Differential diagnostic environment

Differential diagnostic environment - a special blend of nutrients used for species identification of microbes and study their properties. With the growth of bacteria on differential diagnostic environments occurring chemical processes resulting from microbial cells of various enzymes. Some of them can break down proteins, others carbohydrates, others to cause reactions of oxidation and reduction, and so on, Through the action of enzymes in the differential diagnosis of the environment changes.
Differential diagnostic environment can be divided into four main groups.
differential diagnostic environment

Fig. 1-6. Various forms of splitting gelatin. Fig. 7 - 9. Liquid medium with carbohydrate and indicator Andrade: Fig. 7 - the lack of fermentation; Fig. 8 - fermentation with the formation of acid; Fig. 9 - fermentation with production of acid and gas. Fig. 10 - 12. Semi-fluid medium with carbohydrate and indicator BP (from dry medium): Fig. 10 - the lack of fermentation; Fig. 11 - fermentation with the formation of acid; Fig. 12 - fermentation with production of acid and gas. Fig. 13-15. Artificial litmus serum Seitz: Fig. 13 - the lack of fermentation; Fig. 14 - fermentation with the formation of acid; Fig. 15 - fermentation with the formation of alkali. Fig. 16 and 17. Milk with methylene blue: Fig. 16 - no reduction; Fig. 17-reduction. Fig. 18 and 19. Wednesday Simons: Fig. 18-the lack of assimilation citrate; Fig. 19 - assimilation citrate. Fig. 20 - 24. Litmus milk: Fig. 20 - the lack of fermentation; Fig. 21 - fermentation with the formation of acid; Fig. 22 - fermentation with the formation of alkali; Fig. 23 - peptonize; Fig. 24 - reduction. Fig. 25. Dilution collapsed serum (in transmitted light). Fig. 26. Hemolysis on blood agar (in transmitted light). Fig. 27. Blood medium with tellurium potassium.

1. Environment containing protein and revealing the ability of microbes to break down proteins (proteolytic Properties): meat-peptone gelatin "column", rolled equine or bovine serum, milk, blood agar. When sowing bacteria with a puncture in the meat-peptone gelatine, "column" in the case of protein cleavage see dilution protection. When planting on Wednesday with a collapsed whey protein is determined by the dilution protection and pitting on the surface. Splitting a microbe milk detected enlightenment or dissolution originally curdled milk. The presence of hemolytic activity of the studied culture check sowing it in a Petri dish at a special blood agar. The destruction of red blood cells around the colonies (such as hemolytic Streptococcus or Staphylococcus) creating areas of enlightenment.
2. Environment to determine the ability of microbes to break down carbohydrates and vysokostatusnye alcohols (Endo Wednesday, Levin Wednesday, Russell Wednesday, Drygalski - konradi Wednesday, Rapoport - Weintraub Wednesday, Shustova environment). To identify these properties of microorganisms applied also mixed number, i.e. a series of tubes containing nutrient medium, containing various carbohydrates, polyols and indicator. The indicators are a litmus tincture or bromtimol blue. Decomposition of any of carbohydrates with the formation of acid reveal to change the color of the indicator, the formation of gas - filling gas and the emergence of special glass float in liquid medium. Or use semi gissa environment (see) with 0.5% agar with relevant sugars and indicator Andrade. After sowing germ on these environment education acid reveal redness environment, and education gas for the emergence of bubbles in his agar or divide and shift up agar column. For differential diagnostic Wednesdays second group also include starch, agar, used to measure the ability of microbes to break down starch, environment Clarke and others
3. Environment on which reveals the ability of microbes to discolor the dyes are added to the broth: methylene blue, tionen, the litmus paper, the Indigo Carmine, neutral red or others (environment Rotberger, Wednesday Alanskogo). The third group referred to as environment with nitrates that are used to measure the ability of microbes to restore nitrate salts (nitrates) in nitrite (nitrites) and later in ammonia or free nitrogen.
4. Environment, revealing the ability of microbes to absorb substances which are not digested by other microbes, for example the medium with sodium citrate (citrate agar Simons) to distinguish E. coli, which is deprived of the ability to assimilate this environment, from other coliform or the environment oleinovoi sodium for differentiation of diphtheria bacilli from false diphtheria and diphtheroids (agar of Angering).
For differential diagnostic of the media are also environment for differentiation anaerobov, tellurite environment for differentiation diphtheria bacteria, environment with urea, alkaline environment (diedonne agar) for cultivation of V. cholerae and other Cm. also the Identification of microbes.