - for example, representatives of the genus of bacteria and archaea: Bacteroides, Fusobacterium, Butyrivibrio, Methanobacterium). Such anaerobes constantly live in an oxygen-deprived environment. Obligate anaerobes include some bacteria, yeasts, flagellates and ciliates.

Toxicity of oxygen and its forms for anaerobic organisms

An oxygen rich environment is aggressive towards organic life forms. This is due to the formation of reactive oxygen species in the course of life or under the influence of various forms of ionizing radiation, which are much more toxic than molecular oxygen O2. The factor determining the viability of an organism in an oxygen environment is the presence of a functional antioxidant system capable of eliminating: superoxide anion (O2−), hydrogen peroxide (H2O2), singlet oxygen (O), and molecular oxygen (O2) from the internal environment organism. Most often, such protection is provided by one or more enzymes: superoxide dismutase, which eliminates the superoxide anion (O2−) without energy benefits for the body; catalase that eliminates hydrogen peroxide (H2O2) without energy benefits for the body; cytochrome - an enzyme responsible for the transfer of electrons from NAD H to O2. This process provides a significant energy benefit to the body. Aerobic organisms most often contain three cytochromes, facultative anaerobes - one or two, obligate anaerobes do not contain cytochromes. Additional antioxidant protection can be provided by the synthesis or accumulation of low molecular weight antioxidants: vitamin C, A, E, citric and other acids.

Anaerobic microorganisms are the normal microflora of the human body, while in 30-100% of cases they can be the cause of pyoinflammatory diseases.

The presence of anaerobic bacteria in the test material should be suspected under the following criteria: Bad smell of the test sample, Localization of infection near the mucous membrane, Infection after a human or animal bite, Gas in the test material, Previous treatment with drugs that are inactive against anaerobes (antibiotics: aminoglycosides, old quinolones, trimethoprim), Black staining of blood-containing exudates, Presence of "sulfur granules" in secretions, Unique morphology on Gram stain, Absence of growth under aerobic conditions of microorganisms seen in micropreparations from exudate, Growth in the anaerobic zone of the nutrient medium, Anaerobic growth on selective media for anaerobes, Characteristic colonies on anaerobic agar plates, Fluorescence of colonies in ultraviolet light.

Microbiological diagnostics. Currently, the main diagnostic methods are bacteriological with extended identification by biochemical properties, as well as gas chromatography (chemotaxonomy) and PCR (gene diagnostics).

Cultivation of anaerobic organisms. For the cultivation of anaerobes, special methods are used, the essence of which is to remove air or replace it with a specialized gas mixture (or inert gases) in sealed thermostats - anaerostats. Another way to grow anaerobes (most often microorganisms) on nutrient media is to add reducing substances (glucose, sodium formic acid, casein, sodium sulfate, thiosulfate, cysteine, sodium thiogluconate, etc.) that bind peroxide compounds toxic to anaerobes.

General nutrient media for anaerobic organisms. For the general medium of Wilson - Blair, the base is agar-agar with the addition of glucose, sodium sulfite and ferrous chloride. Clostridia form black colonies on this medium by reducing sulfite to sulfide anion, which combines with iron (II) cations to give a black salt. As a rule, black colony formations on this medium appear in the depth of the agar column. The Kitt-Tarozzi medium consists of meat-peptone broth, 0.5% glucose, and pieces of liver or minced meat to absorb oxygen from the medium. Before sowing, the medium is heated in a boiling water bath for 20-30 minutes to remove air from the medium. After sowing, the nutrient medium is immediately filled with a layer of paraffin or paraffin oil to isolate it from oxygen access. GasPak - the system chemically provides a constancy of the gas mixture acceptable for the growth of most anaerobic microorganisms. In a sealed container, water reacts with sodium borohydride and sodium bicarbonate tablets to form hydrogen and carbon dioxide. The hydrogen then reacts with the oxygen of the gas mixture on a palladium catalyst to form water, which is already re-reacting with the hydrolysis of the borohydride. This method was proposed by Brewer and Olgaer in 1965. The developers introduced a disposable hydrogen generating sachet, which was later upgraded to carbon dioxide generating sachets containing an internal catalyst.

Classification anaerobic bacteria is based on the principles of genotypic homology, which allows to determine the phylogenetic relationship, in addition, all anaerobes can be classified according to morphology and relation to Gram color.

Gram-positive: rods (Clostridium, Bifidobacterium, Lactobacillus, Mobiluncus), cocci (Anaerococcus, Peptococcus, Peptostreptococcus, Coprococcus). Gram-negative: rods (Bacteroides, Porphyromonas, Prevotella, Fusobacterium, Leptotrichia), cocci (Acidaminococcus, Veillonella, Megasphaera).

Let us consider representatives of the main taxonomic groups of great medical importance.

Gram-positive spore-forming rods.

spore-forming bacteria of the genusClostridium

Spore-forming anaerobes of the genus Clostridium There are over 150 species. Spores are round or oval in shape, located in the center of the cell subterminally or terminally, depending on the species of the microbe. The diameter of the spore is usually larger than the diameter of the cell, so the cell containing the spore looks swollen and resembles a spindle (from lat. clostridium- spindle). These bacteria, under favorable conditions, can cause gas gangrene, tetanus, botulism, pseudomembranous ulcerative enterocolitis, food poisoning and other diseases associated with clostridial lesions of various organs and systems in humans.

They differ in the mechanism of metabolic processes i.e. without free oxygen. The final acceptor in the respiratory chain are nitrates, sulfates or organic compounds.

Genus Clostridium.

Sticks, large, spore-forming - the diameter of the spore is greater than the diameter of the stick, mobility +/-, the shape is veritino-shaped, the position of the spore is of differential importance, the capsules do not produce (there is an exception). Grow on media (oxygen-free): Kita-Toroczi, Wilson-Blair, deep column of sugar agar, blood agar under anaerobic conditions.

They are biochemically active, have a set of saccharolytic, proteolytic enzymes, decompose substances to gas (ammonia, CO 2), butyric acids.

Ecology of clostridia.

Normally, they are part of the normal microflora of the gastrointestinal tract of animals (especially ruminants) and humans - they digest food, increase peristalsis and at the same time produce toxins that are immediately destroyed by juice proteases.

With fecal masses, they are thrown into the environment and turn into a spore-like form, and remain there for decades. The reservoir of clostridia is the soil. Clostridial anaerobic infection has an exogenous origin - a wound infection. The entrance gate is a wound in which anaerobic favorable conditions are created for the transition of the spore form to the vegetative one.

TETANUS.

Severe, acute infectious disease that has a single pathogen C. tetani and manifests itself with neurological symptoms.

Characterization of C. tetani

The wand was discovered in 1883 by Monastyrsky.

Morphological features:

Mobility +

Spore - on the periphery

Form - rackets

Cultivated - on sugar-blood agaga, Whale-Torotia

· B/C - no saccharolytic enzymes, few proteolytic enzymes.

Conditions for infection with tetanus: wound, childbirth, abortion (outside medical facilities), surgery, blood flow disorders in the wound, bacillus drift into the wound surface with soil, dust, honey. instruments, dressing material, dressing, suture material.

pathogenic properties. The pathogenesis of the disease.

Production of exotoxins - tetanospasmin, tetanolysin. This is a protein that acts remotely - it enters the central nervous system through the nerve processes through axons and suppresses the inhibitory processes of neurotransmitters in synapses > disrupts the transmission of nerve impulses > muscle spasm of different muscle groups. In mild cases, there is muscle contraction around the wound.

Tetanus in newborns: many children are ill in countries where women give birth without medical care and cutting the umbilical cord is done with non-sterile items.

Clinical forms of tetanus: descending in humans - the processes of the head, tetanus, upper limbs, then lower limbs are involved first. Animals have an ascending character.

Laboratory diagnostics.

bacteriological method. Suture material, dressing material, preparations for parenteral administration, soil samples are taken for research. Sowed in anaerobic media (Kita-Torocia) cultivated in an anaerobic balloon for 2-3 days, then checked for sterility (turbidity, gas formation). Material from the patient is rarely taken. and so it is clear that it is tetanus, but they can take blood, cerebrospinal fluid, the contents of the wound. They look for the pathogen itself in the material, or they can look for toxins with the help of a biological test on mice at the same time administer tetanus toxoid > the mouse will survive, and do not inject the toxoid > the mouse dies.

Prevention.

Emergency: performed in case of trauma, wounds, criminal abortions. It includes PST of the wound, then AC-toxoid is injected (for active prevention), the introduction of anti-tetanus serum, anti-tetanus immunoglobulin (ready-made antitoxins - for passive immunization), is carried out selectively under the control of antitoxic immunity - is done using the patient's passive hemagglutination reaction. In adults, 0.2 ml of blood from a finger. If RPHA + in a ratio of 1:20 means a normal protective titer. If the titer is reduced, the second two drugs are administered.

Routine: mandatory immunization of all children from three months to 17 years of age. In adults, military personnel, employees of the Ministry of Emergency Situations, firefighters, miners are immunized.

Tetanus is a preventable infection and getting sick with tetanus is indecent. They only get sick if they don't go to the doctor.

GAS GANGRENE.

(clostridial myonecrosis, clostridial cellulitis)

GH is an acute infectious disease of a polymicrobial nature with severe intoxication of the body with tissue necrosis and the formation of gases in soft tissues.

Pathogens.

C. pefringes, C. septicum, C. hovyi. G+ rods are differentiated by the position of the spore, the presence of flagella, capsule formation, and the production of type-specific toxins. There is no cross immunity.

The causative agent in the spore form enters through deep wounds, tamponed wounds, compression of soft tissues, shrapnel wounds, in which PST was performed after 2 hours after receipt.

Pathogenicity factors: production of exotoxins (12 pieces) - have the property of formants (phospholipases, proteases). They are named after the letters of the Greek alphabet. The main one is toxin b - has the property of lecithinase > acts on cell membrane breaking its permeability. Other toxins cause edema, the third necrosis. Act locally on tissue. Intoxication is associated with the breakdown of tissues.

Immunity.

It is antitoxic in nature (and not on the pathogen). Type-specific, unstressed.

Laboratory diagnostics.

Material: contents of the wound, pieces of affected organs and tissues

Method: bacterioscopy - G+ rods, bacteriological: medium inoculation, biochemical tests (milk curdling, black colonies). Differentiation within the genus according to a biological sample with a culture filtrate containing exotoxin and antitoxic serum of the corresponding pathogen. It is necessary not so much for the diagnosis, but for the treatment.

Specific: urgent administration of anti-gangrenous serum (poly or monovalent).

Surgical: open wound management, placement in a pressure chamber, antibiotics

Prevention.

Planned: sexta-anatoxin (perfringins, septicum, novi, tetanis, botulinum, deficille).

BOTULISM.

Food infection, transmission factors - canned products of meat origin, fish origin, canned mushrooms.

Pathogenicity factors: production of botulinum toxin (the most powerful poison), a single dose of 0.001 mg. Valid exclusively on nervous system, resistant to the action of digestive enzymes, temperature. There are 7 variants of the toxin (by letter of the Latin alphabet), some are resistant to digestive enzymes and bacterial proteases. There are strains of the toxin that are broken down by enzymes. The toxin has high immunogenic properties. Activated by gastric trypsin, proteases food products. They act in nerve synapses where they are fixed and irritated. Most often, the oculomotor nerve, glossopharyngeal nerve, optic nerve are affected > night blindness, ptosis, anisaccaria.

Clinical forms: gastroenteric, neuroparalytic, neurological.

Laboratory diagnostics: detection of toxin in the material from the patient (gastric lavage, blood) and canned food products in a biological sample on mice by neutralizing the toxin.

Treatment: injection of anti-botulinum serum

Prevention: proper food preservation.

Non-clostridial anaerobic infection.

Called by representatives of the following genera:

	P. melaninogenica

It has an endogenous character. all representatives are included in the composition of the normal microflora of the human body (live in the gastrointestinal tract, oral cavity).

Conditions for the occurrence of infections:

Violation of the integrity of the mucous membranes and tissues, while microbes from their natural habitats pass into tissues

Disruption of blood supply to tissues > with compression syndrome

Cancer tumor, its germination > damage to the membranes

Immunocompromised state

Chemotherapy (cytostatics)

Treatment with hormones

Irradiation

Dysbacteriosis

clinical features.

1. It is purulent-inflammatory in nature and manifests itself in the form of abscesses, infiltrates

2. is located near the natural habitats of pathogens

3. Putrid nature of the lesion, tissue necrosis. Putrid smell of exudate > production of large amounts of volatile fatty acids

4. Exudate is colored black, red

5. Gas formation

6. Severe condition of the patient, no focus of infection is visible

7. Infection must be treated with specific antibiotics (penicillins are not treated)

Laboratory diagnostics.

Bacteriological - very difficult, expensive, time-consuming result in 7-14 days. The sampling of the material is taken by aspiration or puncture, observing the rule - the material should not come into contact with atmospheric oxygen. Nutrient media - complex composition of serum, blood media + growth factors + vitamins + adsorbents. Cultivated in anaerostats in the presence of an increased content of CO 2 at a temperature of 37. The grown colony is pigmented (black, gray), fluorescent, morphological identification is not informative (rods, polymorphic, do not form a spore), the exception of Fusobacterium is a spindle. The main method is culture specifics: B. fragilis are cultured in the presence of 40% bile, B. fragilis grows in media with antibiotics (kanamycin), and B. urealyticus does not grow in media with vancomycin. In relation to carbohydrates, B. fragilis - ferment carbohydrates with the formation of fatty acids, B. Urealyticus do not ferment carbohydrates. It is impossible to study antigenic properties with the help of diagnostic serums - they do not exist.

Chemotherapeutic drugs related to the grume metranidazole or drugs of the nitroimidazole series, from the antibiotics clindomycin. Improvement of tissue microcirculation, creation of aerobic conditions, wound oxygenation.

Prevention.

There is no specific.

topic: Corinobacteria, general characteristics. The causative agent of diphtheria.

Genus Corynobacterum, no separate family, order: Actinomecitales. There are more than 20 species within the genus. Species of the most medical importance: C. Diphteriae, pseudodiphteriae, haemiliticum, xerosis, pseudotubercullosis, ulcerens, etc.

General characteristics.

Rod-shaped, have a thickening at one or both ends, immobile, have a microcapsule, in the cell wall they have specific lipids (corinomycolic acid), acid-resistant. Widely distributed in the environment. There are species that live on the human body, are part of the normal microflora (skin, nasopharynx), animals, plants.

Among corynobacteria there are pathogenic - diphtheria, opportunistic - ulcerative lesions (ulcerens), conjunctivitis (xerosis), cystitis, saprophytic.

C. diphtheriae

The causative agent of diphtheria is an acute infectious disease, which is manifested by deep intoxication of the body associated with diphtheria toxin and fibrous inflammation at the location of the pathogen. The name of the disease is from the Greek diphtera - film. The causative agent was discovered by Klebs in diphtheria films. Leffler in 1884 brought in pure culture (BL - Leffler's bacterium). Roux discovered the exotoxin in 1888 and proposed a nutrient medium for cultivation. Bering in 1892 received antitoxic serum from patients and proposed for treatment (received Nobel Prize). Ramon in 1923 developed a method for obtaining diphtheria toxoid.

		toxin production

Toxin formation in the pathogen is encoded by a specific gene, which is part of the temperate phage plasmid, and not part of the cell genome > is not permanent. If the culture is lysogenic (there is a phage in the composition) > toxigenic.

Morphological features.

Sticks, G+, are located at an angle to each other, have volutin grains at the ends > to identify volutin grains, they are stained according to the Neisser method (grains are black, sticks are yellow), simple methylene blue (grains are red, sticks are blue).

cultural properties.

facultative anaerobes. Wednesdays - on simple does not grow. Media groups:

Serum: Roux's medium, Loeffler's medium - the growth of corynobacteria is ahead of all other bacteria.

Tellurite media (elective) - inhibits the mouth of other microbes - Clauberg's blood-tellurite medium, chocolate agar (agar + hemolyzed erythrocytes) gravis gives R colonies, mitis - gives smooth media

Among with the addition of cystiine - Tynsdal's medium

Microorganisms grow in the presence of peptones (not a whole protein), aminopeptones with the obligatory additions of growth factors (iron salts, zinc, vitamins).

biochemical properties.

Sucrose -

Maltose +

Glucose +

Starch +

Cystinase +

Hydrogen sulfide +

pathogenicity factors.

Production of diphtheria histotoxin - has a toxic effect on many types of tissues - specifically blocks protein synthesis in various cells, especially those organs that are intensively supplied with blood (CVS, myocardium, PNS, CNS, kidneys, adrenal glands) is a true exotoxin - immunogenic protein, thermolabile, highly toxic from histotoxin, anatoxin can be obtained by treating with 0.4% formalin at a temperature of 40 for 4 weeks, it loses its toxic effects, but retains its immunogenic properties. The effect of the toxin is due to 2 fractions A and B. Fraction A is a true toxin, is able to penetrate into the cell and inactivate elongation factor 2, which is responsible for elongation of the polypeptide chain on ribosomes, acts only inside the cell > cannot be neutralized by diphtheria serum > the effect affects early stages (first 3 days). Fraction B is involved in the fixation of the toxin on the cell receptors and performs a transmembrane function; it is not a toxin itself. On the stratified epithelium, histotoxin causes a diphtheritic (fibrinous) form of inflammation, which manifests itself in the form of the formation of a film of fibrin. The film adheres tightly to the underlying tissues. On the single-layer and cylindrical epithelium causes croupous inflammation.

The surface structures of a bacterial cell are lipid and protein in nature - help to adhere to the tissue and therefore they are called fusion factors.

Enzymes of adhesion and invasion - neuroamidase, hyaluronidase

Toxion formation - hemotoxin, dermotoxin, necrotoxin, neurotoxin.

The pathogenesis of diphtheria.