From Big Medical Encyclopedia

MICROBIC LANDSCAPE — the characteristic of a condition of a specific microbic biocenosis (association, community) including data on number of microorganisms, their species composition, numerical and space relationship of microbic populations.

The term «microbic landscape» is entered by S. I. Vinogradsky for the characteristic of a microbic biocenosis of the soil. In medical microbiology the term is used for the characteristic of a condition of difficult natural microbic biocenoses of a body of the person (intestines, skin, etc.), is more rare at a research of simpler microbic associations (purulent wounds, the environment of hospital rooms and so forth). For calculation of total number of microorganisms, components biocenosis (see), use two main ways: the direct microscopic account of microorganisms in drugs and calculation of colonies after seeding of material on dense mediums. Direct calculation of microorganisms under a microscope with increase is impossible about X 1000 at concentration of microorganisms less than 10 6 cells on 1 ml, it does not give the chance to distinguish live and lifeless microorganisms and is complicated with a growth of microorganisms in the form of the microcolonies connected with parts of the environment. Seeding of material on mediums does not provide the simultaneous growth of all microorganisms which are in material because of various requirements to conditions of growth. It is considered to be that even during the seeding on special mediums no more than 10% of the microorganisms found under a microscope come to light.

Identification during the studying of L. S. is necessary for recognition various funkts, options of microorganisms (see. Identification of microbes ), fluctuations and the directed changes as a part of a biocenosis in the course of its development (succession) or at changes in the habitat. Identification on morfol, to signs under a microscope is limited to hl. obr. protozoa. Identification of bacteria requires release of pure growths. In practice during the studying of L. S. are limited to a research of number and a ratio of populations of certain groups of microorganisms.

For a research of a spatial relationship of microbic populations prepare the microscopic drugs allowing to observe microorganisms under natural conditions of dwelling. The particularly important became use of the scanning supermicroscope allowing to observe microorganisms directly in the habitat. The research of character of a spatial relationship of populations of microorganisms can supply with the information and on their ecological relationship as a part of a biocenosis.

In the medical relations the greatest value has studying of a landscape of the microbic biocenoses making normal microflora of a body of the person — biocenoses of an oral cavity, intestines, skin etc. (see. Mikroflora of the person ). Each of these biocenoses is normal characterized by a set of constants, obligatory (obligate) microorganisms, and also the non-constant, changing (optional) microflora. The most accurately found individual variations of M. p, healthy faces are connected with structure of optional flora. Individual distinctions of L. S. are not limited to species composition of microorganisms. So, e.g., from the known serol, options of colibacillus on O-antigen in intestines of the person a little more than 10 are regularly found, strains of other serovariant are accidental finds. At a research of L. S. its characteristic can include properties, important from the medical point of view, of the bacterial populations making a biocenosis — medicinal stability, a bakteriotsinogennost, etc.

The factor maintaining a variety of biocenoses of healthy faces and causing changes of L. S. is constant exchange of microflora. At restriction or a complete elimination of such exchange (astronauts, isolation in sterile cabinets according to medical indications) there is depletion of L. S. of biocenoses due to disappearance of non-constant flora, and also restriction of number of distinguishable populations of the nek-ry bacterial types relating to obligate.

Maintenance of constancy and balance of microbic biocenoses substantially depends on a condition of an organism of the owner. Various patol. states can be the cause of shifts as a part of microbic biocenoses and emergence in biocenoses of atypical microorganisms. Changes of L. S. of biocenoses at the person as a result of radiation defeat — increase in total quantity of microorganisms, increase in a share of microorganisms with pathogenic potentialities (hemolitic gram-negative bacteria, staphylococcus), emergence of colibacillus in an oral cavity, on skin and so forth are known.

The most expressed impact on structure of microbic biocenoses of a body of the person is made by prolonged use of antibacterial drugs, especially a broad spectrum of activity: the structure of microbic biocenoses up to disappearance of obligate microflora can sharply change (see. Dysbacteriosis ). In this case there is a reproduction of stable forms of microorganisms, as a rule, possessing pathogenic potentialities (a pyocyanic stick, proteas, a klebsiyella, yeast-like fungi, etc.) that can lead to crushing focal lesions (e.g., intestines, airways, etc.) and to development of septic states.

The characteristic of microflora received during the studying of L. S. of biocenoses of a body of the person, especially in dynamics can serve as the indicator of an immunoreactive condition of a macroorganism, have predictive value or to be criterion of efficiency of therapeutic influences.

Bibliography: Vinogradsky S. N. Microbiology of the soil, M., 1952; Klempar from Kai N. N. G. A. Autoflor's ishalnova as the indicator of radiation defeat of an organism, M., 1966; Odum Yu. Fundamentals of ecology, the lane with English, page 623, M., 1975; P e p e of t of c of L. G. Znacheniye of normal microflora for a human body, M., 1955; Petrovsky V. G. and M and r to about O. P. Mikroflor of the person is normal also of pathology, M., 1976; Ratiner Yu. A., Bala-kleets V. S. and Golubeva I. V. Prick a serological landscape - florae of excrements of healthy people, Zhurn, mikr., epid, and immun., No. 11, page 112, 1973; R about-s e b u r at T. Microorganisms indigenous to man, N. Y., 1962.

S. S. Belokrysenko.