STAPHYLOCOCCUS

From Big Medical Encyclopedia

STAPHYLOCOCCUS (Greek staphyle a bunch + kokkos grain) — motionless gram-positive bacteria this. Micrococcaceae of the sort Staphylococcus. Page — the opportunistic pathogenic bacteriums causing diseases in persons with reduced immunity.

Pages were opened in 1880 independently from each other by L. Pasteur and A. Ogston. The generic name of Staphylococcus was given by A. Ogston, and more detailed description of representatives of a sort is made in 1884 by A. J. F. Rosenbach.

Fig. 8. Staphylococcus aureus pure growth; coloring across Gram; X 800.

S.'s cells have the correct spherical shape to dia. 0,5 — 1,5 microns, share in several planes, forming the accumulations reminding clusters (tsvetn. fig. 8). The main components of a cell wall of S. — peptidoglikan (a synonym: mukopeptid, murein) and ribit-or glitserinteykhoyevy to - you. Contents guanine + tsitozin in DNA makes 30 — 40 mol of %.

Page — optional anaerobe bacterias (see), but more quickly and plentifully grow in the presence of oxygen. At cultivation in aerobic conditions of S. need amino acids and vitamins, in anaerobic — demand in addition uracil and the fermented sources of carbon. A temperature optimum of growth 35 — 40 °, but can grow in an interval 6,5 — 46 °; the optimum of pH 7,0 — 7,5, is possible growth within pH 4,2 — 9,3.

Pages produce a catalase; the majority of strains form methyl-acetyl carbinol on the Wednesday with glucose — positive reaction of Foges — Proskauera (see. Fogesa — Proskauera reaction ), emit ammonia with a growth in argininovy broth, recover nitrates to nitrites or gaseous nitrogen, actively hydrolyze proteins, gippurat, fats and twins. Pages ferment glucose in anaerobic conditions with education milk to - you and split many carbohydrates in aerobic conditions (end products — acetic to - that and insignificant amount of carbonic acid); esculin and starch, as a rule, do not hydrolyze; the indole is not formed. Many strains of S. synthesize carotinoid pigments, and also various extracellular enzymes and toxins. According to the classification approved in 1976. The international subcommittee on taxonomy of stafilokokk and micrococci, the sort Staphylococcus includes 3 look: S. aureus, S. epidermidis and S. saprophyticus; the greatest interest for medicine and veterinary science represents the first look.

S. aureus differs from two other types in a row biol. signs, from to-rykh the greatest differential and diagnostic value have the following: existence of a plazmokoagulaza (koagulazopozitivny) and a thermostable nuclease (DNA-ase), and also ability to ferment a mannitol in anaerobic conditions. Also products of a golden pigment, enzymes are characteristic of S. aureus (hyaluronidase, fibrinolysin, a letsitovitellaza, lizotsimpodobno-go enzyme, etc.) and exotoxins (hemolysins an alpha a beta, scale, a delyia, leukocidin, enterotoxins A, B, C, D, E, F, eksfoliatin And, In). Enzymes and toxins C. play a pathogenetic role in development of a staphylococcal infection (see). The role of the enterotoxins causing symptomatology of food poisonings of a staphylococcal etiology is most proved (see. Toxicoinfections food ), and coloenterites (see), and also the eksfoliatin causing exfoliative dermatitis of newborn children (see. Rittera dermatitis exfoliative ).

The protein A reacting with Fc-fragments of serumal IgG of the person and the majority of mammals is a part of a cell wall of S. aureus. Many S. are capable to formation of superficially located capsule, the main component a cut are to the urono-Vyya to - you. In the conditions of an experimental infection on animals protein A and capsular material show antiphagocytic activity.

The majority of strains of S. aureus has the expressed resistance to antibiotics. Resistance to the majority of these drugs is controlled by the genes located on plasmids (see) that provides a possibility of broad exchange of determinants of stability between separate strains. Resistance to antibiotics considerably is defined by the width of their use in medical practice. For marking of strains of S. aureus during the carrying out epidemiological analysis (see) the method is applied lysotypies (see). It is based on use of 22 phages of the international set with a narrow range of lytic activity. According to lytic similarity a phage are divided into 3 groups, and 4 phages are extra group. The majority of strains of S., for to-rykh multiple resistance to antibiotics is characteristic, treat the III fagogruppa.

S. epidermidis and S. saprophyticus long time considered nonpathogenic S. Odnako this point of view became outdated though the specific weight of these S. which do not have a plazmokoagulaza (koagulazonegativny) in pathology of the person is much less, than strains of S. aureus. The main differentsialno - the diagnostic characters distinguishing S. saprophyticus from S. epidermidis are ability of the first to oxidize a mannitol and trehalose, absence at them fosfatazny activity, novobiocin resistance. Factors of pathogenicity of these S. are studied insufficiently. Are found in S. epidermidis succinate-oksidazny the factor showing selective activity concerning mitochondrions of a liver of mammals, the toxin destroying tissues of an eye, and elastase. S. saprophyticus has selectivity to be adsorbed on epithelial cells of urinary tract. Multiple resistance to antibiotics at S. epidermidis, S. saprophyticus meets less than at S. aureus. Methods biol are applied to intraspecific differentiation of koagulazonegativny S. typings (see. Bioassey ).

In the second half of the 70th g of 20 century 10 new types of S. allocated from the person and animals were described. Representatives of a look S. intermedius and a part of cultures of S. hyicus are koagulazopozitivny, all strains of other types (S. capitis, S. haemolyticus, S. hominis, S. warned, S. cohnii, S. xylosus, S. simulans, S. sciuri) — koagulazonegativ-ny. Though expanded classification of S. did not gain still official recognition, it gained rather wide popularity among specialists.

The main biotopes of S. in an organism of the owner are skin and mucous membranes (see Mikroflor of the person). However during the developing of a staphylococcal infection also other bodies and fabrics can be surprised. Representatives of separate types of S. have main owners, but S.'s distribution in the nature is not always limited to them. The main owner of S. epidermidis, S. hominis, S. capitis is the person; S. aureus, S. saprophyticus, S. cohnii, S. simulans, S. haemolyticus, S. warneri — the person and other primacies; S. intermedius — predators, S. hyicus — artiodactyl; S. xylosus, S. sciuri — all mammals. S. xylosus and S. sciuri are capable, apparently, to free dwelling in the nature since they are quite often found in the soil and water. Within a type of S. aureus it was succeeded to allocate 4 ecological types, the main owners to-rykh are the person and animals. Among cultures of S. aureus of human ecotype there is a group of strains, endemic for hospitals. These S. most often are the reason of sporadic cases and the epidemic outbreaks of an intrahospital staphylococcal infection (see. Intrahospital infections ). They are characterized, as a rule, by multiple medicinal resistance (see. Medicinal stability of microorganisms ) and belonging to I and III fagogruppa. S. aureus is capable to strike any body or body tissue of the person in this connection causes many diseases (see. Staphylococcal infection ). The role of other types of S. in pathology of the person is up to the end not found out.

Microbiological diagnosis of a staphylococcal infection includes allocation of the activator by crops of the studied material on an elective medium, identification of the isolated strain and definition of its sensitivity to antibiotics (see. Staphylococcal infection).

See also Pyogenic bacteria , Cocci .



Bibliography: Akatov A. K. and Zueva of V. S. Stafilokokki, M., 1983; Ignatov V. V. Biochemistry of staphylococcus, Saratov, 1975; With m and r N about in and A. M., T r about I sh to and A. A. and Paderin's N of E. M. Mikrobiologiya and prevention of staphylococcal infections, JI., 1977, bibliogr.; Staphylococcus and a staphylococcal infection, under the editorship of H. R. Ivanova, Saratov, 1980; Rosenbach A. J. F. Mikro-Organismen bei den Wund-Infek-tions-Krankheiten des Menschen, Wiesbaden, 1884; The staphylococci, ed. by J. O. Cohen, N. Y., 1972; Staphylococci and staphylococcal diseases, ed. by J. Jeljaszewicz, Stuttgart — N. Y., 1976; Staphylococci and staphylococcal infections, ed. by J. Jeljaszewicz, Stuttgart — N. Y., 1981.


A. K. Akatov; M. Ya. Korn (tsvetn. rice).

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