Micrococcus luteus is generally harmless but can become an opportunistic pathogen in immunocompromised people or those with indwelling catheters. 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. 2. Oxidase (modified oxidase) test: Positive. Krona chart of microbe shows bacterial classes thought to be present in the sample. Staphylococcus aureus Staphylococcus spp. 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. As its name suggests, mannitol salt agar (MSA) contains 1% mannitol (sugar), 7.5% salt, and agar as a solidifying agent. The catalase test did return positive by bubbling, indicating that it does have the ability to break down the radical hydrogen peroxide into diatomic oxygen and hydrogen. Micrococcus luteus is a Gram-positive to Gram-variable, nonmotile, tetrad-arranging, pigmented, saprotrophic coccus bacterium in the family Micrococcaceae. 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. Micrococcus luteus. CATALASE TEST: Catalases are enzymes that convert hydrogen peroxide (H2O2) into water and oxygen gas. In the presence of atmospheric oxygen, the oxidase enzyme reacts with the oxidase reagent and cytochrome C to form the coloured compound, indophenol indicated as blue or purplish-blue colouration on the disc after the introduction of the bacterial colony on the disc. I then repeated this three more times to further purify the isolate. The GC content of the DNA ranges from about 65 to 75 mol%. 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. Several uncommon strains produce raised colonies with translucent, depressed centers. I grew my isolated in Tryptic Soy Broth (TSB) for a week to prepare for DNA extraction. In contrast to staphylococci, usually, penicillin is sensitive.
Colony pigmentation varies considerably but is usually different shades of yellow or cream-white. Filter paper disks impregnated with tetramethyl-p-phenylenediamine dihydrochloride (oxidase reagent) in dimethyl sulfoxide (DMSO) are used. 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]. 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.
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. Benecky M. J.; Frew J. E.; Scowen N; Jones P, Hoffman B. M (1993). It is often larger thanStaphylococcus. Though today the immuno-compromised patients take the risk of the infection that has grown. Take a clean, scratch free glass slide. 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. 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 mammalian skin that has M. luteus strain is also highly sensitive to the beta-lactam antibiotics. Of those only Vancomycin was closer than 50 millimeters, being 38 millimeters. In the case of a negative test, no colour change is observed. 1995; Wieser et al. Although it's tempting to write a summary of the entire study but it . It is difficult to differentiate Kocuria from Micrococcus with conventional biochemical methods; therefore, these organisms are often reported together as Micrococcus/Kocuria species. Each family of Gram-positive cocci has its own unique configuration. 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. Required fields are marked *. 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. 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. (2019, April 4). The agglutinability of the cells with antiserum containing anti-teichuronic acid antibody was examined. 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. Annals of Allergy, Asthma and Immunology 122(1):17-24. 2014). Catalase is an enzyme produced by the organism to neutralize the toxic effects of hydrogen peroxide in the environment of the cell. So far there are two genome sequences that have been done. Staphylococcus spp. The micrococci produce tetrads consisting of 4 cocci clustered together. This is termed alpha () hemolysis and results in a greenish color surrounding the colony. My goal in this experiment was to isolate, characterize and identify a bacterial colony that arose from a sample taken from my roommates nose. Micrococcus (pleural-micrococci) is free-living in the environment and also normal flora of the skin. Characteristics. 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]. About half of the Micrococcus luteus gram stain was found to carry plasmids of about one to 100MDa in size. 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. Table 1: Graph from Korona showing the percent reads of each organism, and to which taxonomic level. Know more about our courses. There have been several deaths in immuno-compromised children that are caused by leukemia from the pulmonary hemorrhages because of Micrococcus. 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. Hybridization studies show that there is no close genetic relationship between the species of Micrococcus bacteria. This would be read A/NC. Micrococcus luteus. They are normal inhabitants of the human body and may even be essential in keeping the balance among the various . For the detection of oxidase enzyme, filter paper circular disks impregnated with tetramethyl-p-phenylenediamine dihydrochloride in dimethyl sulfoxide are used. 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. They are also catalase-positive and often weakly oxidase-positive ( modified oxidase test positive). They usually can occur in the irregular clusters, tetrads, and in pairs, where the individual cells are about one to 1.8 mm in diameter and these are usually non-motile and non-spore-forming in nature. I also did a fluid thioglycolate test to determine the bacterias oxygen class. I performed a Gram stain test to identify if the bacterium was gram negative or positive, as described in the Lab 4 handout. . M. lylae can be distinguished from the closely related species Micrococcus luteus by lysozyme susceptibility, genetic composition, and the type of cell-wall peptidoglycan. 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. 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). Required fields are marked *. Ans: Although it is a harmless saprophyte, Micrococcus luteus can act as an opportunistic pathogen. . 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. Subscribe to our e-mail newsletter to receive updates. If the agar plate is held up to a light source, you can sometimes see through the agar, as is pictured on the left. 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. The sample was then sequenced using the Illumina MiSeq technology in UAFs DNA Core Lab. If an organism is capable of fermenting the sugar glucose, then acidic byproducts are formed and the pH indicator turns yellow. It has survived for at least 34,000 to 170,000 years, as assessed by 16S rRNA analysis, and possibly much longer. 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. To sample, I used sterile cotton swabs and streaked them on TSA plates. Institute for Quality and Efficiency in Health Care. 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. 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). luteus is rarely found to be responsible for infections. Some Micrococcus are pigmented bacteria; for example, M. luteus produces yellow colonies and M. roseus produces redish colonies. 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. The microdase test is a rapid method to differentiate Staphylococcus (-ve) from Micrococcus +ve) by detection of the enzyme oxidase. When looking at the genetic tests, most of the identified strains in the Korona test are Micrococcus luteus. Most of these are mesophiles; some, like Micrococcus antarcticus which is found in Antarctica, are psychrophiles. Micrococcus Catalase Test: The catalase test facilitates the detection of the enzyme catalase in bacteria. M. luteus is an obligate aerobe (Medical Laboratories). The differentiation is based on the detection of oxidase enzyme. [1] It is urease and catalase positive. We were aiming to isolate a bacterium from this initial environmental sample by using repeated quadrant streaks to isolate single species colonies, therefore producing a pure culture that we could do a multitude of tests on which include Gram staining, genetic analysis and antibiotic testing along with many other tests. 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. Notice that beta-hemolysis results in a total lysis or clearing of the agar in the area of colony growth. 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. Some are based on monoclonal antibodies, and others on simple, rapid . Micrococcus luteus are Gram-positive, to Gram-variable, motile -non motile, that are 0.5 to 3.5 micrometers in diameter and usually arranged in tetrads or irregular clusters. Micrococcus luteus in tetrads arrangement. The nasal cavity microbiome primarily consists of the phyla Actinobacteria, Firmicutes and Proteobacteria (Bassis et al. This technique is centered on the performance of the classic Grams stain. Baird-Parker, A. c.: A classification of micrococci and staphylococci based on physiological and biochemical tests. They also produce yellow or pink colonies when they are grown on the mannitol salt agar, micrococcus flavus, M. terreus, and M. yunnanensis. They contain cytochromes and are resistant to lysostaphin. Micrococcus., h. Shahidi Bonjar. 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. Habitat Micrococcus lives in a wide range of environments such as water, soil, and the dust whereas, Staphylococcus lives in the animal body.