Anaerobic bacterial infections

Anaerobic infection is an infectious process (often a complication of the wound process), caused by anaerobes. Among the pathogens A. and. Two groups of microorganisms are distinguished: spore-forming anaerobes, or clostridia, and non-spore-forming (nonclostridial) anaerobes (see Anaerobes). They are an integral part of normal human microflora, are found in the intestines, organs of the genitourinary system, as well as on the surface of the skin, mucous membranes. Anaerobes of exogenous flora are detected in the soil, in the mass of decomposing organic compounds. An important role is played by such factors as the amount of anaerobes in the wound, the morphology and virulence of the pathogens, the potentiating effect of the microbial associates, etc. Pathogenic properties of anaerobes are realized in the presence of deformed and practically devoid of blood supply of tissue sites, chronic intoxication, accompanied by a decrease in protective reactions of the organism, etc.

Clostridial wound infection can be represented by cellulitis, myositis and myonecrosis or a mixed form. Clostridial cellulitis is characterized by damage to the skin, subcutaneous tissue, as well as perivascular and perineural tissue cases. The most striking clinical sign of cellulite is a sharp swelling of the skin and subcutaneous tissue; Color of skin over the lesion from anemic-pale to saturated-brown. Possible detachment of the epidermis with the formation of blisters containing light yellow or brown exudate without smell. Clostridial myositis and myonecrosis are characterized by local muscle damage; Swelling of the skin and subcutaneous tissue is not typical. In the mixed form of clostridial wound infection, the skin, subcutaneous tissue and especially the muscles are affected. The nature of the changes corresponds to a pronounced cellulitis in combination with a common myonecrosis, especially large muscle masses of the pelvic girdle and lower limbs. This form is a classical gas gangrene and occurs in 55-60% of cases of clostridial lesions. Special clostridial infections are tetanus and botulism.

The development of both clostridial and nonclostridial A. and. Can be fulminant (up to a day after the injury or surgery), acute, or progressive (within 3-4 days), and subacute (more than 4 days).     The clinical picture is diverse, but a number of symptoms can be identified, relatively constant in any form of anaerobic infection. In the area of ​​the lesion, the patient experiences gradually intensifying pains, a febrile condition with a stable high body temperature appears early. Common symptoms associated with intoxication of the body are revealed primarily in the form of dysfunctions. - from euphoria and to a deep coma. There are signs of a circulatory disorder - unstable blood pressure, venous hypotension, blood stasis in internal organs. Developing respiratory failure is accompanied by shortness of breath, a decrease in the concentration of oxygen in the blood.

Almost all the time, hepatic-renal insufficiency, leading to parenchymal jaundice, which can increase due to toxic hemolysis, oliguria and anuria. In the blood, anemia and a decrease in hematocrit, moderate leukocytosis (15-20 × 109 / L), a shift of the leukocyte formula to the left, an increase in ESR are determined.

    

An important feature of A. and. Is the accumulation of gas in the lesion and border zones. By the location of the gas detected on the roentgenogram, one can to a certain extent judge the nature of the anaerobic microflora. For clostridial wound infection, a typically diffuse spread of gas fragmenting the muscle segments or penetrating through loose cellular spaces into segments of the body far removed from the primary focus. For nonclostridial A. and. Typical of the accumulation of gas in the wound area in the form of solitary bubbles or a group of small, but as if united by a common capsule of blisters. In a number of cases on the roentgenogram, the gas is visible above the level of pus in the cavity of the affected organ.

 

The diagnosis

Is based primarily on the evaluation of the clinical picture of the disease. The most important role is assigned to a complex of changes in the lesion focus: the nature of the pain syndrome, the rate of appearance of edema and tissue necrosis, The nature of the exudate, the color of the skin and its temperature, which is decreased with clostridial and increased with non-clostridial infection, crepitation of tissues, etc. The results of bacterioscopy of the wound detachable with the coloring of the drug according to Gram are important. The presence of "coarse", unevenly thickened Gram-positive rods confirms the diagnosis of clostridial infection, and the abundance of coccal microflora is more characteristic of anaerobic nonclostridial or aerobic wound infections.

  

  Differential diagnosis is performed with anaerobic streptococcal myonecrosis, with some forms of putrefactive infection, urinary infiltrates, progressive gangrene of the skin, crepitating cellulite of various etiologies, gangrene in diabetic angiopathy.     Neclostridial A. and. Soft tissue can be manifested by cellulite, fasciitis and myositis (including areas of pronounced myonecrosis), often abundant purulent discharge brown-brown with a sharp, fetid odor, often with gas bubbles and droplets of fat, extensive necrosis Soft tissues. In addition, non-clostridial purulent pleurisy, abscesses of internal organs (lungs, liver, spleen) and brain, peritonitis, postpartum or postabortion metroendometritis, sepsis, septic thrombophlebitis, etc. are possible.

Treatment

    

Treatment of both clostridial and non-clostridial anaerobic wounds is operative: a wide dissection of the lesion and excision of necrotic tissues. Decompression of edematous, deeply located tissues contributes to a wide fasciotomy. The hearth is sanitized as radically as possible, combining it with antiseptic treatment and drainage. In the nearest postoperative period, the wound is left open, it is treated with osmotically active solutions and ointments. If necessary, re-remove the necrosis areas. If the wound infection develops against the background of fracture of the limb bones, the preferred method of immobilization can serve as a gypsum longite. In a number of cases, already in the course of the initial revision of the wound of the limb, such extensive destruction of the tissues is revealed, that the only method of operative treatment is amputation. It is carried out within the limits of healthy tissues, but the stitches on the stump wound are applied no earlier than 1-3 days after the operation, Controlling during this period the probability of recurrence of the infection.

   

 Specific treatment with clostridial infection begins immediately. During the operation, intravenously drip slowly (1 ml / min) treatment dose of polyvalent antigangrenous serum (150,000 IU), diluted in 300-400 ml isotonic sodium chloride solution. Simultaneously, 5 prophylactic doses of serum are administered intramuscularly.

   

 One of the most important components of therapy of A. and. Are antibiotics. Before the determination of the sensitivity of pathogens to antibiotics, wide-spectrum drugs are used. It is also effective to use a combination of antibiotics, for example penicillins (often semisynthetic) and aminoglycosides, cephalosporins and aminoglycosides, etc. Widely used drugs that selectively act on anaerobes: clindamycin (dalacin C), chloramphenicol, metronidazole, carbenicillin, rifampicin, solutions of furagin, dioxidine, etc., as well as hyperbaric oxygenation.

    

The main tasks of the infusion therapy are A.I. Are the maintenance of optimal parameters of hemodynamics, the elimination of microcirculation and metabolism disorders, the achievement of a substitutive and stimulating result. Particular attention is paid to detoxification, using drugs such as haemodesis, neohemodesis, etc., as well as various extracorporeal sorption methods - hemosorption, plasmosorption, etc.