Nutrient medium for Levin. Nutrient media of Rappoport, Endo, Levin, Ressel, Kligler: type of medium, composition, purpose, principle of action
Wednesday Rappoport is an enrichment environment and a differential diagnostic environment. In her compound includes: bile broth 10%, 2% glucose, indicator (sour fuchsin, discolored with alkali; colorless in an alkaline medium, red in an acidic medium). Purpose: for the accumulation of typhoid-paratyphoid bacteria during blood culture of the patient, as well as for the approximate differentiation of typhoid-paratyphoid bacteria. Principle d-i: with the growth of typhoid-paratyphoid bacteria due to the fermentation of glucose, diffuse turbidity and reddening of the medium occur. For paratyphoid bacteria, in contrast to typhoid bacteria, the presence of gas in the float.
Wednesday Endo - differential diagnostic. Compound: MPA, lactose, indicator - basic fuchsin, decolorized with sodium sulfite. Purpose: for sieving the test material in order to obtain isolated colonies. Principle d-I based on the ability of some microorganisms to decompose or not decompose lactose (Salmonella does not decompose and form colorless colonies).
Wednesday Levin is weakly selective and differential diagnostic. In her composition MPA, tactose, indicators: eosin and methylene blue, potassium hydrogen phosphate. Appointment and principle of d-I, see the Endo environment.
Ressel Wednesday Compound: MPA, lactose 1%, glucose 0.1%, indicator (water blue and pink to-ta; in an alkaline environment, pink, in an acidic environment, blue). Purpose: for elimination of "suspicious" colonies in order to isolate pure cultures and determine their enzymatic activity in relation to glucose and lactose. Principle d-I:
Wednesday Kligler - combined, differential diagnostic. Compound: MPA, lactose 1%, glucose 0.1%, sodium thiosulfate, iron II sulfate, indicator - phenol red (in an alkaline medium - red, in an acidic medium - yellow). Purpose: for elimination of "suspicious" colonies in order to identify pure cultures and determine their enzymatic activity in relation to glucose, lactose and the formation of H2S. Principle d-I: enterobacteria, which have the enzyme thiosulfate reductase, reduce thiosulfate to sulfite, while hydrogen sulfide is released, which reacts with iron sulfate - as a result, black iron sulfide is formed.
Serological identification of isolated pure culture using adsorbed monoreceptor O- and H-agglutinating salmonella sera. Serological identification is carried out in the agglutination reaction on a stack with agglutinating adsorbed Salmonella O- and H-sera, these sera can be. 2 types: monoreceptor and polyvalent, they are obtained from specific immune sera by the method of adsorption of antibodies according to Castellani.
Serological identification proceeds sequentially in 3 stages:
1) Establishing the belonging of a culture to serogroups A, B, C, D, E, of the genus Salmonella. In this case, polyvalent O-serum containing antibodies against antigenic receptors 2, 3, 4, 7, 9, 10 is used. Monoreceptor O-sera are used against rare serogroups. When diagnosing paratyphoid A and B, typhoid fever, you can use a mixture of O-sera containing antibodies to receptors 2, 4, 9.
2) With a positive result, to determine whether the test culture belongs to a certain serogroup, the agglutination test is set separately with each monoreceptor O-serum that was part of the polyvalent one: receptor 2 belongs to serogroup A, receptor 4 to serogroup B, receptor 7 - to serogroup C, etc.
3) After determining the serogroup, we determine its species affiliation using the agglutination p-tion with adsorbed monoreceptor H-sera against the H-antigens of the 1st phase of Salmonella, which are part of this serogroup. Then, agglutination is carried out with adsorbed H-sera against H-antigens of the 2nd phase and the antigenic formula of the test culture is finally established.
Bacteriocarrier in typhoid fever. What serological reactions can confirm chronic bacteriocarrier? diagnostics used for this purpose. The only evidence of bacteriocarrier is the isolation from the carrier of cultures S. typhi, S. paratyphi A, S. paratyphi B, using auxiliary methods: serological test and allergic skin test with Vi-typhine (it contains Vi-antigen, which, when interacting with Vi-antibodies gives a local allergic reaction in the form of redness and swelling within 20-30 minutes). A positive p-tion with Vi-typhine indicates that there are Vi-antibodies in the org-me and possibly S. typhi.
Chr. bacteriocarrier is confirmed by RNGA. In this case, Vi-diagnosticum is used, because in the formation of typhoid bacteriocarrier, the manifestation of Vi-antibodies is characteristic; diagnostic titer of the district 1:40.
Methods of infection with typhoid fever. source of infection. Infection with typhoid fever occurs only by the oral route. The source of infection is sick people and bacteria carriers (they are dangerous to others for several years after the illness).
Levin's Wednesday Levin's Wednesday
(lactose eosinmethylene agar) is a differential-selective medium for the isolation of enterobacteria. Allows you to distinguish between lactose-fermenting (form dark blue or black colonies) and non-fermenting lactose to-r(medium color colonies). Proteus forms isolated orange colonies. The medium is prepared by adding to 100 ml of 1.5% MPA, pH 7.2 - 7.4, 2 ml of 0.5% water solution methylene blue, 1.5 ml of 2% eosin solution, 2 g of lactose and 0.2 g of dibasic potassium phosphate, then pour it into Petri dishes. The medium has a light purple color. The industry produces a dry preparation, which is prepared according to the instructions on the label. HP variant - lactose bromthymol medium - does not have inhibitory properties against Klebsiella scleroma.
(Source: Glossary of Microbiology Terms)
See what "Levina Wednesday" is in other dictionaries:
- (M. Levine, born in 1889, Amer. bacteriologist) dense differential diagnostic nutrient medium for the detection of pathogenic bacteria that do not decompose lactose. Enterobacteriaceae (causative agents of typhoid fever, dysentery, etc.); comprises… … Big Medical Dictionary
- (s) (s) an artificial substrate, which is a balanced mixture of nutrients in concentrations and combinations necessary for the growth and division of microorganisms or cells of higher organisms. Adams culture medium, see Adams ... ... Medical Encyclopedia
See Levin Wednesday... Big Medical Dictionary
See Levin's Wednesday (Source: Glossary of Microbiology Terms) ... Dictionary of microbiology
- (tetrabromofluorescein) dye (see Dyes) red and greenish fluorochrome yellow color. Soluble in water and ethanol. It is used for dyeing the cytoplasm and as part of the Romanovsky Giemsa paint, as well as an inhibitor of some bacteria in ... ... Dictionary of microbiology
This term has other meanings, see Children's Music School No. 1. Children's Music School No. 1 in Penza ... Wikipedia
Culturological and social psychological theories describing and explaining human. behavior and social reality through the interaction between people. T.v. elements were contained in the sociology of Simmel, the phenomenology of Husserl and ... ... Encyclopedia of cultural studies
- (coliinfections) diseases caused by bacteria of the genus Escherichia (see). Obligate enteropathogenic variants coli cause a specific disease colienteritis (see). Wedge, picture of E., caused by conditionally pathogenic intestinal ... ... Dictionary of microbiology
Dormitory and scientific. a term denoting: 1) human. individual as a subject of relations and is conscious. activity (a person, in the broad sense of the word) or 2) a stable system of socially significant features that characterize an individual as a member of one or ... ... Philosophical Encyclopedia
T. p. was created by Kurt Lewin, who believed that in order to understand behavior, it is necessary to take into account the entire situation, that is, the gestalt situation. Levin extended his ideas to new areas, taking checkmate as a model of thinking. building ... ... Psychological Encyclopedia
is a nutrient medium for the isolation, enumeration and differentiation of Gram-negative microorganisms of the Enterobacteriaceae family.
Compound
The environment includes:
- peptone
- Potassium phosphate
- lactose
- Eosin Y
- methylene blue
- agar agar
The medium has a pH of about 7 and is stored in the dark. The prepared medium is reddish-lilac in color, non-opalescent with a greenish tint and a slight precipitate if a gel forms in the Petri dishes.
Purpose and principle of operation
This medium was developed by the American microbiologist Levine and is used to differentiate Escherichia coli and Enterobacter aerogenes, as well as for rapid identification of fungi candida albicans. American microbiologists recommend this medium for the isolation, enumeration and separation of gram-negative microorganisms of the intestinal (coliform) group. Methylene blue and eosin inhibit the growth of gram-positive microorganisms to a certain extent. These dyes serve as indicators of lactose digestion. Yeasts and some Gram-positive bacteria, such as Enterococci, can grow as pinpoint colonies on this medium.
Microbiologist Weld proposed the use of Levin agar supplemented with chlortetracycline hydrochloride for rapid identification of fungi. candida albicans in clinical material. The detection of these fungi in such material as faeces, oral and vaginal secretions, nails, skin flakes and others is possible after 24-48 hours when incubated at 35-37 ° C in an atmosphere containing 10% carbon dioxide. However, the cultural properties of fungi vary.
cultural properties
Growth characteristics of reference strains after 24-48 h at 35-37°C.
Strains of microorganisms (ATSS) Growth
Escherichia coli(25922) Plentiful
Pseudomonas aeruginosa(27853) Plentiful
Salmonella typhimurium(14028) Abundant
candida albicans(10231) Good or plentiful (in an atmosphere with 10% carbon dioxide)
Enterobacter aerogenes(13048) Good
Staphylococcus aureus(25923) Weak or absent
Saccharomyces cerevisiae(9763) Weak or absent
Enterococcus faecalis(29212) Suppressed
** The composition is verified and brought to compliance with the necessary parameters
Cooking:
Mix 37.5 g of M022 powder or 27.5 g of M301 powder in 1000 ml of distilled water. Boil to completely dissolve the particles. Add the appropriate carbohydrate to Levin Agar Base (M301) before sterilization. Sterilize by autoclaving at 1.1 atm (121°C) for 15 min. DO NOT OVERHEAT THE MEDIUM. Cool to 50°C and shake to oxidize the methylene blue (to restore it Blue colour and stir the flaky precipitate). If the medium is used on the same day, it does not need to be autoclaved.
Warning: the medium must be stored in the dark to prevent its oxidation in the light.
Principle and evaluation of the result:
This environment was developed by Levine (1, 2) and is used to differentiate Escherichia coli and Enterobacter aerogenes, as well as for rapid identification of fungi candida albicans. American experts recommend this medium for the isolation, enumeration and differentiation of gram-negative microorganisms of the intestinal (coliform) group (3, 4, 5).
Methylene blue and eosin inhibit the growth of gram-positive microorganisms to a certain extent. These dyes serve as differentiating indicators of lactose fermentation. On this medium, yeasts and some gram-positive bacteria, such as enterococci, can grow as pinpoint colonies. Weld (6, 7) suggested the use of Levin agar supplemented with chlortetracycline hydrochloride for the rapid identification of fungi. candida albicans in clinical material. The detection of these fungi in such material as faeces, oral and vaginal secretions, nails, skin flakes and others is possible after 24-48 hours of incubation at 35-37°C in an atmosphere containing 10% carbon dioxide. However, the cultural properties of fungi vary.
Quality control:
Powder Appearance:
Homogeneous free flowing light purple powder.
Finished medium density:
A medium is formed, corresponding in density to a 1.5% agar gel.
Color and transparency of the finished medium:
The prepared medium has a reddish-purple color, opalescent with a greenish tinge and a slight precipitate if a gel forms in the Petri dishes.
Acidity of the environment:
At 25°C, an aqueous solution of M022 (3.75% w/v) has a pH of 7.1 ± 0.2, an aqueous solution of M301 (2.75% w/v) has a pH of 7.3 ± 0.2.
Cultural properties:
Growth characteristics of reference strains after 24-48 hours at 35-37°C.
Strains of microorganisms (ATSS) |
Growth |
Color of colonies on medium M317 |
Escherichia coli (25922) |
Abundant |
Black and blue with a metallic sheen |
Pseudomonas aeruginosa(27853) |
Abundant |
Colorless |
Salmonella typhimurium(14028) |
Abundant |
Colorless |
* Candida albicans(10231) |
good or plentiful |
Colorless |
Enterobacter aerogenes(13048) |
5. Speck M. (Ed.), 1992, Compendium of Methods for the Microbiological Examination of Foods, 3rd ed., APHA, Washington, D.C. 6. Weld J. T., 1952, Arch. Dermat. Syph. 66:691. 7. Weld J. T., 1953, Arch. Dermat. Syph., 67(5):433. Terms and conditions of storage:The powder should be stored below +25°C. Use by the date indicated on the label. Store the prepared medium at +2...8°C in the dark. |
Composition (in terms of 1 liter of finished medium):
Enzymatic peptone, dry - 10.0 g.
Clarified autolyzed yeast extract - 1.5 g.
Lactose - 10.0 g.
Sodium phosphate disubstituted - 2.0 g.
Agar microbiological - 13.0 g.
Sodium chloride - 3.0 g.
Eosin sodium, indicator - 0.4 g.
Methylene blue, indicator - 0.075 g.
Dense nutrient medium for the isolation and differentiation of enterobacteria from the test material on the basis of lactose fermentation.
Mix the dry medium in the amount of 40 g in 1 liter of purified water, bring to a boil and boil until the agar is completely melted (2-3 min), filter through a cotton-gauze filter, pour into sterile bottles and sterilize by autoclaving at a temperature of 112 ° C for 20 min. Cool the sterile medium to a temperature of 45-48°C and pour into sterile Petri dishes; after solidification of agar, dry the dishes at a temperature of 37°C for 40-60 minutes. The color of the finished medium should be reddish brick.
The prepared medium can be stored in a dark place for no more than 7 days at a temperature of 2-8°C until use.
Incubate the inoculations of the studied samples for 18-48 hours at a temperature of 37°C Visual growth control - by the presence or absence and appearance colonies. Lactose-positive microorganisms form opaque colonies from light lilac to purple with or without a metallic sheen. Lactose-negative microorganisms form transparent or translucent colorless colonies (may form pale pink colonies).
Disposal of expired dry media and used prepared nutrient media - in accordance with the requirements of SanPiN 2.1.7.728-99 Rules for the collection, storage and disposal of waste from medical institutions.