STREPTOCOCCI

From Big Medical Encyclopedia

STREPTOCOCCI — bacteria of the sort Streptococcus, this. Streptococcaceae.

For the first time S. are found by T. Billroth in 1874 at an ugly face and wound fevers.

Fig. 9. Streptococcus pyogenes pure growth; coloring across Gram; X 800.

C. — spherical or oval cells of 0,6 in size — 1,0 microns forming chains of various length (tsvetn. fig. 9), gram-positive, optional anaerobe bacterias (see). Distinguish beta and hemolitic (Str. hemolyticus), alpha and hemolitic (Str. viridans) and gamma and not hemolitic Pages. In pathology of the person the beta and hemolitic S. carried in 1958 according to V. D. Belyakov's proposal et al. to ecological group of obligate parasites of the person have the greatest value.

On antigenic distinctions of polysaccharides C. are divided R. S. Lancefield into groups. 20 groups C. are known, to-rye designate capital lat. letters (from And to V). A row alpha and gamma streptococci did not enter into one group. Pages of different groups differ on a habital in the nature, pathogenicity for the person, to the nature of hemolysis and biochemical indicators. The main criterion in S.'s differentiation — belonging to a certain group. For the person pathogens generally beta and hemolitic S. of group A (Str. pyogenes) — causative agents of quinsies (see), hron. tonsillitis (see), scarlet fevers (see), sepsis (see), wound fevers of skin and other fabrics (see. Purulent infection ), acute glomerulonephritis (see), rheumatism (see), ugly faces (see).

Page of group B (Str. agalactiae) cause mastitis (see), urogenital infections at women, sepsis (see) and meningitis (see). Streptococci of groups C, G, H, F often find in a mucous membrane of a pharynx of the person, including at acute respiratory diseases. Page of group D, or fecal S. (see. Enterococci ) — saprophytes of a large intestine of the person — are known also as causative agents of a subacute bacterial endocarditis (see), infections of an uric path. Streptococci of the H, N, F, K, O groups and the green S. deprived of group antigen sometimes find in blood at a septic endocarditis. Not content of group Str antigen. mutans — one of etiol. factors of caries of teeth at the person (see. Caries of tooth ). Pages of other groups seldom are found in the person, they are pathogens generally for animals.

Virulent S. groups A have the capsule interfering phagocytosis on a surface. The hyaluronic acid (see) which is a part of the capsule, not antigenically. The cell wall of S. consists of three layers. The periblast contains type-specific proteinaceous T - and M-antigens (substances), a number of the not type-specific proteinaceous antigens connected or not connected with M-antigens. Group polysaccharide (A-polysaccharide) constructed of beta N - atsetilglyukozamina and rhamnoses is a part of the interlayer. The inner layer contains peptidoglikan, providing rigidity of a cell wall. The cell wall of S. via the capsule leaves the so-called fimbrias including M-antigen and lipoteykhoyevy to - that, S. providing sticking to a mucous membrane. The cytoplasmic membrane of S. consists of proteins and lipids, protoplasm — of a number of proteins and nucleoproteins. F are found in a number of cultures of S. with - the receptors connecting immunoglobulins for account F with - sites that can lead to nonspecific reactions.

Among β-hemolitic S. of group A more than 70 types are found, representatives to-rykh contain various M-antigens. The factor of opalescence (a factor of opacification) is found in 16 types C. — the type-specific lipoproteinaza, definition a cut can be used for typing of these cultures of Page.

A major factor of virulence of S. of group A is M-antigen. The virulent S.'s cultures, svezhevydelenny from patients, containing M-antigen are formative and to breed in blood of the person. Avirulent cultures, free of M-antigen, are englobed in blood of the person without addition of antibodies against M-antigen of homological type. Pages of group A produce the erythrogene toxin important in a pathogeny scarlet fevers (see). The thermostable fraction of erythrogene toxin stimulates hypersensitivity of the slowed-down type (see. Allergy ). Streptococci of groups A, C and G are produced by S-and Au-strep-tolpziny causing hemolysis of erythrocytes. S-and O-streptolysins destroy also lysosomes of cells that can lead to damage of fabrics. Antibodies to S-streptolysin are not found, but inhibitor in normal blood sera is found. The majority of cultures of S. group of A, C, G synthesizes O-streptolysin, to Krom there are antibodies (see). Page of group A and nek-ry other groups produce deoxyribonucleases of 4 types (And, In, C and D). At streptococcal infections of the person the high level of antibodies is found against a deoxyribonuclease of type B. Streptococci of group A produce hyaluronidases of two types (I and II). Antibodies to hyaluronidase like I in high credits meet at streptococcal infections of the person. The nikotinamidadenindinukleotidaza — the enzyme having cardiotoxic and leykotoksichesky effect is found in S. of group A. Fibrinolitic enzyme Streptokinasa produces S.'s most of group A and nek-ry cultures of groups C and G; the purified drugs of Streptokinasa are used with the therapeutic purpose for dissolution of fibrin in exudates and at vascular fibrinferments (see. Streptoliasum ). Proteinase of streptococci of group A — the proteolytic enzyme received in a crystal look — at experimental animals strikes connecting fabric, a myocardium, a thymus gland, a thymus.

Incidence of acute streptococcal infections is highest during the autumn and winter period and has cyclic character: from a meneniye of incidence are noted every 6 — 7 years. Incidence of a glomerulonephritis in different years and in various territories depends on distribution of nefritogenny types C. Streptococci can cause consecutive infection at virus and others inf. the processes affecting upper airways. Rheumatism and a glomerulonephritis carry to not purulent complications of acute streptococcal infections. According to other data, rheumatism (see), a glomerulonephritis (see) and an ugly face (see) — hron. streptococcal infections. It is confirmed by the following: the disease arises after the acute streptococcal infections caused by S. of group A; constantly antibodies to extracellular products, enzymes and antigens of a microbic cell are found With; availability of antigens C. in blood; the number of the first attacks of rheumatism at treatment of acute streptococcal infections is sharply reduced by penicillin and dyurantny drugs of penicillin, napr, Bicillinum and others, for the prevention of the repeated attacks are successfully used.

Origin various patol. processes at infection with one microorganism — by streptococci of group A — it is finally not found out. Nefritogennye S., causing a glomerulonephritis, treat limited number of types, but these types cause also others patol. processes. The set of various types C. is found at rheumatism. At the same time distinctions between S.'s cultures which are marked out at a glomerulonephritis and rheumatism as a result of definition of their lysis with moderate phages of Page are found. Features of rheumatism and a glomerulonephritis are defined probably by emergence of various autoimmune processes because of existence at S. and in body tissues of the general perekrestnoreagiruyushchy antigens. Developing of scarlet fever or quinsy depends on S.'s toxigenicity and level of anti-toxic immunity (see. Scarlet fever ). Character patol. process is defined also by infection atriums (upper respiratory tract infections or skin) and S.'s distribution in an organism.

Antimicrobic immunity to S. of group A tipospetsifichen also depends on existence of antibodies against M-antigen. Standard immunity remains is long, and M - anti-bodies are found in 20 years after the postponed disease. Vaccines from the whole microbic cells are not applied to prevention and treatment in connection with heavy reactions and the sensibilizing action. Attempts to use the purified drugs of M-antigens of different types C. for immunization did not find practical application. During the development of a method of active immunization against S. groups A carry to the main difficulties: standard specificity of immunity; distribution of a large number of types C. and their frequent change; availability of cross reacting antigens capable to cause autoimmune reactions.

Villages of different groups, except for group D, perish during the heating to t ° 56 ° within 30 min. Corrosive sublimate (1% solution) and phenol (5% solution) S. within 15 min. kill. S.'s cultures well maintain drying, especially in the proteinaceous environment, keep viability in the environment, but quickly lose virulence. Pages of group A are highly sensitive to antibiotics of a penicillinic row and do not gain to them stability (see. Medicinal stability of microorganisms ). These antibiotics act bakteritsidno on S. of group A and other groups, except for group D. Streptocides render on S. groups A bacteriostatic effect, and to them stability is easily developed. A certain percent of cultures of S. is steady also against erythromycin, lincomycin and a nek-eye to other antibiotics.

For S.'s detection on mucous membranes of a pharynx, a nose and in pus the material taken by a tampon is immersed in a semi-fluid agar on a bottom of a test tube where drops of blood of a ram contain. After an incubation within 3 — 4 hours at t ° 37 ° make crops on an agar with blood of a ram. Identification (3-hemolitic S. it is made on the basis of detection on an agar of the characteristic colonies surrounded with an active area and microscopy of the smears painted across Gram (see. Grama method ). Apply precipitation in fluid medium with use of the HCl-extracts received from S. to definition of group C. and blood sera of animal, immunizirovanny S. of different groups, and also S.'s koagglyutination by means of the specific antibodies connected at the expense of Fc-sites with staphylococcus supporting A-squirrels. During the use of a koagglyutination cross-reactions between S. of various groups are possible '. The most accurate results at S.'s identification receive groups A at the use of a precipitation test in gel (see. Immunodiffusion ) with blood sera of animals, antibody-containing to A-polysaccharide after removal of antibodies to other antigens.

S.'s typing groups A on existence of T - or M-antigens is applied during the carrying out the epidemiological analysis (see). Definition of type on T-antigen is made in an agglutination test on glass (Griffits's method) with serums against T-antigen.

During the definition of types on the content of M-antigen apply a precipitation test in fluid medium with the type-specific adsorbed serums containing M-antibodies (a method Lansfild).

Definition of sensitivity to antibiotics is carried out only if the allocated S. do not concern to group A or at contraindications to use of penicillin, to S.'s Krom of group A highly sensitive.

See also Bacteria , Pnevmokokki .

Bibliography: V. D.'s white hares, Khodyrev A. P. and T about t about l I am A. A N. Streptococcal infection, JI., 1978, bibliogr.; Questions of immunology and epidemiology of scarlet fever and streptococcal infections, under the editorship of V. I. Ioffe, JI., 1956; Children's infections, under the editorship of P. V. Smirnov, century 1 — 2, M., 1950; The Guide to microbiological diagnosis of infectious diseases, under the editorship of K. I. Matveev, page 298, M., 1973; Bergey’s manual of determinative bacteriology, ed. by R. E. Buchanan a. N. E. Gibbons, Baltimore, 1975; Pathogenic streptococci, ed. by M. T. Parker, Reed-books, 1979; Streptococci and streptococcal diseases, ed. by L. W. Wannamaker a. J. M. Matsen, N. Y., 1972.


I. M. Lyampert; M. Ya. Korn (tsvetn. fig.).

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