Examples of the colony morphology associated with each family is represented on this slide. Intro: Microbes are everywhere, even in the most extreme environments and conditions. Biochemical Tests in Microbiology answer sheet - Biochemical Tests in Microbiology Pre-Laboratory - Studocu Biochemical Tests in Microbiology lab answer sheet biochemical tests in microbiology questions why do some microbes specialize to use different food source than Skip to document Ask an Expert Sign inRegister Sign inRegister Home Unlike other actinobacteria, M. luteus expresses only one resuscitation-promoting factor that is required for the emergence from dormancy and has few other dormancy-related proteins. The sample was then sequenced using the Illumina MiSeq technology in UAFs DNA Core Lab. Like all Staphylococci, S. saprophyticus is also clustering Gram-positive cocci, nonmotile, non-spore-forming, and . The API 20 E test strip results revealed nothing about what the isolate uses as an electron acceptor because every result was negative, and that it likely only uses glucose as an energy and carbon source and oxygen as its electron acceptor. The conflicting results of the metagenome binning and the catalase test influenced this mistake. It has been isolated from human skin. The gram stain of this microbe showed that it is gram positive because it stained purple. Micrococcus luteus Grown on BrainHeart Infusion Agar, Klebsiella characteristics on MacConkey Agar, Clinical Case Leukocyte Vacoulation Bacterial Infection, Segmented neutrophilic granulocyte during degradation, DIC (Disseminated intravascular coagulation), Creatinine Phosphate Kinase (CPK) and CK-MB Overview. The data on the GC content of the DNA, chemical cell wall analysis, and a comparative analysis of the 16S rRNA sequences. 2. Micrococcus was first isolated by Alexander Fleming in 1929, as Micrococcus lysodeikticus before it was known as micrococcus luetus (Ganz et al, 2002) Micrococcus is generally thought of as harmless bacterium, but there have been rare cases of Micrococcus infections in people with compromised immune systems, as occurs with HIV patients. I kept the plate at room temperature for 7 days, and then selected a colony to purify using the pure culture streak plate method. Micrococcus Luteus is a gram positive, non-motile, non-sporing cocci belonging to micrococcea family. It is often larger thanStaphylococcus. Results of the biochemical tests demonstrated that the M. luteus and M. varians strains could be distinguished by their actions on glucose and nitrate reduction (Table I). Of those only Vancomycin was closer than 50 millimeters, being 38 millimeters. For the second control, 100 L of water sample dilutions were plated on agar-agar. [7], In 2003, it was proposed that one strain of Micrococcus luteus, ATCC 9341, be reclassified as Kocuria rhizophila. Complete lysis of the erythrocytes in the vicinity of the growing colony. Most of the Micrococcus infections are discovered through the process of elimination along with the presence of the abundant Micrococcus tetrads in the lesions or cysts. The Gentamicin, Cefoperazone, Vancomycin, Tobramycin, Amikacin, Trimethoprim, and Cefazdin antibiotics showed obvious susceptibility, with most of them having enormous rings of 50 to 52 millimeters while the threshold for resistance is only 15 millimeters. This is a test commonly used when trying to identify Gram-negative enteric bacteria, all of which are glucose fermenters but only some of which produce gas. Micrococcus luteus biochemical test result. They are fairly ubiquitous in the environment, and are small (0.5 to 3.5 micrometers in diameter) and non-motile. To identify our isolate after obtaining the pure culture, we performed many different tests. Because of their diversity, there are a variety of biochemical tests that are used by laboratories to identify the Gram-positive cocci. Cultures:- Nutrient broth cultures of Micrococcus luteus and Proteus vulgaris (young cultures) Procedure: Wet Mount Preparation . Micrococcus luteus uses the amino acids and does not grow in the butt of the slant. Micrococcus luteus was found gram-positive cocci, non-spore forming, non-haemolytic, non-motile aerobic or facultative anaerobes, arranged in pairs, irregular clusters and tetrads. It shows that the sample contains bacteria from the Terrabacteria group. Staphylococci were distinguished by their ability to form acid from glucose anaerobically and sarcinas by the formation of cubical packets. Exposure to these wavelengths of ultraviolet light has been correlated with an increased incidence of skin cancer, and scientists believe this pigment can be used to make a sunscreen that can protect against ultraviolet light.[9]. They are found in soil, dust, water and air, and as part of the normal microbiota of skin. Wikipedia also says that Micrococcus luteus is an obligate aerobe, backing up what my results show (2019). Bacteria Detail., The Editors of Encyclopdia Britannica. Although many of the members of these families have low pathogenicity and are classified as causes of opportunistic infections, those organisms most often cited as pathogens are listed on this slide. I suspect that the API 20E test strip results were negated by having used an inactive colony, as the fluid thyoglycate test failed as well. Thank you for joining me, Karen Krisher, on this Pearl of Laboratory Medicine on Basics of Differentiation of Gram-positive Cocci.. The identification of three different biovars within the species M. luteus has the advantage that the three groups can be differentiated without nomenclatural changes having to be introduced. Colony morphology, the elucidation of the characteristics of the growth of the bacterium on agar medium, in most cases trypticase soy agar containing 5% sheep blood (sBAP). The bacterium also colonizes the human mouth, mucosae, oropharynx and upper respiratory tract. Colonies typically have a lemon-yellow pigment. Biochemical Test Chart (You will not fill in every blank in this chart.) See answer (1) best answer. I used an oxidase test strip and water to determine if cytochrome C oxidase was present, and performed a catalase test to determine if catalase was present. The API test strips lack of results suggests that the I used the wrong test strip, I probably needed to use the Staph test instead of the Strep test, because the Strep test is for when Catalase is absent, but there could have been catalase present. Another test I did to identify my isolate was DNA analysis, described in lab handouts 5 and 7. It has survived for at least 34,000 to 170,000 years, as assessed by 16S rRNA analysis, and possibly much longer. The Micrococcus strains isolated from various infections were most probably misclassified as staphylococci. Micrococcus luteus (left) Alcaligenes faecalis (middle) Reduction of nitrate to nitrite to be used as a final electron acceptor/Nitrate reductase. The differentiation is based on the detection of the oxidase enzymes. I grew my isolated in Tryptic Soy Broth (TSB) for a week to prepare for DNA extraction. After it was sequenced using an Illumina MiSeq at the UAF Core lab, I used the online program Base Space to analyze the reads that I got from sequencing. Alcaligenes faecalis Bacillus megaterium . [3] Its genome was sequenced in 2010 and is one of the smallest genomes of free-living Actinomycetota sequenced to date, comprising a single circular chromosome of 2,501,097 bp.[4]. M. luteus oxidizes carbohydrates to CO2 and water, and it does not produce acid from glucose as well as it does not make arginine dihydrolase or b-galactosidase. Required fields are marked *. Filter paper disks impregnated with tetramethyl-p-phenylenediamine dihydrochloride (oxidase reagent) in dimethyl sulfoxide (DMSO) are used. [2] It resists antibiotic treatment by slowing of major metabolic processes and induction of unique genes[citation needed]. If the infection leads to severe hemodynamic alterations, thus the valve replacement may become necessary. The microbiome of the nasal cavity can also change in response to environmental factors such as geographic location, and hygiene (Rawis et al. Date: FEB.11.2016 For example, M. luteus and M. lylae are 40-50% genetically different. I used the PATRIC software to perform a metagenome binning and to assign a taxonomy to the bacteria. Micrococcaceae. These discrepancies could be due to human error, unpure culture, or an old agar plate. 2019). Pearls of Laboratory Medicine All three types of hemolytic reactions are represented on this slide. In conclusion, some of my results were inconclusive and conflicting. They are normal inhabitants of the human body and may even be essential in keeping the balance among the various . The modified oxidase reagent is prepared as tetramethyl-p-phenylenediamine in certified grade dimethyl sulfoxide. Isolates of the M. luteus have been found to overproduce the riboflavin virus when they are grown on toxic organic pollutants like pyridine. Micrococcus luteus was one of the early examples of novel codon usage,[5][6] which led to the conclusion that the genetic code is not static, but evolves. I performed many tests to find out the colony morphology and physiology. Micrococcus is the Gram-positive cocci that are about 0.5 to 3.5 micrometres in diameter and usually, these are arranged in tetrads or in irregular clusters. Retrieved 22:17, April 16, 2019, from https://en.wikipedia.org/w/index.php?title=Staphylococcus_aureus&oldid=890960280, Your email address will not be published. Biochemical Test and Identification of Staphylococcus aureus. When using a fluid thyoglycollate test it resulted in the isolate being a strict aerobe, with all of the bacterium being at the top of the medium where it is oxygenic. Isolates of the M. luteus have been found to overproduce the riboflavin, Micrococcus Luteus Gram Stain Characteristics, Micrococci have been isolated from the human skin, animal and dairy products, and in beer. View Biochemical Tests Lab Report.docx from BIOL 240 at University of Alaska, Anchorage. I grew my bacteria on an Eosin Methylene Blue (EMB) plate to see if it could ferment lactose and if it could grow with methylene blue which selects for gram negative bacteria. Some Micrococcus are pigmented bacteria; for example, M. luteus produces yellow colonies and M. roseus produces redish colonies. Oral microbial flora of reptiles includes bacteria from Proteus, Porphyromonas, Micrococcus, Salmonella and Staphylococcus genera 5,8,15. Micrococcus A study with 188 micrococci, identified only to the genus level, demonstrated MICs at achievable concentrations for most -lactams, aminoglycosides, glycopeptides, clindamycin and the most active drug in vitro, rifampin. (negative). Streptococci and enterococci are observed to produce pairs and chains of cocci of varying length. It has survived for at least 34,000 to 170,000 years, as assessed by 16S rRNA analysis, and possibly much longer. On top of that, most of the bacterium that were stained were gram negative, which conflicts with this result. Ans: Although it is a harmless saprophyte, Micrococcus luteus can act as an opportunistic pathogen. The staphylococci are characterized by the formation of clusters of many cocci. Mannitol salt agar (MSA) is a selective, differential, and indicator medium used to isolate and identify Staphylococcus aureus from the clinical specimen. The two unifying characteristics of these four families are their coccoid shape and the fact that they stain purple in the Grams method for visualizing bacteria microscopically. Micrococcus luteus is a constituent of the normal human buccal bacterial flora which forms yellowish colonies and appears as a gram-positive coccus typically arranged in tetrads. Its genome has a high G + C content. luteus is rarely found to be responsible for infections. I repeated this process three more times to further purify the colony. Micrococcus species are oxidase-positive, which can be used to distinguish them from other bacteria like most Staphylococcus species, which are generally oxidase-negative. Other articles where Micrococcus luteus is discussed: Micrococcus: found in milk, such as M. luteus, M. varians, and M. freudenreichii, are sometimes referred to as milk micrococci and can result in spoilage of milk products. Welcome to this Pearl of Laboratory Medicine on Basics of Differentiation of Gram-positive Cocci.. The genus Micrococcus consists of Gram-positive spheres occurring in tetrads and in irregular clusters that are usually non-motile and non-spore-forming. Basics of Differentiation of Gram Positive Cocci, Author: Karen Krisher Obtain a glucose fermentation tube. Genus: Micrococcus. Thus, when dealing with Micrococcus infections, it usually takes several cultures that are being grown and examined before one realizes that Micrococcus is indeed the culprit. Enter the email address you signed up with and we'll email you a reset link. Staphylococcus spp. Micrococcus luteus has been shown to survive in oligotrophic environments for extended periods of time. Micrococcus species occur in a wide range of environments, including dust, water, and soil. It has multiple antibiotic resistance genes including dihydropteroate synthase, glycerophosphoryl diester phosphodiesterase, and SSU ribosomal proteins. Micrococcus luteus biochemical test result. Your email address will not be published. Although of low virulence, the germs may become more pathogenic in patients with impaired resistance, colonizing the surface of, Difference Between Cyclic and Non Cyclic Photophosphorylation, Difference Between National Park and Wildlife Sanctuary, CBSE Class 12 Biology Question Paper 2020, CBSE Class 12 Biology Question Paper 2019, CBSE Class 12 Biology Question Paper 2018, CBSE Class 12 Biology Question Paper 2017, CBSE Class 12 Biology Question Paper 2016, CBSE Class 12 Biology Question Paper 2015, CBSE Class 12 Biology Question Paper 2014, CBSE Class 12 Biology Question Paper 2013, CBSE Class 10 Science Question Paper 2020, CBSE Class 10 Science Question Paper 2019, CBSE Class 10 Science Question Paper 2018, CBSE Class 10 Science Question Paper 2017, CBSE Class 10 Science Question Paper 2016, CBSE Class 10 Science Question Paper 2015, CBSE Class 10 Science Question Paper 2014, CBSE Class 10 Science Question Paper 2013, CBSE Class 10 Science Question Paper 2012, CBSE Class 10 Science Question Paper 2011, CBSE Class 10 Science Question Paper 2010, CBSE Class 10 Science Question Paper 2009, CBSE Class 10 Science Question Paper 2008, CBSE Class 10 Science Question Paper 2007, ICSE Class 10 Biology Question Paper 2020, ICSE Class 10 Biology Question Paper 2019, ICSE Class 10 Biology Question Paper 2018, Difference Between Gram positive and Gram negative Bacteria, How are Cactus Adapted to Survive in a Desert - Overview and Facts, Areolar Tissue- Overview, Characteristics, Function and Types, Synovial Fluid - Function, Definition, and Structure, Immunoglobulin - Functions, Antibodies, Differences and Types, Vallisneria Plant- Overview, Structure and Function, Natural Disasters- Overview, Structure and Function, NCERT Solutions for Class 12 Business Studies, NCERT Solutions for Class 11 Business Studies, NCERT Solutions for Class 10 Social Science, NCERT Solutions for Class 9 Social Science, NCERT Solutions for Class 8 Social Science, CBSE Previous Year Question Papers Class 12, CBSE Previous Year Question Papers Class 10. These include the slide or drop catalase test, the tube method, the semiquantitative catalase for the identification of Mycobacterium, M. luteus played an important part in Flemings discovery of, A rare case of prosthetic valve endocarditis is caused by Micrococcus luteus, it is described and compared with the few cases that are reported in the literature, as well as the clinical features, microbiological profile, therapy, and prognosis of common prosthetic valve endocarditis. They can even survive in conditions that have very little of even no oxygen, using glycolysis and alternative electron acceptors to create ATP. Micrococcus luteus pigment (Yellow) GLUCOSE FERMENTATION TEST This test detects the ability of the bacterium to break down glucose to pyruvic acid. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Built with Enlightenment Theme and WordPress. At U.S. Micro Solutions, our microbiology laboratory is a licensed, accredited source for thorough and accurate environmental testing . There are around nine species that are recognized in the genus. Figure 2. Discussion: When looking at all of the results for my isolate, they are not all consistent with Micrococcus luteus. Micrococci have Gram-positive spherical cells ranging from about 0.5 to 3 micrometers in diameter and typically appear in tetrads. The genera Staphylococcus, Micrococcus and Sarcina were recognized. The organism itself is susceptible to almost all drugs, with a few strains being resistant to nitrofurantoin, macrolides and lincomycin (Public Health Canada). While defining the characteristics of the Micrococcus are the ability to produce acid aerobically from the aesculin hydrolysis, glucose glycerol, arginine dihydrolase, motility, major pigment production, and conversion of nitrate to nitrite. "EPR and ENDOR detection of compound I from Micrococcus lysodeikticus catalase". Micrococcus as the cause of infections is easy to overlook because the infections that are caused by this bacterium are rare as well as the bacterium is a natural part of the skin's bacterial flora. Label the slide with the name of the organism; Place 15 - 20 uL of the culture in the middle of the slide PUGVIEW FETCH ERROR: 403 Forbidden National Center for Biotechnology Information 8600 Rockville Pike, Bethesda, MD, 20894 USA Contact Policies FOIA HHS Vulnerability Disclosure National Library of Medicine National Institutes of Health Micrococcus luteus ( M. luteus ), is a Gram-positive bacteria, 0.05 to 3.5 microns in diameter, that is most commonly found in mucous membranes such as the nasal cavities, the upper respiratory tract, and the lining of the mouth. Only the Micrococcus luteus species contained cytochrome c oxidase. I then transferred the pure culture into a TSB slant to preserve it, keeping it at around 3 degrees Celsius in the lab refrigerator. Microbes are too small to be seen by the naked eye; they can survive in conditions that many would think are unlivable like the anaerobic environment in the rumen of cows, hot springs, and cold Antarctic waters (What are microbes, 2010). It grew in circular, entire, convex and creamy yellow pigmented colonies heaving 0.5-2.5 diameter. For example, M. luteus and M. lylae are 40-50% genetically different. The agglutinability of the cells with antiserum containing anti-teichuronic acid antibody was examined. An obligate aerobe, M. luteus is found in soil, dust, water and air, and as part of the normal microbiota of the mammalian skin. Like MSA, this medium also contains the pH indicator, phenol red. The catalase test facilitates the detection of the enzyme catalase in bacteria. Notice that beta-hemolysis results in a total lysis or clearing of the agar in the area of colony growth. The PYRA, PAL, LAP, RIB, ARA, MAN, and TRE tests came up as positive. This can occur due to the presence of a reduced number of proteins that can bind to penicillin. A positive test leads to the development of blue or purple-blue on the disc within two minutes. M. luteus has the capability to show dormancy without the formation of spores. Enterococcus spp. It is an aerobic exopolysaccharide producing bacteria that may be found on the skin, mouth and sometimes in the throat of mammals 13,14. The colony morphology is the same as well, being round, shiny, and sort of flat (Medical Laboratories). Some of the Micrococcus are pigmented bacteria, for example, M. roseus produces reddish colonies and M. luteus produces yellow colonies. Habitat Micrococcus lives in a wide range of environments such as water, soil, and the dust whereas, Staphylococcus lives in the animal body. Bacillus megaterium fermented sugars but didn't grow in the anaerobic area of the butt. AACC.org I think based on all this information, that my microbe is in fact micrococcus luteus as suggested by the PATRIC metagenome binning test, and the krona (Figure 1). The Bacterial Genomic DNA Isolation Kit provides convenient and simple step-by-step method for isolating quality genomic DNA from gram-negative and gram-positive bacterial species. Recently, as an opportunistic pathogen, this organism was recognized and it has been implicated in recurrent bacteremia, septic arthritis, septic shock, endocarditis, intracranial suppuration, meningitis, and cavitating pneumonia in immunosuppressed patients. It is reported here that gliotoxin selectively spares a unique class of haemopoietic stem cell that forms large (HPP) colonies in the presence of mixtures of MCSF and IL3. Many of the tests did line up with M. luteus though, such as the fluid thyoglycate test, which showed that it was an obligate aerobe. Micrococcus species are strictly aerobic Gram-positive cocci arranged in tetrads or irregular clusters, and cells range from 0.5 to 3 m in diameter. Micrococcus luteus was formerly known as Micrococcus lysodeikticus. I also had to do the thyoglycate test 3 times to get a conclusive result, further making me skeptical of how active the culture was during the physical tests during week 6, which is where almost all of the inconsistencies arose. The fluid thioglycallate test showed that the bacteria was an obligate aerobe because the growth was concentrated at the top of the tube in the pink region. A very important test in the categorization of the staphylococci is the coagulase test. Micrococcus luteus is a Gram-positive to Gram-variable, nonmotile, tetrad-arranging, pigmented, saprotrophic coccus bacterium in the family Micrococcaceae. Culture Characteristics: Colonies are shades of yellow or red. Finally, when looking at the API 20E strip none of the results returned positive despite the culture being active and fresh from being streaked recently. The nasal cavity microbiome primarily consists of the phyla Actinobacteria, Firmicutes and Proteobacteria (Bassis et al. Micrococci are microbiologically characterized as gram-positive cocci, 0.5 to 3.5 m (micrometres; 1 m = 10-6 metre) in diameter. They are generally strict aerobes and can generally reduce nitrate. CCTC (English) The skin infections or chronic cutaneous infections that are caused can result in pruritic eruptions of the skin in some of the areas as well as scattered papule lesions with or without central ulcerations. 2. Coagulase Results: The Kocuria rhizophila strain ATCC 9341 has been used in quality control for sterility testing, as a test for the effectiveness of antibiotics and fungicides, and for doxycycline, tetracycline, and chloramphenicol susceptibility testing since 1966 under the designation Micrococcus luteus [4]. Micrococcus luteus | Taxonomy - PubChem Apologies, we are having some trouble retrieving data from our servers. Micrococcus luteus is found in lots of places including skin, soil, dust, water, air, mouth, mucosae, oropharynx, and upper respiratory tract of humans (Wikipedia, Micrococcus luteus, 2019). Baird-Parker, A. c.: A classification of micrococci and staphylococci based on physiological and biochemical tests. The MacConkey agar showed very little growth, and did not have a change in color, indicating that the microbe was gram positive and not a fermenter. The nasal cavity microbiota of healthy adults. Micrococcus Public Health Agency of Canada., Public Health England. Micrococcus is a genus of bacteria that is present in the Micrococcaceae family. M. luteus has one of the smallest genomes of all the bacteria. M. luteus played an important part in Flemings discovery of Lysozyme which is the bodys natural antibiotic. Micrococcus species, members of the family Micrococcaceae, are usually regarded as contaminants from skin and mucous membranes. Micrococcus, genus of spherical bacteria in the family Micrococcaceae that is widely disseminated in nature. The taxonomic assignment of this microbe was micrococcus luteus because it was the only bin that PATRIC gave. I would hypothesise that because we clean our shower regularly, that most of the bacterium un the shower drain would come from people in my family taking a shower, and mostly be from the skin. Colony pigmentation varies considerably but is usually different shades of yellow or cream-white. This test had VP, HIP, ESC, PYRA, aGAL, bGUR, bGAL, PAL, LAP, ADH, RIB, ARA, MAN, SOR, LAC, TRE, INU, RAF, AMD, and GLYG tests. When looking at the antibiotic test results, the isolate is resistant to none of the applied antibiotics, and is only lightly to intermediately resistant to oxacillin. (2019, April 4). When a drop of peroxide is placed on catalase-producing bacteria, bubbles appear when the oxygen gas is formed. (2) Micrococcus spp. The genome of the Micrococcus is rich in guanine and cytosine, they typically exhibit about 65 to 75% GC-content. Note the bright yellow, non-diffusable colony pigment which is a defining characteristic of M. luteus. About half of the Micrococcus luteus gram stain was found to carry plasmids of about one to 100MDa in size. Shape (Cocci/Diplococci/Rods) Cocci. They are usually normal flora but can be opportunistic pathogens in certain immunocompromised patients. 2- M. luteus 3- M.roseus Culture: - Strictly aerobic at 37C incubation (24 hr) - Grow on ordinary media Nutrient agar - Blood agar and on the Blood agar M. roseus (pink) M. luteus (white) M.varians (yellow) - On m annitol salt agar grow given r ise to rose or pink colonies except M. roseus. My goal in this experiment was to isolate, characterize and identify a bacterial colony that arose from a sample taken from my roommates nose. I then repeated this three more times to further purify the isolate. It is a gram positive, coccus shaped microbe, and contains catalase. The Gram stain, while it was gram variable, does not ideally match with the genetic test that resulted in Micrococcus luteus, which can be gram variable but is usually gram positive (Bonjar). The categorization of the Gram-positive cocci based on their possession of the enzyme catalase, a quality which can be easily assayed in the lab. Micrococcus luteus This Gram positive coccus is found in tetrads, irregular clusters, and cubical packets of eight. Hemolysis is the lysis of the sheep erythrocytes within the agar by bacterial toxins (hemolysins) that are produced by the different genera of Gram-positive cocci. Know more about our courses. It is Gram positive, Coagulase positive, catalase and oxidase positive non-motile bacteria. The catalase and the oxidase tests came up negative, because the catalase test did not form bubbles, and the oxidase test did not see a color change. What are the Diseases that are Caused By Micrococcus? M. luteus can also cause septic shocks in immuno-compromised people. 570 . Under the microscope they are round cells. . This is a test for aerobic (able to use oxygen) catalase-positive bacteria such as Staphylococcus and Micrococcus. Results: Regarding the gram stain test, my isolate was gram variable, I ensured that the strain was fresh so that the age of the culture was the same throughout the test. It is difficult to differentiate Kocuria from Micrococcus with conventional biochemical methods; therefore, these organisms are often reported together as Micrococcus/Kocuria species. Reduction of O2 produces superoxide radicals and hydrogen peroxide, or the hydroxyl radical. The family, Micrococcaceae, has been shrinking. Optimum growth temperature is 25-37 C. M. luteus is part of the normal flora of the human skin.Transmission and DiseaseM. Take a clean, scratch free glass slide. I also hypothesize that it will be an aerobic organism, given that I found it in a well aerated environment and it has survived until I cultured it. The micrococci produce tetrads consisting of 4 cocci clustered together. I used the Kirby-Bauer, or disk diffusion test to test for this, described in lab handout 9. Gram Stain:Gram-positive cocci, arranged in clusters that differ from Staphylococcus. 900 Seventh Street, NW Suite 400 This presentation will focus on the laboratory tests useful for the differentiation among the families as opposed to the more complicated differentiation and identification of the organisms within the different genera. These can indicate that the genus of the Micrococcus is more closely related to the genus Arthrobacter than it is to other coccoid genera such as Staphylococcus and Planococcus. The optimum growth temperature is 25-37C. // The tests that did not agree were most likely from not having an active colony used in the experiment, such as the oxidase test being negative or the API 20 E test strip showing that the isolate did not reduce nitrate, which it does, referencing Medical Laboratories. Intermediates or end products of these varied metabolic activities can be detected by performing biochemical assays on a bacterial culture. Some streptococci also possess unique cell wall carbohydrate antigens that can be identified by reactivity with specific indicator antibodies in an agglutination assay (Lancefield typing). Micrococcus also not able to ferment glucose anaerobically (negative) Reply. If an organism is capable of fermenting the sugar glucose, then acidic byproducts are formed and the pH indicator turns yellow. Biochemical Pr Organism Enterococcus faecalis Lactococcus lactis Micrococcus luteus Staphylococcus November 27, 2021 at 9:14 AM Hi sir, why Macrococcus and Micrococcus will not ferment . Included in the observation of the morphology of the colony is the effect that the bacterial growth has on the sheep erythrocytes in the agar medium. The Micrococcus genus is known to be found on dust particles, in water, on skin and skin glands in vertebrates, and some species can be found in milk. There are 3 biovars of this organismand they possess quite diverse chemotaxonomic features with respect to their menaquinone systems, cell-wall compositions, and Fourier transform-infrared (FT-IR) spectroscopy patterns, as well as biochemical properties.