Ans: Micrococci, like many other representatives of the Actinobacteria, can be catabolically versatile, with the ability to utilize a wide range of unusual substrates, such as herbicides, pyridine, chlorinated biphenyls, and oil. Micrococcus luteus (left) Alcaligenes faecalis (middle) Reduction of nitrate to nitrite to be used as a final electron acceptor/Nitrate reductase. The oxygen class and the gram positiveness of the microbe also matches up with that of Micrococcus luteus. Micrococcus has a substantial cell wall in which it may comprise as much as 50% of the cell mass. Obtain a glucose fermentation tube. 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. Basics of Differentiation of Gram Positive Cocci, Author: Karen Krisher In order to determine physiological characteristics of the culture such as cell shape, arrangement, and whether it was gram positive or negative, which helps determine the cell wall type of the microbe, I performed a gram stain. The previous classification of these organisms was much simpler; however, with the use of more advanced genetic sequencing methods, these gram-positive cocci have expanded into 4 separate families and their associated genera. Micrococcus Public Health Agency of Canada., Public Health England. The data on the GC content of the DNA, chemical cell wall analysis, and a comparative analysis of the 16S rRNA sequences. The metabolic pathways required for biomass production in silico were determined based on earlier models of actinobacteria. DNA release from the cell is coupled with adsorption of DNA onto a silica spin-column . 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. Because of their diversity, there are a variety of biochemical tests that are used by laboratories to identify the Gram-positive cocci. Last updated: August 10, 2022 by Sagar Aryal. These include the slide or drop catalase test, the tube method, the semiquantitative catalase for the identification of Mycobacterium tuberculosis. 570 . M. luteus present on the human skin can transform compounds present in sweat into compounds with an unpleasant odour. The antibiotic resistance test showed only minor resistance to the antibiotic Oxacillin, which is likely due to a chance inheritance in the population or complete chance because of the weak strength. They are found in many other places in the, M. luteus has one of the smallest genomes of all the bacteria. They are positive for catalase and oxidase ( modified). Oxidase (modified oxidase) test: Positive. It has been isolated from human skin. Micrococci can often carry plasmids that provide the organism with useful traits. Structure and PhysiologyThis bacteria is Gram-positive, spherical, and an obligate aerobe. The oxidase test was negative, as the strip did not change color at all, where it would have turned purple if it was positive. This microbe forms large, round colonies. [3] With this almost universal range of survivable living conditions that microbes can live in (particularly bacteria), it would be reasonable to assume that there would be at least one variety living in such a nice, wet, and aerated place as my shower drain. This kit utilizes enzymatic reactions to release bacterial DNA from the cell. Characteristics. Micrococcus luteuswere discovered by Sir Alexander Fleming before he discovered penicillin in 1928. In the case of a negative test, no colour change is observed. Micrococcus luteus characteristics possess unusual abilities to tolerate and to use very toxic organic molecules as carbon sources and it combines these activities with tolerance to metals. 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. 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. On top of that, most of the bacterium that were stained were gram negative, which conflicts with this result. As its name suggests, mannitol salt agar (MSA) contains 1% mannitol (sugar), 7.5% salt, and agar as a solidifying agent. Biochemical Test and Identification of Staphylococcus aureus. I grew my isolated in Tryptic Soy Broth (TSB) for a week to prepare for DNA extraction. Staphylococcus aureus Staphylococcus spp. ? Micrococcus varians Micrococcus luteus Staphylococcus saprophyticus Staphylococcus epidermidis Streptococcus pneumoniae Streptococcus mitis They are likely involved in the biodegradation of many other environmental pollutants or detoxification. I chose to sample bacteria from inside my roommates nose. 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. If I were to continue researching this isolate, I would redo the API 20 E test strip with a fresh, active culture to ensure that it can reduce nitrate, and also the oxidase test to ensure that it does have cytochrome c oxidase present, which it should according to Public Health England. Gram Stain:Gram-positive cocci, arranged in clusters that differ from Staphylococcus. Production of bubbles indicates a positive reaction. Micrococcus luteus biochemical test result. 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. 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. The genus Micrococcus consists of Gram-positive spheres occurring in tetrads and in irregular clusters that are usually non-motile and non-spore-forming. 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. Perkins1, Sarah D., Jennie Mayfield2, and Victoria Fraser3 And. 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. 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). The sequencing of Micrococcus luteus was supported because of its major potential role in the case of bioremediation and its importance in the field of biotechnology. M. luteus has a G-C content of about 65-75 mol%. So far there are two genome sequences that have been done. It has multiple antibiotic resistance genes including dihydropteroate synthase, glycerophosphoryl diester phosphodiesterase, and SSU ribosomal proteins. Catalase, if present, will break down the hydrogen peroxide to water and oxygen. 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. Micrococcus luteus biochemical test result. Though not a spore former, the Micrococcus cells can survive for an extended period of time, both at refrigeration temperatures and in nutrient-poor conditions such as sealed in amber. Required fields are marked *. While every effort is made to ensure details distributed by Culture Collections are accurate, Culture Collections cannot be held responsible for any inaccuracies in the data supplied. 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. Pearls of Laboratory Medicine luteus is capable of surviving in environments They are considered as normal comensal of human skin and upper respiratory tract. Finally I used different antibiotic disks to check for its resistance to antibiotics, using Gentamicin, Cefoperazone, Vancomycin, Tobramycin, Amikacin, Trimethoprim, Oxacillin, and Cefazdin. Micrococcus Luteus Oxidase Test: The microdase test, also known as modified oxidase test is a rapid test to differentiate Staphylococcus from Micrococcus which are Gram-positive cocci possessing catalase enzymes. Staphylococcus epidermidis contains cytochrome c which leads to turned purple after oxidation. Then to actually isolate a bacterium, I chose a colony from the initial plate and did a quadrant streak of it to further isolate the bacterium, and then incubated it at 38 degrees Celsius for a week. The bacterium also colonizes the human mouth, mucosae, oropharynx and upper respiratory tract. Coagulase, which is an enzyme involved in the conversion of serum fibrinogen to fibrin, causes the clotting of plasma. It may appear in irregular clusters, groups of four or eight. When viewing the organism microscopically, the staining characteristics of the organism provide important information for identification. It shows that it is mostly Actinobacteria, with some firmicules ,and proteobacteria mixed in (Figure 2). Ans: Although it is a harmless saprophyte, Micrococcus luteus can act as an opportunistic pathogen. Staphylococci were distinguished by their ability to form acid from glucose anaerobically and sarcinas by the formation of cubical packets. I performed a Gram stain test to identify if the bacterium was gram negative or positive, as described in the Lab 4 handout. It grew in circular, entire, convex and creamy yellow pigmented colonies heaving 0.5-2.5 diameter. I also grew it in a MacConkey (MAC) plate to see if it could ferment lactose and if it could grow with both crystal violet and bile salts to further confirm if it was gram negative or positive. Reduction of O2 produces superoxide radicals and hydrogen peroxide, or the hydroxyl radical. All pathogenic strains of S. aureus are coagulase positive whereas the nonpathogenic species (S. epidermidis for example) are coagulase negative. Continuing without changing cookie settings assumes you consent to our use of cookies on this device. 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. They are usually normal flora but can be opportunistic pathogens in certain immunocompromised patients. Some of the species of Micrococcus, such as M. luteus which is yellow in colour, and M. roseus which is red. CATALASE TEST: Catalases are enzymes that convert hydrogen peroxide (H2O2) into water and oxygen gas. 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. Lastly, do not underestimate the variety of different genera in the four families of the Gram- positive cocci that can, under the right circumstances, move from relatively harmless saprophytes to disease-producing opportunists. 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. 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. Micrococcus luteusare Gram-positive cocci mostly arranged in tetrads and larger than Staphylococcus. M. luteus tests positive for catalase, oxidase, utilization of D-glucose, sucrose and D-mannose, and has A2 type peptidoglycan that contains L-lysine as the diagnostic amino acid, MK-8 and MK-8 (H 2) are the major menaquinones (Stackebrandt et al. M. luteus is the majority of reads on the species level. There have been several deaths in immuno-compromised children that are caused by leukemia from the pulmonary hemorrhages because of Micrococcus. Klebsiella pneumoniae Micrococcus luteus Micrococcus roseus Proteus mirabilis Proteus vulgaris Pseudomonas aeruginosa Salmonella typhimurium Serratia marcescens Staphylococcus aureus Staphylococcus epidermidis Streptococcus . The streptococci and enterococci are categorized by expression of either beta, alpha, or gamma hemolysis on sBAP, depending on the genus/species. 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).