ESCHERICHIA

From Big Medical Encyclopedia

EShERYHIYa (Escherichia) — a genus of bacteria of family of Enterobacteria-seaye. The sort Escherichia includes one:

the type of Escherichia coli combining the kinds of bacteria which are fermenting and not fermenting lactose including without formation of gas, and motionless, known earlier under

the names Paracolon, Alkaleszens — Dispar, etc.

Among E. there is a large number of opportunistic and pathogenic kinds of the bacteria differing on enzymatic properties, antigenic structure, sensitivity to bacteriophages, colicines, degree of antagonistic activity and pathogenicity (see Colibacillus). Existence mobile and motionless (true and repressed) mutants, capsular (with the expressed capsule and the microcapsule) and acapsular forms is characteristic of bacteria of this sort. On dense environments E. forms convex colonies of average size, wet, brilliant, transparent and opaque in a transmitted light, a round form with a smooth edge (smooth forms) or more flat, dry with slightly wavy edge (rough forms); the transparent small colonies reminding colonies of shigellas and salmonellas, and also the mucous large colonies similar to colonies klebsiyell meet. In fluid mediums E. grow diffuzno, sometimes form a deposit or a ring on a wall of a test tube at a surface of the environment. On the differential and selection Endo environments (see Endo Wednesday) laktozopolozhitelny strains form the following colonies: fermenting lactose — dark red color with metallic (ink) luster or without it; poorly, in a slowed-up way fermenting lactose — pink colonies or Wednesdays, slabookrashen-ny at color, or colourless with intensively painted center; not fermenting lactose — colourless, and on Ploskirev's circle (see Ploskirev Wednesday) they form colonies with a yellowish shade, quite often similar to colonies of shigellas.

In slantwise transmitted light of colony E. have a pink-green or oranzhevosery luminescence and accurately expressed very tectonics in parallel of the located circles. On morphological, cultural, enzymatic properties pathogenic and nonpathogenic versions E. from each other do not differ. Search pathogenic E. in the studied material most often it is carried out among a set of colonies nonpathogenic E. — representatives of normal intestinal microflora, that very complicates allocation and identification of activators prick - infections. For the diagnostic and epidemiological purposes it is necessary to carry out the serologic typing E. before definition of a serotype (serovar), since not all serotypes E. the serogroup of the same name pathogens for the person.

Have the greatest pathogenicity (see Colibacillus, To an oli-infection) enterotoxigenic E., producing thermolabile or thermostable enterotoxin (see) or at the same time both, and also enteroinvasive E., the possessing pi-lyam, the called K88, K99, 987P antigens, and factors of adhesion. Are eurysynusic at E. saw type I («the general drank»), the role to-rykh in colonization (settling) of intestines is not known. Enteropathogenic E. coli is caused epidemic acute intestinal esherikhioz (see. To an oli-infection), is more often at early children's age.

Bibliography: Borisov L. B. Enteropathogenic colibacilli and their phage, L., 1976; Bergey’s manual of systematic bacteriology, ed. by J. G. Holt, v. 1, Baltimore — L., 1984; Escherich T.

Die Darmbakterien des Sauglings und ihre Beziehungen zur Physiologie der Verdau-ung, Stuttgart, 1886. I. V. Golubeva.

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