micrococcus luteus biochemical tests

Micrococcus luteuswere discovered by Sir Alexander Fleming before he discovered penicillin in 1928. Wieser et al. Gram Stain:Gram-positive cocci, arranged in clusters that differ from Staphylococcus. Micrococcus species, members of the family Micrococcaceae, are usually regarded as contaminants from skin and mucous membranes. 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). . Hybridization studies show that there is no close genetic relationship between the species of Micrococcus bacteria. Label the slide with the name of the organism; Place 15 - 20 uL of the culture in the middle of the slide All three types of hemolytic reactions are represented on this slide. 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). Each genus lends itself to a separate tutorial. appear as agents of infection causing endocarditis. 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. Like MSA, this medium also contains the pH indicator, phenol red. all 3 tests done w/SIM deeps just add Kovac's reagent for Indole test Alcaligenes faecalis (left) - . 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. The genome of the Micrococcus is rich in guanine and cytosine, they typically exhibit about 65 to 75% GC-content. They grow on simple media and their colonies are usually pigmented. All of these are described in the lab 6 handout and were kept in the incubator at 38 degrees Celsius. Enterococcus spp. Streptococcus spp. Depend on Gram stain Test and Biochemical Test find four species of cellulolytic bacteria such as Bacillus subtilis, Pseudomonas diminuta, Micrococcus luteus and Plesiomonas shigelloides. They can even survive in conditions that have very little of even no oxygen, using glycolysis and alternative electron acceptors to create ATP. Although the initial placement of the Gram- positive cocci into broad categories is relatively easy, further classification of some isolates can be challenging and requires a battery of tests to arrive at a definitive identification. Cells are catalase positive, oxidase positive, and exhibit strictly aerobic metabolism. Though today the immuno-compromised patients take the risk of the infection that has grown. Welcome to this Pearl of Laboratory Medicine on Basics of Differentiation of Gram-positive Cocci.. In a temporal study by Kloos and Musselwhite (1975), it was found that micrococci usually constituted from 1 to 20% of the total aerobic bacteria isolated from the skin of the head, legs, and arms, but less than 1% of those isolated from the high bacterial density areas of the nares and axillae. 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. Micrococcus luteus is generally harmless but can become an opportunistic pathogen in immunocompromised people or those with indwelling catheters. Micrococcus Luteus is a gram positive, non-motile, non-sporing cocci belonging to micrococcea family. They are positive for catalase and oxidase ( modified). In the case of a negative test, no colour change is observed. 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. 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). 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. This kit utilizes enzymatic reactions to release bacterial DNA from the cell. It has been associated with causing a variety of illnesses including septic arthritis, meningitis, endocarditis, chronic cutaneous infections in HIV-positive patients, and catheter infections. Micrococcus luteus biochemical test result. There are around nine species that are recognized in the genus. The tetrads of the micrococci, the grape like clusters of the staphylococci, and the pairs and/or chains of the streptococci are shown. Culture Characteristics: Colonies are shades of yellow or red. 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. 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. It grew in circular, entire, convex and creamy yellow pigmented colonies heaving 0.5-2.5 diameter. It is essential for differentiating catalase-positive Micrococcaceae from catalase-negative Streptococcaceae. The PYRA, PAL, LAP, RIB, ARA, MAN, and TRE tests came up as positive. M. luteus has a G-C content of about 65-75 mol%. There have been several deaths in immuno-compromised children that are caused by leukemia from the pulmonary hemorrhages because of Micrococcus. A summary table is included which lists the results of the identification criteria discussed in the tutorial. M. lylae can be distinguished from the closely related species Micrococcus luteus by lysozyme susceptibility, genetic composition, and the type of cell-wall peptidoglycan. // Typical colonies are often described as gray to white, moist or glistening. 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. These families of bacteria produce colonies which are variable both in size, consistency, and the type of hemolysis produced on sBAP. The organism itself is susceptible to almost all drugs, with a few strains being resistant to nitrofurantoin, macrolides and lincomycin (Public Health Canada). Bharath. I then repeated this three more times to further purify the isolate. It is difficult to differentiate Kocuria from Micrococcus with conventional biochemical methods; therefore, these organisms are often reported together as Micrococcus/Kocuria species. [2] It resists antibiotic treatment by slowing of major metabolic processes and induction of unique genes[citation needed]. When looking at the genetic tests, most of the identified strains in the Korona test are Micrococcus luteus. I hypothesized that it would be a bacteria commonly found in the nasal cavities and likely from the aforementioned phyla, so it would likely do best living in an aerobic, humid, and warm environment. 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. 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). Micrococcus are aerobic, Gram-positive cocci ranging in size from 0.5 to 2.0 m in diameter. Micrococcus luteus has been shown to survive in oligotrophic environments for extended periods of time. 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. . [1] It is urease and catalase positive. The partial decomposition of the hemoglobin of the erythrocytes by a weaker hemolysin. Coagulase Results: Perkins1, Sarah D., Jennie Mayfield2, and Victoria Fraser3 And. [7], In 2003, it was proposed that one strain of Micrococcus luteus, ATCC 9341, be reclassified as Kocuria rhizophila. The oxidase test was negative, as the strip did not change color at all, where it would have turned purple if it was positive. Enterobacter aerogenes fermented the sugars but turned to the amino acids. See answer (1) best answer. This suggests that some of the Micrococcus species on the basis of ribosomal RNA analysis eventually can be re-classified into other microbial genera. 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. The family, Micrococcaceae, has been shrinking. Thank you for joining me, Karen Krisher, on this Pearl of Laboratory Medicine on Basics of Differentiation of Gram-positive Cocci.. It has survived for at least 34,000 to 170,000 years, as assessed by 16S rRNA analysis, and possibly much longer. Most of the bacterium in the gram stains were gram negative, but a significant amount, about twenty percent, showed up as gram positive. 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 colony morphology is the same as well, being round, shiny, and sort of flat (Medical Laboratories). Reduction of O2 produces superoxide radicals and hydrogen peroxide, or the hydroxyl radical. M. luteus played an important part in Flemings discovery of Lysozyme which is the bodys natural antibiotic. M. luteus has a G-C content of about 65-75 mol%. Based on the place of origin of the bacterium that I isolated, I hypothesize that it will either be one of the above bacterium or a similar water loving organism, likely one that also forms a biofilm. Luteus is an obligate aerobe (medical. In this presentation, we will discuss the fundamentals of the primary identification of those microorganisms that are members of four main families of Gram-positive cocci, the Micrococcaceae, the Staphylococcaceae, the Streptococcaceae, and the Enterococcaceae. 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). This lines up with M. luteus resistances from the tests. Micrococcus species by the Taxo A Bacitracin disk test can also be differentiated from staphylococcus species. The colony morphology of being yellow, shiny and smooth line up perfectly with M. luteus (Public Health England). Catalase, if present, will break down the hydrogen peroxide to water and oxygen. 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. They also produce yellow or pink colonies when they are grown on the mannitol salt agar, micrococcus flavus, M. terreus, and M. yunnanensis. When performing tests for physiological traits, the results were limited. After observation of the colony and microscopic morphology, the production of catalase by the isolate is documented. They are generally strict aerobes and can generally reduce nitrate. Micrococcus luteus ( Scanning electron micrograph ) Micrococcus luteus is a Gram-positive bacterium of the genus Micrococcus. Maximum production of pigments was observed at 35C, pH 9 and at 4% (W/V) NaCl concentration. As its name suggests, mannitol salt agar (MSA) contains 1% mannitol (sugar), 7.5% salt, and agar as a solidifying agent. Required fields are marked *. The streptococci and enterococci are categorized by expression of either beta, alpha, or gamma hemolysis on sBAP, depending on the genus/species. 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. 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 mammalian skin that has M. luteus strain is also highly sensitive to the beta-lactam antibiotics.