SALMONELLA

From Big Medical Encyclopedia

SALMONELLA (Salmonella) — a genus of the rhabdoid gram-negative bacteria belonging to a tribe of Escherichieae, the Enterobacteriaceae family.

The generic name of Salmonella (S) was offered in 1900 J. Lignieres in honor of the American researcher Salmon (D. E. Salmon), Bacteria suipestifer which described in 1885, Salmonella cholerae suis called now.

S.'s most pathogens both for the person, and for various animals and birds (see. Salmonellosis ). An exception make S. typhi, S. paratyphi And yes S. hirschfeldii, causing inf. diseases only at people (see. Typhoid , Paratify ). S. schottmuelleri is also the activator inf. diseases, it is preferential at people, but can cause inf. diseases and an epizooty at young growth of cattle and chickens.

Fig. 12. Flagellums and fibers at S. typhi (diffraction pattern).

Page — small sticks with the rounded-off ends from 1 to 3 micron long and 0,5 — 0,8 microns wide, as a rule, mobile, thanks to existence peritrikhialno the located flagellums (see fig. 12) though nek-ry serotypes (serovars), e.g. S. gallinarum, are always not mobile. The dispute and capsules is not formed, gramotritsatelna are painted with all aniline paints. Most quickly they grow at t°35 — 37 °. Optimum concentration of hydrogen ions — 7,2 — 7,5. S.'s most well grows on usual mediums, forming small, with a diameter up to 2 — 4 mm, colonies. Enzymatic properties C. are various and can vary within the same serotype that allows to subdivide them into stable biotypes (biovar). Pages split pectine sugar, glucose, a maltose, a mannitol, rhamnose, sorbite, trehalose; concerning an adonit, salicin, sucrose, glutaminic to - you reactions negative; concerning glycerin, dulcite, an inositol, xylose, lactose, acetate, malonate, a mukat, d-tartrate, i-tartrate and l-tartrate various reactions even at the same serotype of Page are observed. Reaction with methylene red positive (see. Fogesa — Proskauera reaction ). Villages form hydrogen sulfide and do not form an indole, cause hydrolysis of urea (nek-ry and gelatin), do not produce phenyl-lanindezaminazu, have a lysinedecarboxylase and an ornithinedecarboxylase, recover nitrites.

In 1966 Mr. F. Kauffmann subdivided the sort Salmonella into 4 subgenus on the basis of their enzymatic properties, and first of all on ability of growth in the presence of potassium cyanide, at the same time as the III subgenus S. included the bacteria of Arizona which made earlier independent sort. In further S. were subdivided into 5 subgenus — I, II, III, IV, V.

The antigenic structure of S. is difficult. They possess somatic (About) and flagellar (N) antigens; besides, nek-ry antigens from group superficial (or capsular) To - the anti-genes which are localized in the microcapsule covering a cell wall of bacteria can be found in them. O-antigens are lipopolisakharidam (see). Specificity of O-antigen is defined by existence of superficial polisakharidny chains. According to the content of these or those O-antigens of a salmonella divide into the serological groups designated by capital letters of the Latin alphabet (A, B,C,D etc.), at the same time separate antigenic factors designate in the Arab figures (e.g., O-antigen of group A — 1,2,12; O-antigen of group B — 1,4, 5,12,27, etc.). O-antigen termostabilen, maintains t°100 ° within 2,5 hours, slightly collapses autoclaving at t ° 120 ° within 30 minutes, is inactivated by formalin, rezistenten to alcohols and divorced to - there.

N-antigens are proteins. Their specificity is defined by amino-acid structure and molecular structure of protein of flagellums — a flagelina. N-antigens can exist in two serological phases: 1st (specific) and 2nd (nonspecific). Antigenic factors of the 1st phase designate lowercase letters of the Latin alphabet (a, b, with, d etc.), antigens of the 2nd phase — the Arab figures or lowercase letters of the Latin alphabet with the Arab figures (1,2; 1,5; e, n, x; e, n, z15, etc.). N-antigen termolabilen, collapses heating at t ° 75 — 100 °, salt to - that and alcohols, but is steady against formalin. Depending on availability of N-antigens 1 or 2nd of a phase distinguish monophase and diphase serotypes.

Belongs to group of K-antigens Vi-antigen (see), the representing polymer N-acetylaminohexuronic to - you. It termolabilen, collapses at boiling within 10 minutes, is sensitive to action to - t and ethanol.

At serological identification of salmonellas (see. Salmonellosis ) three main antigens (O-, H-and Vi-antigens) are taken into account that is the basis for the diagnostic antigenic scheme of Kauffmann — Whyte, representing the catalog of the antigens having diagnostic value. In this scheme according to structure of O-antigens C. are distributed in the O-groups combining serotypes. More than fifty Au-group combining apprx. 2000 serotypes of salmonellas are known. The fullest diagnostic antigenic skhekhma of Kauffmann — Whyte is published by the International center WHO for salmonellas in 1980. By means of specific standard bacteriophages S., nek-ry from serotypes, can be subdivided into fagotipa (see. Lysotypy ). As epidemic markers S.'s various antibacterial drugs resistance, and first of all to antibiotics can be used. Usually at the strains allocated from patients, ranges of resistance of activators to antibiotics, or their antibiotikogramma are similar. Emergence of stability to chemotherapeutic drugs at S. is connected with acquisition of special factors of resistance by them, or R-factors (see), therefore for epidemiol. the characteristic of R-factors including studying of markers of stability (antibiotikogramma), konjyugativnost, group of incompatibility, ability to inhibit a factor of fertility (fi+), and also a pier is important the analysis. the weight (weight) of plasmid DNA (see. Plasmids ).

Villages have rather high degree of resistance to influence of various environmental factors. At t 57 ° (in fluid medium) most of them perishes within 1 — 3 min. Boiling kills with S. instantly, at the same time even at very low temperatures (— 20 °) they are capable to remain a long time viable. According to various researchers, in water of open reservoirs and in drinking water they endure completely 120 days, in the soil — from 1 to 9 month, in room dust — from 80 days to 18 months, in sausages — from 60 to 130 days, in the frozen meat — from 6 to 13 months, in eggs — up to 13 months.

S.'s identification is based on definition of their biochemical and serological properties; belonging of culture to a certain serotype is established on the basis of the integrated serologic assay of somatic and flagellar antigens which is carried out by means of monoreceptor serums taking into account data on their enzymatic properties.



Bibliography: Blyuger A. F., Novitsky I. N. and Terebkova 3. F Salmonellosis, Riga, 1975; G. P. Salmonella's Guelder-rose in surrounding Wednesday, M., 1978; Kauffman F. Family of colibacilli, the lane with English page 21, M., 1959; Schur I. W. Diseases of a salmonellezny etiology, M., 1970; Bergey's manual of determinative bacteriology, ed. by R. E. Buchanan a. N. E. Gibbons, Baltimore, 1975; Enterobacteriaceae-Infektionen (Epidemiologie und Laborato-riumsdiagnostik), hrsg. v. J. Sedlak u. H. Rische, Lpz., 1968; KelterbornE. Salmonella-species, Namen und Vorkom-men, Lpz., 1967.


V. A. Kilesso.

Яндекс.Метрика