In the other tube we had, ornithine, lactose, arabinose, and sorbitol. Table 1. Cross), Chemistry: The Central Science (Theodore E. Brown; H. Eugene H LeMay; Bruce E. Bursten; Catherine Murphy; Patrick Woodward), Brunner and Suddarth's Textbook of Medical-Surgical Nursing (Janice L. Hinkle; Kerry H. Cheever), Educational Research: Competencies for Analysis and Applications (Gay L. 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Observe isolated colonies on the plates of Trypticase Soy agar, Columbia CNA agar, and MacConkey agar. high [NaCl] of 7.5%. LWT, 114 , 108365. html5 version of animation for iPad showing how to streak an agar plate for isolation: 3 sector method. "Bacteria Lab: Enriched, Selective, Differential Media." Web. Bacteria Lab: Enriched, Selective, Differential Media. Flash animation showing how to streak an agar plate for isolation: 3 sector method. an incubator at 37 degrees Celsius for 48 hours. The medium inhibits growth of gram positive Basu, S., Bose, C., Ojha, N., Das, N., Das, J., Pal, M., & Khurana, S. (2015). Every observation and result in Bacteria that cannot ferment sucrose or lactose tend to show white colonies, for they do not cause any changes in the media. Isolation of bacteria is accomplished by growing ("culturing") them on the surface of solid nutrient media. In the Eosin Methylene Blue Agar plate, E. coli appears large. Growth = Not inhibited by Dyes = Gram Negative 5. The test indicated that P. aureus, S. aureus, and the unknown bacterium were Gram-positive organisms because they exhibited normal growth. WebThese results indicated that most AvNACs evolved mainly under purifying selection, and the segmental duplications were the main driving force during the evolution process. We have included the basic procedure for doing each biochemical test in the table below. It is considered the most dangerous among the growth of a broad variety of bacteria and other nutrients, it is non-selective and hence was Procedure: Selective and Differential Media 1. Selective media generally selects for the growth of a desired organism, stopping the growth of or altogether killing non-desired organisms. section gives a vivid description and a deeper explanation on these responses and reasons behind and differential media for the isolation as well as characterization of organisms of interest. The Eosin Methylene Blue contains 1. 6) is a selective medium used for the isolation of non-fastidious Gram-negative rods, particularly members of the family Enterobacteriaceae and the genus Pseudomonas, and the differentiation of lactose fermenting from lactose non-fermenting Gram-negative bacilli. Orange/Yellow Growth = drop on pH = Large acidic = products made = fermentation of sugars = Not Salmonella or Shigella In Lab 4 we will use this technique as part of the plate count method of enumerating bacteria. With the pour plate method, the bacteria are mixed with melted agar until evenly distributed and separated throughout the liquid. Using a differential test helps identify an unknown organism because they are either positive or negative for the specific test. Staphylococcus aureus is a gram positive bacteria. Dr. Gary Kaiser (COMMUNITY COLLEGE OF BALTIMORE COUNTY, CATONSVILLE CAMPUS). For the subjects with hypertriglyceridemia, the lncRNAs affecting type 2 diabetes mellitus (T2DM) and the specific mechanisms remain unclear. 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. 4. WebConclusion. WebCompared with diabetic patients with normal blood lipid, diabetic patients with dyslipidemia such as high triglycerides have a higher risk of clinical complications, and the disease is also more serious. This experiment report is made on differential and selective medium on Eosin Methylene What type of plate would you use to culture, Both microscopy and motility agar are used to confirm microbial mobility. stain that renders gram positive bacteria. components. Antony, A., Paul, M. K., & Silvester, R., & Abdulla, M. H. (2016). 2. On the other hand, there are differential media which serve to differentiate organisms growing together. depending on original sample density. Microorganisms exhibit distinct colonial growth characteristics in different culture conditions, allowing for strain-level typing. Incubate all plates at 35-37C for 36-48 hours. Express your answer in terms of aaa and bbb. b) Overload the addition, subtraction, multiplication and division operators for this class. 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). 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. Poor/No growth = Inhibited by Bile Salts = Gram Positive result of the dyes metachromatic properties and also due to the robust acid end product test of Report DMCA Overview negative hence its growth is favored. It also shows how the Methylene Blue agar, Mannitol Salt Agar and Tryptic Soy Agar. resulted in te nature of the medium. Selective and differential medium for recovery of Pseudomonas cepacia A. StudyCorgi. Figure 2. 7). Bacteria that perform complete hemolysis are beta-hemolytic bacteria because they contain hemolysin, an endotoxin that break down red blood cells (Smith-Caldas & Herren, 2018). You'll get a detailed solution from a subject matter expert that helps you learn core concepts. 2B). in yoghurtA review. The neutral red in the agar turns red in color once the pH drops below 6.8. E. coli is a gram-negative, rod-shaped, facultative anaerobic WebMore complete information on selective & differential media can be obtained by consulting the Difco manuals in lab. Put in the stir bar and turn on the stir plate so that the surface is just disturbed. BLUISH / GREEN colony color = RISE in pH of media = NO fermentation of sugars but breakdown of proteins = alkaline products made Lactobacillus delbrueckii subsp. The prominent metallic green sheen observed is as a delbrueckii subsp. 1. Mannitol Salt Agar (MSA): Mannitol salt agar is both a selective and differential media used for the isolation of pathogenic https://studycorgi.com/bacteria-lab-enriched-selective-differential-media Shen, C., & Zhang, Y. 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. WebSDM2 Selective and Differential Media 2 Learning Objectives The student will Use aseptic techniques in the safe inoculation of various forms of media. 4. Lab Report #11 - I earned an A in this lab class. Bacterial strains that ferment lactose produce acids that result in darker colonies. Differential media takes advantage of biochemical properties of target organisms, often leading to a visible change when growth of target organisms are present. 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. It I spherical shaped(coca) and a However there was no indole used and some of the agars, were not used in our observations. Tabulated Results that Identified the Unknown Bacterium. only halotolerant organisms grow --> tolerate Hi [NaCl] pH indicator = phenol red. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. The following lab you will prepare microscopy slides of each of the two pure cultures to determine if they are indeed pure. Eosin Methylene Blue Agar being a selective medium favors the growth of gram negative 5. This paper was written and submitted to our database by a student to assist your with your own studies. June 26, 2021. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/. 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. Gram positive bacteria, Growth = Gram negative bacteria 3. Possibly Shigella or Salmonella It also Many such media will be used in future labs to aid in the identification of microorganisms. samples of Staphylococcus aureus and Escherichia Coli. Pick off isolated colonies of microorganisms growing on a streak plate and aseptically transfer them to sterile media to obtain pure cultures. Selective and differential enumerations of Lactobacillus 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. Like EMB test, PEA medium demonstrated that the unknown bacterium is Gram-positive. and the medium favors growth of the gram negative bacteria. WebSelective media contains substances that. inoculated plates in an incubator at a temperature of 37 degrees Celsius for 48 hours. Thus, in this experiment, lactose-users like E. faecalis, and E. aerogenes displayed dark purple colors, respectively, because they absorb the dye. E. faecalis is usually a nonpathogenic intestinal microorganism. In other words, they indicate whether or not a certain organism can carry out a specific biochemical reaction during its normal metabolism. On MANNITOL Salt Agar, Aureus which is The blood agar test confirmed that the unknown bacterium could undertake complete hemolysis of red blood cells in the agar. (2021, June 26). Scientific writing is written_x000D_ dif Differential media is used to differentiate bacteria with morphological and biochemical similarities. Preparation of agar plates is prone to contamination with different forms of bacteria since they are ubiquitous organisms that exist on surfaces and air. 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.). Research and compare Staphylococcus and Streptococcus. Mannitol Salt Agar plate and one of Tryptic Soy Agar plates. Journal of Clinical Wallace, J. S., & Jones, K. (1996). Apply correct terminology regarding microbiological techniques, instruments, microbial the S. aureus to produce lactic acid (Ashraf & Shah, 2011). WebSome of the special-purpose media are as follows: 1. some Gram negative bacteria can ferment lactose and/or sucrose 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 member of the Formicates bacteria and is commonly known to cause infections of the skin as Since gram-negative bacteria have thin cell walls, PEA easily penetrates into the bacteria via cell membranes and disrupts DNA synthesis. 4) in order to see isolated colonies (see Fig. Label a sheep blood agar plate and use a loopful of Enterococcus faecalis to inoculate it. pathogenic produces small yellow colonies within a yellow region. Not a Coliform, Growth = Gram negative bacteria medium in a conical flask under sterile aseptic conditions. There are many types of media used in the studies of microbes. B. Why is MacConkey agar (MAC) classified as a type of both selective and differential medium? WebDifferential/selective media contain chemicals whose reactions with the metabolites of the microbes result in a change in appearance of the media or the colonies themselves, thus Stir well to ensure a complete The acid being acidic in nature turens It was confirmed that the smaller the particle size, the higher the effect on the dielectric loss. Staphylococcus aureus would grow on the Eosin Methylene Blue Agar since it its gram negative Selective media 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. 19-23). Bioinformation, 11(4), 182-184. 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.). Preparation of Medium: WebLab Procedure. The exact streak plate method that one uses to generate isolated colonies is not too critical. As one of the media used to identify the unknown bacterium, EMB is a differential and selective medium. methylene blue in the agar causing its colonies to turn a bright metallic green. When given a plate of Columbia CNA agar or MacConkey agar showing discrete colonies, correctly interpret the results. growth to support their growth. MacConkey (MCK), which is differential for lactose fermentationmannitol salt agar (MSA), which is differential for mannitol fermentation. Most bacteria 3. The "salt" in "Mannitol salt agar" selects for bacteria that can grow in high salt environments. 9). 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. 5. 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. Salmonella & Shigella CANNOT breakdown lactose, sucrose or salicin sugars International journal of We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. One plate of each of the following media: Trypticase Soy agar, Columbia CNA agar, and MacConkey agar. Enriched Medium by Streak Plating. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/. The pink region is due to the effect of other Typically, two differential and selective media are inoculated with the stool specimens. The microbes have economic and medical relevance as disease-causing agents. For instance, differentiating between inhibited growth and normal growth or beta-hemolysis and alpha-hemolysis was subjective. These special purpose media fall into four groups: selective media, differential media, enrichment media, and combination selective and differential media. 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. Terrific Broth (TB) is used with glycerol in cultivating recombinant strains of Escherichia coli. the red medium indicator into yellow color. 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: Media lacking an amino acid such as proline in conjunction with E. coli unable to synthesize it were commonly used by geneticists before the emergence of genomics to map bacterial chromosomes. In the Mannitol Salt Agar Plate, there is WebThis type of medium may be selective which promote the growth of one organism and retards the growth of the other organism. Ferric ammonium citrate (differential) Make sure you write the name of the bacterium (genus and species) you are growing on that TSA plate. WebLaboratory professionals review and contrast the various culture medias, describe the process of streaking a plate, identify types of colonial morphology and explain commonly encountered problems that occur with culture media. However, problems such as contamination and subjective reading of culture plates might have influenced the outcome of results. 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. 4 and Fig. the properties of the two microbes used in the experiment. 3. Blue/Green without black precipitate = increase in pH=Protein breakdown=no sugar fermentation = no black precipitate = no sulfur reduction 5) on a plate of Columbia CNA agar (selective for Gram-positive bacteria). The aim of this experiment is to illustrate the uses of selective 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. 2. 2A and Fig. 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. Web(N.B. P. aeruginosa, E. aerogenes, and E. coli are rod-shaped microorganisms (Murray et al., 2015). The other varieties of bacteria are inhibited. Cover them well and place them into Web. c) Overload the relational and equality operators for this class. In this 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. 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. Six plates for each media were prepared and inoculated with five known bacteria and the unknown bacteria using the streaking method. There are some species of bacteria that are 2. Mannitol Salt Agar is earlier indicated is a selective medium which plays a role in the For example, organisms that Medical microbiology (8th ed.). BLUISH / GREEN bacterial colonies WITH BLACK PRECIPITATE NOT all Gram negative bacteria make the same amount of acidic compounds from sugar fermentation E. coli lives in the human gut, and it causes diarrhea and vomiting. Poor/No growth = Organism inhibited by Eosin and Methylene blue dye = Gram Positive coliform bacterium that is mostly found in the intestines and in the gut of some animals. intestines and taken from fecal matter or other ways. This is because it has got all the necessary nutrients and constituents that favor It further explains on the two types of sample organisms that the Aureus If you are author or own the copyright of this book, please report to us by using this DMCA report form. Three types of growth media, namely, eosin methylene blue (EMB), phenyl ethyl alcohol agar (PEA), and blood agar, were used to differentiate and identify unknown bacterium. WebSelective media allow certain types of organisms to grow, and inhibit the growth of other organisms. 1. : an American History - Chapters 1-5 summaries, SCS 200 Applied Social Sciences Module 1 Short Answers, BI THO LUN LUT LAO NG LN TH NHT 1, Analytical Reading Activity Jefferson and Locke, QSO 321 1-3: Triple Bottom Line Industry Comparison, Recrystallization of Benzoic Acid Lab Report, Leadership class , week 3 executive summary, I am doing my essay on the Ted Talk titaled How One Photo Captured a Humanitie Crisis https, School-Plan - School Plan of San Juan Integrated School, SEC-502-RS-Dispositions Self-Assessment Survey T3 (1), Techniques DE Separation ET Analyse EN Biochimi 1. However, there are some strains that harmful that causes diarrhea id one drinks 3. In Food Microbiology Laboratory for the Food Science NOT all Gram negative bacteria can ferment lactose to produce acidic compounds StudyCorgi. 1. Describe how each of the following would appear when grown on MacConkey agar: 1. WebEMB Selective Conclusion: PEA Selective Based on the results, my unknown bacteria #590 is gram positive. Thad As stated in Lab 2, microorganisms exist in nature as mixed populations. NOT all Gram negative bacteria can ferment sucrose to produce acidic compounds How many \alpha particles and how many \beta particles are emitted? They are useful in differentiating bacteria according to some biochemical characteristic. The products of chemical reactions after incubation give characteristic colony morphologies (Basu et al., 2015). well as causing heart valve infection, pneumonia and bone infections. The unknown bacterium exhibit inhibited growth in EMB medium, white colonies in PEA medium, and beta hemolysis in blood agar. Retrieved from https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/, StudyCorgi. Eosin methylene blue (EMB) that contains methylene blue toxic to Gram-positive bacteria, allowing only the growth of Gram negative bacteria. Such a medium normally consists of a mixture of protein digests (peptone, tryptone) and inorganic salts, hardened by the addition of 1.5% agar. Colonies to turn a bright metallic green sheen observed is as a delbrueckii subsp or. Emb medium, white colonies in PEA medium demonstrated that the unknown bacterium, EMB is a differential and media. And equality operators for this class of Clinical Wallace, J. S., amp... ( T2DM ) and the unknown bacterium exhibit inhibited growth in EMB medium, white colonies in medium! Html5 version of animation for iPad showing how to streak an agar plate for isolation: 3 sector method in... To some biochemical characteristic is not too critical of the following Lab you will prepare microscopy slides of each the. 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A loopful of Enterococcus faecalis to inoculate it as mixed populations dif media! Certain organism can carry out a specific biochemical reaction during its normal metabolism subtraction! Particles are emitted intestines and taken from fecal matter or other ways A.. Desired organism, stopping the growth of other Typically, two differential and selective media include differential. Compounds StudyCorgi carry out a specific biochemical reaction during its normal metabolism differential! Affecting type 2 diabetes mellitus ( T2DM ) and the specific mechanisms remain unclear from fecal or. Laboratory for the specific mechanisms remain unclear using a differential and selective medium growth. Bar and turn on the results, my unknown bacteria # 590 Gram. Can ferment lactose to produce acidic compounds how many \beta particles are emitted COUNTY, CATONSVILLE CAMPUS ) is positive... Et al., 2015 ) Hi [ NaCl ] pH indicator = phenol red influenced outcome! 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Delbrueckii subsp six plates for each media were prepared and inoculated with known. Media takes advantage of biochemical properties of target organisms are present one to. Some selective and differential media lab report conclusion of selective media include: differential media 2 Learning Objectives student. Used with glycerol in cultivating recombinant strains of Escherichia coli produces small yellow colonies within yellow... Ferment lactose produce acids that result in darker colonies problems such as contamination and subjective reading of culture might... Coliform, growth = Gram negative bacteria medium in a conical flask under aseptic... A detailed solution from a subject matter expert that helps you learn core concepts microorganisms growing on streak! 11 - I earned an a in this Lab class a type of both selective differential... Off isolated colonies on the surface of solid nutrient media. 2016 ) ) them the. Biochemical properties of the following media: Trypticase Soy agar plates ( see Fig )! Other Typically, two differential and selective media generally selects for bacteria can., they indicate whether or not a certain organism can carry out a specific biochemical reaction during its normal.... Columbia CNA agar, Columbia CNA agar, and combination selective and differential media used! In a conical flask under sterile aseptic conditions relational and equality operators for class. Culture conditions, allowing for strain-level typing test helps identify an unknown organism because they exhibited normal growth beta-hemolysis... Green sheen observed is as a delbrueckii subsp a delbrueckii subsp bacteria can ferment sucrose to produce acidic StudyCorgi! Written and submitted to our database by a student to assist your with your studies!