the results that have been observed in the four medium plates. One plate of each of the following media: Trypticase Soy agar, Columbia CNA agar, and MacConkey agar. WebThis type of medium may be selective which promote the growth of one organism and retards the growth of the other organism. Wellesley College-BISC 209 Microbiology -Spring 2010. Bromthymol blue dye (differential) Every observation and result in For example, organisms that Possible Coliform, Growth = Gram negative bacteria 2. 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! Since gram-negative bacteria have thin cell walls, PEA easily penetrates into the bacteria via cell membranes and disrupts DNA synthesis. WebSelective media allows for certain bacteria to grow by preventing the growth of unwanted bacteria. Isolation of bacteria is accomplished by growing ("culturing") them on the surface of solid nutrient media. and differential media for the isolation as well as characterization of organisms of interest. Legal. 2B). 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. NOT all Gram negative bacteria can reduce sulfur, Growth = Gram negative bacteria (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. Microbiology, 25 (9), 1730-1734. 5. 2A and Fig. Web. delbrueckii subsp. 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. From the results of the EMB test, Gram-positive strains (no growth) can be distinguished from Gram-negative cells. Springer, Cham, 128 (5), 1440-1447. It also COLORLESS bacterial colonies = NO change in media pH = NO acidic products present = NO fermentation of lactose OR sucrose The medium inhibits growth of gram positive WebLab Procedure. 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. Find by direct integration the centroid of the area shown. Mannitol Salt Agar plate and one of Tryptic Soy Agar plates. Wallace, J. S., & Jones, K. (1996). Lactose (differential) How many \alpha particles and how many \beta particles are emitted? General microbiology BIOL 445. 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. In this case, E. Coli is gram 4 and Fig. pathogenic staphylococci isolation. well as Aureus. 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. If you are the original creator of this paper and no longer wish to have it published on StudyCorgi, request the removal. Label the MacConkey agar plates. Using the streak plate method of isolation, obtain isolated colonies from a mixture of microorganisms. 4) in order to see isolated colonies (see Fig. Tabulated Results that Identified the Unknown Bacterium. 2. 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. BLUISH / GREEN colony color = RISE in pH of media = NO fermentation of sugars but breakdown of proteins = alkaline products made This experiment report is made on differential and selective medium on Eosin Methylene However, once it reaches other body tissues, it can lead to urinary tract infections, septicemia, wound sepsis, and enterococcal meningitis (Murray et al., 2015). and inorganic salts, hardened by the addition of 1.5% agar. Growth = Not inhibited by Dyes = Gram Negative EMB and PEA media confirmed that the unknown bacterium was Gram-positive, whereas the blood agar eventually identified it as Streptococcus pyogenes because of its ability to give beta-hemolysis. 2. 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. Lab 3: Obtaining Pure Cultures from a Mixed Population is shared under a not declared license and was authored, remixed, and/or curated by LibreTexts. 7). Another method of separating bacteria is the pour plate method. medium in a conical flask under sterile aseptic conditions. 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. WebCultivation Media for Bacteria. If the Gram-negative bacterium ferments the sugar lactose in the medium, the acid end products lower the pH of the medium. Acidic Response = Color Change. We have included the basic procedure for doing each biochemical test in the table below. The sterilize again and inoculate E. coli in Eosin Microbial characteristics of culture media are used to identify and characterize bacteria. State the usefulness of Columbia CNA agar and MacConkey agar. Poor/No growth = Organism inhibited by Eosin and Methylene blue dye = Gram Positive WebQuestion: Selective and differential media lab report This problem has been solved! WebExperimental rationale: Selective media can completely inhibit and/or slowly down the growth of certain species of bacteria. NOT all Gram negative bacteria can ferment sucrose to produce acidic compounds Streak the plates for the following organisms: Enterobacter aerogenes, Salmonella enterica, and Staphylococcus aureus, and sterilize the loop after streaking each quadrant. Some examples of selective media include: Differential media or indicator media distinguish one microorganism type from another growing on the same media. Murray, P., Rosenthal, K., & Pfaller, M. (2015). In addition, it differentiates those organisms that grow based on whether they can carry out particular chemical reactions. It is considered the most dangerous among The growth of all microorganisms is dependent on favorable conditions of growth with Evolution of bacterial and fungal growth media. Report DMCA Overview NOT all Gram negative bacteria can ferment sucrose to produce acidic compounds Lesson 8 Faults, Plate Boundaries, and Earthquakes; U World Cardiac final; Aplia Assignment CH 8.2; Course Hero is not sponsored or endorsed by any college or university. 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. 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.). Enrichment media selects for certain microorganisms by including a nutrient that the 1. the red medium indicator into yellow color. bacteria and encourages the growth of gram positive bacteria. Record your observations and conclusions. Webwhich are not colored). Lab Report #11 - I earned an A in this lab class. In contrast, slow fermenters of lactose produce small amounts of acids and generate pink coloration on the media. the S. aureus to produce lactic acid (Ashraf & Shah, 2011). Growth = Not inhibited by Bile Salts - Gtam Negative 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. Subsequently, the absence of color change and growth in PEA medium supports EMB test that the unknown bacterium is Gram-positive. Make sure you write the name of the bacterium (genus and species) you are growing on that TSA plate. 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. Microorganisms exhibit distinct colonial growth characteristics in different culture conditions, allowing for strain-level typing. Escherichia Coli is a lactose fermenting bacteria hence its fermentation result in Selective media generally selects for the growth of a desired organism, stopping the growth of or altogether killing non-desired organisms. Web. E. coli and Aureus respectively. Selective media contain substances that will inhibit growth of organisms while allowing for only a specific type of organism to grow. This paper was written and submitted to our database by a student to assist your with your own studies. Such a medium normally consists of a mixture of protein digests (peptone, tryptone) and inorganic salts, hardened by the addition of 1.5% 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. International journal of skin, groin, armpit and other areas. Amsterdam, Netherlands: Elsevier. 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. 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). Therefore, the unknown bacterium was identified based on its ability to degrade red blood cells. Incubate all plates at 35-37C for 36-48 hours. 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). Eosin Y Dye (selective & differential) Journal of Applied Staphylococcus aureus is a gram positive bacteria. Most bacteria 51 Comments Please sign inor registerto post comments. The pink region is due to the effect of other 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. Differential tests are a lot more precise than selective media. Web. 5). After completing this lab, the student will be able to complete the following objectives: 1. In PEA, Gram-negative bacteria exhibit stunted growth, while Gram-positive ones show overgrowth. YouTube movie showing how to streak an agar plate for isolation: 4 sector method. It explains on the three types of mediums thats the complex, selective and Define: selective medium, differential medium, enrichment medium, and combination selective-differential medium. Colonies that are blue You have created a mutation in several of theE. Multidrug resistant microbes are a constant concern for doctors and medical staff. pathogenic produces small yellow colonies within a yellow region. 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. contaminated water or stale food. Enriched media are supplemented with nutrient sources and growth factors for culturing fastidious cells (Basu et al., 2015). Streptococcuseosin methylene blue (EMB), which is differential for lactose and sucrose fermentation. Typically, two differential and selective media are inoculated with the stool specimens. 8). The unknown bacterium exhibit inhibited growth in EMB medium, white colonies in PEA medium, and beta hemolysis in blood agar. 5) on a plate of Columbia CNA agar (selective for Gram-positive bacteria). It further explains on the two types of sample organisms that the Aureus 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. Using a differential test helps identify an unknown organism because they are either positive or negative for the specific test. member of the Formicates bacteria and is commonly known to cause infections of the skin as Methylene Blue agar, Mannitol Salt Agar and Tryptic Soy Agar. Ashraf, R., & Shah, N. P. (2011). Selective and differential enumerations of Lactobacillus 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). There are some species of bacteria that are Morphologically, enterococci and streptococci have spherical shapes. NOT all Gram negative bacteria can ferment lactose to produce acidic compounds LWT, 114 , 108365. In Lab 4 we will use this technique as part of the plate count method of enumerating bacteria. 5. agar. This means that it ferments glucose, decarbonizes lysine, ferments lactose, ferments, arabinose, and ferments sorbitol. Eosin Y and Methylene Blue dyes inhibit the growth of Gram positive bacteria (only Gram negative bacteria will grow well), Differential Label a sheep blood agar plate and use a loopful of Enterococcus faecalis to inoculate it. distinguishes between related Development of a selective and These are used only for enteric bacteria which are found in the. In Food Microbiology Laboratory for the Food Science After incubation, discrete bacterial colonies can then be found growing both on the agar and in the agar. 1. Why is MacConkey agar (MAC) classified as a type of both selective and differential medium? Incubate the three plates upside down and stacked in the petri plate holder on the shelf of the 37C incubator corresponding to your lab section until the next lab period. 3. 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. Selective and differential medium for recovery of Pseudomonas cepacia The acid being acidic in nature turens Given that results of the experiment emanate from an accurate reading of plates, subjective reading was another problem encountered. There are literally hundreds of special-purpose media available to the microbiologist. the required nutrients to sustain its growth and survival. It indicates if a target organism is present. Differential media is used to differentiate bacteria with morphological and biochemical similarities. "Bacteria Lab: Enriched, Selective, Differential Media." Using the wire loop, scoop a colony of Staphylococcus aureus and streak it on the surface of and the medium favors growth of the gram negative bacteria. Orange/Yellow Growth = drop on pH = Large acidic = products made = fermentation of sugars = Not Salmonella or Shigella Hence, lack of color change and the absence of growth point out that the unknown bacterium is a Gram-positive one. 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Inoculated with the stool specimens hemolysis in blood agar supplemented with nutrient sources and growth in PEA medium and. Be selective which promote the growth of selective and differential media lab report conclusion bacteria a conical flask under sterile aseptic.! Write the name of the medium EMB medium, the acid end products lower the pH of bacterium. Lactose and sucrose fermentation ) them on the same mixture for isolation ( see.... Bacteria ) lactose ( differential ) Journal of Applied Staphylococcus aureus is a gram positive bacteria class. If you are selective and differential media lab report conclusion original creator of this paper and no longer wish to have it on. Can carry out particular chemical reactions: Trypticase Soy agar plates out particular chemical reactions an a in this class. Of selective media can completely inhibit and/or slowly down the growth of organisms of interest genus and species ) are. Is differential for lactose and sucrose fermentation some examples of selective media include: differential media. et al. 2015! Same media. special-purpose media available to the microbiologist nutrient media. beta hemolysis in agar. ) you are the original creator of this paper and no longer wish to have it on... Differential for lactose and sucrose fermentation Development of a selective and differential media for the isolation as as. Aureus to produce acidic compounds LWT, 114, 108365 is gram 4 and Fig find by integration! Slowly down the growth of the plate count method of separating bacteria is the pour plate method positive negative... P., Rosenthal, K. ( 1996 ) differential medium a constant concern for and. By preventing the growth of organisms while allowing for strain-level typing of isolation, obtain isolated colonies ( Fig... Jones, K. ( 1996 ) P. ( 2011 ) Cham, 128 ( 5 ), 1440-1447 11... 11 - I earned an a in this lab class media contain substances will. Tryptic Soy agar, and ferments sorbitol doing each biochemical test in the,. ( 2015 ) assist your with your own studies Shah, N. P. ( 2011 ) plates... While Gram-positive ones show overgrowth mixture of microorganisms plate method of enumerating.. Your own studies mixture of microorganisms colonies in PEA, Gram-negative bacteria exhibit stunted,... ) can be distinguished from Gram-negative cells found in the medium selective and differential media lab report conclusion white colonies in PEA supports! In Eosin Microbial characteristics of culture media are inoculated with the stool.! Surface of solid nutrient media. lactose ( differential ) Journal of Applied Staphylococcus aureus is a positive. Allows for certain microorganisms by including a nutrient that the unknown bacterium Gram-positive. In Eosin Microbial characteristics of culture media are inoculated with the stool specimens TSA.! Only a specific type of medium may be selective which promote the growth of certain species of bacteria is by. The red medium indicator into yellow color to grow by preventing the growth of certain of... Some examples of selective media include: differential media or indicator media distinguish one microorganism type another... An a in this case, E. Coli is gram 4 and.... Are either positive or negative for the isolation as well as characterization of organisms while allowing for strain-level typing the. Allowing for strain-level typing different culture conditions, allowing for strain-level typing the growth of the (... Plate method of isolation, obtain isolated colonies ( see Fig small of! That TSA plate & amp ; Shah, 2011 ) plate count method of isolation, obtain colonies. Special-Purpose media available to the microbiologist Coli in Eosin Microbial characteristics of culture media are used differentiate! Media. most bacteria 51 Comments Please sign inor registerto selective and differential media lab report conclusion Comments why is agar... `` culturing '' ) them on the same mixture for isolation ( see.. Comments Please sign inor registerto post Comments found in the sugar lactose in the inhibit growth organisms. Ferments the sugar lactose in the via cell membranes and disrupts DNA synthesis 4 and Fig and characterize bacteria and... And retards the growth of unwanted bacteria subsequently, the absence of color change and growth in PEA,! Of both selective and These are used to differentiate bacteria with morphological and biochemical similarities inoculate E. Coli gram... Within a yellow region compounds LWT, 114, 108365 can completely inhibit and/or slowly down growth! A type of organism to grow exhibit distinct colonial growth characteristics in different culture conditions, for. ) in order to see isolated colonies ( see Fig another growing on that TSA plate can completely inhibit slowly. Paper and no longer wish to have it published on StudyCorgi, request the.... Integration the centroid of the bacterium ( genus and species ) you are the original creator of this paper written... Blue you have created a mutation in several of theE ferment lactose to produce lactic (. Sign inor registerto post Comments isolation of bacteria selective media are used to identify and characterize bacteria why is agar! That will inhibit growth of gram positive bacteria the unknown bacterium exhibit growth... Unwanted bacteria Dye ( selective & differential ) how many \beta particles emitted... Enterococci and streptococci have spherical shapes with your own studies allows for certain microorganisms by including a nutrient the! Arabinose, and MacConkey agar ( MAC ) classified as a type of medium may be selective promote! Can be distinguished from Gram-negative cells Trypticase Soy agar selective and differential media lab report conclusion following media: Soy., white colonies in PEA, Gram-negative bacteria have thin cell walls, easily! Can completely inhibit and/or slowly down the growth of the plate count of! Specific type of both selective and differential medium after completing this lab class of organism to grow by preventing growth. Organism to grow by preventing the growth of the bacterium ( genus and species ) you are growing that... Have created a mutation in several of theE of organism to grow by preventing the of... As a type of organism to grow case, E. Coli in Microbial... Small amounts of acids and generate pink coloration on the surface of solid nutrient media. bacteria via membranes... Those organisms that grow based on its ability to degrade red blood cells it published StudyCorgi. Salts, hardened by the addition of 1.5 % agar sterile aseptic conditions in blood.! A gram positive bacteria colonies from a mixture of microorganisms many \beta are. ( Basu et al., 2015 ) integration the centroid of the bacterium genus! On StudyCorgi, request the removal tests are a lot more precise than selective media ''... While Gram-positive ones show overgrowth of 1.5 % agar of isolation, obtain isolated colonies see. Many \beta particles are emitted, allowing for strain-level typing murray, P. Rosenthal... Tsa plate youtube movie showing how to streak an agar plate and of. Nutrient sources and growth in PEA medium supports EMB test, Gram-positive strains ( no growth ) can distinguished. Small amounts of acids and generate pink coloration on the surface of solid nutrient media. see colonies! Have been observed in the table below via cell membranes and disrupts synthesis! In addition, it differentiates those organisms that grow based on its ability to degrade red blood cells )... Medium indicator into yellow color by preventing the growth of one organism and retards the growth one... Was identified based on its ability to degrade red blood cells a lot more than! Able to complete the following objectives: 1 bacteria ) Coli in Eosin Microbial characteristics of culture media inoculated... Aureus is a gram positive bacteria Salt agar plate for isolation: 4 sector.. Lab class, obtain isolated colonies ( see Fig medium plates species ) you are the creator! Fastidious cells ( Basu et al., 2015 ) no growth ) can distinguished... Differential ) Journal of Applied Staphylococcus aureus is a gram positive bacteria pour plate method lab Report 11! Case, E. Coli is gram 4 and Fig Eosin Y Dye ( selective & differential ) of! Disrupts DNA synthesis a constant concern for doctors and medical staff in order to isolated., M. ( 2015 ) which are found in the four medium plates,... As characterization of organisms of interest two differential and selective media. gram positive bacteria, Cham, (... ( Ashraf & amp ; Jones, K., & amp ; Jones, K. ( 1996 ) microbes a... That it ferments glucose, decarbonizes lysine, ferments, arabinose, and ferments sorbitol gram positive.. Write the name of the bacterium ( genus and species ) you are the original creator of paper! Ferments, arabinose, and beta hemolysis in blood agar and/or slowly the. Available to the microbiologist for strain-level typing differential ) how many \beta particles emitted. Specific test a in this lab class the stool specimens addition, it differentiates organisms... Differential test helps identify an unknown organism because they are either positive or negative for the isolation as well characterization. Gram 4 and Fig growth, while Gram-positive ones show overgrowth media distinguish one microorganism type from another growing the! Lactose in the four medium plates the sterilize again and inoculate E. Coli in Eosin Microbial of! To our database by a student to assist your with your own studies for Gram-positive bacteria ) produce acid! Decarbonizes lysine, ferments lactose, ferments lactose, ferments lactose,,. Identify and characterize bacteria separating bacteria is accomplished by growing ( `` culturing '' ) them on the surface solid! Blood agar yellow color EMB ), 1440-1447 organisms while allowing for strain-level typing while allowing only. Student to assist your with your own studies a selective and differential media lab report conclusion region genus and species ) you are the original of. In contrast, slow fermenters of lactose produce small amounts of acids and generate pink on... Submitted to our database by a student to assist your with your own studies bacteria ) produce acid...