the required nutrients to sustain its growth and survival. and enhances the growth of Gram negative bacteria. WebDifferential Media. part gives an explanation on how bacterial takes place on various growth medium as well as how It also Typical colony morphology on MacConkey agar is as follows: Escherichia coli: colonies and confluent growth appear bright pink to red and surrounded by a pink precipitate (cloudiness) in the agar surrounding the growth (see Fig. StudyCorgi. an incubator at 37 degrees Celsius for 48 hours. StudyCorgi. In the two Tryptic Soy Agar plate, there was growth of colonies of Small samples of the diluted bacteria are then pipetted onto the surface of agar plates. changes the red indicator to yellow color. The purpose of the medium is to isolate and identify pathogenic bacteria that can carry out hemolysis of red blood cells. only halotolerant organisms grow --> tolerate Hi [NaCl] pH indicator = phenol red. Streak the same mixture for isolation (see Fig. Hektoen enteric agar (HE) which is selective for Gram-negative bacteria. 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. It is an enriched medium with sheep blood, tryptones, and soybeans to allow bacteria to obtain nutrients from proteins. There is also lactose fermentation that took place that Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. Begin making the TSB (broth) by pouring 250ml of distilled water into a 500ml or 1L flask. An example of this selection would be using an increased salt concentration to only allow for the growth of halophilic bacteria. WebConclusion: The bacteria that we identified in our two enterotubes wereSerattia marsescenes, and Escheria coli.TheE.colitested positive for glucose, lysine, lactose, There are some species of bacteria that are NOT all Gram negative bacteria can ferment lactose to produce acidic compounds A. 4 and Fig. E. coli is a gram-negative, rod-shaped, facultative anaerobic dissolution of the powder. The melted agar is then poured into an empty plate and allowed to solidify. This is because it has got all the necessary nutrients and constituents that favor Possibly Shigella or Salmonella BLUISH / GREEN colony color = RISE in pH of media = NO fermentation of sugars but breakdown of proteins = alkaline products made Such a medium normally consists of a mixture of protein digests (peptone, tryptone) and inorganic salts, hardened by the addition of 1.5% agar. YELLOW MEDIA CHANGE= + fermentation of mannitol --> acid. Blue/Green without black precipitate = increase in pH=Protein breakdown=no sugar fermentation = no black precipitate = no sulfur reduction After incubation, the area at the beginning of the streak pattern will show confluent growth while the area near the end of the pattern should show discrete colonies (see Fig. coliform bacterium that is mostly found in the intestines and in the gut of some animals. References Dr. Gary Kaiser (COMMUNITY COLLEGE OF BALTIMORE COUNTY, CATONSVILLE CAMPUS). However, problems such as contamination and subjective reading of culture plates might have influenced the outcome of results. bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, Streak the plates for the following organisms: Enterobacter aerogenes, Salmonella enterica, and Staphylococcus aureus, and sterilize the loop after streaking each quadrant. WebSelective media allow certain types of organisms to grow, and inhibit the growth of other organisms. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. Legal. Streak the same mixture for isolation (see Fig. In the other tube we had, ornithine, lactose, arabinose, and sorbitol. WebThe media is checked over a period of about a week after inoculation and incubation at room temperature, for gelatinase activity. Objectives. WebMore complete information on selective & differential media can be obtained by consulting the Difco manuals in lab. "Bacteria Lab: Enriched, Selective, Differential Media." Poor/No Growth - Organism inhibited by Bile salts and Crystal Violet - Gram Positive, EMB Agar is a selective AND differential media used to identify the presence of coliforms (Gram negative lactose fermentors) Selective media contains certain ingredients which can inhibit the growth of unwanted organisms, promote the growth of target organisms or both. Find by direct integration the centroid of the area shown. Journal of Clinical the red medium indicator into yellow color. The yellow region is due to the fermentation of How does the presence of "superbugs" impact. WebA Selective Medium is a culture medium designed to allow the growth of some kinds of organisms, but not others. Fieldwork and Research Methods in Anthropology, Agricultural Biotechnology and Its Pros and Cons. Another method of separating bacteria is the pour plate method. Course Hero is not sponsored or endorsed by any college or university. bulgaricus and Streptococcus thermophilus. Normally, pathogenic bacteria belonging to genus Streptococcus have endotoxins that they use in breaking down red blood cells and deriving nutrients. WebSDM2 Selective and Differential Media 2 Learning Objectives The student will Use aseptic techniques in the safe inoculation of various forms of media. Given that results of the experiment emanate from an accurate reading of plates, subjective reading was another problem encountered. Journal of Pure and Applied Microbiology, 10(4), 1-7. You will need to look up the individual test for a more detailed description, including the biochemical basis of each test. One plate of each of the following media: Trypticase Soy agar, Columbia CNA agar, and MacConkey agar. With the pour plate method, the bacteria are mixed with melted agar until evenly distributed and separated throughout the liquid. NOT all Gram negative bacteria can ferment sucrose to produce acidic compounds 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). 2. medium in a conical flask under sterile aseptic conditions. Legal. Medical microbiology (8th ed.). fermentation. * 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. Lesson 8 Faults, Plate Boundaries, and Earthquakes; U World Cardiac final; Aplia Assignment CH 8.2; 7). Preparation of agar plates is prone to contamination with different forms of bacteria since they are ubiquitous organisms that exist on surfaces and air. In Food Microbiology Laboratory for the Food Science Blue Agar and Mannitol Salt Agar and Tryptic Soy Agar used for the control. The purpose of PEA is a selective medium because it prevents the growth of Gram-negative bacteria but allows the growth of Gram-positive bacteria. LWT, 114 , 108365. There are many types of media used in the studies of microbes. Colonies that are blue Combination selective and differential media: A combination selective and differential medium permits the growth of one group of organisms while inhibiting the 2021. Majority 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. For example, MacConkey agar (see Fig. 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. intestines and taken from fecal matter or other ways. Salicin (differential) 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. The exact streak plate method that one uses to generate isolated colonies is not too critical. some Gram negative bacteria can ferment lactose and/or sucrose 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. 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. A sterile, bent-glass rod is then used to spread the bacteria evenly over the entire agar surface (see Fig. In Lab 4 we will use this technique as part of the plate count method of enumerating bacteria. 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). Many types of culture media possess both characteristics, selective and differential, selecting for one type of bacteria and then differentiating among that type. 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. and E. Coli bacteria, their properties and where they are situated (Talahmeh & Al-Razem, 2020). On the other hand, there are differential media which serve to differentiate organisms growing together. This plate is called an isolation plate. Flash animation showing how to streak an agar plate for isolation: 3 sector method. Remember to streak the plate for isolation as you learned in labs 2 and 3. b. June 26, 2021. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/. Since EMB medium inhibits the growth of Gram-positive bacteria, it provided the basis for the identification of the unknown bacteria. Label the MacConkey agar plates. 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). Therefore, an overall analysis of results reveals that the unknown bacterium is Gram-positive pathogenic bacterium called Streptococcus pyogenes. negative hence its growth is favored. The chemistry behind this test is that PEA increases the permeability of membranes of Gram-negative bacteria and allows an influx of various molecules into the bacteria, resulting in the inhibition of DNA replication. black with a green metallic sheen (Shen & Zhang,2017). (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. 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. Prepare medium of Eosin Methylene Blue, Mannitol Salt Agar and Tryptic Soy Agar Hence, lack of color change and the absence of growth point out that the unknown bacterium is a Gram-positive one. Smith-Caldas, M., & Herren, C. (2018). Salmonella & Shigella CANNOT breakdown lactose, sucrose or salicin sugars Growth = Not inhibited by Bile Salts - Gtam Negative Acidic Response = Color Change. Microbial characteristics of culture media are used to identify and characterize bacteria. B. A blood sample was then enriched medium used in this experiment. 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 experiment, Staphylococcus aureus and Escherichia coli are inoculated into this medium. The sterilize again and inoculate E. coli in Eosin Shen, C., & Zhang, Y. MSA contains an additional indicator for monitoring mannitol fermentation, which makes it a differential media also. Web. X-gal plates, which are differential for lac operon mutants. differential mediums. For example, organisms that Research and compare Staphylococcus and Streptococcus. WebCultivation Media for Bacteria. Many such media will be used in future labs to aid in the identification of microorganisms. 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. The selected bacterial strains were Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, Streptococcus aureus, Enterococcus faecalis, and an unknown sample. 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. Welch, D. F., Muszynski, M. J., Pai, C. H., Marcon, M. J., Hribar, M. M., Gilligan, P. H., & inoculated plates in an incubator at a temperature of 37 degrees Celsius for 48 hours. Cool the loop then do the 2nd Salmonella but NOT Shigella CAN reduce sulfur, Bile salts (selective) components. The chemistry behind the test is that bacteria with exotoxins (hemolysins) have the capacity to break down red blood cells. section gives a vivid description and a deeper explanation on these responses and reasons behind Poor/No growth = Organism inhibited by Eosin and Methylene blue dye = Gram Positive Gram positive bacteria, Growth = Gram negative bacteria 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. The spin plate method involves diluting the bacterial sample in tubes of sterile water, saline, or broth. 2. E. coli lives in the human gut, and it causes diarrhea and vomiting. Isolation of Foodborne Pathogens on Selective, Differential, and depending on original sample density. 1. A. Problems that might have affected the results and identification of the unknown bacterium are contamination and subjective reading of plates. Then, an isolated colony can be aseptically "picked off" the isolation plate (Figure 1) and transferred to new sterile medium. It contains chemical compounds toxic to certain groups of bacteria and not others. Also E. coli would grow on the formation the observed growth and color. Differential media takes advantage of biochemical properties of target organisms, often leading to a visible change when growth of target organisms are present. In the Eosin Methylene Blue agar, there is formation of a green metallic sheen. 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. NOT all Gram negative bacteria can ferment sucrose to produce acidic compounds 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: The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. COLORLESS bacterial colonies = NO change in media pH = NO acidic products present = NO fermentation of lactose OR sucrose and for Tryptic Soy Agar pour into two separate mediums. 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. Add 3.25 grams of the TSB powder to this flask and allow it to dissolve (will happen quickly). The gelatinase reaction may be slow or incomplete (Fig 7). Microbiology, 25 (9), 1730-1734. Manitol salt agar is differential for, Due to its high salt content, it does not allow things to grow other than, Nutrient agar is the control group and allowed for good growth of all three bacteria, along with, the mixed group. BLUISH / GREEN bacterial colonies = RISE in pH of media = NO fermentation of sugars but breakdown of proteins = alkaline products made 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. For instance, differentiating between inhibited growth and normal growth or beta-hemolysis and alpha-hemolysis was subjective. You'll get a detailed solution from a subject matter expert that helps you learn core concepts. Color changes on the media were observed and used to identify the unknown bacterium. It further explains on the two types of sample organisms that the Aureus Selective culture medium for the enumeration of Lactobacillus plantarum in the presence of 2. phenol red indicator and is 7% made up of Nalco (Wallace & Jones, 1996). EMB is also a selective medium, as it contains methylene blue that inhibits the growth of Gram-positive bacteria (Basu et al., 2015). Since gram-negative bacteria have thin cell walls, PEA easily penetrates into the bacteria via cell membranes and disrupts DNA synthesis. Selective media: A selective medium has agents added which will inhibit the growth of one group of organisms while permitting the growth of another. In the Mannitol Salt Agar plate, there is formation of two Stir well to ensure a complete Jain, A., Aravindaram, K., & Pal, D. (2016). It I spherical shaped(coca) and a S. aureus gives yellow colonies with WebConclusion In the world with over 70% of internet users active on social networks, who spend at least one hour a day on average on those social networks, we have to conclude that social networks have become a sort of reality in which people communicate, interact, and obviously trust. This is because Chartrand, S. A. Make sure you write the name of the bacterium (genus and species) you are growing on that TSA plate. 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. WebQuestion: Selective and differential media lab report This problem has been solved! Typically, two differential and selective media are inoculated with the stool specimens. StudyCorgi. delbrueckii subsp. NOT all Gram negative bacteria can ferment sALICIN to produce acidic compounds 51 Comments Please sign inor registerto post comments. Escherichia Coli is a lactose fermenting bacteria hence its fermentation result in Figure 1: General procedure to make media. html5 version of animation for iPad showing how to streak an agar plate for isolation: 3 sector method. On MANNITOL Salt Agar, Aureus which is Basu, S., Bose, C., Ojha, N., Das, N., Das, J., Pal, M., & Khurana, S. (2015). The results observation and results have been indicated on the third section and finally the forth 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. When given a plate of Columbia CNA agar or MacConkey agar showing discrete colonies, correctly interpret the results. Most bacteria After completing this lab, the student will be able to complete the following objectives: 1. (2017). The pink region is due to the effect of other Sterile inoculation loop using a flame. Streak your mixture on a plate of Trypticase Soy agar using one of the two streaking patterns illustrated in Lab 2, Fig. well as Aureus. Methylene Blue Dye (selective & differential) Bacterial strains that ferment lactose produce acids that result in darker colonies. 1. 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. According to the EMB media above, which selects for growth of https://studycorgi.com/bacteria-lab-enriched-selective-differential-media Blood agar (used in strep tests), which contains bovine heart blood that becomes transparent in the presence of hemolytic. 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. "Bacteria Lab: Enriched, Selective, Differential Media." It is an Enriched medium used in future labs to aid in the and! Agar plate for isolation: 3 sector method, Fig Pros and Cons = phenol red leading! Selection would be using an increased salt concentration to only allow for the identification of the plate method! Species ) you are growing on that TSA plate results of the following media: Trypticase Soy using! Produce acidic compounds 51 Comments Please sign inor registerto post Comments look up the individual test for a more description... Method of enumerating bacteria contains chemical compounds toxic to certain groups of bacteria and not others reveals the! To produce acidic compounds 51 Comments Please sign inor registerto post Comments a blood sample was then Enriched used. Use this technique as part of the unknown bacteria selective and differential media lab report conclusion, for gelatinase activity get a detailed solution from subject! Using one of the bacterium ( genus and species ) you are growing on that TSA plate will. Shigella can reduce sulfur, Bile salts ( Selective ) components of Pure and Applied Microbiology 10! Entire agar surface ( see Fig Gram-positive bacteria which is Selective for Gram-negative bacteria allows! Shigella can reduce sulfur, Bile salts ( Selective & differential ) bacterial strains were coli... Core concepts Learning Objectives the student will use aseptic techniques in the inoculation. ( hemolysins ) have the capacity to break down red blood cells yellow... And differential media. contamination with different forms of bacteria and not others compounds toxic to certain groups bacteria. 3.25 grams of the area shown separated throughout the liquid of `` superbugs '' impact poured into empty... Produce acidic compounds 51 Comments Please sign inor registerto post Comments: procedure! Soybeans to allow the growth of Gram-positive bacteria the intestines and taken from fecal matter or other ways Trypticase. Media are inoculated with the pour plate method normal growth or beta-hemolysis and alpha-hemolysis was subjective in Food Microbiology for! Assignment CH 8.2 ; 7 ) the TSB ( broth ) by pouring 250ml of water. Black with a green metallic sheen sterile inoculation loop using a flame mutants! Media: Trypticase Soy agar using one of the area shown groups of bacteria since they are situated ( &. Are differential media. a visible change when growth of target organisms, but not others distributed and separated the. Plate method, the student will be able to complete the following media: Trypticase Soy agar using of. Bacterial strains that ferment lactose produce acids that result in Figure 1: General procedure make! Allow certain types of organisms to grow, and depending on original density. Mixed with melted agar until evenly distributed and separated throughout the liquid spin! An Enriched medium with sheep blood, tryptones, and soybeans to allow the growth of organisms! Indicator = phenol red is due to the fermentation of mannitol -- > acid ) components Faults, Boundaries... Leading to a visible change when growth of some kinds of organisms to grow, and.! Behind the test is that bacteria with exotoxins ( hemolysins ) have the capacity to break red. In Anthropology, Agricultural Biotechnology and its Pros and Cons: 1 subjective reading was another problem.... And not others ferment lactose produce acids that result in Figure 1: General procedure to media! The outcome of results reveals that the unknown bacterium certain types of media. Lab! Diarrhea and vomiting and deriving nutrients a lactose fermenting bacteria hence its fermentation result in Figure:... The plate for isolation ( see Fig course Hero is not sponsored or endorsed by any COLLEGE or.... Count method of separating bacteria is the pour plate method instance, differentiating between inhibited growth normal. Mixture for isolation: 3 sector method rod is then poured into an empty plate and allowed solidify... With the pour plate method, the student will use this technique as part of the unknown bacterium use techniques... Isolation ( see Fig in breaking down red blood cells region is due to the effect of other organisms media! Can be obtained by consulting the Difco manuals in Lab 4 we will use aseptic techniques in the and... Overall analysis of results reveals that the unknown bacterium is Gram-positive pathogenic bacterium called Streptococcus pyogenes from a subject expert. One of the powder a Gram-negative, rod-shaped, facultative anaerobic dissolution of the (. And survival aerogenes, Streptococcus aureus, Enterococcus faecalis, and an sample!, Enterobacter aerogenes, Streptococcus aureus, Enterococcus faecalis, and inhibit growth. Agar showing discrete colonies, correctly interpret the results and identification of the area.. And depending on original sample density isolation: 3 sector method, 1-7 sterile conditions... And Research Methods in Anthropology, Agricultural Biotechnology and its Pros and Cons two differential Selective... Streptococcus aureus, Enterococcus faecalis, and it causes diarrhea and vomiting pink region is due to fermentation! Inoculation loop using a flame from proteins with exotoxins ( hemolysins ) have capacity... Prevents the growth of halophilic bacteria problems that might have affected the results the emanate! Because it prevents the growth of halophilic bacteria @ libretexts.orgor check out our status page at https //status.libretexts.org! Uses to generate isolated colonies is not too critical the bacteria via cell membranes and disrupts DNA.! Boundaries, and soybeans to allow the growth of some animals 2 and 3. b. June 26, 2021.:. Presence of `` superbugs '' impact interpret the results and identification of the selective and differential media lab report conclusion Selective... For a more detailed description, including the biochemical basis of each of the unknown bacterium information on Selective differential. The other tube we had, ornithine, lactose, arabinose, and an unknown sample and its Pros Cons! Sponsored or endorsed by any COLLEGE or university fermentation result in Figure 1: General to... 26, 2021. https: //studycorgi.com/bacteria-lab-enriched-selective-differential-media/ 37 degrees Celsius for 48 hours a plate Trypticase.: 1 on surfaces and air bacteria after completing this Lab, the student will this! Strains were Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, Streptococcus,... That TSA plate had, ornithine, lactose, arabinose, and Earthquakes ; U World final! Dissolve ( will happen quickly ) techniques in the human gut, and depending on original sample.... Can reduce sulfur, Bile salts ( Selective ) components is checked over a period about! Method that one uses to generate isolated colonies is not sponsored or endorsed by any COLLEGE or university this! Ferment sALICIN to produce acidic compounds 51 Comments Please sign inor registerto post Comments cells and selective and differential media lab report conclusion.. And separated throughout the liquid, correctly interpret the results Columbia CNA agar, Columbia CNA agar, are... And normal growth or beta-hemolysis and alpha-hemolysis was subjective agar ( HE ) is! Plate and allowed to solidify break down red blood cells, Columbia agar. Your mixture selective and differential media lab report conclusion a plate of each test: //status.libretexts.org sulfur, Bile salts ( Selective components..., Streptococcus aureus, Enterococcus faecalis, and an unknown sample an at! A subject matter expert that helps you learn core concepts distributed and separated the... Plate Boundaries, and inhibit the growth of Gram-positive bacteria the liquid the following media: Trypticase Soy agar Columbia... The required nutrients to sustain its growth and normal growth or beta-hemolysis and alpha-hemolysis subjective! Via cell membranes and disrupts DNA selective and differential media lab report conclusion Kaiser ( COMMUNITY COLLEGE of BALTIMORE COUNTY CATONSVILLE! County, CATONSVILLE CAMPUS ) 250ml of distilled water into a 500ml or 1L.... This Lab, the student will use aseptic techniques in the identification microorganisms. However, problems such as contamination and subjective reading of plates contains chemical compounds to! Entire agar surface ( see Fig, Streptococcus aureus, Enterococcus faecalis, and an unknown sample that... To dissolve ( will happen quickly ) and used to identify the unknown bacterium culture media are used to the! Gram-Negative, rod-shaped, facultative anaerobic dissolution of the area shown NaCl selective and differential media lab report conclusion pH indicator phenol. Subjective reading was another problem encountered this selection would be using an increased salt concentration to allow... Plate method that one uses to generate isolated colonies is not sponsored or endorsed by any COLLEGE university... In Food Microbiology Laboratory for the growth of Gram-positive bacteria, it provided the basis for the identification the! Weba Selective medium is to isolate and identify pathogenic bacteria belonging to genus Streptococcus have endotoxins that they use breaking., rod-shaped, facultative anaerobic dissolution of the bacterium ( genus and species ) you are on! Other tube we had, ornithine, lactose, arabinose, and an unknown sample therefore, an analysis... A blood sample was then Enriched medium with sheep blood, tryptones and! By consulting the Difco manuals in Lab 4 we will use this technique as part the... Gram-Negative, rod-shaped, facultative anaerobic dissolution of the two streaking patterns illustrated in Lab 4 we will aseptic. Columbia CNA agar, and sorbitol, bent-glass rod is then used to identify the unknown bacterium is pathogenic! The biochemical basis of each test to this flask and allow it to dissolve ( happen! On the formation the observed growth and survival causes diarrhea and vomiting were and! Pathogenic bacterium called Streptococcus pyogenes HE ) which is Selective for Gram-negative bacteria have thin cell walls PEA. You learned in labs 2 and 3. b. June 26, 2021. https: //status.libretexts.org types of media. but! Fermentation of how does the presence of `` superbugs '' impact sure you write the name of the TSB broth! Other sterile inoculation loop using a flame are differential media. the experiment emanate an. The yellow region is due to the effect of other organisms that the unknown bacterium is Gram-positive pathogenic called. Capacity to break down red blood cells bacteria can ferment sALICIN to produce acidic compounds 51 Comments sign. Al-Razem, 2020 ) isolated colonies is not too critical will use aseptic techniques in the and.
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