From Big Medical Encyclopedia

EHRLICH REACTION (P. Ehrlich, is mute. the doctor, the bacteriologist and the biochemist, 1854 — 1915) — one of options of reactions of aromatic aldehydes with an indole or its derivatives, at to-rykh are formed intensively painted products. AA. the river is applied as one of tests of identification of microbes (see).

In 1898 — 1899 by P. Ehrlich it was established that at addition of tg-dimethylaminobenzaldehyde to urine at acid pH there is a weak red coloring. In 1900 D. Proscher studied chemism of reaction, to-ruyu characterized as reaction to an indole (see). Further Freynd and Lebakh (M. of Freund, Lebach) defined that the tg-dimethylaminobenzal-degida interacts with one molecule one molecule of an indole, edges is in the so-called indoleninovy form which is characterized by movement of double bonds. Reaction was widely used for definition of an indole in urine and excrements. In 1906 reported to A. Bohme about a possibility of its use for differentiation of bacteria and recommended to use solution No. 1 (гс-диметиламиш^ benzaldehyde — 4 g, 96% alcohol — 380 ml, concentrated salt to - that 80 ml) and the solution No. 2 (sated during the heating solution of potassium persulphate). For statement of reaction added to bouillon culture of microorganisms consistently solutions No. 1, No. 2 and intensively mixed. In the presence of an indole red coloring appeared. In 1928 N. Kovacs offered modification of reaction for definition of an indole, a cut use in a crust, time.

For statement of reaction use solution of the following structure: amyl (isoamyl) alcohol — 150 ml, the p-dimetilaminobenzalde-guide — 10 g, concentrated salt to - they are 50 ml. Aldehyde is dissolved in alcohol, and then slowly added to - that. Solution is kept in the refrigerator. For the accounting of reaction add 0,5 ml of solution to 1 — 2 ml of 24-hour bouillon culture and stir up. In the presence of an indole the layer forming on a surface of broth is painted in red color.

Source of an indole in intestines of the person and animals is tryptophane, to-ry under the influence of the bacterial enzyme of a tryptophanase catalyzing splitting of a side chain of amino acid breaks up with formation of an indole, ammonia, pyroracemic to - you and other products.

By means of E. the river or its modification can differentiate an indole - positive and the indolnegationist-nye microorganisms. Microorganisms of the sorts Escherichia, Edward-siella, types of Gitrobacter intermedius, Proteus vulgaris, P. morganii, P. rettgeri, P. inconstans, Vibrio cholerae belong to indolpo-lozhitelny; to indolnegative — Salmonella, Klebsiella, Enterobacter, Serratia, Shigella sonnei, Proteus mirabilis, Yersinia pestis. To forming an indole with lateness and changeably species of bacteria of Shigella dysenteriae, S. flexneri, S.boy-dii and Yersinia enterocolitica belong.

Bibliography: Short determinant of bacteria of Bergi, under the editorship of J. Hoult, the lane, with English, M., 1980; The reference book on microbiological and virologic methods of a research, under the editorship of M. O * Birgera, page 191, M., 1982; Whyte A., etc., Fundamentals of biochemistry, t. 1, page, 43, 108, t. 2, page 964, M., 1981; Bohme A. Die Ap-wendung der Ehrlichschen Indolreaktionen fur bacteriologische Zwecke, Zbl. Bakts, Abt. 1, Bd 40, S. 129, 1905 — 1906; To o-vks N. Eine vereinfachte Methode zum Nachweis der Indolbildung durch Bakte-rien, Z., Immun. - Forsch., Bd 55, S. 311, 1928. A. M. Dombrovsky.