Once a presumptive identification has been made based on colony and microscopic morphology and the catalase reaction, additional tests can be performed to establish the genus and species of the organism. Catalase test was the first biochemical test to be done . The categorization of bacteria in the clinical laboratory is based on the reactivity of the organism when stained by the Grams staining reagents. What is the biochemical test for Micrococci roseus? M. luteus has a G-C content of about 65-75 mol%. It is essential for differentiating catalase-positive Micrococcaceae from catalase-negative Streptococcaceae. 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. (2019, April 4). Beta-hemolysis is a defining characteristic of Staphylococcus aureus and a certain streptococci. 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. SUMMARY: 1250 Gram-positive and catalase-positive cocci were isolated from bacon, pig and human skin and dust, and their morphology, physiology and biochemical characters examined. Micrococci have Gram-positive types of spherical cells that are ranging from about 0.5 to three micrometres in diameter and typically they appear in tetrads. Colonies typically have a lemon-yellow pigment. 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). Finally I used different antibiotic disks to check for its resistance to antibiotics, using Gentamicin, Cefoperazone, Vancomycin, Tobramycin, Amikacin, Trimethoprim, Oxacillin, and Cefazdin. See answer (1) best answer. Many members of the genus have been reclassified into other genera. This microbe is coccus shaped and forms in tetrads. Enterococcus spp. Micrococcus are aerobic, Gram-positive cocci ranging in size from 0.5 to 2.0 m in diameter. Care must be taken when using a sample of organism acquired from a sBAP since erythrocytes also produce catalase. Another set of tests that I performed were physiological tests, including testing for oxygen class with fluid thyoglycate, checking for catalase using hydrogen peroxide, checking for cytochrome c oxidase using oxidase test strips, and using an API 20 E test strip to test for various different physiological traits such as Sulphur reduction, which had 20 different tests. Micrococcus luteus pigment (Yellow) GLUCOSE FERMENTATION TEST This test detects the ability of the bacterium to break down glucose to pyruvic acid. Micrococcus luteus has been shown to survive in oligotrophic environments for extended periods of time. Oral microbial flora of reptiles includes bacteria from Proteus, Porphyromonas, Micrococcus, Salmonella and Staphylococcus genera 5,8,15. The results of these tests provide a biochemical profile, or "fingerprint," that can be used to classify or even identify the bacterial species. The configurations are the result of the plane of cellular division exhibited by the organism. Maximum production of pigments was observed at 35C, pH 9 and at 4% (W/V) NaCl concentration. 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. (2) Micrococcus spp. I performed a Gram stain test to identify if the bacterium was gram negative or positive, as described in the Lab 4 handout. Organisms commonly found on the body include Micrococcus, Staphylococcus, and Corynebacterium species (Dermnet New Zeland). Micrococci have been isolated from the human skin, animal and dairy products, and in beer. 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]. It has been isolated from human skin. Rawis M, and AK Ellis (2019). Other Micrococcus isolates produce various useful products, such as long-chain aliphatic hydrocarbons for lubricating oils. M. luteus causes odours in humans when breaking down the components of sweat. This microbe forms large, round colonies. Under the microscope they are round cells. The identified reads only made up a total of twenty seven percent of the total reads, but the majority of those reads were for M. luteus. This would be read as K/A. I then repeated this three more times to further purify the isolate. Take a clean, scratch free glass slide. Discussion: When looking at all of the results for my isolate, they are not all consistent with Micrococcus luteus. M. luteus has the capability to show dormancy without the formation of spores. What are the Diseases that are Caused By Micrococcus? The majority of staphylococcal species produce non-pigmented colonies with smooth margins, as opposed to the important pathogen, Staphylococcus aureus, which produces the characteristic colonies seen here. 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 can be easily be mistaken for staphylococci, as they are very similar morphologically and physiologically (Wikipedia, Staphlyococcus Aureus). 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 been isolated from human skin. To identify our isolate after obtaining the pure culture, we performed many different tests. Staphylococcus saprophyticus is a Gram-positive, coagulase-negative coccus that is an important part of the group of microorganisms causing urinary tract infections (UTIs), particularly in young sexually active females. Therefore I used this as my location to take my environmental sample from. Production of bubbles indicates a positive reaction. Though today the immuno-compromised patients take the risk of the infection that has grown. The data on the GC content of the DNA, chemical cell wall analysis, and a comparative analysis of the 16S rRNA sequences. Reduction of O2 produces superoxide radicals and hydrogen peroxide, or the hydroxyl radical. Examples of the colony morphology associated with each family is represented on this slide. Micrococcus species occur in a wide range of environments, including dust, water, and soil. The catalase test facilitates the detection of the enzyme catalase in bacteria. Is Micrococcus luteus indole positive? Coagulase production is used as a virulence factor by the organism. Isolates of the M. luteus have been found to overproduce the riboflavin virus when they are grown on toxic organic pollutants like pyridine. They also produce yellow or pink colonies when they are grown on the mannitol salt agar, micrococcus flavus, M. terreus, and M. yunnanensis. I used an API Strep test to determine more of the sugars the bacteria could ferment. Abstract Micrococcus luteus IFO 3333 cells, both treated with chemical reagents and non-treated, were observed with a scanning electron microscope (SEM). Wieser et al. They are found in many other places in the, M. luteus has one of the smallest genomes of all the bacteria. Table 2: Graph of the genomic reads by taxonomic level using Korona. I used Prokka Genome Annotation to identify which genes are present in the bacterium, Kraken Metagenomics to identify what the DNA reads correlated to on different taxonomic levels, and SPAdes Genome Assembler to determine how many contigs were produced from the reads that were produced. Welcome to this Pearl of Laboratory Medicine on Basics of Differentiation of Gram-positive Cocci.. On top of that, most of the bacterium that were stained were gram negative, which conflicts with this result. 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. The name of the genus is also called " Germanized " is written as Micrococcus. For example, M. luteus and M. lylae are 40-50% genetically different. Note the bright yellow, non-diffusable colony pigment which is a defining characteristic of M. luteus. They grow in circular, entire, convex, and creamy yellow-pigmented colonies with diameters of approximately 4 mm after 2-3 days at 37C. [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]. The Micrococcus strains isolated from various infections were most probably misclassified as staphylococci. 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. M. luteus is an obligate aerobe (Medical Laboratories). Habitat Micrococcus lives in a wide range of environments such as water, soil, and the dust whereas, Staphylococcus lives in the animal body. This is likely either a cause of human error, unpure cultures, or not using agar plates that are fresh enough for the test. Klebsiella pneumoniae Micrococcus luteus Micrococcus roseus Proteus mirabilis Proteus vulgaris Pseudomonas aeruginosa Salmonella typhimurium Serratia marcescens Staphylococcus aureus Staphylococcus epidermidis Streptococcus . 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. Staphylococci are either producers of the enzyme coagulase or non-producers. Micrococcus spp. The mammalian skin that has M. luteus strain is also highly sensitive to the beta-lactam antibiotics. From four species that have been identify, only Bacillus subtilis and Pseudomonas diminuta that show ability to block pathogen bacteria Edwardsiella tarda. The colony forms as a yellow, shiny round blob. Basics of Differentiation of Gram Positive Cocci, Author: Karen Krisher For example, Micrococcus varians is now known as Kocuria varians. This can occur due to the presence of a reduced number of proteins that can bind to penicillin. The first control consisted of plates of agar-agar to test sterility. These organisms range in virulence potential from commensal organisms found on the skin and mucous membranes to pathogens associated with serious infections. When a drop of peroxide is placed on catalase-producing bacteria, bubbles appear when the oxygen gas is formed. The taxonomic assignment of this microbe was micrococcus luteus because it was the only bin that PATRIC gave. 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. Recent reports, however, confirm that micrococci may be associated with human infections, particularly in immunosuppressed patients. Micrococcus spp. Alpha-hemolytic colonies often assume a greenish hue. They are considered as normal comensal of human skin and upper respiratory tract. 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. The micrococci produce tetrads consisting of 4 cocci clustered together. The third image represents the colony morphology of many of the streptococci and enterococci. Date: FEB.11.2016 Subscribe to our e-mail newsletter to receive updates. 2-9 In these reports micrococci were identified on the basis of their . Its genome has a high G + C content. I repeated this process three more times to further purify the colony. Source: Trainee Council in English, Hello, my name is Dr. Karen Krisher. The large polysaccharide molecule starch contains two parts, amylose and amylopectin, these are rapidly hydrolyzed using a hydrolase called alpha-amylase to produce smaller molecules: dextrins, maltose, and glucose.