Anaerobic infection

An anaerobic wound infection attracts the attention of surgeons, infectious disease specialists, microbiologists and other specialists. This is due to the fact that anaerobic infection occupies a special place due to the exceptional severity of the disease course, high mortality (14-80%), frequent cases of deep disability of patients. Anaerobam and their associations with aerobes now belongs to one of the leading places in human infectious pathology.

Anaerobic infection can develop as a result of injuries, surgical interventions, burns, injections, as well as with complicated course of acute and chronic purulent diseases of soft tissues and bones, vascular diseases against the background of atherosclerosis, diabetic angioneuropathy. Depending on the cause of the infectious disease of soft tissues, the nature of the lesion and its localization, anaerobic microorganisms show up in 40-90% of cases. Thus, according to some authors, the frequency of anaerobic excretion in bacteremia does not exceed 20%, and with phlegmon of the neck, odontogenic infection, intra-abdominal purulent processes, it reaches 81-100%.

Traditionally, the term "anaerobic infection" refers only to infections caused by clostridia. However, in modern conditions, the latter do not participate in infectious processes as often, in only 5-12% of cases. The main role is assigned to non-spore forming anaerobes. Combining both types of pathogens is that the pathological effect on tissues and organs is carried out by them under conditions of general or local hypoxia using the anaerobic pathway of metabolism.

[1], [2], [3], [4], [5]

Pathogens of anaerobic infection

By and large, the causative agents of anaerobic infection are pathological processes caused by obligate anaerobes, which develop and exert their pathogenic effect under anoxic conditions (strict anaerobes) or at low oxygen concentrations (microaerophiles). However, there is a large group, the so-called facultative anaerobes (Streptococcus, Staphylococcus, Proteus, Escherichia coli, etc.), which get into hypoxia conditions, switch from aerobic to anaerobic metabolism and are able to cause the development of an infectious process clinically and pathomorphologically similar to typical anaerobic.

Anaerobes are ubiquitous. More than 400 kinds of anaerobic bacteria are isolated in the human gastrointestinal tract, which is their main habitat. The ratio of aerobes to anaerobes is 1: 100.

Below is a list of the most common anaerobes, whose participation in infectious pathological processes in the human body is proven.

Microbiological classification of anaerobes

• Anaerobic Gram-positive sticks
  • Clostridium perfringes, sordellii, novyi, histolyticum, septicum, bifermentans, sporogenes, tertium, ramosum, butyricum, bryantii, difficile
  • Actinomyces israelii, naeslundii, odontolyticus, bovis, viscosus
  • Eubacterium limosum
  • Propionibacterim acnes
  • Bifidobacterium bifidum
  • Arachnia propionica
  • Rothia dentocariosa
• Anaerobic Gram-positive cocci
  • Peptostreptococcus anaerobius, magnus, asaccharolyticus, prevotii, micros
  • Peptococcus niger
  • Ruminococcus flavefaciens
  • Coprococcus eutactus
  • Gemella haemolysans
  • Sarcina ventriculi
• Anaerobic gram-negative rods
  • Bacteroides fragilis, vulgatus, thetaiotaomicron, distasonis, uniformis, caccae, ovatus, merdae,
  • stercoris, ureolyticus, gracilis
  • Prevotella melaninogenica, intermedia, bivia, loescheii, denticola, disiens, oralis, buccalis, veroralis, oulora, corporis
  • Fusobacterium nucleatum, necrophorum, necrogenes, periodonticum
  • Porphyromonas endodontalis, gingivalis, asaccharolitica
  • Mobiluncus curtisii
  • Anaerorhabdus furcosus
  • Centipeda periodontii
  • Leptotrichia buccalis
  • Mitsuokella multiacidus
  • Tissierella praeacuta
  • Wolinella succinogenes
• Anaerobic gram-negative cocci
  • Veillonella parvula

In most pathological infectious processes (92.8-98.0% of cases), anaerobes are identified in association with aerobes and, in the first place, with streptococci, staphylococci and bacteria of the Enterobacteriaceae family, non-fermenting gram-negative bacteria.

Among the many classifications of anaerobic infections in surgery the most complete and responsive to the needs of clinicians is the classification proposed by AP Kolesov et al. (1989).

Classification of anaerobic infection in surgery

According to the microbial etiology:

• clostridial;
• non-clostridial (peptostreptococcal, peptococcal, bacteroid, fuzobacterial, etc.).

By the nature of microflora:

• monoinfection;
• polyinfections (caused by several anaerobes);
• mixed (anaerobic-aerobic).

On the affected part of the body:

• infections of soft tissues;
• infections of internal organs;
• infection of bones;
• infection of serous cavities;
• bloodstream infection.

By prevalence:

• local, limited;
• unlimited, tending to spread (regional);
• system or generalized.

By source of infection:

• exogenous;
• endogenous.

By origin:

• out-of-hospital;
• hospital-acquired.

For reasons of occurrence:

• traumatic;
• spontaneous;
• iatrogenic.

Most anaerobes are natural inhabitants of the skin and mucous membranes of a person. More than 90% of all anaerobic infections are endogenous. Exogenous infections include only clostridial gastroenteritis, clostridial post-traumatic cellulitis and myonecrosis, infections after human and animal bites, septic abortion and some others.

Endogenous anaerobic infection develops in the event that conditionally pathogenic anaerobes appear in places unusual for their habitat. Penetration of anaerobes into tissues and the bloodstream occurs during surgical interventions, with trauma, invasive manipulation, decay of tumors, with translocation of bacteria from the intestine in acute abdominal cavity diseases and sepsis.

However, for the development of infection, it is not enough simply to get bacteria into unnatural places of their existence. For the introduction of anaerobic flora and the development of an infectious pathological process, it is necessary to participate in additional factors, which include large blood loss, local tissue ischemia, shock, starvation, stress, overfatigue, etc. An accompanying disease (diabetes mellitus, collagenoses, malignant tumors, ), long reception of hormones and cytostatics, primary and secondary immunodeficiencies against HIV infection and other chronic infectious and autoimmune diseases.

One of the main factors in the development of anaerobic infections is the decrease in the partial pressure of oxygen in the tissues, which arises as a result of common causes (shock, blood loss, etc.) and local hypoxia of tissues in conditions of insufficient arterial blood flow (occlusive vascular diseases) the number of shell-shocked, crushed, non-viable tissues.

Unreasonable and inadequate antibiotic-co-therapy, aimed mainly at suppressing antagonistic aerobic flora, also contributes to the unhindered development of anaerobes.

Anaerobic bacteria possess a number of properties that allow them to manifest their pathogenicity only when favorable conditions appear. Endogenous infections occur when the natural balance between the immune defense of the body and virulent microorganisms is disturbed. Exogenous anaerobic infection, and in particular clostridial infection, is more pathogenic and clinically proceeds more severely than the infection caused by non-spore-forming bacteria.

Anaerobes have pathogenicity factors that promote their invasion of the tissue, reproduction and manifestation of pathogenic properties. These include enzymes, products of life and decay of bacteria, antigens of cell walls, etc.

So bacteroids, which mainly live in different parts of the gastrointestinal tract, upper respiratory tract and lower parts of the urinary tract, are able to develop factors that promote their adhesion to the endothelium and damaging it. Severe disorders of microhemocirculation are accompanied by increased vascular permeability, erythrocyte sludge, microthrombogenesis with the development of immunocomplex vasculitis, which determine the progressing course of the inflammatory process and its generalization. Heparinase anaerobic promotes the emergence of vasculitis, micro- and macro-thrombophlebitis. The capsule of anaerobes is a factor that dramatically increases their virulence, and even takes them to the first place in associations. Secretion of the bacteroids neuraminidase, hyaluronidase, fibrinolysin, superoxide dismutase due to their cytotoxic effect leads to destruction of tissues and the spread of infection.

Bacteria of the genus Prevotella produce endotoxin, whose activity exceeds the action of lipopolysaccharides of bacteroides, and also produce phospholipase A, which breaks the integrity of membranes of epithelial cells, which leads to their death.

The pathogenesis of lesions caused by bacteria of the genus Fusobacterium is due to the ability to secrete leukocidin and phospholipase A, which have a cytotoxic effect and facilitate invasion.

Gram-positive anaerobic cocci normally colonize the oral cavity, large intestine, upper respiratory tract, vagina. Their virulent and pathogenic properties have not been adequately studied, despite the fact that they are often detected during the development of very severe purulent-necrotic processes of different localization. It is possible that the pathogenicity of anaerobic cocci is due to the presence of a capsule, the action of lipopolysaccharides, hyaluronidase, and collagenase.

Clostridia can cause both exogenous and endogenous anaerobic infection.

Their natural habitat is the soil and large intestine of humans and animals. The main generative feature of clostridia is sporulation, which causes their resistance to unfavorable environmental factors.

C. Perfringens, the most common pathogenic microorganism, identified at least 12 toxins-enzymes and enterotoxin, which determine its pathogenic properties:

• alpha-Toxin (lecithinase) - shows dermatoneukrotic, hemolytic and lethal effects.
• beta-Toxin - causes tissue necrosis and has a lethal effect.
• sigma-Toxin - shows hemolytic activity.
• theta-Toxin - has dermatonekroticheskoe, hemolytic and lethal effect.
• e-Toxins - cause lethal and dermatonecrotizing effects.
• To-toxin (collagenase and gelatinase) - destroys the reticular tissue of muscles and connective tissue collagen fibers, has a necrotizing and lethal effect.
• Lamda-Toxin (proteinase) - cleaves like fibrinolysin denatured collagen and gelatin, causing necrotic properties.
• gamma and nu-Toxins - have a lethal effect on laboratory animals.
• mu and v-Toxins (hyaluronidase and deoxyribonuclease) - increase the permeability of tissues.

Anaerobic infection is extremely rare in the form of a monoinfection (less than 1% of cases). The pathogenicity of anaerobic pathogens is manifested in association with other bacteria. Symbiosis of anaerobes with each other, as well as with some kinds of facultative anaerobes, especially streptococci, bacteria of the Enterobacteriaceae family, nonfermentative gram-negative bacteria, allows the creation of synergistic associative links facilitating their invasion and manifestation of pathogenic properties.

[6], [7], [8], [9]

How is anaerobic soft tissue infection manifested?

Clinical manifestations of anaerobic infection involving anaerobes are determined by the ecology of pathogens, their metabolism, pathogenicity factors that are realized in conditions of a decrease in the general or local immuno-protective forces of the macroorganism.

Anaerobic infection, regardless of the location of the focus, has a number of very characteristic clinical signs. These include:

• erasure of local classic signs of infection with a predominance of symptoms of general intoxication;
• localization of the focus of infection in the habitats of anaerobes;
• an unpleasant putrefactive odor of exudate, which is a consequence of anaerobic oxidation of proteins;
• the predominance of the processes of alterative inflammation over the exudative with the development of tissue necrosis;
• gas formation with development of emphysema and crepitation of soft tissues due to the formation of poorly soluble in water anaerobic metabolism products of bacteria (hydrogen, nitrogen, methane, etc.);
• serous-hemorrhagic, purulent-hemorrhagic and purulent exudate with brown, gray-brown color of discharge and presence of small droplets of fat in it;
• staining of wounds and cavities in black;
• the development of infection on the background of long-term use of aminoglycosides.

If the patient has two or more of the above signs, the probability of anaerobic infection in the pathological process is very high.

Purulent-necrotic processes occurring with the participation of anaerobes can be conditionally divided into three clinical groups:

1. The purulent process is local in nature, occurs without significant intoxication, quickly stops after surgical treatment or even without it, patients usually do not need intensive additional therapy.
2. Infectious process in the clinical course practically does not differ from usual purulent processes, proceeds favorably, as usual phlegmon with moderately expressed phenomena of intoxication.
3. Purulent-necrotic process proceeds violently, often maliciously; progresses, occupying vast areas of soft tissue; rapid development of severe sepsis and MI with an unfavorable prognosis of the disease.

Anaerobic infection of soft tissues differs heterogeneity and diversity both in severity of the pathological processes caused by them, and in pathomorphological changes that develop in tissues with their participation. Various anaerobes, as well as aerobic bacteria, can cause the same type of disease. At the same time, the same bacteria under different conditions can cause different diseases. However, in spite of this, several basic clinical and pathomorphological forms of infectious processes involving anaerobes can be identified.

Different types of anaerobes can cause both superficial and deep purulent-necrotic processes with the development of serous and necrotic cellulites, fasciitis, myositis and myonecrosis, combined lesions of several structures of soft tissues and bones.

Clostridial anaerobic infection is marked by aggressive aggressiveness. In most cases, the disease is severe and rapid, with the rapid development of sepsis. Clostridial anaerobic infection develops in patients with various types of soft tissue and bone injuries in the presence of certain conditions, which include massive tissue contamination by the ground, the presence in the wound of areas of necrotic and crushed, bloodless tissues, the presence of foreign bodies. Endogenous clostridial anaerobic infection occurs in acute paraproctitis, after operations on the abdominal organs and lower extremities in patients with obliterating vascular diseases and diabetes mellitus. Less common is an anaerobic infection that develops as a result of a human or animal bite, injecting drugs.

Clostridial anaerobic infection occurs in the form of two major pathomorphological forms: cellulitis and myonecrosis.

Clostridial cellulite (creping cellulite) is characterized by the development of necrosis of subcutaneous or intermuscular tissue in the wound area. It proceeds relatively favorably. Wide timely dissection of the wound and excision of nonviable tissues in most cases ensures recovery.

In patients with diabetes and obliterating diseases of the vessels of the lower limbs, the chances of a favorable outcome of the disease are less likely, since in the form of cellulitis the infectious process proceeds only at the first stages, then the purulent-necrotic lesion of tissues quickly passes to deeper structures (tendons, muscles, bones). A secondary gram-negative anaerobic infection is associated with the involvement of the whole complex of soft tissues, joints and bone structures into the purulent-necrotic process. The moist gangrene of the limb or its segment is formed, which is why it is often necessary to resort to amputation.

Clostridial myonecrosis (gas gangrene) is the most severe form of anaerobic infection. The duration of the incubation period is from several hours to 3-4 days. There is a strong, burgeoning pain in the wound, which is the earliest local symptom. The state remains unchanged. Later, there is progressive swelling. The wound becomes dry, a malodorous discharge with bubbles of gas appears. The skin acquires a bronze color. Quickly formed intradermal blisters with serous-hemorrhagic exudate, foci of moist necroses of skin of purplish-cyanotic and brown color. Gaseous formation in tissues is a common sign of anaerobic infection.

In parallel with local signs, the general condition of the patient also worsens. Against the backdrop of massive endotoxicosis, the processes of dysfunction of all organs and systems with the development of severe anaerobic sepsis and septic shock, from which patients die, if surgical care in full will not be provided in time, are rapidly growing.

A characteristic sign of infection is the defeat of the necrotic process of muscles. They become flabby, dull, bleed badly, do not shrink, acquire a dirty brown color and have a consistency of "boiled meat". With the progression of the process, anaerobic infection quickly passes to other muscle groups, neighboring tissues with the development of gas gangrene.

The rare cause of clostridial myonecrosis are injections of medications. The treatment of such patients is a difficult task. Saving lives are possible units of patients. One of these cases is illustrated by the following case history.

Anaerobic streptococcal cellulitis and myositis occur as a result of various wounds of soft tissues, surgical operations and manipulations. They are caused by Gram-positive facultative anaerobes Streptococcus spp. And anaerobic cocci (Peptostreptococcus spp., Peptococcus spp.). The disease is characterized by the development in the early stages of predominantly serous, and late necrotic cellulite or myositis and proceeds with symptoms of severe intoxication, often turning into septic shock. Local symptoms of infection are erased. Edema of tissues and hyperemia are not expressed, fluctuations are not determined. Gas formation occurs rarely. With necrotic cellulite, cellulose looks faded, bleeds badly, is gray in color, and is abundantly impregnated with serous and serous-purulent exudate. Skin covers are involved in the inflammatory process again: there are cyanotic spots with uneven edges, blisters with serous contents. Affected muscles look edematous, poorly contracted, impregnated with serous, serous-purulent exudate.

Due to the scarcity of local clinical signs and the prevalence of symptoms of severe endotoxicosis, surgery is often delayed. Timely surgical treatment of the inflammatory focus with intensive antibacterial and detoxification therapy quickly interrupts the course of anaerobic streptococcal cellulite or myositis.

Synergistic necrotic cellulite is a severe, rapidly progressive purulent-necrotic cellulose disease caused by associative nonclostridial anaerobic infection and aerobes. The disease proceeds with uncontrollable destruction of cellulose and secondary involvement of adjacent tissues (skin, fascia, muscles) in the purulent-necrotic process. Skin is most often involved in the pathological process. Appear purple-cyanotic discharge spots without a clear boundary, which later turn into moist necrosis with ulceration. With the progression of the disease, extensive arrays of various tissues and, above all, muscles are involved in the infectious process, non-clostridial gangrene develops.

Necrotic fasciitis is a synergistic anaerobic-aerobic rapidly progressive purulent necrotic process with damage to the superficial fasciae of the body. In addition to anaerobic neklostridialnoy infection pathogens are often streptococci, staphylococci, enterobacteria and Pseudomonas aeruginosa, determined, as a rule, in association with each other. In most cases, the underlying areas of fiber, skin, and superficial muscle layers are involved in the inflammatory process again. Typically, necrotizing fasciitis develops after a soft tissue injury and surgical interventions. The minimal external signs of infection usually do not correspond to the severity of the patient's condition and the massive and widespread destruction of tissues that are detected intraoperatively. Delayed diagnosis and later surgery often lead to a fatal outcome of the disease.

Fournier syndrome (Fournier, J., 1984) is one of the varieties of anaerobic infection. It is manifested by progressive necrosis of the skin and deep tissue of the scrotum with rapid involvement of the perineum, pubic, and penis into the skin process. Often, moist anaerobic gangrene of perineal tissue (gangrene Fournier) is formed. The disease develops spontaneously or as a result of a minor injury, acute paraproctitis or other purulent perineal diseases and occurs with severe symptoms of toxemia and septic shock. Often it ends with the death of the sick.

In a real clinical situation, especially in the late stages of the infectious process, it is sometimes difficult to distinguish between the above described clinical and morphological forms of diseases caused by anaerobes and their associations. Often in the course of surgical intervention, several anatomical structures are immediately affected as necrotic fasciolitis or fasciomyositis. Often the progressive nature of the disease leads to the development of non-clostridial gangrene with the involvement of the entire thickness of soft tissues in the infectious process.

Purulent necrotic process caused by anaerobes can spread to soft tissues from the internal organs of the abdominal and pleural cavities affected by the same infection. One of the factors predisposing to this is inadequate drainage of deep purulent focus, for example, with empyema of the pleura and peritonitis, in the development of which anaerobes participate in almost 100% of cases.

Anaerobic infection is characterized by a violent onset. The symptoms of severe endotoxicosis usually come to the fore (high fever, chills, tachycardia, tachypnea, lack of appetite, inhibition, etc.), which often 1-2 days ahead of the development of local signs of the disease. At the same time, a part of the classic symptoms of purulent inflammation (edema, hyperemia, soreness, etc.) falls out or remains hidden, which complicates timely prehospital and sometimes intrahospital diagnostics of anaerobic phlegmon and delays the beginning of surgical treatment. It is characteristic that often the patients themselves do not connect their "malaise" to the local inflammatory process until a certain time.

In a significant number of cases, especially with anaerobic necrotic fasciolitis or myositis, when only mild hyperemia or swelling of the tissues in the absence of fluctuation predominate in the local symptomatology, the disease proceeds under the mask of another pathology. These patients are often hospitalized with a diagnosis of erysipelas, thrombophlebitis, lymphovenous insufficiency, ileofemoral thrombosis, deep vein thrombosis, pneumonia, and others, and sometimes to non-surgical departments of the hospital. The late diagnosis of severe soft tissue infection is fatal for many patients.

How is anaerobic infection recognized?

Anaerobic infection of soft tissues differentiates with the following diseases:

• purulent-necrotic lesions of soft tissues of other infectious etiology;
• various forms of erysipelas (erythematous-buleznoy, bulezno-hemorrhagic);
• hematomas of soft tissues with intoxication phenomena;
• bladder dermatoses, severe toxic dermis (polymorphic exudative erythema, Stephen-Johnson syndrome, Lyell syndrome, etc.);
• deep vein thrombosis of the lower limbs, ileofemoral thrombosis, Paget-Shreter syndrome (subclavian vein thrombosis);
• syndrome of prolonged crushing of tissues in the early stages of the disease (at the stage of purulent complications, the attachment of anaerobic infection is determined, as a rule);
• frostbite of II-IV degree;
• gangrenous-ischemic changes of soft tissues on the background of acute and chronic thrombobliterating diseases of the arteries of the extremities.

Infectious emphysema of soft tissues, which develops as a result of the vital activity of anaerobes, must be differentiated from the emphysema of another etiology associated with pneumothorax, pneumoperitoneum, perforation of the hollow organs of the abdominal cavity into retroperitoneal tissue, surgical procedures, washing of wounds and cavities with hydrogen peroxide solution, etc. In addition to crepitation Soft tissues usually lack local and general signs of anaerobic infection.

The intensity of the purulent-necrotic process during anaerobic infection depends on the nature of the interaction of the macro- and microorganism, and on the possibilities of immune defense to resist the factors of bacterial aggression. Lightning anaerobic infection is characterized by the fact that already during the first day a widespread pathological process develops that affects tissues on a large extent and is accompanied by the development of severe sepsis, uncorrected PON and septic shock. This malignant variant of infection leads to the death of more than 90% of patients. In the acute form of the disease, these disorders develop in the body for several days. Subacute anaerobic infection is characterized by the fact that the relationship between the macro- and microorganism is more balanced, and with the timely initiation of complex surgical treatment, the disease has a more favorable outcome.

Microbiological diagnosis of anaerobic infection is extremely important not only in connection with scientific interest, but also necessary for practical needs. Until now, the clinical picture of the disease is the main method of diagnosing anaerobic infection. However, only microbiological diagnosis with the identification of an infectious agent is likely to give an answer about participation in the pathological process of anaerobes. Meanwhile, the negative response of the bacteriological laboratory does not in any way reject the possibility of anaerobic involvement in the development of the disease, since according to some data about 50% of anaerobes are uncultivated.

Anaerobic infection is diagnosed by modern high-precision methods of indication. These include, first of all, gas-liquid chromatography (GLC) and mass spectrometry, based on the registration and quantitative determination of metabolites and volatile fatty acids. The data of these methods correlate with the results of bacteriological diagnosis in 72%. The sensitivity of GLC is 91-97%, specificity is 60-85%.

Other promising methods for the isolation of pathogens-anaerobes, including those from the blood include the Lachema, Bactec, Isolator systems, the coloring of preparations for the detection of bacteria or their antigens in the blood of acridine yellow, immunoelectrophoresis, immunoenzymatic analysis, and others.

An important task of clinical bacteriology at the present stage is the expansion of studies of the species composition of pathogens with the identification of all species involved in the development of the wound process, including anaerobic infection.

It is believed that most of the infections of soft tissues and bones have a mixed, polymicrobial nature. According to VP Yakovlev (1995), with extensive purulent soft tissue diseases, obligate anaerobes occur in 50% of cases, in combination with aerobic bacteria in 48%, in monoculture anaerobes are detected only in 1.3%.

However, it is difficult to determine the true ratio of the species composition with the participation of facultative-anaerobic, aerobic and anaerobic microorganisms in practice. To a large extent, this is due to the difficulty in identifying anaerobic bacteria due to some objective and subjective reasons. The first one can be attributed to the capriciousness of anaerobic bacteria, their slow growth, the need for special equipment, high-nutrient media with specific additives for their cultivation, etc. To the second, there are significant financial and time costs, the need for strict implementation of the protocols of multi-stage and multiple studies, and a shortage of qualified specialists.

Nevertheless, in addition to academic interest, the identification of anaerobic microflora is of great clinical importance both in determining the etiology of the primary purulent necrotic focus and sepsis, and in constructing therapeutic tactics, including antibiotic therapy.

Below we demonstrate the standard schemes for studying the microflora of purulent focus and blood in the presence of clinical signs of anaerobic infection, used in the bacteriological laboratory of our clinic.

Each study begins with a Gram stain of the smear-print from the deep tissues of the purulent focus. This study is one of the methods for rapid diagnosis of wound infections and can give an approximate answer within one hour about the nature of the microflora present in the purulent focus.

It is necessary to use the means of protecting microorganisms from the toxic effects of oxygen for which they use:

• microanoisate for cultivation of crops;
• commercial gas-generator packages (GasPak or HiMedia) to create conditions for anaerobiosis;
• anaerobiosis indicator: planting P. Aeruginosa on Simons citrate under anaerobic conditions (P. Aeruginosa does not utilize citrate, and the color of the medium does not change).

Immediately after the operation, smears and biopsy specimens from deep sections of the wound taken from one locus are delivered to the laboratory. For transportation of samples, special transport systems of several types are used.

If there is a suspicion of bacteremia, the blood is sifted in parallel into 2 vials (10 ml each) with commercial media for aerobic and anaerobic microorganisms.

Sowing is carried out by disposable plastic loops on several media:

1. on the freshly broken Schadler blood agar with the vitamin K + hemin complex for cultivation in a microanoaerostat. In the initial seeding, a disk with kanamycin is used to create elective conditions (most anaerobes are naturally resistant to aminoglycosides);
2. 5% blood agar for culturing under aerobic conditions;
3. on enrichment medium for cultivation in a microanero-aerostate (the probability of pathogen release is increased, thioglycolic or iron-sulfite is suspected for a clostridial infection.

Microanoaerostat and a 5% blood agar plate are placed in a thermostat and incubated at +37 C for 48-72 h. The smears delivered on the glasses are stained with Gram. It is advisable during the operation to take a few strokes of the wound detachable.

Already with microscopy in a number of cases it is possible to make a presumptive conclusion about the nature of the infection, since certain types of anaerobic microorganisms have a characteristic morphology.

The acquisition of a pure culture serves as confirmation of the diagnosis of clostridial infection.

After 48-72 hours of incubation, grown in aerobic and anaerobic conditions, the colonies are compared by their morphology and by the results of microscopy.

Colonies grown on Shedler agar are checked for aerotolerance (several colonies of each type). They are scattered in parallel by sectors into two cups: with Shedler agar and 5% blood agar.

Colonies grown on the relevant sectors under aerobic and anaerobic conditions are considered to be indifferent to oxygen and are examined according to existing techniques for facultative anaerobic bacteria.

Colonies grown only under anaerobic conditions are regarded as obligate anaerobes and identified, given:

• morphology and size of colonies;
• presence or absence of hemolysis;
• presence of pigment;
• growing into agar;
• catalase activity;
• generic sensitivity to antibiotics;
• cell morphology;
• biochemical features of the strain.

Significantly facilitates the identification of microorganisms the use of commercial test systems containing more than 20 biochemical tests that can determine not only the genus, but also the type of microorganism.

Micro preparations of some types of anaerobes, isolated in pure culture are presented below.

Detection and identification of an anaerobic pathogen from blood is possible in rare cases, such as P. Niger culture, isolated from the patient's blood with a picture of severe wound anaerobic sepsis against the background of phlegmon of the thigh.

Sometimes in the association of microorganisms there may be contaminants that do not have an independent etiological role in the infectious-inflammatory process. The isolation of such bacteria in monoculture or in associations with pathogenic microorganisms, especially when analyzing biopsies from the deep sections of the wound, may indicate a low nonspecific resistance of the organism and, as a rule, is associated with a poor prognosis of the disease. Similar results of bacteriological investigation are not uncommon in severe weakened patients, in patients with diabetes mellitus, with immunodeficiency states against a background of various acute and chronic diseases.

In the presence of a purulent focus in soft tissues, bones or joints and the clinical picture of anaerobic infection (clostridial or non-clostridial), the overall frequency of anaerobic release is 32%, according to our data. The frequency of detection of obligate anaerobes in the blood for these diseases is 3.5%.

How is anaerobic infection treated?

Anaerobic infection mainly treats surgical intervention methods and complex intensive therapy. At the heart of surgical treatment is radical GOOGO with subsequent re-treatment of a large wound and the closure of its accessible plastic methods.

The time factor in the organization of surgical care plays an important, sometimes crucial, role. The delay in the operation leads to the spread of the infection to large areas, worsening the patient's condition and increasing the risk of the intervention itself. The steadily progressing nature of the course of anaerobic infection is an indication for emergency or urgent surgical treatment, which should be performed after a short-term preliminary preoperative preparation consisting in the elimination of hypovolemia and gross violations of homeostasis. In patients with septic shock, surgical intervention is possible only after stabilizing blood pressure and resolving oligoanuria.

Clinical practice has shown that it is necessary to abandon the so-called "lamp-like" incisions, widely accepted decades ago and not forgotten by some surgeons, without necrectomy. Such a tactic leads to the death of patients in almost 100% of cases.

During the surgical treatment, it is necessary to perform a wide dissection of tissues affected by infection, with the entry of incisions to the level of visually unchanged sites. The spread of anaerobic infection is marked by aggressive aggression, overcoming various barriers in the form of fascia, aponeuroses and other structures, which is not typical for infections that occur without the dominant participation of anaerobes. Pathomorphological changes in the focus of infection can be extremely heterogeneous: the areas of serous inflammation alternate with foci of superficial or deep tissue necrosis. The latter can be removed from each other for considerable distances. The maximum pathological changes in the tissues in some cases are detected far from the entrance gate of the infection.

In connection with the marked features of the spread in anaerobic infections, a thorough revision of the inflammatory focus with a broad mobilization of skin-fat and skin-fascial flaps, dissection of fascia and aponeuroses with revision of intermuscular, paravasal, paraneural fiber, muscle groups and each muscle separately. Insufficient revision of the wound leads to an underestimation of the prevalence of phlegmon, the volume and depth of tissue damage, which leads to insufficient full of GOOG and inevitable progression of the disease with the development of sepsis.

At GOOGO, it is necessary to remove all non-viable tissues regardless of the extent of the lesion. Foci of the skin of pale-cyanotic or crimson coloration are already devoid of blood supply due to vascular thrombosis. They should be removed by a single unit with the underlying fatty tissue. Also, all affected areas of the fascia, aponeurosis, muscle and intermuscular tissue are to be excised. In areas adjacent to serous cavities, large vascular and nerve trunks, joints, with nekrektomii need to exercise a certain restraint.

After the radical GOHO, the edges and bottom of the wound must be visually unchanged tissues. The area of the wound after the operation can occupy from 5 to 40% of the surface of the body. Do not be afraid of the formation of very large wound surfaces, since only complete necroctomy is the only way to save the patient's life. Palliative same surgical treatment inevitably leads to progression of phlegmon, syndrome of systemic inflammatory response and worsening of disease prognosis.

With anaerobic streptococcal cellulite and myositis in the stage of serous inflammation, surgical intervention should be more restrained. Wide dilution of skin-fat flaps, circular exposure of a group of affected muscles with the dilution of intermuscular tissue is sufficient to arrest the process with adequate intensive detoxification and directed antibacterial therapy. With necrotic cellulitis and myositis, surgical tactics are similar to those described above.

In clostridial myositis, depending on the extent of the lesion, the muscle, group or several muscle groups, non-viable parts of the skin, subcutaneous fat and fascia are removed.

If a significant lesion of tissues (gangrene or the possibility of the latter) is detected during revision of the operating wound with insignificant perspectives of retaining the functional capacity of the limb, then in this situation amputation or limb exacerbation is indicated. A radical intervention in the form of a truncated limbs should also resort in patients with extensive tissue damage one or more of the segments with symptoms of severe sepsis and MODS nekorrigiruemoy, when the prospect of limb salvage is fraught with loss of life of the patient, as well as fulminant anaerobic infections.

Amputation of an extremity at anaerobic infection has the features. It is carried out in a circular fashion, without the formation of skin-muscle flaps, within the healthy tissues. To obtain a longer limb stump, AP Kolesov et al. (1989) suggest amputation at the border of the pathological process with dissection and dilution of the soft tissues of the stump. In all cases, the stump wound is not sutured, openly with loose tamponade ointments on a water-soluble basis or with iodophor solutions. The group of patients who have limb amputation is the most severe. Postoperative lethality, despite the ongoing intensive care, remains high - 52%.

Anaerobic infection is characterized by the fact that the inflammation has a prolonged nature with a delay in the phase change of the wound process. The phase of cleansing the wound from necrosis is sharply tightened. The development of granulations is delayed due to the polymorphism of the processes occurring in soft tissues, which is associated with gross microcirculatory disorders, secondary infection of the wound. With the same is the need for repeated surgical treatment of pyo-necrotic focus (Fig. 3.66.1), in which the removal is carried secondary necrosis, the disclosure of new purulent streaks and pockets, careful readjustment wound using additional methods of feedback (ultrasonic cavitation treatment pulsating jet antiseptics, ozonation, etc.). The progression of the process with the spread of anaerobic infection to new sites serves as an indication for an emergency repeated HOGO. Refusal of terminal necrectomy is possible only after persistent relief of the local pyoinflammatory process and SIRS phenomena.

The nearest postoperative period in patients with severe anaerobic infection takes place in the intensive care unit, where intensive detoxication therapy, antibiotic therapy, treatment for multiple organ dysfunction, adequate analgesia, parenteral and enteral nutrition, etc. The patient is referred to the surgical department as a positive dynamics during the wound process, the completion of the stage of repeated surgical treatment of the purulent focus, and sometimes also of the plastic ones atelstv resistant clinical and laboratory phenomena elimination OPA.

Antibiotic therapy is an important link in the treatment of patients with a disease such as anaerobic infection. Given the mixed microbial etiology of the primary purulent-necrotic process, first of all, preparations of a wide spectrum of action, including antianaerobic drugs, are prescribed. The most commonly used combinations of drugs: cephalosporins II-IV generation or fluoroquinolones in combination with metronidazole, dioxidine or clindamycin, carbapenems in monotherapy.

Control over the dynamics of the course of the wound process and sepsis, microbiological monitoring of the wounds and other biological media that are detachable from the wounds allow making timely adjustments to the composition change, dosage and methods of administration of antibiotics. So, during treatment of severe sepsis against an anaerobic infection, antibiotic regimens can vary from 2 to 8 or more times. Indications for its abolition are persistent relief of inflammatory phenomena in primary and secondary purulent foci, wound healing after plastic surgery, negative results of blood cultures and absence of fever for several days.

An important component of complex surgical treatment of patients with anaerobic infection is the local treatment of the wound.

The use of this or that bandage is planned depending on the stage of the wound process, pathomorphological changes in the wound, the type of microflora, and also its sensitivity to antibiotics and antiseptics.

In the first phase of the wound process in the case of anaerobic or mixed infection, the choice drugs are ointments on a hydrophilic basis with an anti-anaerobic effect - dioxycol, streptonitol, niticide, iodopyron, 5% dioxin ointment, etc. If there are gram-negative flora in the wound, and antiseptics - 1% solutions of iodophores, 1% solution of dioxidine, solutions of miramistine, sodium hypochlorite, etc.

In recent years, we have widely used modern application-sorption therapy for wounds with biologically active swelling sorbents of multicomponent action on the wound process such as lysosorb, colladia sorb, diotevin, anilodiothein, etc. These agents cause pronounced anti-inflammatory, hemostatic, antimicrobial, antimicrobial effect on virtually all species bacterial flora, allow necrolysis, transform the wound detachable into a gel, sorb and remove toxins, decay products and micro nye body outside of the wound. The use of biologically active drainage sorbents allows in the early period to stop the purulent necrotic process, inflammatory phenomena in the wound area and prepare it for plastic closure.

The formation of extensive wound surfaces arising from the surgical treatment of a common purulent focus creates a problem of their rapid closure by various types of plastics. Perform the plastic surgery as soon as possible, as far as the condition of the wound and patient allows. Practically, it is possible to perform the plastic surgery not earlier than the end of the second - the beginning of the third week, which is associated with the above described features of the wound process during anaerobic infection.

Early plasty of the purulent wound is considered one of the most important elements of the complex surgical treatment of anaerobic infection. Rapid elimination of extensive wound defects, through which a massive loss of proteins and electrolytes is carried out, wound contamination with hospital polyantibiotic-resistant flora involving tissues in the secondary purulent-necrotic process is pathogenetically justified and necessary surgical intervention aimed at treating sepsis and preventing its progression.

In the early stages of plastic surgery, simple and least traumatic methods should be used, which include plastic with local tissues, dosed tissue stretching of tissues, ADP, a combination of these methods. Complete (one-stage) cutaneous plasty can be performed in 77.6% of patients. In the remaining 22.4% of patients, the wound defect in connection with the peculiarities of the course of the wound process and its vastness can be closed only in stages.

The lethality in the group of patients who underwent a complex of plastic interventions was almost 3.5 times lower than in the group of patients who did not make plastic or performed late in the period, respectively, 12.7% and 42.8%.

The total postoperative mortality in severe anaerobic infection of soft tissues, with the prevalence of purulent necrotic focus on an area of more than 500 cm ^2, is 26.7%.

Knowledge of the clinical features of the flow allows a practical surgeon at an early stage to identify such a life-threatening disease as anaerobic infection and plan a set of response diagnostic and treatment measures. Timely radical surgical treatment of an extensive purulent-necrotic focus, repeated stage necrosectomy, early cutaneous plastic in combination with multicomponent intensive therapy and adequate antibacterial treatment can significantly reduce the lethality and improve the results of treatment.