From Big Medical Encyclopedia

OLKENITSKY ENVIRONMENT (I. S. Olkenitsky, the Soviet microbiologist) — the differential and diagnostic environment for bacteria of intestinal group containing three sugars and urea.

The lake of page consists of the following components: 100 ml of nutrient agar, 1 g of lactose, 1 g of sucrose, 0,1 g of glucose, 1 g of urea, 0,02 g of Mohr's salt (binary salt of ferrous sulfate and ammonium), 0,03 g of sodium thiosulphate, 0,4 zhl 0,4% of solution of phenol red.

For O.'s preparation by the village in one test tube dissolve Mohr's salt with sodium thiosulphate and a small amount of a distilled water, in other test tube — urea with carbohydrates. Then all ingredients mix with the sterile melted agar, establish pH 7,2 — 7,4; Wednesday is spilled on test tubes, sterilized fluid steam 3 days in a row 20 min. After sterilization Wednesday is mown, it shall have light pink color.

Villages carry out crops of the studied pure growth of bacteria on O. on a beveled surface in the beginning, and then a prick deep into of a column. The incubation is carried out during 18 — 48 hours at t ° 37 °.

Yellowing of a slanted part of an agar indicates splitting of lactose, sucrose or both sugars; yellowing of a column of an agar — on splitting of glucose. In a column of an agar note availability of gas in the form of bubbles or ruptures of the environment.

The lake of page allows to define splitting of urea with formation of ammonia and carbon dioxide gas. Ammonia, neutralizing to - that, formed during the splitting of glucose, changes color of a column of an agar on red (to crimson). Addition to the environment of Mohr's salt and sodium thiosulphate allows to reveal at the studied culture formation of hydrogen sulfide on blackening of Wednesday as a result of transformation of ferrous sulfate into the sulfide having black color.

See also Differential and diagnostic environments .

Bibliography: Olkenitsky I. S. A three-sugar agar with urea for studying of microbes of intestinal group, Laborat, business, No. 5, page 40, 1958; The Guide to microbiological diagnosis of infectious diseases, under the editorship of K. I. Matveev, page 174, M., 1973; The Reference book on microbiological and virologic methods of a research, under the editorship of M. O. Birger, page 62, M., 1973.

E. Pashkov.