After gram staining, it was revealed that unknown 1 microscopic morphology was Gram positive cocci in clusters Staphylococcus epidermiclis. When observed under the microscope, the bacteria’s morphology displayed a purple color, round shape, and clustered together like bundles of grapes. It was difficult to locate the specimen due to the student’s lack of experience with using the microscope. The student forgot to use the stage clip to hold the slide in place, which made it difficult to control the specimen. There was also concern that without the professor’s assistance, the student will make error with bacteria classification.
Unknown 2
After gram staining, it was revealed that unknown 2 microscopic morphology was Gram negative rods Echerichia
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The student also forget to apply aseptic technique throughout experiment, which made experiment vulnerable to contamination.
Unknown 3
After gram staining, it was revealed that unknown 3 microscopic morphology was Gram positive cocci in chains Enterococcus faecalis. When observed under the microscope, the bacteria’s morphology displayed a purple color, round shape, and in short chains. Enterococcus faecalis is most often found in large intestine of humans2. It is known to cause endocarditis and bacteremia, urinary tract infections (UTI), meningitis, and other infections in humans3.
There were challenges while conducting the experiment due to student’s lack of experience. There was concern about over or under decolorization, which can alter the purple color of Gram positive into pink color of Gram negative and vice versa.
Unknown 4
After gram staining, it was revealed that unknown 4 microscopic morphology was Gram positive rods Bacillus subtilis. When observed under the microscope, the bacteria’s morphology displayed a purple color with rod shape. This bacteria is found in soil and vegetation. It is most favorable in mesophilic temperature ranging between 25-35 degrees Celsius4
Upon receiving the unknown Microorganism (M.O.) #16, I prepared a slide by cleaning and drying it. Then, using a bottle of water I placed sterile drop of water on the slide and used an inoculating loop, flame sterilized, I took a small sample of the unknown growth in my agar slant and smeared it onto the slide in a dime sized circle and then heat fixed it for ten minutes. After ten minutes had passed, I collected the ingredients needed to perform a gram stain. I got the primary stain, crystal violet, and flooded my smear for sixty seconds, and then rinsed the color off with water until the water ran clear. I then flooded the smear with the mordant, grams iodine, and let that sit on the slide for sixty seconds as well. I then rinsed the grams iodine off with water and applied alcohol to the smear to decolorize the cells; however I made sure not to over decolorize and only put enough drops on the smear till the purple ran clear. I then rinsed the slide with water and flooded the smear with safranin the counter stain and let it sit for sixty seconds and then rinsed the color off with water. I blo...
Digestion of the haemolytic and non-haemolytic cells allowed for easier identification of fragments during electrophoresis analysis. Lane 12 in figure 3 show the size markers of SPP1 digested with EcoR1 while lanes 6 and 7 show samples of pK184hlyA and pBluescript digested with EcoR1 and Pst1. Lane 4 was loaded with plasmid DNA from haemolytic cells digested with EcoR1 and Pst1 while lane 5 was loaded with EcoR1 and Pst1 digested DNA from non-haemolytic cells. There was a lack of technical success in both lanes due to no bands appearing in lane 4 and only a single band appearing in lane 5. Theoretically, two bands should appear in both lanes after successful to allow for fragment identification. A possible explanation for the single, large fragment in lane 5 is that successful digestion did not take place and the plasmid was only cut at one restriction site leaving a large linear fragment of plasmid DNA. The absence of bands in lane 4 could be because there was not enough plasmid loaded into the lane. Another possibility could be that low plasmid yield as obtained when eluting the experimental samples in order to purify it. Lanes 8 and 9 belonged to another group and show technical success as two bands were present in both the haemolytic (lane 8) and non-haemolytic (lane 9) lanes. If the
The isolate possesses some enzymes required for hydrolytic reactions. Hydrolytic enzymes found to be secreted from the bacterium, are -amylase, casein, and PYRase. In the starch hydrolysis and casein tests, there was a zone of clearing around the bacterium, which was indicative of the secreted enzymes necessary to break down starch and casein. In the PYR test, the presence of PYRase was detected by a color change to red on the PYR disc after the addition of the PYR reagent (p-dimethylaminocinnamaldehyde). Hydrolytic enzymes for which the EI tested negative were urease, gelatinase, and DNAse. In the Urea Hydrolysis test, it was observed that the urea broth did not have a color change, indicating that there was no urease secreted to break down urea in the broth. Similarly, there was no gelatinase present to break down gelatin in the Gelatin Hydrolysis test, so the nutrient gelatin remained solid. It was concluded that the EI does not possess DNase because there was no clearing zone around the bacteria, indicating that DNA had not been
The first day an unknown sample was assigned to each group of students. The first test applied was a gram stain to test for gram positive or gram-negative bacteria. The morphology of the two types of bacteria was viewed under the microscope and recorded. Then the sample was put on agar plates using the quadrant streak method for isolation. There were three agar plates; one was incubated at room temperature, the second at 30 degrees Celsius, and the third at 37 degrees Celsius. By placing each plate at a different temperature optimal growth temperature can be predicted for both species of bacteria.
The Gram positive bacteria has been nicknamed Posi. The Gram positive species’ morphology includes having an opaque opacity with a smooth margin. The moisture content of the Gram positive species is shiny and the pigmentation is gold. The Gram positive species grows at an optimal temperature of 37°C. The shape of the Gram positive species is a cocci, with an arrangement of grapelike clusters. The Gram positive species’ size ranges from .5-1.5 µm. Oxygen requirement of the Gram positive species is facultative, and has complete lysis of red blood cells. All results are summarized in Table
The purpose of this study is to identify an unknown bacterium from a mixed culture, by conducting different biochemical tests. Bacteria are an integral part of our ecosystem. They can be found anywhere and identifying them becomes crucial to understanding their characteristics and their effects on other living things, especially humans. Biochemical testing helps us identify the microorganism present with great accuracy. The tests used in this experiment are rudimentary but are fundamental starting points for tests used in medical labs and helps students attain a better understanding of how tests are conducted in a real lab setting. The first step in this process is to use gram-staining technique to narrow down the unknown bacteria into one of the two big domains; gram-negative and gram-positive. Once the gram type is identified, biochemical tests are conducted to narrow down the specific bacterial species. These biochemical tests are process of elimination that relies on the bacteria’s ability to breakdown certain kinds of food sources, their respiratory abilities and other biochemical conditions found in nature.
The results of the gram stain test were cocci and purple. This indicated that the unknown bacteria were gram positive. The gram stain test eliminated Escherichia coli, Klebsiella pneumonia, Salmonella enterica, and Yersinia enterocolitica as choices because these bacteria are gram negative. Next a Blood Agar plate was used because in order to do a MSA or a Catalase test there needs to be a colony of the bacteria. The result of the Blood Agar plate was nonhemolytic.
The purpose of this laboratory is to learn about cultural, morphological, and biochemical characteristics that are used in identifying bacterial isolates. Besides identifying the unknown culture, students also gain an understanding of the process of identification and the techniques and theory behind the process. Experiments such as gram stain, negative stain, endospore and other important tests in identifying unknown bacteria are performed. Various chemical tests were done and the results were carefully determined to identify the unknown bacteria. First session of lab started of by the selection of an unknown bacterium then inoculations of 2 tryptic soy gar (TSA) slants, 1 nutrient broth (TSB), 1 nutrient gelatin deep, 1 motility
Staphylococcus epidermidis is classified as a bacterium. This particular bacterium is identified in laboratory testing by its forms of clusters and a violet stain. The violet stain indicates that the staphylococcus epidermidis is gram- positive meaning that it is sphere shaped and does not contain an outer cell membran). This type of Staphylococcus does not typically cause disease in healthy people. However, S. epidermidis is quite the opportunist.
G. vaginalis cells are gram-negative to gram-variable. These cells are nonmotile, small, pleomorphic rods that do not have endospores, flagella, or typical capsules. In vaginal fluid smears, the Gram reaction may vary from positive to negative (Catlin, 1992). G. vaginalis is viewed in non-crowded areas in a Papanicolaou preparation. Their morphology and staining reactions are affected by the bacteria’s physiological state. Both coccobacilli and longer forms occur in 24 hour cultures of G. vaginalis on blood agar. Their average dimensions are 0.4 by 1.0 to 1.5µm. The cells do not elongate into filaments although they can be up to 2 to 3µm (Catlin, 1992).
Enterococcus faecalis is a genus of gram positive cocci and form short chains or are arranged in pairs. They are nonmotile, facultative anaerobic organisms and can survive in harsh conditions in nature. There are over 15 species of the Enterococcus genus but about 90% of clinical isolates are E. faecalis. E. faecalis is a nosocomial pathogen because it is commonly found in the hospital environment and can cause life-threatening infections in humans. It is a bacterium that normally inhabits the intestinal tract in humans and animals but when found in other body locations it can cause serious infections. The most common sites for E. faecalis infections are the heart, bloodstream, urinary tract, and skin wounds. Due to vancomycin-resistant Enterococci, many antibiotics have been shown ineffective in the treatment. In this paper, I will describe the ecology and pathology of E. faecalis; the antibacterial resistance; treatment; and, what you can do to prevent Enterococcus infection.
Its morphology consists of a rod-shaped gram negative bacteria that is commonly found in soil, water, vegetation, human intestines, as well as the intestines of animals. Its presence can be good or bad. The family Enterobacteriaceae consists of a large number of genera which are genetically and biochemically related to one another. Escherichia coli is a component of the family. This bacterium was discovered by a German pediatrician and bacteriologist named Theodor Escherich in 1885.
Bacteria play a large role in our health, the environment, and most aspects of life. They can be used in beneficial ways, such as decomposing wastes, enhancing fertilizer for crops, and breaking down of substances that our bodies cannot. However, many bacteria can also be very harmful by causing disease. Understanding how to identify bacteria has numerous applications and is incredibly important for anyone planning to enter the medical field or begin a career in research. Having the background knowledge of identifying an unknown bacteria may one day aid healthcare professionals diagnose their patient with a particular bacterial infection or help researchers determine various clinical, agricultural, and numerous other uses for bacteria.
Many steps were taken in order to narrow down and figure out which bacterium unknown 413 is. One of the first step taken in identifying unknown 413 was to do a gram stain. The gram stain, which was purple, resulted in gram-positive cocci. The gram-positive eliminated all the possibilities of unknown 413 being any gram-negative bacteria such as Escherichia coli, Enterococcus faecalis etc. The cocci morphology result eliminated any possibilities of it being any bacteria that are a rod. This left five different genera: Staphylococcus, Lactococcus, Micrococcus, and Enterococcus as a choice for the unknown.
The duration of the experiment should be increased as the thermal death times of B. subtilis at 60, 70 and 80°C were unable to be determined within 110 minutes. The duration can be increased to 180 minutes so as to better investigate its thermal death times. If the presence of bacterial growth was still observed after 180 minutes of exposure, it can be assumed that B. subtilis is able to survive well in that temperature. An exposure time of one day can be carried out to confirm this assumption.