This is designated as beta ()-hemolysis. Gram Staining. Micrococcus luteus is a coccus shaped gram-positive bacteria. Source publication +9 Isolation and Identification of Potential Pathogenic Bacteria in Living Carp (Cyprinus carpio Linnaeus, 1758) Sold in. Washington, DC 20001 I repeated this process three more times to further purify the colony. They occur in pairs, tetrads or clusters but not in chains. 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. The negative oxidase result conflicts with M. luteus (Public Health England). [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]. I used the Kirby-Bauer, or disk diffusion test to test for this, described in lab handout 9. Once the culture was deemed pure enough, I inoculated a slant tube. I performed a Gram stain test to identify if the bacterium was gram negative or positive, as described in the Lab 4 handout. 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. Motility (Motile / Non-Motile) Non-Motile. Cells are catalase positive, oxidase positive, and exhibit strictly aerobic metabolism. I then streaked the exposed swab onto a petri dish to allow the organisms to grow, incubating them at 25 degrees Celsius in a dark cabinet. The results of this analysis are shown in table 1. Hybridization studies show that there is no close genetic relationship between the species of Micrococcus bacteria. This can occur due to the presence of a reduced number of proteins that can bind to penicillin. They are found in many other places in the environment, including dust, water, and soil. Micrococcus luteus ( Scanning electron micrograph ) Micrococcus luteus is a Gram-positive bacterium of the genus Micrococcus. I kept the plate at room temperature for 7 days, and then selected a colony to purify using the pure culture streak plate method. 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 luteus, a commonly found member of the Micrococcaceae, produces round colonies which are convex (curving outward) with smooth, entire margins. 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. Micrococcus., h. Shahidi Bonjar. See answer (1) best answer. M. luteus has one of the smallest genomes of all the bacteria. In Wikipedia, The Free Encyclopedia. 2. The tetrads of the micrococci, the grape like clusters of the staphylococci, and the pairs and/or chains of the streptococci are shown. The differentiation is based on the detection of the oxidase enzymes. After observation of the colony and microscopic morphology, the production of catalase by the isolate is documented. When performing tests for physiological traits, the results were limited. They can be found in boiling hot springs; they can be found in frigid waters in the artic. 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. Methods: To start isolating the bacterium, I used a sterile swab wet with deionized water provided by the lab to pick up bacteria from the shower drain. 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. Staphylococcus aureus. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Built with Enlightenment Theme and WordPress. When viewing the organism microscopically, the staining characteristics of the organism provide important information for identification. Micrococcus, genus of spherical bacteria in the family Micrococcaceae that is widely disseminated in nature. 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. The family, Micrococcaceae, has been shrinking. It is an opportunistic pathogen, only pathogenic enough to cause disease in weakened immune systems (Medical Laboratories). Its genome has a high G + C content. Notice that beta-hemolysis results in a total lysis or clearing of the agar in the area of colony growth. Where the M. luteus can cause severe skin infections and is sometimes clinically mistaken for Staphylococcus aureus. M. luteus is found in the soil, dust, water, and human skin flora. 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. As mentioned, the type of hemolytic reaction produced on sBAP is a major clue toward the identification of the genus. Genus: Micrococcus. Micrococcus is a spherical bacterium found on dead or decaying organic matter while Staphylococcus is a gram-positive bacterial genus that produces a bunch of grape-like bacterial clusters. Other Micrococcus isolates produce various useful products, such as long-chain aliphatic hydrocarbons for lubricating oils. The differentiation is based on the detection of oxidase enzyme. The name of the genus is also called " Germanized " is written as Micrococcus. The conflicting results of the metagenome binning and the catalase test influenced this mistake. Growth can produce colonies of a certain size and consistency, as well as pigmentation. Welcome to this Pearl of Laboratory Medicine on Basics of Differentiation of Gram-positive Cocci.. Micrococcus luteus in tetrads arrangement. Figure 2. Catalase test was the first biochemical test to be done . The GC content of the DNA ranges from about 65 to 75 mol%. Simple biochemical tests like the one above have always been an important aid to identification of bacteria, because the different bacterial groups and species have characteristic metabolic activities. As its name suggests, mannitol salt agar (MSA) contains 1% mannitol (sugar), 7.5% salt, and agar as a solidifying agent. They are seldom motile and are non-sporing. This matches up with the PATRIC metagenome binning which also showed some impurities (Figure 1). It is Gram-positive cocci in tetrads, catalase-positive, coagulase-negative, arranged in clusters that differ from Staphylococcus in attacking sugars oxidatively which may appear in irregular clusters, groups of four or eight. However, the most promising antibiotic regimen that is proposed for the treatment of the Micrococcus luteus seems to be a combination of amikacin, vancomycin, and rifampicin. The organism itself is susceptible to almost all drugs, with a few strains being resistant to nitrofurantoin, macrolides and lincomycin (Public Health Canada). Required fields are marked *. If acid is produced, the pH indicator will turn yellow. You can change these settings at any time, but that may impair functionality on our websites. Only those with compromised immune systems are thought to be susceptible to an infection.DisinfectionM. Micrococcus spp. The microbiome of the nose. Table 2: Graph of the genomic reads by taxonomic level using Korona. (2019, March 14). appear as agents of infection causing endocarditis. Although the Micrococcus rarely causes infections or problems in the body, with the compromised immune systems, it has been known to get certain skin infections that are caused by Micrococcus luteus. When looking at the genetic tests, most of the identified strains in the Korona test are Micrococcus luteus. The bacterium also colonizes the human mouth, mucosae, oropharynx and upper respiratory tract. It is a gram positive, coccus shaped microbe, and contains catalase. 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. They are catalase positive and often oxidase positive although this reaction may be weak (see Table 23.3 ). Institute for Quality and Efficiency in Health Care. Finally I used different antibiotic disks to check for its resistance to antibiotics, using Gentamicin, Cefoperazone, Vancomycin, Tobramycin, Amikacin, Trimethoprim, Oxacillin, and Cefazdin. Micrococcus spp. The EMB plate is also selective for gram-negative bacteria which is probably why the bacteria didnt grow on it. Millions of microbes live both on and in the human body and can both make help us survive or make us sick, less than 1% of bacteria cause disease (What are microbes, 2010). Staphylococci were distinguished by their ability to form acid from glucose anaerobically and sarcinas by the formation of cubical packets. Retrieved 06:20, April 16, 2019, from https://en.wikipedia.org/w/index.php?title=Micrococcus_luteus&oldid=887698104, Wikipedia contributors. Filter paper disks impregnated with tetramethyl-p-phenylenediamine dihydrochloride (oxidase reagent) in dimethyl sulfoxide (DMSO) are used. 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). Streptococci and enterococci are observed to produce pairs and chains of cocci of varying length. 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 oxygen class of the microbe, obligate aerobe, matches up with the predictions I had made about it because the bacteria was originally sourced in a nostril. Micrococcus luteus has been shown to survive in oligotrophic environments for extended periods of time. I also did a fluid thioglycolate test to determine the bacterias oxygen class. Optimum growth temperature is 25-37 C. Streptococcus pneumoniae and a group of streptococci referred to as viridans (green) streptococci are examples of bacteria producing alpha-hemolysis. The staphylococci are characterized by the formation of clusters of many cocci. Micrococcus also not able to ferment glucose anaerobically (negative) Reply. This microbe forms large, round colonies. The colony took 16 days to be purified. 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. The reactions of the four isolates indicated that they belonged to the species M. Zuteus (Kocur & Martinec, 1972). The oxidase test results suggest that the microbe does not contain oxidase, despite what the metagenome binning test showed. Micrococcus species occur in a wide range of environments, including dust, water, and soil. 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. Because of their diversity, there are a variety of biochemical tests that are used by laboratories to identify the Gram-positive cocci. 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. (2) Micrococcus spp. 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. As the microbe is gram positive this means that it has a large peptidoglycan layer and lacks a lipopolysaccharide layer. Alpha-hemolytic colonies often assume a greenish hue. Further biochemical tests to identify include the catalase and oxidase test, and typical tests of a "colorful series . Micrococcus luteus can synthesize the iso-branched and anteiso-branched alkenes by the head-to-head condensation of fatty-acid thioesters. 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. Some Micrococcus are pigmented bacteria; for example, M. luteus produces yellow colonies and M. roseus produces redish colonies. My goal in this experiment was to isolate, characterize and identify a bacterial colony that arose from a sample taken from my roommates nose. Krona chart of microbe shows bacterial classes thought to be present in the sample. Micrococcus lutues are Gram positive cocci that are 0.5 to 3.5 m in diameter and arranged in tetrads or irregular clusters. Mannitol salt agar (MSA) is a selective, differential, and indicator medium used to isolate and identify Staphylococcus aureus from the clinical specimen. 1. These families of bacteria produce colonies which are variable both in size, consistency, and the type of hemolysis produced on sBAP. The nasal cavity microbiome primarily consists of the phyla Actinobacteria, Firmicutes and Proteobacteria (Bassis et al. Most of the bacterium in the gram stains were gram negative, but a significant amount, about twenty percent, showed up as gram positive. They are catalase and oxidase positive whereas urease negative. Your email address will not be published. Last updated: August 10, 2022 by Sagar Aryal. They also produce yellow or pink colonies when they are grown on the mannitol salt agar, micrococcus flavus, M. terreus, and M. yunnanensis. I then transferred the pure culture into a TSB slant to preserve it, keeping it at around 3 degrees Celsius in the lab refrigerator. [1] It is urease and catalase positive. In future works with this microbe, I probably would want to purify the culture more and redo the tests. They are likely involved in the biodegradation of many other environmental pollutants or detoxification. The colonies are a pale, translucent yellow, and are shiny when looked at in the light. Oral microbial flora of reptiles includes bacteria from Proteus, Porphyromonas, Micrococcus, Salmonella and Staphylococcus genera 5,8,15. M. luteus is the majority of reads on the species level. Micrococcus Luteus is a gram positive, non-motile, non-sporing cocci belonging to micrococcea family. They grow on simple media and their colonies are usually pigmented. Another test I did to identify my isolate was DNA analysis, described in lab handouts 5 and 7. 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. Recent reports, however, confirm that micrococci may be associated with human infections, particularly in immunosuppressed patients. 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. AACC.org Staphylococcus epidermidis contains cytochrome c which leads to turned purple after oxidation. It is an aerobic exopolysaccharide producing bacteria that may be found on the skin, mouth and sometimes in the throat of mammals 13,14. All pathogenic strains of S. aureus are coagulase positive whereas the nonpathogenic species (S. epidermidis for example) are coagulase negative. It is difficult to differentiate Kocuria from Micrococcus with conventional biochemical methods; therefore, these organisms are often reported together as Micrococcus/Kocuria species. What are the Uses of Micrococcus Gram Stain? This suggests that some of the Micrococcus species on the basis of ribosomal RNA analysis eventually can be re-classified into other microbial genera. It has multiple antibiotic resistance genes including dihydropteroate synthase, glycerophosphoryl diester phosphodiesterase, and SSU ribosomal proteins. They grow in circular, entire, convex, and creamy yellow-pigmented colonies with diameters of approximately 4 mm after 2-3 days at 37C. The bubbling reaction is almost immediate and distinct in appearance. 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. Organisms commonly found on the body include Micrococcus, Staphylococcus, and Corynebacterium species (Dermnet New Zeland). The staphylococci and micrococci are catalase producers while the streptococci, enterococci, and a variety of other Gram-positive cocci are catalase-negative. Make a tape label writing the color dot, your name, and the name of the media. Although of low virulence, the germs may become more pathogenic in patients with impaired resistance, colonizing the surface of heart valves. 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 The typical microscopic morphology of the Gram-positive cocci when using the Grams stain is represented in these three images. 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. Micrococcus spp. Figure 1. It shows that it is mostly Actinobacteria, with some firmicules ,and proteobacteria mixed in (Figure 2).

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