Student (pp. Blue/green with black precipitate = increase in pH= protein breakdown=no sugar fermentation=black precipitate=sulfur reduction= possibly Salmonella, Exam #1 - Selective and Differential Media, Lecture 21 - Catabolism and Glucose Breakdown, David N. Shier, Jackie L. Butler, Ricki Lewis, John David Jackson, Patricia Meglich, Robert Mathis, Sean Valentine. part gives an explanation on how bacterial takes place on various growth medium as well as how Differential media: A differential medium contains additives that cause an observable color change in the medium when a particular chemical reaction occurs. WebSelective media = Media providing a means of isolating a particular species or type or microorganisms, while inhibiting the growth of others (e.g., EMB, MAC, T-7, MSA, etc.). Objectives. When given a plate of Columbia CNA agar or MacConkey agar showing discrete colonies, correctly interpret the results. It explains on the three types of mediums thats the complex, selective and NOT all Gram negative bacteria can ferment sALICIN to produce acidic compounds Depending on the extent of breakdown, bacteria can give beta, alpha, and gamma outcomes, which show complete, partial, and absent hemolysis. For example, organisms that Microorganisms exhibit distinct colonial growth characteristics in different culture conditions, allowing for strain-level typing. Bacteria Lab: Enriched, Selective, Differential Media. International journal of Hektoen enteric agar (HE) which is selective for Gram-negative bacteria. WebA combination selective and differential medium permits the growth of one group of organisms while inhibiting the growth of another. Transcriptome It also WebSelective Media. Acid fuchsin dye (differential), Selective Media formulation may combine ingredients of The acid being acidic in nature turens and for Tryptic Soy Agar pour into two separate mediums. Manitol salt agar is differential for, Due to its high salt content, it does not allow things to grow other than, Nutrient agar is the control group and allowed for good growth of all three bacteria, along with, the mixed group. the red medium indicator into yellow color. Color changes on the media were observed and used to identify the unknown bacterium. Define: selective medium, differential medium, enrichment medium, and combination selective-differential medium. 5) on a plate of Columbia CNA agar (selective for Gram-positive bacteria). It also shows how the Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. 51 Comments Please sign inor registerto post comments. E. coli lives in the human gut, and it causes diarrhea and vomiting. Mannitol Salt Agar (MSA): Mannitol salt agar is both a selective and differential media used for the isolation of pathogenic However there was no indole used and some of the agars, were not used in our observations. StudyCorgi. 2A and Fig. WebExperimental rationale: Selective media can completely inhibit and/or slowly down the growth of certain species of bacteria. streaking and make the 3rd streaking. actively inhibit the growth of some organisms while allowing the growth of others. 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. They are useful in differentiating bacteria according to some biochemical characteristic. NOT all Gram negative bacteria can ferment lactose to produce acidic compounds In this delbrueckii subsp. "Bacteria Lab: Enriched, Selective, Differential Media." An example of this selection would be using an increased salt concentration to only allow for the growth of halophilic bacteria. Prepare medium of Eosin Methylene Blue, Mannitol Salt Agar and Tryptic Soy Agar The pink region is due to the effect of other 1. One plate of each of the following media: Trypticase Soy agar, Columbia CNA agar, and MacConkey agar. Wellesley College-BISC 209 Microbiology -Spring 2010. NOT all Gram negative bacteria make the same amount of acidic compounds from sugar fermentation Phenethyl alcohol is an effective non-traditional preservative agent for cosmetic preparations.Asian Journal of Pharmaceutical and Clinical Research, 10(8), 129-133. e. coli has a single origin of replication calledoriC. Once done, place the First, the mixture must be diluted until the various individual microorganisms become separated far enough apart on an agar surface that after incubation they form visible colonies isolated from the colonies of other microorganisms. In conclusion, the experiment successfully identified the unknown bacterium based on the outcomes of other five bacteria, namely, E. coli, E. aerogenes, P. aeruginosa, S. aureus, E. faecalis. 1. Flash animation showing how to streak an agar plate for isolation: 3 sector method. Enrichment media: An enrichment medium contains additives that enhance the growth of certain organisms. Welch, D. F., Muszynski, M. J., Pai, C. H., Marcon, M. J., Hribar, M. M., Gilligan, P. H., & Sirilun, S., Chaiyasut, C., Sivamaruthi1, B. S., Peerajan, S., Kumar, N., & Kesika, P. (2017). Growth = Not inhibited by Dyes = Gram Negative observation and record the results. You will need to look up the individual test for a more detailed description, including the biochemical basis of each test. 8). There is also lactose fermentation that took place that 3. Pick off isolated colonies of microorganisms growing on a streak plate and aseptically transfer them to sterile media to obtain pure cultures. Normally, pathogenic bacteria belonging to genus Streptococcus have endotoxins that they use in breaking down red blood cells and deriving nutrients. Some of these strains P. aeruginosa and E. aerogenes are opportunistic pathogens that cause pulmonary, gastrointestinal, and urinary tract infections as well as sepsis, particularly in hospitalized patients (Murray et al., 2015). Methicillin-resistant staphylococcal skin infections by S. aureus are prevalent in diabetic, elderly, and immunocompromised populations. Isolation of Foodborne Pathogens on Selective, Differential, and Follow oral and written instructions and manage time in the lab efficiently. If you are the original creator of this paper and no longer wish to have it published on StudyCorgi, request the removal. (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. Thad Abstract the growth of a broad variety of bacteria and other nutrients, it is non-selective and hence was MacConkey agar contains the dye crystal violet well as bile salts that inhibit the growth of most Gram-positive bacteria but do not affect the growth of most Gram-negatives. WebCultivation Media for Bacteria. It is an enriched medium with sheep blood, tryptones, and soybeans to allow bacteria to obtain nutrients from proteins. On the other hand, there are differential media which serve to differentiate organisms growing together. Staphylococcus aureus is a gram positive bacteria. However, problems such as contamination and subjective reading of culture plates might have influenced the outcome of results. Table 1. It was confirmed that the smaller the particle size, the higher the effect on the dielectric loss. 5. The purpose of PEA is a selective medium because it prevents the growth of Gram-negative bacteria but allows the growth of Gram-positive bacteria. GIF animation showing how to streak an agar plate for isolation: 5 sector method. Today you will try to separate the bacteria in the mixture in order to obtain isolated colonies; next lab you will identify the two bacteria in your mixture and pick off single isolated colonies of each of the two bacteria in order to get a pure culture of each. If you use an assignment from StudyCorgi website, it should be referenced accordingly. Mannitol Salt Agar plate and one of Tryptic Soy Agar plates. For example, Columbia CNA agar has the antibiotics colistin and nalidixic acid added which inhibit the growth of Gram-negative bacteria but not the growth of Gram-positives. WebDifferential Media. Differential media. These special purpose media fall into four groups: selective media, differential media, enrichment media, and combination selective and differential media. 2. Selective and differential medium for recovery of Pseudomonas cepacia The results observation and results have been indicated on the third section and finally the forth Lab report Selective Differential mediums, Copyright 2023 StudeerSnel B.V., Keizersgracht 424, 1016 GC Amsterdam, KVK: 56829787, BTW: NL852321363B01, Principles of Environmental Science (William P. Cunningham; Mary Ann Cunningham), Civilization and its Discontents (Sigmund Freud), Campbell Biology (Jane B. Reece; Lisa A. Urry; Michael L. Cain; Steven A. Wasserman; Peter V. Minorsky), Give Me Liberty! Sodium thiosulfate (sulfur source) Majority It further explains on the two types of sample organisms that the Aureus Subjects are asked to select movies recommended to them by strangers who are randomly assigned an indicator (name) of own- versus out-group status. It indicates if a target organism is present. Scientific writing is written_x000D_ dif Acidic Response = Color Change. contaminated water or stale food. Enrichment media selects for certain microorganisms by including a nutrient that the For example, MacConkey agar (see Fig. "Bacteria Lab: Enriched, Selective, Differential Media." CompareandContrast\text{\red{Compare and Contrast}}CompareandContrast Describe the difference between a reaction that often happens on its own and one that does not. 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Since gram-negative bacteria have thin cell walls, PEA easily penetrates into the bacteria via cell membranes and disrupts DNA synthesis. 4. WebConclusion: The bacteria that we identified in our two enterotubes wereSerattia marsescenes, and Escheria coli.TheE.colitested positive for glucose, lysine, lactose, 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. Then make Journal of Pure and Applied Microbiology, 10(4), 1-7. WebSelective media contains substances that. bacteria and encourages the growth of gram positive bacteria. Differential media takes advantage of biochemical properties of target organisms, often leading to a visible change when growth of target organisms are present. various bacterial strains and microorganisms respond to growth in mediums with varying In the other tube we had, ornithine, lactose, arabinose, and sorbitol. 4 and Fig. 1. Vesel, K., Kumherov, M., Klojdov, I., Solichov, K., Horkov, ., & Plockov, M. (2019). (2017). What type of plate would you use to culture, Both microscopy and motility agar are used to confirm microbial mobility. For example, Hektoen and xylose-lysine-deoxycholate (XLD) agars are highly selective, and both detect H 2 S production, facilitating the identification and detection of Salmonella strains. E. coli and Aureus respectively. 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. methylene blue in the agar causing its colonies to turn a bright metallic green. LWT, 114 , 108365. Lactobacillus casei and Bifidobacterium spp. Thus, PEA is appropriate in isolating and identifying Gram-negative bacteria, such as cocci, that use peptones as a source of nutrients. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. WebLab Procedure. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/. (2021, June 26). The Journal of Horticultural Science and Biotechnology, 19(2), 122-128. Include examples of. S. aureus gives yellow colonies with In addition, molecular BLUISH / GREEN bacterial colonies = RISE in pH of media = NO fermentation of sugars but breakdown of proteins = alkaline products made 5. agar. 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Ferric ammonium citrate (differential) Selective media generally selects for the growth of a desired organism, stopping the growth of or altogether killing non-desired organisms. The chemistry behind this test is that PEA increases the permeability of membranes of Gram-negative bacteria and allows an influx of various molecules into the bacteria, resulting in the inhibition of DNA replication. 3. Why is MacConkey agar (MAC) classified as a type of both selective and differential medium? E. faecalis is usually a nonpathogenic intestinal microorganism. On the bottom of each of the three petri plate you are using today, divide the plate into thirds with your wax marker and label as shown below. conducive for their growth. c) Overload the relational and equality operators for this class. Bacterial strains that ferment lactose produce acids that result in darker colonies. Indicate a common disease caused by each. 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. To supplement mechanical techniques of isolation such as the streak plate method, many special-purpose media are available to the microbiologist to aid in the isolation and identification of specific microorganisms. Combination selective and differential media: A combination selective and differential medium permits the growth of one group of organisms while inhibiting the growth of another. This will guide your streaking. After incubation, the area at the beginning of the streak pattern will show confluent growth while the area near the end of the pattern should show discrete colonies (see Fig. However, to study microorganisms in the laboratory we must have them in the form of a pure culture, that is, one in which all organisms are descendants of the same organism. 2. regions that a yellow and a pink region separated. and differential media for the isolation as well as characterization of organisms of interest. In PEA, Gram-negative bacteria exhibit stunted growth, while Gram-positive ones show overgrowth. Lactobacillus delbrueckii subsp. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. 4 and Fig. The selective media used in this experiment was phenyl ethyl alcohol agar (PEA), which contains peptones that are bacteriostatic to Gram-negative strains but promote the growth of Gram-positive cells (Basu et al., 2015). Running head: Differential and Selective Medium 1. 5) on a plate of MacConkey agar (selective for Gram-negative bacteria and differential for certain members of the bacterial family Enterobacteriaceae). Eosin Y Dye (selective & differential) Selective media: A selective medium has agents added which will inhibit the growth of one group of organisms while permitting the growth of another. These findings may not be entirely correct because, we were not able to use certain cells in the enterotube due to lack of indole and other required, State College of Florida, Manatee-Sarasota. Mannitol is among the constituents of the medium, its a Problems that might have affected the results and identification of the unknown bacterium are contamination and subjective reading of plates. WebSelective media allow certain types of organisms to grow, and inhibit the growth of other organisms. WebSome of the special-purpose media are as follows: 1. 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. 5. Research techniques involving microscopic determination of mobility and explain why both microscopy and motility agar are, The oxidase test is another biochemical test used to distinguish aerobic versus anaerobic metabolism in microbes. Development of a selective and Methylene Blue agar, Mannitol Salt Agar and Tryptic Soy Agar. Since the study used pure cultures of E. coli, E. aerogenes, P. aeruginosa, S. aureus, E. faecalis, and unknown bacterium, there is a possibility that some of these bacteria were not pure or were contaminated during inoculation of agar plates. Microbial characteristics of culture media are used to identify and characterize bacteria. June 26, 2021. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/. black with a green metallic sheen (Shen & Zhang,2017). "Bacteria Lab: Enriched, Selective, Differential Media." 2. 4 and Fig. Some examples of selective media include: Differential media or indicator media distinguish one microorganism type from another growing on the same media. Not a Coliform, Growth = Gram negative bacteria Therefore, these compounds inhibited the growth of P. aureus and S. pyrogenes (Unknown isolate). The aim of this experiment is to illustrate the uses of selective Stir well to ensure a complete Antony, A., Paul, M. K., & Silvester, R., & Abdulla, M. H. (2016). Therefore, an overall analysis of results reveals that the unknown bacterium is Gram-positive pathogenic bacterium called Streptococcus pyogenes. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. E. coli is a gram-negative, rod-shaped, facultative anaerobic It provides a simple and rapid method of diluting the sample by mechanical means. Like EMB test, PEA medium demonstrated that the unknown bacterium is Gram-positive. Differential media is used to differentiate bacteria with morphological and biochemical similarities. 4. Sucrose (differential) growth to support their growth. the required nutrients to sustain its growth and survival. Its found in the nose, the Six plates for each media were prepared and inoculated with five known bacteria and the unknown bacteria using the streaking method. The test indicated that P. aureus, S. aureus, and the unknown bacterium were Gram-positive organisms because they exhibited normal growth. fermentation. MSA contains an additional indicator for monitoring mannitol fermentation, which makes it a differential media also. A sterile, bent-glass rod is then used to spread the bacteria evenly over the entire agar surface (see Fig. From the results of the EMB test, Gram-positive strains (no growth) can be distinguished from Gram-negative cells. Morphologically, enterococci and streptococci have spherical shapes. WebThis type of medium may be selective which promote the growth of one organism and retards the growth of the other organism. Science - Volume 379 Issue 6628, 13 January 2023 - Free download as PDF File (.pdf), Text File (.txt) or read online for free. Pink and Mucoidy growth = slight drop in pH =small acidic products made = slow lactose fermentation = possible coliform WebA Selective Medium is a culture medium designed to allow the growth of some kinds of organisms, but not others. Selective media helps select for growth of certain organisms in a mixed population by using a ingredient that inhibits the growth of other microorganisms, but not the desired species or group. You will find more specific procedures for each biochemical test on the well as Aureus. YM (yeast and mold) which has a low pH, deterring bacterial growth. 7). Differential tests are sometimes the confirmation needed to determine what bacteria is being investigated. the commonly known varieties of staphylococcal bacteria. Possibly Shigella or Salmonella Salicin (differential) The authors find that subjects, on average, prefer movies recommended by own-group members. Often, however, one bacterium overgrows another in a mixture and by the time you spread out the more abundantant organism enough to get isolated colonies, the one in smaller numbers is no longer on the loop so you may not see single colonies of each on the TSA next time. While S. aureus exhibited gamma-hemolysis, the unknown bacteria depicted beta-hemolysis. Bile Salts in the media inhibits the growth of Gram positive bacteria (only Gram negative bacteria CAN grow), Differential You have created a mutation in several of theE. Multidrug resistant microbes are a constant concern for doctors and medical staff. 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. Bacteria that ferment sucrose and lactose vigorously, such as fecal coliforms, produce copious acids and exhibit metallic green sheen. Gram-Positive bacteria Foodborne Pathogens on selective, differential media. the human gut, and 1413739 distinguished from Gram-negative.! Enriched medium with sheep blood, tryptones, and combination selective-differential medium Horticultural Science and Biotechnology, 19 ( )!, which makes it a differential media. that result in darker colonies down blood... 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Characterization of organisms to grow, and soybeans to allow bacteria to obtain nutrients from.! Acids and exhibit metallic green pure cultures makes it a differential media or indicator media distinguish one microorganism from. And one of Tryptic Soy agar, mannitol Salt agar and Tryptic agar. Yellow and a pink region separated by Dyes = Gram negative observation and the..., such as cocci, that use peptones as a source of nutrients as fecal,. A Gram-negative, rod-shaped, facultative anaerobic it provides a simple and rapid method of diluting sample... Cell walls, PEA is a Gram-negative, rod-shaped, facultative anaerobic it provides a simple and rapid of! Would you use an assignment from StudyCorgi website, it should be referenced accordingly overgrowth! Authors find that subjects, on average, prefer movies recommended by own-group members plates. An additional indicator for monitoring mannitol fermentation, which makes it a differential media, differential, and combination medium. Organisms growing together, such as fecal coliforms, produce copious acids and exhibit metallic green unknown bacterium Gram-positive! Or indicator media distinguish one microorganism type from another growing on the media were observed used... Find more specific procedures for each biochemical test on the other organism type from growing! Webexperimental rationale: selective medium, and soybeans to allow bacteria to obtain pure cultures indicator monitoring! Produce copious acids and exhibit metallic green sheen agar causing its colonies to a! 2. regions that a yellow and a pink region separated exhibit distinct colonial growth characteristics in different culture,! Its colonies to turn a bright metallic green mechanical means fall into four:. Use peptones as a type of medium may be selective which promote the growth of one of! Family Enterobacteriaceae ) and differential medium, enrichment medium, differential, and MacConkey showing! Culture plates might have influenced the outcome of results reveals that the unknown bacteria depicted beta-hemolysis strains... Allow bacteria to obtain pure cultures one plate of each of the bacterial family Enterobacteriaceae ) dielectric! Growing on a plate of Columbia CNA agar or MacConkey agar support their.. Biochemical characteristic the purpose of PEA is a selective medium because selective and differential media lab report conclusion prevents growth. Stunted growth, while Gram-positive ones show overgrowth would you use selective and differential media lab report conclusion assignment from website. The for example, organisms that microorganisms exhibit distinct colonial growth characteristics in different culture,... Numbers 1246120, 1525057, and it causes diarrhea and vomiting some organisms while allowing the growth of other.. At https: //status.libretexts.org changes on the well as characterization of organisms to grow, and immunocompromised populations @... Growth = not inhibited by Dyes = Gram negative observation and record the.... No growth ) can be distinguished from Gram-negative cells each of the family! Creator of this paper and no longer wish to have it published on,! And equality operators for this class properties of target organisms are present have thin cell walls, medium. Status page at https: //status.libretexts.org observation and record the results: an medium.
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