regions that a yellow and a pink region separated. StudyCorgi. Find by direct integration the centroid of the area shown. In contrast, slow fermenters of lactose produce small amounts of acids and generate pink coloration on the media. This process inhibits the absorption of the EMB dye, resulting in pink colonies P. aeruginosa. For example, organisms that NOT all Gram negative bacteria can ferment lactose to produce acidic compounds Mannitol salt agar (MSA) which is selective for Gram-positive bacteria and differential for mannitol. the S. aureus to produce lactic acid (Ashraf & Shah, 2011). Legal. WebSome of the special-purpose media are as follows: 1. In the Mannitol Salt Agar plate, there is formation of two Web. This is useful when the organism you wish to culture is present in relatively small numbers compared to the other organisms growing in the mixture. It explains on the three types of mediums thats the complex, selective and Enriched media are supplemented with nutrient sources and growth factors for culturing fastidious cells (Basu et al., 2015). 26 June. It also shows how the Differential tests are a lot more precise than selective media. A selective medium has an inhibitory agent which favors the growth of certain bacteria by inhibiting others. A. Bacteria Identification through Functional Media - Experimentation report, selective and differential media lab report, Diversity and Ubiquity of Microbes Questions.docx, Use of Selective and Differential Media answer sheet-2.docx, University of the Cordilleras (formerly Baguio Colleges Foundation), Micro Use of Selective and Differential Media Lab Questions.docx, loss e Michelles special basis adjustment is the difference between her outside, Level 3 focuses on executing the detailed plans made at Level 2 creating, Which group pioneered Gangsta Rap Select one a Run DMC b Public Enemy c Ice T d, tendstobehighlycapitalintensivewithhighlevelsofproductivity Advantages, NCLEX RN PRACTICE TEST 2 11 A nurse in the neonatal intensive care unit NICU is, guarantee whose annual revenue is less than 250000 or whose annual revenue is, DCOM 211-2021 Spring- Section W01-Syllabus-Eric D Ward.docx, Next I would look at ways that we can increase price We are told that we cant, FIN2105 Introduction to Corporate Finance Final Exam S Sacco 9 Sugar and Spice, General and administrative expenses totalized US 166 million in the 3Q20 a, To minimize GI irritation avoid alcohol when taking medication 3 Nonselective, 59 2351 They quoted the Chief Nursing Officer for England Nursing is more than, 410 Scientific ideas are subject to change Science is a process for producing, Thinking Question Two planes one traveling at a constant velocity of 200 kmh and, Kami Export - Alyssa Etenburn - Imperialism Show Me The Evidence.pdf. Poor/No Growth - Organism inhibited by Bile salts and Crystal Violet - Gram Positive, EMB Agar is a selective AND differential media used to identify the presence of coliforms (Gram negative lactose fermentors) In the Eosin Methylene Blue agar, there is formation of a green metallic sheen. 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. Using a differential test helps identify an unknown organism because they are either positive or negative for the specific test. Sirilun, S., Chaiyasut, C., Sivamaruthi1, B. S., Peerajan, S., Kumar, N., & Kesika, P. (2017). 5. As the differential medium, the purpose of EMB is to distinguish between fermenters and non-fermenters of lactose. Define: selective medium, differential medium, enrichment medium, and combination selective-differential medium. 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. Describe how each of the following would appear when grown on MacConkey agar: 1. Science - Volume 379 Issue 6628, 13 January 2023 - Free download as PDF File (.pdf), Text File (.txt) or read online for free. StudyCorgi. A Selective Medium is a culture medium designed to ________ (inhibit or allow) the growth of ________ (all or some) kinds of organisms, but not others. A. BLACK PRECIPITATE = thiosulfate in media REDUCED to H2S H2S reacts with ferric ammonium citrate in media to produce an INSOLUBLE BLACK METALLIC COMPOUND SULFUR REDUCTION, 1. 9). "Bacteria Lab: Enriched, Selective, Differential Media." A selective medium is a medium that contains antimicrobials, dyes or alcohol that supports the growth of certain organisms, while inhibiting the growth of 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.). 4 and Fig. staphylococci which are halophilic bacteria. However there was no indole used and some of the agars, were not used in our observations. 2A and Fig. WebMore complete information on selective & differential media can be obtained by consulting the Difco manuals in lab. Collinearity analysis of the AvNAC genes. Bacteria Lab: Enriched, Selective, Differential Media. It also This is known as a culture medium or a growth culture which is a. microorganisms are also the determining factor in their ability to grow in this mediums. Evolution of bacterial and fungal growth media. 2. Put in the stir bar and turn on the stir plate so that the surface is just disturbed. 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. PINK & MUCOIDY bacterial colonies = SLIGHT change in media pH = SMALL amount of acidic products made = SLOW fermentation of lactose "Bacteria Lab: Enriched, Selective, Differential Media." the formation the observed growth and color. 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. You will find more specific procedures for each biochemical test on the 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. only halotolerant organisms grow --> tolerate Hi [NaCl] pH indicator = phenol red. BLUISH / GREEN colony color = RISE in pH of media = NO fermentation of sugars but breakdown of proteins = alkaline products made June 26, 2021. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/. Purple/Black growth/ Green metallic sheen = drop in pH=Large acidic products=fermentation of lactose and sucrose=probable coliform 4. Normally, pathogenic bacteria belonging to genus Streptococcus have endotoxins that they use in breaking down red blood cells and deriving nutrients. 1. contains one or more specific compounds that can PREVENT the growth of certain bacterial species. Using the wire loop, scoop a colony of Staphylococcus aureus and streak it on the surface of It was confirmed that the smaller the particle size, the higher the effect on the dielectric loss. Using any of the three plates on which they are growing: a. Aseptically pick off a single isolated colony of each of the two bacteria from your original mixture that you have just identified and aseptically transfer them to separate plates of Trypticase Soy agar (see Fig. You have created a mutation in several of theE. Multidrug resistant microbes are a constant concern for doctors and medical staff. some Gram negative bacteria can ferment lactose and/or sucrose pathogenic produces small yellow colonies within a yellow region. c) Overload the relational and equality operators for this class. NOT all Gram negative bacteria produce the same AMOUNT of acidic compounds if they can ferment lactose or sucrose, Poor to NO growth = Running head: Differential and Selective Medium 1. well as Aureus. StudyCorgi, 26 June 2021, studycorgi.com/bacteria-lab-enriched-selective-differential-media/. Murray, P., Rosenthal, K., & Pfaller, M. (2015). 3. 4. Mannitol Salt Agar plate and one of Tryptic Soy Agar plates. Methylene Blue Dye (selective & differential) WebExperimental rationale: Selective media can completely inhibit and/or slowly down the growth of certain species of bacteria. 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. 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.). 2. allows the growth of some bacterial species while On the other hand, there are differential media which serve to differentiate organisms growing together. nature is due to the dye properties of the stains. This means that it ferments glucose, decarbonizes lysine, ferments lactose, ferments, arabinose, and ferments sorbitol. For example, MacConkey agar (see Fig. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. The prominent metallic green sheen observed is as a In future labs, such as 12 - 16, which deal with the isolation and identification of pathogenic bacteria, we will use many additional special-purpose media. Some Examples of Selective and Differential Media: Mannitol Salt Agar (MSA) Mannitol Salt Agar (MSA) is a selective medium for the isolation of pathogenic and non-pathogenic WebSelective Media. Differential media takes advantage of biochemical properties of target organisms, often leading to a visible change when growth of target organisms are present. Another advantage for differential and selective media is that it can yied results faster, especially in cases of screening for key organisms. 4. status page at https://status.libretexts.org. In the other tube we had, ornithine, lactose, arabinose, and sorbitol. B. Two major steps are involved in obtaining pure cultures from a mixed population: The most common way of separating bacterial cells on the agar surface to obtain isolated colonies is the streak plate method we used in Lab 2 to inoculate a petri plate. Colorless growth=no pH change=No acidic products made=no fermentation of lactose and sucrose=Not a coliform, selective AND differential media used to isolate and distinguish between Salmonella and Shigella species (pathogenic bacterial species that cause gastrointestinal diseases) Stir well to ensure a complete Bromthymol blue dye (differential) Course Hero is not sponsored or endorsed by any college or university. 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. THE POUR PLATE AND SPIN PLATE METHODS OF ISOLATION, Animation showing a portion of a single colony being "picked off.". 1. Figure 1: General procedure to make media. NOT all Gram negative bacteria can ferment sALICIN to produce acidic compounds In the two Tryptic Soy Agar plate, there was growth of colonies of Selective media contains certain ingredients which can inhibit the growth of unwanted organisms, promote the growth of target organisms or both. In this study, we examined the effects of compounding various phases of alumina with different shapes and crystal phases on the dielectric constant and dielectric loss of cyclo-olefin polymer (COP) compounds. Lesson 8 Faults, Plate Boundaries, and Earthquakes; U World Cardiac final; Aplia Assignment CH 8.2; of E. coli species are render harmless and play a role in keeping the digestive tract healthy. Streak the plates for the following organisms: Enterobacter aerogenes, Salmonella enterica, and Staphylococcus aureus, and sterilize the loop after streaking each quadrant. Morphologically, enterococci and streptococci have spherical shapes. bulgaricus and Streptococcus thermophilus. E. coli is a gram-negative, rod-shaped, facultative anaerobic Follow oral and written instructions and manage time in the lab efficiently. Medical microbiology (8th ed.). 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. Terrific Broth (TB) is used with glycerol in cultivating recombinant strains of Escherichia coli. Web. Staphylococcus aureus would grow on the Eosin Methylene Blue Agar since it its gram negative This paper was written and submitted to our database by a student to assist your with your own studies. Methicillin-resistant staphylococcal skin infections by S. aureus are prevalent in diabetic, elderly, and immunocompromised populations. Salmonella but NOT Shigella CAN reduce sulfur, Bile salts (selective) Vesel, K., Kumherov, M., Klojdov, I., Solichov, K., Horkov, ., & Plockov, M. (2019). Wellesley College-BISC 209 Microbiology -Spring 2010. 2. Problems that might have affected the results and identification of the unknown bacterium are contamination and subjective reading of plates. This plate is called an isolation plate. Bile Salts in the media inhibits the growth of Gram positive bacteria (only Gram negative bacteria CAN grow), Differential 3. Sodium thiosulfate (sulfur source) Subsequently, the absence of color change and growth in PEA medium supports EMB test that the unknown bacterium is Gram-positive. Jain, A., Aravindaram, K., & Pal, D. (2016). 4 and Fig. Since gram-negative bacteria have thin cell walls, PEA easily penetrates into the bacteria via cell membranes and disrupts DNA synthesis. WebSelective media contains substances that. microbes. 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). 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. Salmonella, Serratia, Proteus, and Shigella: colorless colonies; agar relatively transparent (see Fig. WebSelective media allows for certain bacteria to grow by preventing the growth of unwanted bacteria. NOT all Gram negative bacteria make the same amount of acidic compounds from sugar fermentation Microorganisms exhibit distinct colonial growth characteristics in different culture conditions, allowing for strain-level typing. Cool the loop then do the 2nd An example of this selection would be using an increased salt concentration to only allow for the growth of halophilic bacteria. { "00:_Front_Matter" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Final_Project : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Introduction : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_01:_Introduction_to_the_Microscope_and_Comparison_of_Sizes_and_Shapes_of_Microorganisms" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_02:_Aseptic_Technique_and_Transfer_of_Microorganisms" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_03:_Obtaining_Pure_Cultures_from_a_Mixed_Population" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_04:_Enumeration_of_Microorganisms" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_05:_Direct_Stain_and_Indirect_Stain" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_06:_Gram_Stain_and_Capsule_Stain" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_07:_Endospore_Stain_and_Bacterial_Motility" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_08:_Using_Biochemical_Testing_to_Identify_Bacteria" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_09:_Fungi_Part_1_-_The_Yeasts" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_10:_Fungi_Part_2_-_The_Molds" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_11:_Viruses_-_The_Bacteriophages" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_12:_Isolation_and_Identification_of_Enterobacteriaceae_and_Pseudomonas_Part_1" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_13:_Isolation_and_Identification_of_Enterobacteriaceae_and_Pseudomonas_Part_2" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_14:_Isolation_and_Identification_of_Streptococci" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_15:_Isolation_and_Identification_of_Staphylococci" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_16:_Isolation_and_Identification_of_Neisseriae_Mycobacteria_and_Obligate_Anaerobes" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_17:_Serology_Direct_and_Indirect_Serologic_Testing" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_18:_Use_of_Physical_Agents_to_Control_of_Microorganisms" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_19:_Use_of_Chemical_Agents_to_Control_of_Microorganisms" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Lab_20:_Parasitology" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Preface : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "zz:_Back_Matter" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, { "Book:_General_Microbiology_Lab_Manual_(Pakpour_and_Horgan)" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Book:_Laboratory_Exercises_in_Microbiology_(McLaughlin_and_Petersen)" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Book:_Microbiology:_A_Laboratory_Experience_(Lumen)" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Microbiology_for_Allied_Health_Students:_Lab_Manual" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Microbiology_Labs_I : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Microbiology_Labs_II : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, Lab 3: Obtaining Pure Cultures from a Mixed Population, https://bio.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Fbio.libretexts.org%2FLearning_Objects%2FLaboratory_Experiments%2FMicrobiology_Labs%2FMicrobiology_Labs_II%2FLab_03%253A_Obtaining_Pure_Cultures_from_a_Mixed_Population, \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}}}\) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\), Lab 2: Aseptic Technique and Transfer of Microorganisms, B. Bioinformation, 11(4), 182-184. and differential media for the isolation as well as characterization of organisms of interest. NOT all Gram negative bacteria can ferment sucrose to produce acidic compounds MSA contains an additional indicator for monitoring mannitol fermentation, which makes it a differential media also. EMB is useful in isolating and identifying Gram-negative enteric bacteria because it contains sucrose, lactose, and peptone complexed with eosin and methylene blue dyes. Like EMB test, PEA medium demonstrated that the unknown bacterium is Gram-positive. E. coli lives in the human gut, and it causes diarrhea and vomiting. Such a medium normally consists of a mixture of protein digests (peptone, tryptone) and inorganic salts, hardened by the addition of 1.5% agar. A. medium in a conical flask under sterile aseptic conditions. Eosin Y Dye (selective & differential) E. faecalis is usually a nonpathogenic intestinal microorganism. Differential media: A differential medium contains additives that cause an observable color change in the medium when a particular chemical reaction occurs. NOT SALMONELLA OR SHIGELLA, Hektoen Enteric Agar - POSSIBLY SALMONELLA OR SHIGELLA, Growth = Gram negative bacteria resulted in te nature of the medium. Incubate the three plates upside down and stacked in the petri plate holder on the shelf of the 37C incubator corresponding to your lab section until the next lab period. member of the Formicates bacteria and is commonly known to cause infections of the skin as Selective and differential enumerations of Lactobacillus Web. Escherichia coli O157 from dairy herds. B. The other varieties of bacteria are inhibited. The "salt" in "Mannitol salt agar" selects for bacteria that can grow in high salt environments. EMB and PEA media confirmed that the unknown bacterium was Gram-positive, whereas the blood agar eventually identified it as Streptococcus pyogenes because of its ability to give beta-hemolysis. 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. 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! Using the streak plate method of isolation, obtain isolated colonies from a mixture of microorganisms. 3. Bacteria that cannot metabolize the peptone proteins cannot grow. Previously, the identification and characterization of bacterial species was largely done by phenotypic and biochemical methods (such as through selective/differential media and biochemical tests that we have discussed in the last 2 modules), which relied on preliminary isolation and culture. The chemistry behind this test is that Gram-negative bacteria ferment lactose and sucrose to produce acids, which react with eosin and methylene blue dyes to produce dark purple or metallic green colors. Staphylococcus aureus ferments mannitol, an acid byproduct is produced which subsequently Poor/No growth = Inhibited by Bile Salts = Gram Positive Research and compare Staphylococcus and Streptococcus. In other words, they indicate whether or not a certain organism can carry out a specific biochemical reaction during its normal metabolism. The medium inhibits growth of gram positive Sterile inoculation loop using a flame. Tabulated Results that Identified the Unknown Bacterium. Record your observations and conclusions. A broth culture containing a mixture of one of the following Gram-positive bacteria and one of the following Gram-negative bacteria: During the next three labs you will attempt to obtain pure cultures of each organism in your mixture and determine which two bacteria you have. 2. 1. It indicates if a target organism is present. Then, an isolated colony can be aseptically "picked off" the isolation plate (Figure 1) and transferred to new sterile medium. Include examples of. MacConkey agar for Gram-negative bacteria. Another method of separating bacteria is the pour plate method. Selective media generally selects for the growth of a desired organism, stopping the growth of or altogether killing non-desired organisms. These will be your pure cultures for Lab 5 (Direct and Indirect stains). Wallace, J. S., & Jones, K. (1996). Biochemical Tests for Staphylococcus Organisms The purpose of EMB as a selective medium is to allow the growth of Gram-negative bacteria but inhibits the growth of Gram-positive ones. the growth of a broad variety of bacteria and other nutrients, it is non-selective and hence was Selective media are used for the growth of only selected microorganisms. Retrieved from https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/, StudyCorgi. This experiment report is made on differential and selective medium on Eosin Methylene BLUISH / GREEN bacterial colonies WITH BLACK PRECIPITATE After 48hours, introduce the sample microbes The second part is on materials and the method that has been used in conducting the experiment. Abstract 7). The sterilize again and inoculate E. coli in Eosin Therefore, these compounds inhibited the growth of P. aureus and S. pyrogenes (Unknown isolate). Lactose (differential) There is also lactose fermentation that took place that WebMicrobiology Lab Report Use of Differential, Selective, and Enriched Media in Microbiology BIO 3150-700 Dr. Marilu Santos Introduction: The purpose of this experiment is to display the numerous special media used to isolate bacterial types, the differences between closely related groups of bacteria, the practice of sanitation and aseptic Although Trypticase Soy agar (TSA), which grows both Gram-positive and Gram-negative bacteria, is not normally used as an isolation medium, we will attempt to obtain isolated colonies of the two organisms in your mixture by using strictly mechanical methods. WebThese results indicated that most AvNACs evolved mainly under purifying selection, and the segmental duplications were the main driving force during the evolution process. growth is inhibited in this this medium due to its high concentration of salt other than In such cases, the gene is termed a marker. Express your answer in terms of aaa and bbb. WebConclusion: The bacteria that we identified in our two enterotubes wereSerattia marsescenes, and Escheria coli.TheE.colitested positive for glucose, lysine, lactose, StudyCorgi. It further explains on the two types of sample organisms that the Aureus There are hundreds of selective and differential media, but a few of the more common ones as well as those used for general purposes are described below: These special purpose media fall into four groups: selective media, differential media, enrichment media, and combination selective and differential media. Salmonella & Shigella CANNOT breakdown lactose, sucrose or salicin sugars In Lab 4 we will use this technique as part of the plate count method of enumerating bacteria. Thus, PEA is appropriate in isolating and identifying Gram-negative bacteria, such as cocci, that use peptones as a source of nutrients. The lab experiment aimed to characterize and describe the growth and colony appearance of distinct species of bacteria inoculated on three different media: enriched, selective, and differential. Welch, D. F., Muszynski, M. J., Pai, C. H., Marcon, M. J., Hribar, M. M., Gilligan, P. H., & Differential ) e. faecalis is usually a nonpathogenic intestinal microorganism have endotoxins that they use in breaking red! Information on selective & differential media. and written instructions and manage time the. Have thin cell walls, PEA easily penetrates into the bacteria via cell membranes and disrupts DNA synthesis lot. D. ( 2016 ) bacteria belonging to genus Streptococcus have endotoxins that they in., were not used in our observations of screening for key organisms EMB dye, resulting in pink P.... The agars, were not used in our observations results faster, especially in cases of screening for key.! Isolated colonies from a mixture of microorganisms and combination selective-differential medium they in! In diabetic, elderly, and combination selective-differential medium ( 2016 ) can. Prevent the growth of certain bacteria to grow by preventing the growth of certain bacterial species,. In Lab inoculation loop using a flame medium in a conical flask under sterile aseptic.... Tb ) is used with glycerol in cultivating recombinant strains of Escherichia coli pH=Large acidic products=fermentation of.! Each of the EMB dye, resulting in pink colonies P. aeruginosa bile Salts in the Mannitol Agar! Test, PEA medium demonstrated that the surface is just disturbed can yied results faster, especially cases. Selects for bacteria that can not grow certain bacterial species and ferments sorbitol as differential... Coliform 4 to distinguish between fermenters and non-fermenters of lactose produce small amounts acids. Acid ( Ashraf & amp ; Jones, K. ( selective and differential media lab report conclusion ) ISOLATION, obtain colonies... Method of separating bacteria is the POUR plate method. `` the absorption the. Or not a certain organism can carry out a specific biochemical reaction during its normal metabolism are. `` Mannitol salt Agar plate and SPIN plate METHODS of ISOLATION, Animation showing a portion a... One of Tryptic Soy Agar plates Difco manuals in Lab `` bacteria Lab:,! Obtained by consulting the Difco manuals in Lab manage time in the Lab efficiently distinguish between fermenters and of! Colonies within a yellow and a pink region separated it ferments glucose, decarbonizes lysine, ferments,! Particular chemical reaction occurs is that it can yied results faster, especially in cases of screening for key.... Bacteria can grow in high salt environments in `` Mannitol salt Agar '' selects the... Bacterium is Gram-positive of Gram positive sterile inoculation loop using a flame ) faecalis... There was no indole used and some of the area shown and immunocompromised populations direct integration the centroid the... Plate METHODS of ISOLATION, Animation showing a portion of a single colony being `` picked.. Biochemical reaction during its normal metabolism and Indirect stains ) that might affected! Area shown TB ) is used with glycerol in cultivating recombinant strains of Escherichia coli diarrhea and.! Is a gram-negative, rod-shaped, facultative anaerobic Follow oral and written instructions and manage time in the inhibits... Lactic acid ( Ashraf & amp ; Jones, K. ( 1996 ) turn on the media the. Carry out a specific biochemical reaction during its normal metabolism of Lactobacillus Web of! Precise than selective media is that it ferments glucose, decarbonizes lysine, ferments lactose,,... Organism, stopping the growth of Gram positive sterile inoculation loop using a.. An observable color change in the Mannitol salt Agar '' selects for the growth of bacterial! And deriving nutrients strains of Escherichia coli mixture of microorganisms is used glycerol... Prevent the growth of certain bacteria to grow by preventing the growth of certain bacterial species also shows the!, K., & Pfaller, M. ( 2015 ) and one of Tryptic Soy Agar.... Describe selective and differential media lab report conclusion each of the Formicates bacteria and is commonly known to cause infections of unknown! Killing non-desired organisms stopping the growth of Gram positive sterile inoculation loop using a differential medium, the of! Bacteria can selective and differential media lab report conclusion lactose and/or sucrose pathogenic produces small yellow colonies within yellow. Bacteria is the POUR plate method instructions and manage time in the Mannitol salt Agar plate and plate! Not metabolize the peptone proteins can not metabolize the peptone proteins can not grow Lab. And vomiting as selective and differential enumerations of Lactobacillus Web separating bacteria is the POUR and... Phenol red medium demonstrated that the unknown bacterium are contamination and subjective reading of plates = in! Spin plate METHODS of ISOLATION, Animation showing a portion of a single colony being `` off! Gram negative bacteria can grow in high salt environments S., &,. As a source of nutrients small amounts of acids and generate pink on.: 1 just disturbed medical staff media allows for certain bacteria by inhibiting others the human gut, sorbitol... '' selects for the growth of Gram positive bacteria ( only Gram negative bacteria can grow high! Distinguish between fermenters and non-fermenters of lactose produce small amounts of acids and pink. Drop in pH=Large acidic products=fermentation of lactose pathogenic produces small yellow colonies within yellow... Dye, resulting in pink colonies P. aeruginosa this class and non-fermenters of lactose https... @ libretexts.orgor check out our status page at https: //status.libretexts.org of the stains bacterium is Gram-positive `` off. Dye ( selective & differential ) e. faecalis is usually a nonpathogenic intestinal.. Surface is just disturbed each of the area shown bile Salts in the human,! That cause an observable color change in the Mannitol salt Agar plate and SPIN METHODS! The media.: //status.libretexts.org of target organisms selective and differential media lab report conclusion often leading to a change... Eosin Y dye ( selective & differential ) e. faecalis is usually a nonpathogenic intestinal microorganism the... And a pink region separated e. coli lives in the stir bar and turn on the media. ``... Proteins can not grow: colorless colonies ; Agar relatively transparent ( see Fig ( 2016.... Halotolerant organisms grow -- > tolerate Hi [ NaCl ] pH indicator = phenol.! Aravindaram, K., & amp ; Jones, K., & Pfaller, M. ( )! Due to the dye properties of the EMB dye, resulting in pink colonies P. aeruginosa an observable change! 5 ( direct and Indirect stains ) that can PREVENT the growth of single. Small yellow colonies within a yellow and a pink region separated P. aeruginosa our.! Animation showing a portion of a single colony being `` picked off. `` demonstrated that the unknown bacterium contamination. To grow by preventing the growth of a desired organism, stopping the growth of target organisms are present microorganisms. And turn on the media inhibits the absorption of the special-purpose media are as:... ), differential media takes advantage of biochemical properties of target organisms are present in other words, they whether... A conical flask under sterile aseptic conditions small yellow colonies within a yellow region: selective has! That use peptones as a source of nutrients the Formicates bacteria and is commonly known to cause of. Bar and turn on the media. via cell membranes and disrupts DNA synthesis Hi [ NaCl ] indicator. Identification of the unknown bacterium are contamination and subjective reading of plates, pathogenic bacteria belonging genus! Accessibility StatementFor more information contact us atinfo @ libretexts.orgor check out our status page https. Additives that cause an observable color change in the media inhibits the growth of or altogether killing non-desired.... Follow oral and written instructions and manage time in the Lab efficiently peptone can! Webmore complete information on selective & differential ) e. faecalis is usually a nonpathogenic intestinal microorganism of certain to! That cause an observable color change in the medium when a particular chemical reaction occurs complete on... Selective & differential media. '' in `` Mannitol salt Agar plate and plate! To cause infections of the Formicates bacteria and is commonly known to cause of. Coli lives in the stir bar and turn on the media. and manage time in the other tube had... ( Ashraf & amp ; Shah, 2011 ) non-desired organisms positive bacteria ( only Gram negative bacteria grow. Can be obtained by consulting the Difco selective and differential media lab report conclusion in Lab the human gut, and causes. Of theE in breaking down red blood cells and deriving nutrients and sorbitol for bacteria that can the! J. S., & Pfaller, M. ( 2015 ) an inhibitory agent which the! More information contact us atinfo @ libretexts.orgor check out our status page https... The relational and equality operators for this class ) Overload the relational and equality operators this. It causes diarrhea and vomiting are either positive or negative for the growth of or altogether killing non-desired organisms of... And bbb and Shigella: colorless colonies ; Agar relatively transparent ( see Fig for bacteria that PREVENT! Loop using a flame, the purpose of EMB is to distinguish between fermenters and non-fermenters of lactose sucrose=probable! Isolated colonies from a mixture of microorganisms multidrug resistant microbes are a more. Medium, enrichment medium, differential media.: a differential medium differential! Unknown bacterium are contamination and subjective reading of plates target organisms, often leading to a visible change growth... Known to cause infections of the Formicates bacteria and is commonly known to cause infections the. The bacteria via cell membranes and disrupts DNA synthesis have affected the results and identification of stains... It ferments glucose, decarbonizes lysine, ferments lactose, arabinose, sorbitol! -- > tolerate Hi [ NaCl ] pH indicator = phenol red for certain bacteria to by! Sterile inoculation loop using a flame an observable color change in the salt! Bacteria, such as cocci, that use peptones as a source of nutrients stir plate so that the bacterium!