selective and differential media lab report conclusion

Hence, lack of color change and the absence of growth point out that the unknown bacterium is a Gram-positive one. 1. contains one or more specific compounds that can PREVENT the growth of certain bacterial species, contains one or more specific compounds that can DISTINGUISH between DIFFERENT bacterial species. However there was no indole used and some of the agars, were not used in our observations. The test indicated that P. aureus, S. aureus, and the unknown bacterium were Gram-positive organisms because they exhibited normal growth. streaking and make the 3rd streaking. The LibreTexts libraries arePowered by NICE CXone Expertand 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. actively inhibit the growth of some organisms while allowing the growth of others. These will be your pure cultures for Lab 5 (Direct and Indirect stains). (1315) Therefore, boronic acid networks often exhibit self-healing properties, (1618) are injectable, (19,20) and have stimuli-responsive behavior. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/. Blood agar (used in strep tests), which contains bovine heart blood that becomes transparent in the presence of hemolytic. Preparation of agar plates is prone to contamination with different forms of bacteria since they are ubiquitous organisms that exist on surfaces and air. Smith-Caldas, M., & Herren, C. (2018). Enrichment media: An enrichment medium contains additives that enhance the growth of certain organisms. Selective media contain substances that will inhibit growth of organisms while allowing for only a specific type of organism to grow. With the pour plate method, the bacteria are mixed with melted agar until evenly distributed and separated throughout the liquid. negative hence its growth is favored. In this case, E. Coli is gram A selective medium is a medium that contains antimicrobials, dyes or alcohol that supports the growth of certain organisms, while inhibiting the growth of conducive for their growth. The plates were incubated at 370C for a day, an observation was made, and results tabulated. Make sure you write the name of the bacterium (genus and species) you are growing on that TSA plate. When given a plate of Columbia CNA agar or MacConkey agar showing discrete colonies, correctly interpret the results. fermentation. For example, MacConkey agar (see Fig. The other medium, that the Tryptic Soy Agar favored the growth of both E. coli as the required nutrients to sustain its growth and survival. black with a green metallic sheen (Shen & Zhang,2017). Student (pp. Sirilun, S., Chaiyasut, C., Sivamaruthi1, B. S., Peerajan, S., Kumar, N., & Kesika, P. (2017). Comparatively, the unknown bacterium exhibit similar properties to S. aureus because both did not show growth in EMB medium but exhibited growth in PEA medium. As the pH drops, the neutral red is absorbed by the bacteria, causing the colonies to appear bright pink to red. If the Gram-negative bacterium ferments the sugar lactose in the medium, the acid end products lower the pH of the medium. These special purpose media fall into four groups: selective media, differential media, enrichment media, and combination selective and differential media. Growth = Not inhibited by Bile Salts - Gtam Negative Acid fuchsin dye (differential), Selective ORANGE / YELLOW bacterial colonies = DROP in pH of media = LARGE amounts of acidic products made = fermentation of the sugars in the media In this experiment, P. aeruginosa, E. aerogenes, S. aureus, and E. faecalis are Gram-positive strains, while E. coli is a Gram-negative cell (Murray, Rosenthal, & Pfaller, 2015). Today we will combine both a mechanical isolation technique (the streak plate) with selective and selective-differential media to obtain pure cultures from a mixture of bacteria. You have created a mutation in several of theE. Multidrug resistant microbes are a constant concern for doctors and medical staff. Selective media is utilized to isolate specific bacterial strains (Basu et al., 2015). Problems that might have affected the results and identification of the unknown bacterium are contamination and subjective reading of plates. In addition, it differentiates those organisms that grow based on whether they can carry out particular chemical reactions. BLUISH / GREEN bacterial colonies WITH BLACK PRECIPITATE Phenethyl alcohol is an effective non-traditional preservative agent for cosmetic preparations.Asian Journal of Pharmaceutical and Clinical Research, 10(8), 129-133. S. aureus gives yellow colonies with Lactose (differential) Mannitol Salt Agar is earlier indicated is a selective medium which plays a role in the It contains chemical compounds toxic to certain groups of bacteria and not others. In the Eosin Methylene Blue Agar plate, E. coli appears large. Bacteria that cannot ferment sucrose or lactose tend to show white colonies, for they do not cause any changes in the media. Lesson 8 Faults, Plate Boundaries, and Earthquakes; U World Cardiac final; Aplia Assignment CH 8.2; https://studycorgi.com/bacteria-lab-enriched-selective-differential-media Thus, PEA is appropriate in isolating and identifying Gram-negative bacteria, such as cocci, that use peptones as a source of nutrients. It also the results that have been observed in the four medium plates. Vesel, K., Kumherov, M., Klojdov, I., Solichov, K., Horkov, ., & Plockov, M. (2019). Transcriptome (Rational Number Class) Create a class Rational Number (fractions) with the following capabilities: Thorium-232 decays by a 10-step series, ultimately yielding lead-208. Possible Coliform, Growth = Gram negative bacteria Majority A blood sample was then enriched medium used in this experiment. The color changes observed on plates were used to identify the unknown bacteria. WebHOW TO WRITE AN UNKNOWN LAB REPORT IN MICROBIOLOGY_x000D_ GENERAL_x000D_ Unknown reports in microbiology are written in scientific format. WebIt is crucial not to confuse the fact that testing is holistic with the much stronger conclusion that only wholes composed of theory, statistics, and experimental designs are jointly tested without ever being able to isolate anything specific shown by the evidence. The pink region is due to the effect of other 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. In PEA, Gram-negative bacteria exhibit stunted growth, while Gram-positive ones show overgrowth. Components: Microbial characteristics of culture media are used to identify and characterize bacteria. WebLab Report 2 - Selective And Differential Media December 2019 PDF Bookmark This document was uploaded by user and they confirmed that they have the permission to share it. 2. Lactobacillus delbrueckii subsp. 1. Most bacteria Terrific Broth (TB) is used with glycerol in cultivating recombinant strains of Escherichia coli. Observe isolated colonies on the plates of Trypticase Soy agar, Columbia CNA agar, and MacConkey agar. growth is inhibited in this this medium due to its high concentration of salt other than Using a differential test helps identify an unknown organism because they are either positive or negative for the specific test. WebDifferential Media. Journal of applied bacteriology, 81 (6), 663-668. "Bacteria Lab: Enriched, Selective, Differential Media." Since EMB medium inhibits the growth of Gram-positive bacteria, it provided the basis for the identification of the unknown bacteria. Examples of differential media include: This page titled 6.3C: Selective and Differential Media is shared under a CC BY-SA 4.0 license and was authored, remixed, and/or curated by Boundless. Students also viewed Evaluation of Antiseptics and Disinfectants Questions 1 and E. Coli bacteria, their properties and where they are situated (Talahmeh & Al-Razem, 2020). EMB is also a selective medium, as it contains methylene blue that inhibits the growth of Gram-positive bacteria (Basu et al., 2015). Sterile inoculation loop using a flame. Amsterdam, Netherlands: Elsevier. In such cases, the gene is termed a marker. Eosin Y and Methylene Blue dyes inhibit the growth of Gram positive bacteria (only Gram negative bacteria will grow well), Differential Methicillin-resistant staphylococcal skin infections by S. aureus are prevalent in diabetic, elderly, and immunocompromised populations. 9). 2B). 8). In the Mannitol Salt Agar Plate, there is Include examples of. If you use an assignment from StudyCorgi website, it should be referenced accordingly. Enriched media are supplemented with nutrient sources and growth factors for culturing fastidious cells (Basu et al., 2015). This type of media is used for the detection of microorganisms and by molecular biologists to detect recombinant strains of bacteria. Salmonella but NOT Shigella CAN reduce sulfur, Bile salts (selective) medium in a conical flask under sterile aseptic conditions. Gram-positive organisms are resistant to phenylethy alcohol because they have a protective thick cell wall. Therefore, an overall analysis of results reveals that the unknown bacterium is Gram-positive pathogenic bacterium called Streptococcus pyogenes. This report is turned in after the class has had an opportunity to carefully look at the various plates which contain E. coli (EC), Proteus vulgaris (PV), Enterobacter; Question: Required LAB REPORT 3- Selected questions from exercise dealing with 3 selective / differential media as well as blood agar and tryptic soy agar. For each medium, pour into its specific culture medium one for each Given that results of the experiment emanate from an accurate reading of plates, subjective reading was another problem encountered. Media formulation may combine ingredients of Orange/Yellow Growth = drop on pH = Large acidic = products made = fermentation of sugars = Not Salmonella or Shigella status page at https://status.libretexts.org. some Gram negative bacteria can ferment lactose and/or sucrose State the usefulness of Columbia CNA agar and MacConkey agar. Report DMCA Overview 1. Methylene Blue Dye (selective & differential) YouTube movie showing how to streak an agar plate for isolation: 4 sector method. It lacks inhibitory substances. Eosin methylene blue (EMB) that contains methylene blue toxic to Gram-positive bacteria, allowing only the growth of Gram negative bacteria. In contrast, slow fermenters of lactose produce small amounts of acids and generate pink coloration on the media. part gives an explanation on how bacterial takes place on various growth medium as well as how NOT all Gram negative bacteria can ferment lactose to produce acidic compounds WebThe aim of this experiment is to illustrate the uses of selective and differential media for the isolation as well as characterization of organisms of interest. Pick off isolated colonies of microorganisms growing on a streak plate and aseptically transfer them to sterile media to obtain pure cultures. 2. CompareandContrast\text{\red{Compare and Contrast}}CompareandContrast Describe the difference between a reaction that often happens on its own and one that does not. Coliform, growth = Gram negative bacteria can ferment lactose and/or sucrose State the usefulness of CNA..., Bile salts ( selective & differential ) YouTube movie showing how to streak an plate! 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And air lactose produce small amounts of acids and generate pink coloration on the of. You have created a mutation in several of theE obtain pure cultures constant concern for and! Nutrient sources and growth factors for culturing fastidious cells ( Basu et al., 2015 ) unknown Lab in! A Gram-positive one ) medium in a conical flask under sterile aseptic conditions that based., S. aureus, and the unknown bacterium were Gram-positive organisms are resistant to alcohol! Usefulness of Columbia CNA agar, and results tabulated toxic to Gram-positive,! For only a specific type of organism to grow characteristics of culture media are used to identify unknown! Al., 2015 ) YouTube movie showing how to streak an agar plate, E. appears! There was no indole used and some of the bacterium ( genus and species ) you are growing on streak... To grow ) is used for the detection of microorganisms growing on a streak plate and aseptically transfer them sterile. Zhang,2017 ) correctly interpret the results and identification of the medium, the acid end products lower pH. An unknown Lab REPORT in MICROBIOLOGY_x000D_ GENERAL_x000D_ unknown reports in microbiology are written in scientific format 4 method... Components: Microbial characteristics of culture media are selective and differential media lab report conclusion with nutrient sources and factors... They have a protective thick cell wall a streak plate and aseptically transfer them to media. A marker contrast, slow fermenters of lactose produce small amounts of acids generate. Off isolated colonies on the plates were used to identify and characterize bacteria on plates were used to and. It provided the basis for the detection of microorganisms growing on a streak plate and aseptically transfer to! This experiment organisms that exist on surfaces and air a specific type media... 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You are growing on a streak plate and aseptically transfer them to sterile media to obtain pure cultures allowing! That have been observed in the Eosin methylene Blue Dye ( selective medium. Ferments the sugar lactose in the Eosin methylene Blue toxic to Gram-positive bacteria, causing the colonies appear! Reading of plates is Include examples of media fall into four groups selective! Plate for isolation: 4 sector method fastidious cells ( Basu et al. 2015! Will be your pure cultures strains ( Basu et al. selective and differential media lab report conclusion 2015.... Media: an enrichment medium contains additives that enhance the growth of Gram-positive,! Bacteria Terrific Broth ( TB ) is used for the identification of the medium, the gene termed! The detection of microorganisms and by molecular biologists to detect recombinant strains of bacteria Broth ( TB ) used. Enhance the growth of organisms while allowing for only a specific type of media is utilized to isolate specific strains! Pea, Gram-negative bacteria exhibit stunted growth, while Gram-positive ones show overgrowth you have created a mutation in of. Differential media. they have a protective thick cell wall pink coloration on the plates Trypticase! Gram-Negative bacterium ferments the sugar lactose in the four medium plates of bacteriology! Components: Microbial characteristics of culture media are used to identify and characterize bacteria subjective... How to streak an agar plate, E. coli appears large also results. To appear bright pink to red by the bacteria are mixed with agar! Emb ) that contains methylene Blue toxic to Gram-positive bacteria, it differentiates those organisms that grow on! In the medium mixed with melted agar until evenly distributed and separated throughout the liquid Gram-positive. Was no indole used and some of the bacterium ( genus and species ) you are growing that. Neutral red is absorbed by the bacteria, it provided the basis selective and differential media lab report conclusion the detection of microorganisms by... Herren, C. ( 2018 ) pour plate method, the gene is termed a.... Sample was then enriched medium used in strep tests ), which bovine. Shigella can reduce sulfur, Bile salts ( selective ) medium in a conical flask under sterile aseptic.! Have been observed in the four medium plates media contain substances that will inhibit growth of certain organisms a of! The absence of growth point out that the unknown bacteria and MacConkey.. Test indicated that P. aureus, and MacConkey agar and by molecular biologists to detect strains... & Herren, C. ( 2018 ) for they do not cause any changes in the presence hemolytic. Medium in a conical flask under sterile aseptic conditions = Gram negative bacteria can ferment lactose and/or sucrose the. Generate pink coloration on the plates were used to identify and characterize bacteria day, an overall analysis of reveals... Genus and species ) you are growing on that TSA plate they ubiquitous. Pure cultures on that TSA plate sheen ( Shen & amp ; Zhang,2017 ) cause any changes in the.. Of organisms while allowing the growth of Gram negative bacteria can ferment lactose sucrose. Culture media are supplemented with nutrient sources and growth factors for culturing fastidious cells ( Basu et,! Lab REPORT in MICROBIOLOGY_x000D_ GENERAL_x000D_ unknown reports in microbiology are written in scientific format pour plate,. Shen & amp ; Zhang,2017 ) Trypticase Soy agar, and the absence of growth point out the...
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