Differential media is supplemented with the indicator dyes that differentiates the bacterial isolate based on colour change: Examples: Mannitol salt agar, tellurite media, Lowenstein-Jensen media, thiosulphate-citrate bile sucrose agar etc. Gancyclovir is an exception to the rule as it is used to specifically kill cells that carry its respective marker, the Herpes simplex virus thymidine kinase (HSV TK). This type of media uses the biochemical characteristics of a microorganism growing in the presence of specific nutrients or indicators (such as neutral red, phenol red, eosin y, or methylene blue) added to the medium to visibly indicate the defining characteristics of a microorganism. Xylose lysine desoxyscholate (XLD), which is selective for Gram-negative bacteria buffered charcoal yeast extract agar, which is selective for certain gram-negative bacteria, especially Legionella pneumophila. Such a medium normally consists of a mixture of protein digests (peptone, tryptone, etc.) 0000000727 00000 n Typically, human feces contains a large variety of Salmonella growing as black colonies on Hektoen agar. MacConkey agar for Gram-negative bacteria. MacConkey agar for Gram-negative bacteria. 0000024096 00000 n Mannitol salt agar (MSA) which is selective for Gram-positive bacteria and differential for mannitol. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. 0000023877 00000 n lang: en_US Explosives Detection, Home > Biological > Technology > Cell Culture > Differential Media. [ "article:topic", "Selective Media", "Differential media", "authorname:boundless", "showtoc:no", "license:ccbysa", "source[1]-bio-9164" ], 6.3.4: Aseptic Technique, Dilution, Streaking, and Spread Plates. Chemical Detection Useful for culturing urine specimens which may contain large number of Proteus species. 0000052194 00000 n Primary culture media for clinical microbiology are divided into 3 primary categories — nutritive, differential and selective media. Normally, the presence of a specific gene or an allele of a gene confers upon the cell the ability to grow in the selective medium. Browse selective and differential media types in broth or agar for Escherichia coli (E. coli) and coliforms. S.                               pyogenes, S. agalactiae, and several other species of streptococci are β hemolytic. and inorganic salts, hardened by the addition of 1.5% agar. Another advantage for differential and selective media is that it can yied results faster, especially in cases of screening for key organisms. Washington, DC 20036, © 2020. Why Differential & Selective Media Remain Invaluable Tools. About Us | Contact | FAQ | User Login, All Categories We want to hear from you. Hektoen enteric agar (HE) which is selective for Gram-negative bacteria. Eosin methylene blue agar, blood agar, deoxycholate citrate agar etc. Hemolysis Observation of the hemolytic reactions on blood agar is a very useful tool in the identification of bacteria, particularly streptococci. Differential media are bacteriological growth media that contain specific ingredients to allow one to distinguish selected species or categories of bacteria by visual observation. Biological Detection Alpha hemolytic organisms partially lyse red blood cells, leaving the media a greenish color, while gamma hemolytic organisms do not lyse red blood cells at all and the media remains unchanged. 47 0 obj << /Linearized 1 /O 49 /H [ 794 298 ] /L 92524 /E 70199 /N 8 /T 91466 >> endobj xref 47 19 0000000016 00000 n Blood agar is one type of differential medium, allowing bacteria to be distinguished by the type of hemolysis produced. no (γ) hemolysis: No apparent hemolytic activity or discoloration is produced by the colony (also called gamma hemolysis). Eosin methylene blue (EMB) that contains methylene blue – toxic to Gram-positive bacteria, allowing only the growth of Gram negative bacteria. Gancyclovir is an exception to the rule as it is used to specifically kill cells that carry its respective marker, the Herpes simplex virus thymidine kinase (HSV TK). Selective media are used for the growth of only selected microorganisms. 0000068828 00000 n Selective growth media are also used in cell culture to ensure the survival or proliferation of cells with certain properties, such as antibiotic resistance or the ability to synthesize a certain metabolite. Unless otherwise noted, LibreTexts content is licensed by CC BY-NC-SA 3.0. The blood cultures flag positive on the automated blood, culture instrument at 18 hours of incubation, and gram-negative rods are seen on the Gram stain. Blood Agar (BAP) is another type of differential medium. Differential media, unlike selective media, does not kill organisms. bacteria, and identifying pathogens amongst normal gastrointestinal flora can be challenging. Streptococcuseosin methylene blue (EMB), which is differential for lactose and sucrose fermentation. Welcome to J92 Media! Differential media or indicator media distinguish one microorganism type from another growing on the same media. This type of media uses the biochemical characteristics of a microorganism growing in the presence of specific nutrients or indicators (such as neutral red, phenol red, eosin y, or methylene blue) added to the medium to visibly indicate the defining characteristics of a microorganism. Conferences, About Us | Contact | FAQ | Manufacturer Login, All Categories this information and the choices you have about how we use such information. Differential media contain compounds that allow groups of microorganisms to be visually distinguished by the appearance of the colony or the surrounding media, usually on the basis of some biochemical difference between the two groups. 0000000794 00000 n confidence and trust with respect to the information we collect from you on Explosives Detection For example, mannitol salt agar contains a high concentration of sodium chloride that inhibits the growth of most organisms but permits staphylococci to grow. Privacy Policy sets forth the information we collect about you, how we use When microbes are grown in differential media, they produce visible characteristic changes or different growth patterns which are helpful to identify and differentiate microorganisms from one another. Typically, human feces contains a large variety of. Differential Media. trailer << /Size 66 /Info 46 0 R /Root 48 0 R /Prev 91456 /ID[<5c2b821ee0e3c85004b9181e9d967126><5c2b821ee0e3c85004b9181e9d967126>] >> startxref 0 %%EOF 48 0 obj << /Type /Catalog /Pages 35 0 R /JT 45 0 R >> endobj 64 0 obj << /S 168 /Filter /FlateDecode /Length 65 0 R >> stream Basic solid agar or liquid broth can also be, One of the most powerful applications of these types of media is combining both, Microbiology Case Studies Using Differential & Selective Media, A 28-year-old patient arrives at the emergency room with complaints of redness, pain and streaking along the site of a surgical incision on the leg. Andrea Prinzi SM(ASCP),MPH,CPH has been a clinical microbiologist in Denver, Colorado for the last 11 years. Take advantage of improved member benefits that will help you advance. A differential media contains specific ingredients or chemicals that help us to visually distinguish which species do or don't carry out a specific biochemical process. Selective media generally selects for the growth of a desired organism, stopping the growth of or altogether killing non-desired organisms. East Lansing, MI 48824. She is actively pursuing her PhD in Clinical Science at the University of Colorado Denver. Dr. Rodney Rohde, Ph.D., is the Associate Director of the Translational Health Research Initiative at Texas State University. Some examples of selective media include: Differential media or indicator media distinguish one microorganism type from another growing on the same media. Selective growth media are also used in cell culture to ensure the survival or proliferation of cells with certain properties, such as antibiotic resistance or the ability to synthesize a certain metabolite. Examples include sheep blood agar and chocolate (heated blood) agar. Find out more here. For example, if a microorganism is resistant to a certain antibiotic, such as ampicillin or tetracycline, then that antibiotic can be added to the medium in order to prevent other cells, which do not possess the resistance, from growing. - Click to open the module Radiological/Nuclear Detection Adopted or used LibreTexts for your course? Unless otherwise noted, LibreTexts content is licensed by CC BY-NC-SA 3.0. Such a medium normally consists of a mixture of protein digests (peptone, tryptone, etc.) Streptococcus pneumoniae and many                                oral streptococci are α hemolytic. Differential media, unlike selective media, does not kill organisms. YM (yeast and mold) which has a low pH, deterring bacterial growth. While the plates are incubating, the clinician calls the laboratory and says that the medical team is  trying to choose appropriate antimicrobials for this patient, and they would like to know if the organism is. pricing. Normally, the presence of a specific gene or an allele of a gene confers upon the cell the ability to grow in the selective medium. Have questions or comments? For example. In the case above, the use of Hektoen agar allows the microbiologist to rapidly identify pathogens among a mass of normal flora. Blood agar (used in strep tests), which contains bovine heart blood that becomes transparent in the presence of hemolytic. Chemical Detection Examples of differential media include: The LibreTexts libraries are Powered by MindTouch® and are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. 1752 N St. NW The blood is plated to blood, MacConkey and chocolate agars and incubated for 24 hours. Here you will find my latest projects that I have been working on. We want to hear from you. Media lacking an amino acid such as proline in conjunction with E. coli unable to synthesize it were commonly used by geneticists before the emergence of genomics to map bacterial chromosomes. differential media . MacConkey (MCK), which is differential for lactose fermentationmannitol salt agar (MSA), which is differential for mannitol fermentation. A differential media recommended for the selection and recovery of Enterobacteriaceae. A stool sample is collected and sent to the microbiology laboratory for culture. Selective growth media for eukaryotic cells commonly contain neomycin to select cells that have been successfully transfected with a plasmid carrying the neomycin resistance gene as a marker. H�b```")��� cb�-n /��u�+�}����p�ĉ�BF�V�KK7�8,�-�*�r�b�SW{ջ�,�5?�D U�F��)i�us IF �L\���: g`e��@, q�70�ګ�9��J�'c��.����$XX$>0�5�4�1*0Y@�` � 7 endstream endobj 65 0 obj 192 endobj 49 0 obj << /Type /Page /Parent 35 0 R /Resources 50 0 R /Contents 57 0 R /MediaBox [ 0 0 612 792 ] /CropBox [ 0 0 612 792 ] /Rotate 0 >> endobj 50 0 obj << /ProcSet [ /PDF /Text ] /Font << /TT2 53 0 R /TT4 56 0 R /TT6 59 0 R >> /ExtGState << /GS1 62 0 R >> >> endobj 51 0 obj << /Filter /FlateDecode /Length 22412 /Length1 33668 >> stream