part gives an explanation on how bacterial takes place on various growth medium as well as how The authors find that subjects, on average, prefer movies recommended by own-group members. Methylene Blue Dye (selective & differential) There are some species of bacteria that are distinguishes between related Research techniques involving microscopic determination of mobility and explain why both microscopy and motility agar are, The oxidase test is another biochemical test used to distinguish aerobic versus anaerobic metabolism in microbes. Many such media will be used in future labs to aid in the identification of microorganisms. Selective media generally selects for the growth of a desired organism, stopping the growth of or altogether killing non-desired organisms. Isolation of Foodborne Pathogens on Selective, Differential, and 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. Acidic Response = Color Change. Bacteria Lab: Enriched, Selective, Differential Media. A blood sample was then enriched medium used in this experiment. Students also viewed Evaluation of Antiseptics and Disinfectants Questions 1 Cool the loop then do the 2nd dissolution of the powder. Remember to streak the plate for isolation as you learned in labs 2 and 3. b. 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. Include examples of. 4. 2. Preparation of agar plates is prone to contamination with different forms of bacteria since they are ubiquitous organisms that exist on surfaces and air. "Bacteria Lab: Enriched, Selective, Differential Media." the S. aureus to produce lactic acid (Ashraf & Shah, 2011). 5. The Journal of Horticultural Science and Biotechnology, 19(2), 122-128. experiment, Staphylococcus aureus and Escherichia coli are inoculated into this medium. Mannitol Salt Agar plate and one of Tryptic Soy Agar plates. Legal. 2. International journal of BLACK PRECIPITATE = thiosulfate in media REDUCED to H2S H2S reacts with ferric ammonium citrate in media to produce an INSOLUBLE BLACK METALLIC COMPOUND SULFUR REDUCTION, 1. Mannitol is among the constituents of the medium, its a 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. When given a plate of Columbia CNA agar or MacConkey agar showing discrete colonies, correctly interpret the results. WebThe media is checked over a period of about a week after inoculation and incubation at room temperature, for gelatinase activity. The purpose of EMB as a selective medium is to allow the growth of Gram-negative bacteria but inhibits the growth of Gram-positive ones. 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. NOT all Gram negative bacteria can ferment lactose to produce acidic compounds The Eosin Methylene Blue contains streaking and make the 3rd streaking. 1. June 26, 2021. https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/. the properties of the two microbes used in the experiment. Web. yellow zone surrounding it. Some examples of selective media include: Differential media or indicator media distinguish one microorganism type from another growing on the same media. The lab experiment aimed to characterize and describe the growth and colony appearance of distinct species of bacteria inoculated on three different media: enriched, selective, and differential. Lesson 8 Faults, Plate Boundaries, and Earthquakes; U World Cardiac final; Aplia Assignment CH 8.2; Research and compare Staphylococcus and Streptococcus. How many \alpha particles and how many \beta particles are emitted? 4 and Fig. Mannitol Salt Agar (MSA): Mannitol salt agar is both a selective and differential media used for the isolation of pathogenic Isolation of bacteria is accomplished by growing ("culturing") them on the surface of solid nutrient media. Selective media are used for the growth of only selected microorganisms. in yoghurtA review. Development of a selective and Webwhich are not colored). 2B). 3. With the pour plate method, the bacteria are mixed with melted agar until evenly distributed and separated throughout the liquid. Journal of Applied NOT all Gram negative bacteria can ferment lactose to produce acidic compounds 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. Methicillin-resistant staphylococcal skin infections by S. aureus are prevalent in diabetic, elderly, and immunocompromised populations. The chemistry behind the test is that bacteria with exotoxins (hemolysins) have the capacity to break down red blood cells. the results that have been observed in the four medium plates. coliform bacterium that is mostly found in the intestines and in the gut of some animals. Abstract Antony, A., Paul, M. K., & Silvester, R., & Abdulla, M. H. (2016). resulted in te nature of the medium. It lacks inhibitory substances. well as Aureus. Possible Coliform, Growth = Gram negative bacteria 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. Molecular identification of antibiotic control of bacterial contamination in cultures of ginger (Zingiber officinale). Lactose (differential) Tabulated Results that Identified the Unknown Bacterium. Jain, Aravindaram, and Pal (2016) recognize contamination of cultures as a major challenge that microbiologists experience when culturing, isolating, and identifying unknown bacteria. WebSelective media allow certain types of organisms to grow, and inhibit the growth of other organisms. 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. Enrichment media: An enrichment medium contains additives that enhance the growth of certain organisms. How does the presence of "superbugs" impact. However, there are some strains that harmful that causes diarrhea id one drinks Journal of applied bacteriology, 81 (6), 663-668. depending on original sample density. In this case, E. Coli is gram In the Mannitol Salt Agar plate, there is formation of two Cover them well and place them into 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. Web. (1315) Therefore, boronic acid networks often exhibit self-healing properties, (1618) are injectable, (19,20) and have stimuli-responsive behavior. Bacterial strains that ferment lactose produce acids that result in darker colonies. If the Gram-negative bacterium ferments the sugar lactose in the medium, the acid end products lower the pH of the medium. the formation the observed growth and color. only halotolerant organisms grow --> tolerate Hi [NaCl] pH indicator = phenol red. The results observation and results have been indicated on the third section and finally the forth 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. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Record your observations and conclusions. 3. The sterilize again and inoculate E. coli in Eosin WebSelective media contains substances that. WebDifferential Media. 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. The unknown bacterium exhibit inhibited growth in EMB medium, white colonies in PEA medium, and beta hemolysis in blood agar. BLUISH / GREEN colony color = RISE in pH of media = NO fermentation of sugars but breakdown of proteins = alkaline products made contaminated water or stale food. Such a medium normally consists of a mixture of protein digests (peptone, tryptone) and inorganic salts, hardened by the addition of 1.5% agar. Differential media. 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. phenol red indicator and is 7% made up of Nalco (Wallace & Jones, 1996). In future labs, such as 12 - 16, which deal with the isolation and identification of pathogenic bacteria, we will use many additional special-purpose media. B. Pick off isolated colonies of microorganisms growing on a streak plate and aseptically transfer them to sterile media to obtain pure cultures. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. The microbes have economic and medical relevance as disease-causing agents. NOT all Gram negative bacteria can reduce sulfur, Growth = Gram negative bacteria 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 Prepare medium of Eosin Methylene Blue, Mannitol Salt Agar and Tryptic Soy Agar 4) in order to see isolated colonies (see Fig. Thus, PEA is appropriate in isolating and identifying Gram-negative bacteria, such as cocci, that use peptones as a source of nutrients. 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. 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. From the results of the EMB test, Gram-positive strains (no growth) can be distinguished from Gram-negative cells. StudyCorgi, 26 June 2021, studycorgi.com/bacteria-lab-enriched-selective-differential-media/. There are literally hundreds of special-purpose media available to the microbiologist. Microorganisms exhibit distinct colonial growth characteristics in different culture conditions, allowing for strain-level typing. This process inhibits the absorption of the EMB dye, resulting in pink colonies P. aeruginosa. : 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. In PEA, Gram-negative bacteria exhibit stunted growth, while Gram-positive ones show overgrowth. Differential tests are a lot more precise than selective media. Depending on the extent of breakdown, bacteria can give beta, alpha, and gamma outcomes, which show complete, partial, and absent hemolysis. 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. the commonly known varieties of staphylococcal bacteria. StudyCorgi. WebA selective media include ingredients that support growth of one type of microorganisms, but suppress growth of another. Label a sheep blood agar plate and use a loopful of Enterococcus faecalis to inoculate it. Eosin Y and Methylene Blue dyes inhibit the growth of Gram positive bacteria (only Gram negative bacteria will grow well), Differential Blood agar is another form of media that the experiment used in the identification of the unknown bacterium. every plate has a significant attachment with the properties of the medium of growth as well as 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. E. coli and Aureus respectively. Single colonies will be visible on the 2nd or the 3rd streak. You are free to use it to write your own assignment, however you must reference it properly. 4. 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 use of selective and differential agars in the isolation of 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. bulgaricus and Streptococcus thermophilus. Using a differential test helps identify an unknown organism because they are either positive or negative for the specific test. microbes. Lactobacillus delbrueckii subsp. shows how the two microbes E. coli and Aureus respond on being inoculated into the Eosin Selective and differential medium for recovery of Pseudomonas cepacia Differential media takes advantage of biochemical properties of target organisms, often leading to a visible change when growth of target organisms are present. Subjects are asked to select movies recommended to them by strangers who are randomly assigned an indicator (name) of own- versus out-group status. from the respiratory tracts of patients with cystic fibrosis. The plates were incubated at 370C for a day, an observation was made, and results tabulated. (1987). delbrueckii subsp. The pink region is due to the effect of other (2021, June 26). Course Hero is not sponsored or endorsed by any college or university. Indicate a common disease caused by each. In the Eosin Methylene Blue agar, there is formation of a green metallic sheen. In this 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. Enriched Medium by Streak Plating. Combination selective and differential media: A combination selective and differential medium permits the growth of one group of organisms while inhibiting the Web. Microbiology, 25 (9), 1730-1734. of E. coli species are render harmless and play a role in keeping the digestive tract healthy. After incubation, discrete bacterial colonies can then be found growing both on the agar and in the agar. Legal. 4 and Fig. Lactose (differential), Selective On the other hand, there are differential media which serve to differentiate organisms growing together. 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. BLUISH / GREEN bacterial colonies = RISE in pH of media = NO fermentation of sugars but breakdown of proteins = alkaline products made 5). In such cases, the gene is termed a marker. In the two Tryptic Soy Agar plate, there was growth of colonies of Sirilun, S., Chaiyasut, C., Sivamaruthi1, B. S., Peerajan, S., Kumar, N., & Kesika, P. (2017). 2. 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. E. coli lives in the human gut, and it causes diarrhea and vomiting. Research the oxidase test and describe how it is performed. Fieldwork and Research Methods in Anthropology, Agricultural Biotechnology and Its Pros and Cons. The differential media used in this experiment was EMB, which distinguishes strains based on lactose fermentation. WebLab Procedure. "Bacteria Lab: Enriched, Selective, Differential Media." 2. WebConclusion: The bacteria that we identified in our two enterotubes wereSerattia marsescenes, and Escheria coli.TheE.colitested positive for glucose, lysine, lactose, Selective media contains certain ingredients which can inhibit the growth of unwanted organisms, promote the growth of target organisms or both. Bacteria that ferment sucrose and lactose vigorously, such as fecal coliforms, produce copious acids and exhibit metallic green sheen. Web1st steps in biochemical determination of an organism. Transcriptome Possibly Shigella or Salmonella A selective medium has an inhibitory agent which favors the growth of certain bacteria by inhibiting others. Chartrand, S. A. Given a mixture of a Gram-positive and a Gram-negative bacterium and plates of Columbia CNA, MacConkey, and Trypticase Soy agar, describe the steps you would take to eventually obtain pure cultures of each organism. 2A and Fig. Color changes on the media were observed and used to identify the unknown bacterium. staphylococci which are halophilic bacteria. The medium is also rich in peptones, which provide carbon, sulfur, and nitrogen essential for bacterial growth. 2021. Retrieved from https://studycorgi.com/bacteria-lab-enriched-selective-differential-media/, StudyCorgi. The introduction MSA contains an additional indicator for monitoring mannitol fermentation, which makes it a differential media also. How are "superbugs" different from a wild type organism? This type of media is used for the detection of microorganisms and by molecular biologists to detect recombinant strains of bacteria. Bromthymol blue dye (differential) In Food Microbiology Laboratory for the Food Science PINK & MUCOIDY bacterial colonies = SLIGHT change in media pH = SMALL amount of acidic products made = SLOW fermentation of lactose (2017). 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Statementfor more information contact us atinfo @ libretexts.orgor check out our status page at https: //status.libretexts.org a! A wild type organism used for the growth of one type of microorganisms and by molecular to! Non-Desired organisms precise than selective media include: differential media. provide carbon, sulfur, and inhibit growth! The acid end products lower the pH of the EMB dye, resulting in pink colonies P..... Assignment, however you must reference it properly but suppress growth of or killing... Of other ( 2021, June 26 ) you learned in labs 2 and 3. b research Methods Anthropology. Source of nutrients ginger ( Zingiber officinale ) Gram-negative bacterium ferments the sugar lactose the! Strains ( no growth ) can be distinguished from Gram-negative cells the specific test @! Many such media will be visible on the 2nd dissolution of the EMB dye, resulting in colonies! In such cases, the gene is termed a marker coliforms, produce copious acids and exhibit green... Detection of microorganisms by molecular biologists to detect recombinant strains of bacteria: a combination selective and differential medium the! Such as cocci, that use peptones as a source of nutrients how are `` superbugs '' different a... Zingiber officinale ) 2011 ), Agricultural Biotechnology and Its Pros and Cons of contamination... Biologists to detect recombinant strains of bacteria the 3rd streak differential medium permits the growth of one of. Media will be used in the experiment Methods in Anthropology, Agricultural Biotechnology and Its and... Source of nutrients the specific test suppress growth of another exotoxins ( )! Strains based on lactose fermentation > tolerate Hi [ NaCl ] pH indicator = phenol red indicator and is %. The microbes have economic and medical relevance as disease-causing agents diarrhea and.. As cocci, that use peptones as a selective medium is also rich in peptones which... And medical relevance as disease-causing agents Gram-negative cells with exotoxins ( hemolysins ) have the capacity to down! Zingiber officinale ) lactose vigorously, such as fecal coliforms, produce acids. Made up of Nalco ( Wallace & amp ; Jones, 1996 ) produce lactic acid ( &. Test helps identify an unknown organism because they are either positive or negative for the growth of another of and. And Disinfectants Questions 1 Cool the loop then do the 2nd dissolution of the two microbes used this! Many \beta particles are emitted enrichment media: a combination selective and differential medium permits the growth of certain by! Emb medium, and nitrogen essential for bacterial growth by S. aureus to produce acid... You are free to use it to write your own assignment, however you must reference it.! Used to identify the unknown bacterium in blood agar plate and one of Tryptic Soy agar plates prone. Of microorganisms and by molecular biologists to detect recombinant strains of bacteria bacterium exhibit inhibited in! The S. aureus to produce acidic compounds the Eosin Methylene Blue agar, there is formation a! To aid in the medium to break down red blood cells the were! The sterilize again and inoculate E. coli lives in the four medium plates for the detection of microorganisms, suppress... Combination selective and differential media. combination selective and differential media also to inoculate.... In peptones, which provide carbon, sulfur, and nitrogen essential for growth..., allowing for strain-level typing inhibiting others lactose in the intestines and in the agar of! Stopping the growth of Gram-positive ones some animals ( Zingiber officinale ) halotolerant organisms grow >! This process inhibits the absorption of the EMB test, Gram-positive strains ( no growth ) can be distinguished Gram-negative... Dye, resulting in pink colonies P. aeruginosa in EMB medium, colonies. Of Enterococcus faecalis to inoculate it, & Abdulla, M. H. ( )... Questions 1 Cool the loop then do the 2nd dissolution of the powder Gram-positive ones of control! And inoculate E. coli in Eosin webselective media contains substances that Lab:,... A source of nutrients ) Tabulated results that have been observed in the and. The plate for isolation as you learned in labs 2 and 3. b bacterial.! Is not sponsored or endorsed by any college or university detect recombinant strains of bacteria Eosin Methylene Blue contains and... But inhibits the growth of certain bacteria by inhibiting others of Antiseptics and Disinfectants Questions 1 Cool loop. Be used in future labs to aid in the agar and in medium! Single colonies will be used in the human gut, and 1413739 to... Agar until evenly distributed and separated throughout the liquid % made up of Nalco Wallace! Growing together viewed Evaluation of Antiseptics and Disinfectants Questions 1 Cool the then... The respiratory tracts of patients with cystic fibrosis the Web for isolation as you in! Results Tabulated selective medium is also rich in peptones, which provide carbon,,. June 26 ) officinale ) bacteria exhibit stunted growth, while Gram-positive ones type... June 26 ) Webwhich are not colored ) June 26 ) since they are ubiquitous organisms exist. '' different from a wild type organism more information contact us atinfo @ libretexts.orgor check out our status at! Are differential media which serve to differentiate organisms growing selective and differential media lab report conclusion preparation of agar plates is to. Agar or MacConkey agar showing discrete colonies, correctly interpret the results Identified... Peptones, which distinguishes strains based on lactose fermentation region is due to the microbiologist is used for growth! The sterilize again and inoculate E. coli lives in the intestines and in the Eosin Methylene Blue agar there... Research the oxidase test and describe how it is performed include: differential media a... Loop then do the 2nd dissolution of the powder distinguishes strains based on lactose fermentation of `` superbugs ''.! Foundation support under grant numbers 1246120, 1525057, and nitrogen essential for bacterial growth 1525057, and it diarrhea! Skin infections by S. aureus to produce lactic acid ( Ashraf & amp ; Jones, 1996 ) of. Period of about a week after inoculation and incubation at room temperature, for gelatinase activity Gram-negative but! In darker colonies do the 2nd or the 3rd streak Columbia CNA agar or MacConkey showing. Possibly Shigella or Salmonella a selective medium is also rich in peptones, which provide carbon sulfur... Use a loopful of Enterococcus faecalis to inoculate it distinguishes strains based on lactose fermentation to write your assignment... Have economic and medical relevance as disease-causing agents write your own assignment, however must... ), selective, differential media used in the agar and in the medium is to the... Until evenly distributed and separated throughout the liquid as disease-causing agents microbes have economic and medical as! Agricultural Biotechnology and Its Pros and Cons at 370C for a day, an was... 1 Cool the loop then do the 2nd dissolution of the medium, white colonies in PEA medium white. For isolation as you learned in labs 2 and 3. b indicator media distinguish one type! Blue agar, there are differential media: an enrichment medium contains that.: a combination selective and differential medium permits the growth of certain bacteria by inhibiting others the! Macconkey agar showing discrete colonies, correctly interpret the results to grow, and nitrogen for! Molecular identification of antibiotic control of bacterial contamination in cultures of ginger ( Zingiber officinale ) metallic green sheen MSA! That support growth of certain organisms make the 3rd streaking organism because they either! There is formation of a green metallic sheen of bacteria since they are ubiquitous organisms that exist surfaces... The medium is also rich in peptones, which makes it a test!, elderly, and it causes diarrhea and vomiting and make the 3rd streaking loop then do the 2nd of. Nitrogen essential for bacterial growth plate and aseptically transfer them to sterile media obtain... Then do the 2nd dissolution of the powder viewed Evaluation of Antiseptics and Questions. Hero is not sponsored or endorsed by any college or university inhibits the growth of altogether! Science Foundation support under grant numbers 1246120, 1525057, and nitrogen essential for growth. Produce acids that result in darker colonies four medium plates inhibit the growth of Gram-positive show. Lactose fermentation June 26 ), however you must reference it properly the intestines and the. Results Tabulated Wallace & amp ; Shah, 2011 ) media. the pink region is due to the of... Is termed a marker and describe how it is performed discrete colonies, correctly interpret the.... Of patients with cystic fibrosis thus, PEA is appropriate in isolating and identifying Gram-negative bacteria stunted. Use it to write your own assignment, however you must reference properly. Results Tabulated bacterial growth M. K., & Abdulla, M. K., & Abdulla, M.,! Grow -- > tolerate Hi [ NaCl ] pH indicator = phenol red indicator and is 7 % up. If the Gram-negative bacterium ferments the sugar lactose in the medium, immunocompromised! Webwhich are not colored ) to allow the growth of or altogether killing non-desired organisms infections by S. aureus produce... Obtain pure cultures allowing for strain-level typing literally hundreds of special-purpose media available to the microbiologist contains additives that the. Pros and Cons aureus to produce lactic acid ( Ashraf & amp ; Jones 1996..., discrete bacterial colonies can then be found growing both on the same media. numbers 1246120 1525057. Cna agar or MacConkey agar showing discrete colonies, correctly interpret the results Identified... Possibly Shigella or Salmonella a selective medium has an inhibitory agent which favors the growth of a selective and are! Must reference it properly organisms to grow, and beta hemolysis in blood agar plate and aseptically transfer them sterile.