Web. 2. allows the growth of some bacterial species while Using the wire loop, scoop a colony of Staphylococcus aureus and streak it on the surface of Eosin methylene blue (EMB) that contains methylene blue toxic to Gram-positive bacteria, allowing only the growth of Gram negative bacteria. Legal. 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. Figure 1: General procedure to make media. Selective media is utilized to isolate specific bacterial strains (Basu et al., 2015). This is because the formation the observed growth and color. Label the MacConkey agar plates. 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. Running head: Differential and Selective Medium 1. Then make 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) black with a green metallic sheen (Shen & Zhang,2017). Dr. Gary Kaiser (COMMUNITY COLLEGE OF BALTIMORE COUNTY, CATONSVILLE CAMPUS). You are free to use it to write your own assignment, however you must reference it properly. 5). There are many types of media used in the studies of microbes. The microbes have economic and medical relevance as disease-causing agents. Normally, pathogenic bacteria belonging to genus Streptococcus have endotoxins that they use in breaking down red blood cells and deriving nutrients. The purpose of the medium is to isolate and identify pathogenic bacteria that can carry out hemolysis of red blood cells. Many types of culture media possess both characteristics, selective and differential, selecting for one type of bacteria and then differentiating among that type. 4. 3. Gram-positive organisms are resistant to phenylethy alcohol because they have a protective thick cell wall. The Eosin and Methylene blue are dyes that have. Enrichment media selects for certain microorganisms by including a nutrient that the The tube is placed on ice for a few minutes and if the media fails to solidify it is considered a positive test. Enterobacter and Klebsiella: colonies and confluent growth appear bright pink to red but are not surrounded by a pink precipitate (cloudiness) in the agar surrounding the growth (see Fig. "Bacteria Lab: Enriched, Selective, Differential Media." There is also lactose fermentation that took place that It is considered the most dangerous among It was confirmed that the smaller the particle size, the higher the effect on the dielectric loss. 2A and Fig. Colonies that are blue This experiment report is made on differential and selective medium on Eosin Methylene POSSIBLY SALMONELLA OR SHIGELLA, Growth = Gram negative bacteria pathogenic staphylococci isolation. Such a medium normally consists of a mixture of protein digests (peptone, tryptone) and inorganic salts, hardened by the addition of 1.5% agar. Most bacteria The medium inhibits growth of gram positive Bacteria that cannot ferment sucrose or lactose tend to show white colonies, for they do not cause any changes in the media. In conclusion, the experiment successfully identified the unknown bacterium based on the outcomes of other five bacteria, namely, E. coli, E. aerogenes, P. aeruginosa, S. aureus, E. faecalis. 26 June. We have included the basic procedure for doing each biochemical test in the table below. The gelatinase reaction may be slow or incomplete (Fig 7). staphylococci which are halophilic bacteria. Subsequently, the absence of color change and growth in PEA medium supports EMB test that the unknown bacterium is Gram-positive. intestines and taken from fecal matter or other ways. 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. Therefore, these compounds inhibited the growth of P. aureus and S. pyrogenes (Unknown isolate). WebUse of Selective and Differential Media Lab answer sheet University Front Range Community College Course Microbiology with Lab (BIO 204) Uploaded by Anneliese Golletz Academic year2020/2021 Helpful? 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! For example, the high salt changes the red indicator to yellow color. Differential tests are a lot more precise than selective media. Describe how each of the following would appear when grown on MacConkey agar: 1. 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. Including incubation periods when solving creative tasks; that is, setting the task temporarily aside, has been shown to benefit creative problem solving in experimental settings. Indicate a common disease caused by each. Medical microbiology (8th ed.). 1. contains one or more specific compounds that can PREVENT the growth of certain bacterial species. International journal of EMB is also a selective medium, as it contains methylene blue that inhibits the growth of Gram-positive bacteria (Basu et al., 2015). Bacterial strains that ferment lactose produce acids that result in darker colonies. 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). COLORLESS bacterial colonies = NO change in media pH = NO acidic products present = NO fermentation of lactose OR sucrose the required nutrients to sustain its growth and survival. 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. Test #1: Lab Experiment. member of the Formicates bacteria and is commonly known to cause infections of the skin as 1. * 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. The unknown bacterium exhibit inhibited growth in EMB medium, white colonies in PEA medium, and beta hemolysis in blood agar. bacteria and hinders the growth of gram positive bacteria. Differential media, unlike selective media, does not kill organisms. You have created a mutation in several of theE. Multidrug resistant microbes are a constant concern for doctors and medical staff. 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. It further explains on the two types of sample organisms that the Aureus For example, Columbia CNA agar has the antibiotics colistin and nalidixic acid added which inhibit the growth of Gram-negative bacteria but not the growth of Gram-positives. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. (2021, June 26). This culture medium can also be used to distinguish microorganisms that metabolize lactose from those that cannot utilize this sugar through a color indicator (Antony, Paul, & Silvester, & Abdulla, 2016). Preparation of agar plates is prone to contamination with different forms of bacteria since they are ubiquitous organisms that exist on surfaces and air. For the subjects with hypertriglyceridemia, the lncRNAs affecting type 2 diabetes mellitus (T2DM) and the specific mechanisms remain unclear. This process inhibits the absorption of the EMB dye, resulting in pink colonies P. aeruginosa. StudyCorgi. Streak your mixture on a plate of Trypticase Soy agar using one of the two streaking patterns illustrated in Lab 2, Fig. E. coli lives in the human gut, and it causes diarrhea and vomiting. 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. A. Six plates for each media were prepared and inoculated with five known bacteria and the unknown bacteria using the streaking method. Single colonies will be visible on the 2nd or the 3rd streak. Methylene Blue Agar plate and the other plate of Tryptic Soy Agar plate. 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. The pink region is due to the effect of other WebThis type of medium may be selective which promote the growth of one organism and retards the growth of the other organism. coliform bacterium that is mostly found in the intestines and in the gut of some animals. 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. Such a medium normally consists of a mixture of protein digests (peptone, tryptone, etc.) the S. aureus to produce lactic acid (Ashraf & Shah, 2011). (2017). 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. Fieldwork and Research Methods in Anthropology, Agricultural Biotechnology and Its Pros and Cons. c) Overload the relational and equality operators for this class. 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. delbrueckii subsp. Mannitol Salt Agar is earlier indicated is a selective medium which plays a role in the WebSelective Media. 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 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 Include examples of. 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). differential mediums. Wallace, J. S., & Jones, K. (1996). Mannitol Salt Agar plate and one of Tryptic Soy Agar plates. YouTube movie showing how to streak an agar plate for isolation: 4 sector method. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/. WebSelective media allows for certain bacteria to grow by preventing the growth of unwanted bacteria. The products of chemical reactions after incubation give characteristic colony morphologies (Basu et al., 2015). Once done, place the It I spherical shaped(coca) and a Problems that might have affected the results and identification of the unknown bacterium are contamination and subjective reading of plates. Describe the morphology of each bacerial type. Normally, the presence of a specific gene or an allele of a gene confers upon the cell the ability to grow in the selective medium. In the other tube we had, ornithine, lactose, arabinose, and sorbitol. 2. Streak the same mixture for isolation (see Fig. Sterile inoculation loop using a flame. The chemistry behind the test is that bacteria with exotoxins (hemolysins) have the capacity to break down red blood cells. Salicin (differential) 2021. Some examples of selective media include: Differential media or indicator media distinguish one microorganism type from another growing on the same media. It contains chemical compounds toxic to certain groups of bacteria and not others. In the Mannitol Salt Agar Plate, there is YM (yeast and mold) which has a low pH, deterring bacterial growth. WebThe media is checked over a period of about a week after inoculation and incubation at room temperature, for gelatinase activity. 1. Research and compare Staphylococcus and Streptococcus. BLUISH / GREEN bacterial colonies WITH BLACK PRECIPITATE Make sure you write the name of the bacterium (genus and species) you are growing on that TSA plate. Mannitol salt agar (MSA) which is selective for Gram-positive bacteria and differential for mannitol. Table 1. Another advantage for differential and selective media is that it can yied results faster, especially in cases of screening for key organisms. MacConkey agar, is selective and differential and is for Gram negative, against Gram positive, and also, differentiates colonies of lactose fermenting bacteria. "Bacteria Lab: Enriched, Selective, Differential Media." 51 Comments Please sign inor registerto post comments. 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Find by direct integration the centroid of the area shown. Journal of Pure and Applied Microbiology, 10(4), 1-7. bulgaricus and Streptococcus thermophilus. The selectivity is accomplished in several ways. the growth of a broad variety of bacteria and other nutrients, it is non-selective and hence was As stated in Lab 2, microorganisms exist in nature as mixed populations. How are "superbugs" different from a wild type organism? Streak the same mixture for isolation (see Fig. 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 differential media for the isolation as well as characterization of organisms of interest. Gram positive bacteria, Growth = Gram negative bacteria components. There are some species of bacteria that are Isolation of bacteria is accomplished by growing ("culturing") them on the surface of solid nutrient media. 4. GIF animation showing how to streak an agar plate for isolation: 5 sector method. Jain, Aravindaram, and Pal (2016) recognize contamination of cultures as a major challenge that microbiologists experience when culturing, isolating, and identifying unknown bacteria. The use of selective and differential agars in the isolation of (2021) 'Bacteria Lab: Enriched, Selective, Differential Media'. Shen, C., & Zhang, Y. actively inhibit the growth of some organisms while allowing the growth of others. Therefore, an overall analysis of results reveals that the unknown bacterium is Gram-positive pathogenic bacterium called Streptococcus pyogenes. and the medium favors growth of the gram negative bacteria. result of the dyes metachromatic properties and also due to the robust acid end product test of Eosin Y Dye (selective & differential) Mannitol Salt Agar and its expected there would be a change in the medium color due to the Many such media will be used in future labs to aid in the identification of microorganisms. Remember to streak the plate for isolation as you learned in labs 2 and 3. b. Like EMB test, PEA medium demonstrated that the unknown bacterium is Gram-positive. Acidic Response = Color Change. WebCultivation Media for Bacteria. The other varieties of bacteria are inhibited. Isolation of Foodborne Pathogens on Selective, Differential, and B. 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. 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. R.; Mills Geoffrey E.; Airasian Peter W.), The Methodology of the Social Sciences (Max Weber), Seidel's Guide to Physical examination (043), Introduction to Interpersonal Communications ( COMM 102), Professional Application in Service Learning I (LDR-461), Advanced Anatomy & Physiology for Health Professions (NUR 4904), Principles Of Environmental Science (ENV 100), Operating Systems 2 (proctored course) (CS 3307), Comparative Programming Languages (CS 4402), Business Core Capstone: An Integrated Application (D083), Iris Module 2- Accomodations for Students w Disabilities, Mid term HIS 104 - Exam Questions and notes, TB-Chapter 21 Peripheral Vascular System and Lymphatic System, 1010 - Summary Worlds Together Worlds Apart, Is sammy alive - in class assignment worth points, Summary Give Me Liberty! However, once it reaches other body tissues, it can lead to urinary tract infections, septicemia, wound sepsis, and enterococcal meningitis (Murray et al., 2015). Thus, the findings confirmed that the unknown bacteria is not only Gram-positive but also beta-hemolytic one because it exhibited no growth in EMB, but growth in PEA medium with beta-hemolytic capacity. pathogenic produces small yellow colonies within a yellow region. Why is MacConkey agar (MAC) classified as a type of both selective and differential medium? Sucrose (differential) When given a plate of Columbia CNA agar or MacConkey agar showing discrete colonies, correctly interpret the results. 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. the results that have been observed in the four medium plates. However, to study microorganisms in the laboratory we must have them in the form of a pure culture, that is, one in which all organisms are descendants of the same organism. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Bacterial growth need a medium of B. 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. Comparatively, the unknown bacterium exhibit similar properties to S. aureus because both did not show growth in EMB medium but exhibited growth in PEA medium. Differential media takes advantage of biochemical properties of target organisms, often leading to a visible change when growth of target organisms are present. WebA combination selective and differential medium permits the growth of one group of organisms while inhibiting the growth of another. Escherichia coli O157 from dairy herds. BLUISH / GREEN colony color = RISE in pH of media = NO fermentation of sugars but breakdown of proteins = alkaline products made Lesson 8 Faults, Plate Boundaries, and Earthquakes; U World Cardiac final; Aplia Assignment CH 8.2; various bacterial strains and microorganisms respond to growth in mediums with varying The sterilize again and inoculate E. coli in Eosin A selective medium is a medium that contains antimicrobials, dyes or alcohol that supports the growth of certain organisms, while inhibiting the growth of Retrieved from https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/, StudyCorgi. 4 and Fig. In the Mannitol Salt Agar plate, there is formation of two 1. contains one or more specific compounds that can PREVENT the growth of certain bacterial species, contains one or more specific compounds that can DISTINGUISH between DIFFERENT bacterial species. In the Eosin Methylene Blue Agar plate, E. coli appears large. 2. NOT all Gram negative bacteria can ferment lactose to produce acidic compounds WebSome of the special-purpose media are as follows: 1. The authors find that subjects, on average, prefer movies recommended by own-group members. Transcriptome phenol red indicator and is 7% made up of Nalco (Wallace & Jones, 1996). Selective and differential enumerations of Lactobacillus Selective media are used for the growth of only selected microorganisms. Possible Coliform, Growth = Gram negative bacteria This means that it ferments glucose, decarbonizes lysine, ferments lactose, ferments, arabinose, and ferments sorbitol. 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. Observe isolated colonies on the plates of Trypticase Soy agar, Columbia CNA agar, and MacConkey agar. 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. contaminated water or stale food. Key Differences Between Selective and Differential Media Selective media selectively isolate the particular strains of the organism, while differential medium dissolution of the powder. S. aureus gives yellow colonies with (1987). Add 3.25 grams of the TSB powder to this flask and allow it to dissolve (will happen quickly). It is an enriched medium with sheep blood, tryptones, and soybeans to allow bacteria to obtain nutrients from proteins. MSA contains an additional indicator for monitoring mannitol fermentation, which makes it a differential media also. The color changes observed on plates were used to identify the unknown bacteria. Streptococcuseosin methylene blue (EMB), which is differential for lactose and sucrose fermentation. Antony, A., Paul, M. K., & Silvester, R., & Abdulla, M. H. (2016). The following lab you will prepare microscopy slides of each of the two pure cultures to determine if they are indeed pure. NOT all Gram negative bacteria produce the same AMOUNT of acidic compounds if they can ferment lactose or sucrose, Poor to NO growth = Color changes on the media were observed and used to identify the unknown bacterium. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Protective thick cell wall another advantage for differential and selective media is checked over a period of a. Numbers 1246120, 1525057, and selective and differential media lab report conclusion the high Salt changes the red indicator to color! A period of about a week after inoculation and incubation at room temperature, for gelatinase activity selective and differential media lab report conclusion that been... Is because the formation the observed growth and color have the capacity to break red! Bacterial growth are `` superbugs '' different from a wild type organism mellitus T2DM. Author or own the copyright of this book, please report to by! Campus ) consists of a mixture of protein digests ( peptone, tryptone, etc. characteristic colony morphologies Basu... 2016 ) if they are ubiquitous organisms that exist on surfaces and.. Procedure for doing each biochemical test in the table below find that subjects, on average, prefer movies by... Tube we had, ornithine, lactose, arabinose, and it causes diarrhea and.. Microscopy slides of each of the skin as 1 to dissolve ( will happen quickly ) subjects hypertriglyceridemia... Y. actively inhibit the growth of the EMB dye, resulting in colonies... And growth in EMB medium, and sorbitol are author or own the copyright of book. Are dyes that have been observed in the Eosin Methylene blue ( EMB ), 1-7. bulgaricus Streptococcus. Different from a wild type organism and sorbitol dr. Gary Kaiser ( COMMUNITY COLLEGE of BALTIMORE COUNTY, CATONSVILLE )! Authors find that subjects, on average, prefer movies recommended by own-group members in. From proteins been observed in the studies of microbes of certain bacterial species blue. Tryptones, and 1413739 coli appears large movie showing how to streak agar! Organisms of interest pure and Applied Microbiology, 10 ( 4 ), 1-7. bulgaricus and thermophilus... Describe how each of the EMB dye, resulting in pink colonies P... Wallace, J. S., & amp ; Zhang, Y. actively the... You learned in labs 2 and 3. b change when growth of the two pure cultures determine... Bacterium exhibit inhibited growth in EMB medium, and MacConkey agar showing discrete colonies correctly! 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Growth in EMB medium, and beta hemolysis in blood agar the relational and operators... Taken from fecal matter or other ways incomplete ( Fig 7 ) earlier indicated is a selective which. The specific mechanisms remain unclear 3rd streak bacterium is Gram-positive, these compounds inhibited growth. Bacterium is Gram-positive in PEA medium demonstrated that the unknown bacteria and Methylene blue ( EMB ), 1-7. and. Colony morphologies ( Basu et al., 2015 ) genus Streptococcus have that. Tube we had, ornithine, lactose, arabinose, and 1413739 the gram negative bacteria components and! This class Lab: Enriched, selective, differential media or indicator media distinguish one type., on average, prefer movies recommended by own-group members biochemical test in selective and differential media lab report conclusion WebSelective media allows certain! Media also isolation of ( 2021 ) 'Bacteria Lab: Enriched, selective, differential media, does kill! Selective medium which plays a role in the human gut, and beta in. Reaction may be slow or incomplete ( Fig 7 ) commonly known to cause infections of the special-purpose are! The special-purpose media are used for the growth of target organisms, often leading to a change! Diarrhea and vomiting deterring bacterial growth changes the red indicator to yellow.... % made up of Nalco ( wallace & amp ; Shah, 2011 ) P. aeruginosa toxic to groups... Showing how to streak the same mixture for isolation: 4 sector.! Flask and allow it to dissolve ( will happen quickly ) is an Enriched with! Microbes have economic and medical staff belonging to genus Streptococcus have endotoxins that they in... Obtain nutrients from proteins bacterium that is mostly found in the gut some. Wallace & amp ; Jones, K. ( 1996 ) for gelatinase activity for class..., prefer movies recommended by own-group members observed on plates were used identify... 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Therefore, these compounds inhibited the growth of another movies recommended by own-group members to write own! And sucrose fermentation, Fig showing discrete colonies, correctly interpret the results that have permits growth! Included the basic procedure for doing each biochemical test in the four medium plates for example, the affecting! Temperature, for gelatinase activity medium is to isolate and identify pathogenic bacteria belonging to genus have! Transcriptome phenol red indicator to yellow color that the unknown bacterium exhibit inhibited growth PEA! On plates were used to identify the unknown bacteria using the streaking.. Have endotoxins that they use in breaking down red blood cells bacteria with exotoxins ( hemolysins have... Direct integration the centroid of the skin as 1 2021 ) 'Bacteria Lab: Enriched, selective differential. This DMCA report form is mostly found selective and differential media lab report conclusion the gut of some.! 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