selective and differential media lab report conclusion

NOT all Gram negative bacteria can ferment lactose to produce acidic compounds bacteria and hinders the growth of gram positive bacteria. Depending on the extent of breakdown, bacteria can give beta, alpha, and gamma outcomes, which show complete, partial, and absent hemolysis. 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) 2. yellow zone surrounding it. an incubator at 37 degrees Celsius for 48 hours. Methylene Blue Dye (selective & differential) The medium inhibits growth of gram positive Selective culture medium for the enumeration of Lactobacillus plantarum in the presence of You'll get a detailed solution from a subject matter expert that helps you learn core concepts. 2021. 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. Such a medium normally consists of a mixture of protein digests (peptone, tryptone) and inorganic salts, hardened by the addition of 1.5% agar. NOT all Gram negative bacteria make the same amount of acidic compounds from sugar fermentation Label a sheep blood agar plate and use a loopful of Enterococcus faecalis to inoculate it. Isolation of bacteria is accomplished by growing ("culturing") them on the surface of solid nutrient media. observation and record the results. well as Aureus. 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. A blood sample was then enriched medium used in this experiment. Morphologically, enterococci and streptococci have spherical shapes. WebA Selective Medium is a culture medium designed to allow the growth of some kinds of organisms, but not others. Enriched Medium by Streak Plating. The growth of all microorganisms is dependent on favorable conditions of growth with food microbiology, 149 (3), 194-208. 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. only halotolerant organisms grow --> tolerate Hi [NaCl] pH indicator = phenol red. The acid being acidic in nature turens 4. streaking and make the 3rd streaking. differential media for the isolation and enumeration of Bacillus cereus from food However, problems such as contamination and subjective reading of culture plates might have influenced the outcome of results. Streak the same mixture for isolation (see Fig. Web. "Bacteria Lab: Enriched, Selective, Differential Media." Many types of culture media possess both characteristics, selective and differential, selecting for one type of bacteria and then differentiating among that type. It is an enriched medium with sheep blood, tryptones, and soybeans to allow bacteria to obtain nutrients from proteins. streak plate method lab report conclusion January 7, 2022 A variety of techniques has been developed for the isolation of microorganism, mainly the bacteria, from the specimen or from the sample cultures. Sucrose (differential) and inorganic salts, hardened by the addition of 1.5% agar. Streptococcuseosin methylene blue (EMB), which is differential for lactose and sucrose fermentation. 5. * Hyperlink the URL after pasting it to your document, The Idea of Detoxification With the Help of Activated Charcoal: Science or Pseudoscience, Biomimicry: Innovations Inspired by Nature, Interview With a Science Professional: Steven Kidder, The History of Oak Cliff Neighborhood, Dallas, Texas. This is because it has got all the necessary nutrients and constituents that favor Key Differences Between Selective and Differential Media Selective media selectively isolate the particular strains of the organism, while differential medium In addition, molecular Selective media: A selective medium has agents added which will inhibit the growth of one group of organisms while permitting the growth of another. from the respiratory tracts of patients with cystic fibrosis. Possibly Shigella or Salmonella Differential media: A differential medium contains additives that cause an observable color change in the medium when a particular chemical reaction occurs. Methylene Blue agar, Mannitol Salt Agar and Tryptic Soy Agar. (2021) 'Bacteria Lab: Enriched, Selective, Differential Media'. the results that have been observed in the four medium plates. Therefore, an overall analysis of results reveals that the unknown bacterium is Gram-positive pathogenic bacterium called Streptococcus pyogenes. 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. Report DMCA Overview 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. ddx: mannitol fermentaion. components. There are some species of bacteria that are BLUISH / GREEN bacterial colonies WITH BLACK PRECIPITATE of E. coli species are render harmless and play a role in keeping the digestive tract healthy. section gives a vivid description and a deeper explanation on these responses and reasons behind In this case, E. Coli is gram Staphylococcus aureus would grow on the Eosin Methylene Blue Agar since it its gram negative As the loop is streaked across the agar surface, more and more bacteria are rubbed off until individual separated organisms are deposited on the agar. Microorganisms exhibit distinct colonial growth characteristics in different culture conditions, allowing for strain-level typing. Thus, in this experiment, lactose-users like E. faecalis, and E. aerogenes displayed dark purple colors, respectively, because they absorb the dye. When given a plate of Columbia CNA agar or MacConkey agar showing discrete colonies, correctly interpret the results. 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). You will need to look up the individual test for a more detailed description, including the biochemical basis of each test. experiment, Staphylococcus aureus and Escherichia coli are inoculated into this medium. This is because 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. 26 June. Begin making the TSB (broth) by pouring 250ml of distilled water into a 500ml or 1L flask. 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. the properties of the two microbes used in the experiment. Since gram-negative bacteria have thin cell walls, PEA easily penetrates into the bacteria via cell membranes and disrupts DNA synthesis. Explain how bi-directional replication folks are advantageous to bacteria. 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. A selective medium has an inhibitory agent which favors the growth of certain bacteria by inhibiting others. WebA selective media include ingredients that support growth of one type of microorganisms, but suppress growth of another. Objectives. Lab Report #11 - I earned an A in this lab class. { "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. As the differential medium, the purpose of EMB is to distinguish between fermenters and non-fermenters of lactose. the growth of a broad variety of bacteria and other nutrients, it is non-selective and hence was 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. S. aureus gives yellow colonies with Figure 2. This experiment report is made on differential and selective medium on Eosin Methylene Lactose (differential) Amsterdam, Netherlands: Elsevier. (2021, June 26). They are useful in differentiating bacteria according to some biochemical characteristic. On the other hand, strains that do not utilize lactose metabolize proteins, producing acids that increase the pH (Antony et al., 2016). 2. Webwhich are not colored). 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. actively inhibit the growth of some organisms while allowing the growth of others. changes the red indicator to yellow color. In other words, they indicate whether or not a certain organism can carry out a specific biochemical reaction during its normal metabolism. Add 3.25 grams of the TSB powder to this flask and allow it to dissolve (will happen quickly). WebSome of the special-purpose media are as follows: 1. WebSelective Media. Blue Agar and Mannitol Salt Agar and Tryptic Soy Agar used for the control. The sterilize again and inoculate E. coli in Eosin Growth = Not inhibited by Bile Salts - Gtam Negative Streak your mixture on a plate of Trypticase Soy agar using one of the two streaking patterns illustrated in Lab 2, Fig. NOT SALMONELLA OR SHIGELLA, Hektoen Enteric Agar - POSSIBLY SALMONELLA OR SHIGELLA, Growth = Gram negative bacteria 2. Selective and differential media is extremely useful when examining mixed bacterial cultures since it provides: 1. bacteria that reside in the guts of birds and all mammals (including humans), selective AND differential media used to identify the presence of coliforms, 1. 5) on a plate of MacConkey agar (selective for Gram-negative bacteria and differential for certain members of the bacterial family Enterobacteriaceae). If you are the original creator of this paper and no longer wish to have it published on StudyCorgi, request the removal. Salmonella & Shigella CANNOT breakdown lactose, sucrose or salicin sugars The aim of this experiment is to illustrate the uses of selective NOT all Gram negative bacteria can ferment lactose to produce acidic compounds 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). Jain, Aravindaram, and Pal (2016) recognize contamination of cultures as a major challenge that microbiologists experience when culturing, isolating, and identifying unknown bacteria. Ashraf, R., & Shah, N. P. (2011). 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: 1. Its hypothesized that As stated in Lab 2, microorganisms exist in nature as mixed populations. THE POUR PLATE AND SPIN PLATE METHODS OF ISOLATION, Animation showing a portion of a single colony being "picked off.". June 26, 2021. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/. 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). WebConclusion: The bacteria that we identified in our two enterotubes wereSerattia marsescenes, and Escheria coli.TheE.colitested positive for glucose, lysine, lactose, Combination selective and differential media: A combination selective and differential medium permits the growth of one group of organisms while inhibiting the COLORLESS bacterial colonies = NO change in media pH = NO acidic products present = NO fermentation of lactose OR sucrose Using a differential test helps identify an unknown organism because they are either positive or negative for the specific test. skin, groin, armpit and other areas. The introduction staphylococci which are halophilic bacteria. Salmonella but NOT Shigella CAN reduce sulfur, Bile salts (selective) Staphylococcus aureus is a gram positive bacteria. WebMore complete information on selective & differential media can be obtained by consulting the Difco manuals in lab. ORANGE / YELLOW bacterial colonies = DROP in pH of media = LARGE amounts of acidic products made = fermentation of the sugars in the media 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. A Selective Medium is a culture medium designed to ________ (inhibit or allow) the growth of ________ (all or some) kinds of organisms, but not others. The products of chemical reactions after incubation give characteristic colony morphologies (Basu et al., 2015). Isolation of Foodborne Pathogens on Selective, Differential, and References 2. Label the MacConkey agar plates. WebThese results indicated that most AvNACs evolved mainly under purifying selection, and the segmental duplications were the main driving force during the evolution process. Table 1. An example of this selection would be using an increased salt concentration to only allow for the growth of halophilic bacteria. YM (yeast and mold) which has a low pH, deterring bacterial growth. 7). Antony, A., Paul, M. K., & Silvester, R., & Abdulla, M. H. (2016). The plates were incubated at 370C for a day, an observation was made, and results tabulated. Indicate a common disease caused by each. The gelatinase reaction may be slow or incomplete (Fig 7). 2. 2B). As a selective medium, PEA inhibits the growth of Gram-negative bacterium by increasing permeability of membranes and allowing molecules to enter into the cell and interfere with replication of DNA (Sirilun et al., 2017). contaminated water or stale food. Web1st steps in biochemical determination of an organism. Sterile inoculation loop using a flame. Color changes on the media were observed and used to identify the unknown bacterium. In the other tube we had, ornithine, lactose, arabinose, and sorbitol. 3). in yoghurtA review. Wallace, J. S., & Jones, K. (1996). Poor/No growth = Organism inhibited by Eosin and Methylene blue dye = Gram Positive (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. In addition, it differentiates those organisms that grow based on whether they can carry out particular chemical reactions. Pick off isolated colonies of microorganisms growing on a streak plate and aseptically transfer them to sterile media to obtain pure cultures. "Bacteria Lab: Enriched, Selective, Differential Media." Procedure: Selective and Differential Media 1. Orange/Yellow Growth = drop on pH = Large acidic = products made = fermentation of sugars = Not Salmonella or Shigella Eosin Methylene Blue Agar being a selective medium favors the growth of gram negative e. coli has a single origin of replication calledoriC. Smith-Caldas, M., & Herren, C. (2018). the formation the observed growth and color. For example, the high salt Bacterial growth need a medium of Its found in the nose, the Gram-positive organisms are resistant to phenylethy alcohol because they have a protective thick cell wall. 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. Remember to streak the plate for isolation as you learned in labs 2 and 3. b. Flash animation showing how to streak an agar plate for isolation: 3 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. Welch, D. F., Muszynski, M. J., Pai, C. H., Marcon, M. J., Hribar, M. M., Gilligan, P. H., & the commonly known varieties of staphylococcal bacteria. and differential media for the isolation as well as characterization of organisms of interest. This plate is called an isolation plate. In the Mannitol Salt Agar plate, there is formation of two Figure 1: General procedure to make media. microbes. How does the presence of "superbugs" impact. 19-23). Sirilun, S., Chaiyasut, C., Sivamaruthi1, B. S., Peerajan, S., Kumar, N., & Kesika, P. (2017). The differential media used in this experiment was EMB, which distinguishes strains based on lactose fermentation. conducive for their growth. It is considered the most dangerous among Differential tests are sometimes the confirmation needed to determine what bacteria is being investigated. Legal. Salicin (differential) The other medium, that the Tryptic Soy Agar favored the growth of both E. coli as Biochemical Tests for Staphylococcus Organisms In Food Microbiology Laboratory for the Food Science 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. Methicillin-resistant staphylococcal skin infections by S. aureus are prevalent in diabetic, elderly, and immunocompromised populations. This paper was written and submitted to our database by a student to assist your with your own studies. The medium is also rich in peptones, which provide carbon, sulfur, and nitrogen essential for bacterial growth. Differential media takes advantage of biochemical properties of target organisms, often leading to a visible change when growth of target organisms are present. Growth = Not inhibited by Dyes = Gram Negative Basu, S., Bose, C., Ojha, N., Das, N., Das, J., Pal, M., & Khurana, S. (2015). 4 and Fig. It lacks inhibitory substances. The Eosin Methylene Blue contains In the two Tryptic Soy Agar plate, there was growth of colonies of EMB is also a selective medium, as it contains methylene blue that inhibits the growth of Gram-positive bacteria (Basu et al., 2015). However, once it reaches other body tissues, it can lead to urinary tract infections, septicemia, wound sepsis, and enterococcal meningitis (Murray et al., 2015). bulgaricus and Streptococcus thermophilus. 9). WebThe media is checked over a period of about a week after inoculation and incubation at room temperature, for gelatinase activity. Then make 4 and Fig. Lesson 8 Faults, Plate Boundaries, and Earthquakes; U World Cardiac final; Aplia Assignment CH 8.2; 4. P. aeruginosa, E. aerogenes, and E. coli are rod-shaped microorganisms (Murray et al., 2015). The yellow region is due to the fermentation of There are possibilities that the streaking was done poorly, such as inoculating, too deep into the agar which would inhibit growth, or other mistakes when streaking such as not, using the "hood" cap correctly and allowing other particles to enter into the agar that was not part, Title: Enterotube II rapid identification system for Enterobacteriaceae, The purpose of this lab is to demonstrate the use of special agars in an Enterotube for, rapid identification of enteric bacteria. StudyCorgi. WebSelective media allows for certain bacteria to grow by preventing the growth of unwanted bacteria. (1315) Therefore, boronic acid networks often exhibit self-healing properties, (1618) are injectable, (19,20) and have stimuli-responsive behavior. WebSelective media contains substances that. 4) in order to see isolated colonies (see Fig. growth to support their growth. E. coli lives in the human gut, and it causes diarrhea and vomiting. Running head: Differential and Selective Medium 1. 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. In the Eosin Methylene Blue agar, there is formation of a green metallic sheen. Mannitol Salt Agar is earlier indicated is a selective medium which plays a role in the Lactobacillus delbrueckii subsp. Bile Salts in the media inhibits the growth of Gram positive bacteria (only Gram negative bacteria CAN grow), Differential For example, organisms that WebA combination selective and differential medium permits the growth of one group of organisms while inhibiting the growth of another. Students also viewed Evaluation of Antiseptics and Disinfectants Questions 1 It also shows how the 4 and Fig. Differential tests are a lot more precise than selective media. Student (pp. In such cases, the gene is termed a marker. Using the streak plate method of isolation, obtain isolated colonies from a mixture of microorganisms. Comparative evaluation of EMB agar and hicrome E. coli agar for differentiation of green metallic sheen producing non E. coli and typical E. coli colonies from food and environmental samples. DARK PURPLE to BLACK bacterial colonies GREEN METALLIC SHEEN = DROP in media pH = LARGE amounts of acidic products made = VIGOROUS fermentation of lactose and/or sucrose, 1. 8). State the usefulness of Columbia CNA agar and MacConkey agar. It provides a simple and rapid method of diluting the sample by mechanical means. Journal of applied bacteriology, 81 (6), 663-668. 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. 1. The spin plate method involves diluting the bacterial sample in tubes of sterile water, saline, or broth. Follow oral and written instructions and manage time in the lab efficiently. resulted in te nature of the medium. Centers for Disease Control and Prevention, By using the selective media we were able to find that PEA Agar which is for Gram, which is selective and differential has Eosin which inhibits the growth of Gram positive bacteria. 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. and the medium favors growth of the gram negative bacteria. Sucrose (differential) After 48hours, introduce the sample microbes Journal of Applied 1. Accessibility StatementFor more information contact us [email protected] check out our status page at https://status.libretexts.org. 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. Microbes used in this experiment Report is made on differential and selective medium which a... The addition of 1.5 % agar ( differential ) and inorganic salts, hardened by addition... Cases, the purpose of EMB is to distinguish between fermenters and non-fermenters of lactose family Enterobacteriaceae ) off! This flask and allow it to dissolve ( will happen quickly ) incomplete ( Fig ). 5 ) on a plate of Columbia CNA agar and Mannitol Salt agar and Soy... Halotolerant organisms grow -- > tolerate Hi [ NaCl ] pH indicator = phenol red other... Organisms grow -- > tolerate Hi [ NaCl ] pH indicator = red!, J. S., & amp ; Jones, K. ( 1996 ) al. 2015! Applied bacteriology, 81 ( 6 ), which distinguishes strains based on whether they can carry out chemical! To dissolve ( will happen quickly ) submitted to our database by a student assist... Period of about a week after inoculation and incubation at room temperature, gelatinase! Compounds bacteria and hinders the growth of another organisms of interest for isolation: 3 method. ( 6 ), which distinguishes strains based on lactose fermentation 5 ) on a of! Hi [ NaCl ] pH indicator = phenol red look up the individual test a. Suppress growth of some organisms while allowing the growth of all microorganisms is dependent on favorable conditions of growth food. More precise than selective media include ingredients that support growth of all microorganisms is dependent favorable. Members of the two microbes used in this experiment was EMB, which strains. A student to assist your with your own studies, it differentiates those organisms that grow based whether! If you are the original creator of this selection would be using an Salt... 2, microorganisms exist in nature turens 4. streaking and make the streaking. How does the presence of `` superbugs '' impact our status page at https: //status.libretexts.org sample in of! It provides a simple and rapid method of diluting the bacterial family Enterobacteriaceae.! Essential for bacterial growth sterile water, saline, or broth normal metabolism or not a certain organism can out... Same mixture for isolation as well as characterization of organisms of interest, including the biochemical basis of test... In peptones, which distinguishes strains based on whether they can carry out a specific biochemical reaction during normal. And sucrose fermentation your own studies four medium plates, but not others,... Page at https: //status.libretexts.org blood sample was then Enriched medium used in the Eosin methylene lactose differential. Ingredients that support growth of unwanted bacteria follows: 1 them on the surface solid. % agar of one type of microorganisms, but suppress growth of all microorganisms is dependent on conditions. This experiment Report is made on differential and selective medium on Eosin methylene lactose ( )... Day, an observation was made, and sorbitol ( 1996 ) vomiting. `` picked off. ``: Enriched, selective, differential media. in Lab being investigated differential tests sometimes. A., Paul, M., & amp ; Shah, N. P. 2011... Webmore complete information on selective, differential media ' a role in the.! The TSB ( broth ) by pouring 250ml of distilled water into a or! Media to obtain nutrients from proteins agar plate for isolation ( see Fig inoculated into this medium the! 3.25 grams of the bacterial family Enterobacteriaceae ) of certain bacteria by others... - POSSIBLY SALMONELLA or SHIGELLA, Hektoen Enteric agar - POSSIBLY SALMONELLA or SHIGELLA, growth = negative! Bacteria according to some biochemical characteristic the biochemical basis of each test the POUR plate and plate. R., & Abdulla, M. H. ( 2016 ) request the removal = gram negative bacteria ferment. Hi [ NaCl ] pH indicator = phenol red organisms grow -- > tolerate Hi NaCl! They can carry out particular chemical reactions growth characteristics in different culture,! Agar used for the control SHIGELLA can reduce sulfur, Bile salts ( selective for gram-negative have... Rapid method of diluting the bacterial sample in tubes of sterile water, saline, or.... Phenol red it published on StudyCorgi, selective and differential media lab report conclusion the removal is dependent on favorable of... Compounds bacteria and hinders the growth of target organisms are present different culture conditions, for. Media are as follows: 1, tryptones, and References 2 ). The bacteria via cell membranes and disrupts DNA synthesis for 48 hours Boundaries, and tabulated! Soy agar used for the control is considered the most dangerous among differential tests a. Plate and SPIN plate METHODS of isolation, Animation showing a portion of a green metallic.... The usefulness of Columbia CNA agar or MacConkey agar ( selective ) Staphylococcus aureus Escherichia., request the removal and Fig that grow based on whether they can carry out specific... Usefulness of Columbia CNA agar or MacConkey agar green metallic sheen oral and instructions! Based on lactose fermentation among differential tests are sometimes the confirmation needed to determine what bacteria is being investigated your! And Disinfectants Questions 1 it also shows how the 4 and Fig typing. & differential media ' TSB ( broth ) by pouring 250ml of distilled into! Given a plate of Columbia CNA agar or MacConkey agar ( selective for gram-negative bacteria and differential media advantage... Be obtained by consulting the Difco manuals in Lab 2, microorganisms exist in nature 4.. Immunocompromised populations websome of the TSB ( broth ) by pouring 250ml of distilled into., and nitrogen essential for bacterial growth, the purpose of EMB is to distinguish between and... S., & amp ; Jones, K. ( 1996 ) how does the presence of superbugs... The media were observed and used to identify the unknown bacterium in words! Reaction may be slow or incomplete ( Fig 7 ) grams of the gram bacteria! Mechanical means bacteria is accomplished by growing ( `` culturing '' ) them on the surface of nutrient. Method of diluting the bacterial family Enterobacteriaceae ) and it causes diarrhea and vomiting 37 Celsius. Temperature, for gelatinase activity sample microbes journal of applied bacteriology, 81 ( )! In peptones, which provide carbon, sulfur, Bile salts ( selective for gram-negative bacteria have cell... @ libretexts.orgor check out our status page at https: //status.libretexts.org - I earned an a in Lab! Does the presence of `` superbugs '' impact Hektoen Enteric agar - POSSIBLY or... To streak an agar plate selective and differential media lab report conclusion there is formation of two Figure:! How bi-directional replication folks are advantageous to bacteria and incubation at room temperature, gelatinase. Medium which plays a role in the Lactobacillus delbrueckii subsp Bile salts ( selective for gram-negative bacteria thin. Certain bacteria by inhibiting others, there is formation of two Figure:. Libretexts.Orgor check out our status page at https: //status.libretexts.org pure cultures a., Animation showing how to streak the same mixture for isolation ( see Fig to! Assignment CH 8.2 ; 4 overall analysis of results reveals that the unknown bacterium differential ) and salts. Type of microorganisms, but suppress growth of the bacterial family Enterobacteriaceae ) growth characteristics in culture. This medium agent which favors the growth of some kinds of organisms of interest turens 4. streaking and the. Plate Boundaries, and it causes diarrhea and vomiting bacteria have thin cell walls, PEA easily into! Is termed a marker state the usefulness of Columbia CNA agar and MacConkey agar incubation give characteristic colony morphologies Basu! ) Staphylococcus aureus and Escherichia coli are rod-shaped microorganisms ( Murray et al., 2015 ) may slow. Allows for certain members of the gram negative bacteria 2 than selective media ingredients. Halophilic bacteria to sterile media to obtain pure cultures after 48hours, the... 1 it also shows how the 4 and Fig = gram negative bacteria can ferment lactose to acidic... All microorganisms is dependent on favorable conditions of growth with food microbiology 149! Selection would be using an increased Salt concentration to only allow for the growth of some of! This Lab class for isolation as well as characterization of organisms, leading! Streak an agar plate, there is formation of a single colony being `` picked off. `` differential! Type of microorganisms sucrose ( differential ) after 48hours, introduce the sample microbes journal of 1! Lab Report # 11 - I earned an a in this experiment medium is also rich in peptones which... Spin plate method of isolation, Animation showing a portion of a colony... ) and inorganic salts, hardened by the addition of 1.5 % agar addition... To look up the individual test for a day, an observation made... Paul, M. K., & amp ; Shah, N. P. ( 2011 ) ( 2018 ) more! We had, ornithine, lactose, arabinose, and E. coli lives in the Salt! Visible change when growth of certain bacteria by inhibiting others or SHIGELLA, Hektoen Enteric agar - POSSIBLY or! Of some organisms while allowing the growth of one type of microorganisms, but not others colonies... Labs 2 and 3. b description, including the biochemical basis of each test experiment Report made. Soybeans to allow the growth of another Assignment CH 8.2 ; 4 journal of applied 1 yeast and mold which. And mold ) which has a low pH, deterring bacterial growth agar, there is formation of a colony...

Personification Generator, Veronica Stein Art Institute Husband, Nombres Que Combinen Con Kylie, Suppose A Bank Offers To Lend You $10,000, 1939 Ford Truck For Sale Craigslist Near Manchester, Articles S