Microbiology is the study of microscopic organisms such as virus, Protista and bacteria. It’s important to know and to identify what kind of bacteria and how we can treat it since is found everywhere in society. Also to know what kind of bacteria it is by the performing different biochemical test and be able to differentiate the bacteria. This is use in the medial field where is important to know what kind of bacteria there dealing with and know how to treat it.
The purpose of the study was to identify what are unknown bacteria by applying all the methods that we have learn in microbiology for the identification of are unknown. We apply the different test and be able to recognize the different characteristic of are unknown. Each test has its own purpose to help identify the bacteria by the reaction.
A scientist named Christian Gram invented a technique called gram staining by which is colorized that is separated into two groups Gram positive and Gram negative. In bacteria most have rigid cell walls in which is accountable for the shape of the organism. Within the cell wall of the bacteria it identifies whether the bacteria is gram positive or negative. In the cell wall there a lot of difference that determines the bacteria is gram is positive or negative for example the thickness and the amount of peptidoglycan later presences or absence of outer membrane and teichoic acids. Where gram positive have two later and negative has three layers. Gram positive the cell wall is a single layer, primarily composed of peptidoglycan, does not contain outer membrane and contains negatively charged teichoc acids, this result of a blue color indicator. For gram negative is more complex that the Gram positive, its membrane lies outside of th...
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...the result there was a bit of ambiguity, that I had to redo some test all over again just to make sure. I even had to streak a plate again because of the spring break vacation, probably the bacteria died during that time and also there was contamination on them. Even though I had my TSIA slant backup I didn’t have that much bacteria to work on since I had to keep repeating some of the test.
After gathering my result of each biochemical test and eliminating organism that wasn’t my unknown with the given result I still kept second guessing myself between E.coli and Salmonella. Even though TSIA and the SIM were different I couldn’t get the result of the TSIA as A/A but instead K/A. I look back to the microbiology slide on lab 5 and compare my result to the picture on the slide to help me figure it out. Therefore it was concluded that the unknown was Escherichia coli.
I identified the genus and species of an unknown bacterial culture, #16, and I applied the following knowledge of morphologic, cultural and metabolic characteristics of the unknown microorganism according to the laboratory manual as well as my class notes and power point print outs. I was given an incubated agar slant labeled #16 and a rack of different tests to either examine or perform myself; the tests are as follows: Gram Stain; Nutrient Gelatin Test; Carbohydrate Fermentation; Dextrose, Lactose and Sucrose; IMVIC tests; Citrate, Indole, Mythel-Red and Vogues Proskauer test; as well as a Urease and TSI Test. Materials and Methods/Results Upon receiving the Microorganism (M.O.) #16, I prepared a slide by cleaning and drying it. Then, using a bottle of water I placed a 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.
Each test that was used in the lab for the unknown bacteria had been performed on many different bacteria and shown that each test has different results depending on the bacteria given. The first test, the Gram stain, confirmed that the unknown bacterium was a gram negative bacilli. After performing the remainder of the tests and comparing them to the twelve negative bacteria that it could be out of it was basically a process of elimination. Basically looking at all the results and seeing which tests separated positive verses negative results the most. After reviewing all of the tests the first test that stuck out besides the gram stain was the lactose fermentation, followed by the citrate utilization test and then by the indole test. The lactose fermentation test eliminated seven of the 12 bacteria. From the five bacteria left the citrate utilization test eliminated who more of the bacteria, and last the indole test eliminated two of the three bacteria left leaving only one bacterium left. After comparing the results to the results of the 12 tests and separating which tests were positive and negative for each it was obvious that the bacteria had to be Shigella
...indole, it is motile, there is no urease present and there is no coagulase activity. By deduction and logical reasoning Unknown 10a was determined to be Escherichia coli.
In this lab project, the microbiology students were given 2 unknown bacteria in a mixed broth each broth being numbered. The goal of this project is to determine the species of bacteria in the broth. They had to separate and isolate the bacteria from the mixed broth and ran numerous tests to identify the unknown bacteria. The significance of identifying an unknown bacteria is in a clinical setting. Determining the exact bacteria in order to prescribe the right treatment for the patient. This project is significant for a microbiology students because it gives necessary skills to them for future careers relating to clinical and research work.
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.
After the end of the experiment the unknown 10 sample was Staphylococcus epidermidis. Came to this conclusion by first beginning with a Gram Stain test. By doing this test it would be easier to determine which route to take on the man made flow chart. Gram positive and gram negative bacteria have a set of different tests to help determine the unknown bacterium. Based on the different tests that were conducted in lab during the semester it was determined that the blood agar, MSA, and catalase test are used for gram positive bacteria while Macconkey, EMB, TSI, and citrate tests are used for gram negative bacteria. 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. This indicated that there was no lysis of red blood cells. By looking at the plate there was no change in the medium. Next an MSA test was done and the results showed that there was growth but no color change. This illustrates that the unkown bacteria could tolerate high salt concentration but not ferment mannitol. The MSA plate eliminated Streptococcus pneumonia and Streptococcus pyogenes as choices since the bacteria can’t grow in high salt concentration. Staphylococcus aureus could be eliminated because not only did the unknown bacteria grow but also it didn’t change color to yellow. Lastly a Catalase test was done by taking a colony from the Blood Agar plate...
I also inoculated a tryptic soy broth (TSB), a nutrient gelatin deep, a motility agar deep, a fluid thioglycollate medium (FTM) tube, and a TSA plate with my unknown culture. All of these inoculated media were incubated until the next class period (about 48 hours). Then when I came to class most of my inoculated tubes and my streak plate appeared to have growth. The next step I took was making a gram stain to determine the gram reaction and cellular morphology of my unknown. I used my working slant to do this, after careful examination of the gram stain, I learned that my unknown was a gram-positive bacterium. I then preceded by making a negative stain to see the size of the cells of my unknown bacteria. The cell shape was cocci and the cells occurred in clusters of tetrads. After discovering that my unknown bacteria was gram-positive cocci, I turned to page 207 of the lab manual to narrow down my options, there was only four out of the gram-positive list that were
The eighteenth exercise of the laboratory manual titled Unknown Identification and Bergey’s Manual is an experiment to identify an unknown bacterium. In this exercise, a student must randomly choose a numbered bacterium available to the class. The keys in Appendix H, located on the last pages of the book, are the major helpful tools in this exercise because it provides completed steps of tests that needs to be performed in order to distinguish certain bacteria. This means that in this exercise, various types of tests and techniques must be performed to identify the chosen unknown bacterium. The unknown bacterium that I selected was number thirty-nine in which I discovered as the Bacillus megaterium after conducting several tests.
The Gram stain is a system used to characterize bacteria based on the structural characteristics of their cell walls. A Gram-positive cell will stain purple if cell walls are thick and a Gram-negative cell wall appears pink. Most bacteria can be classified as belonging to one of four groups (Gram-positive cocci, Gram-positive bacilli, Gram-negative cocci, and Gram-negative bacilli) (Phenotypic analysis. (n.d.).
mutans was problematic due to its difference with Bergey’s Manual result for the catalase test. However, after comparing it with a peers results, it seems very possible that the strain we are working with varies from the strain used in Bergey’s. Bacteria possess the ability to develop varying phenotypes within the same species due to frequent mutation and horizontal gene transfer. Therefore, it is possible that the results obtained in our lab may vary from those provided in Bergey’s Manual. Arriving to the conclusion that the Gram negative bacteria was Klebsiella pneumoniae was much more direct. Using Bergey’s Flowchart for identification, the bacteria shared the test results and had a similar shape and
Inconsistencies in this lab could have caused variations in data collecting. Collecting data from one petri dish was challenging because something could have been different on other petri dishes if this experiment was tested on several petri dishes. This could have been different because the other petri dishes could have had more micro-organisms in Section 2 instead of Section 1, or no bacteria could have grown at all in every section of the petri dish.- Second, nothing grew in section B even though there were no disinfectants in that section. The reason why the bacteria and mold might have grown in sections 1, 2, and 3 was because in the process of making the experiment, the coffee filter papers were touched with glove free hands and were not clean. If this lab was run again, some changes would be to wear rubber gloves, do not pour the hand sanitizers on the coffee filter paper but just pour one pump straight into the petri dish, have more than one petri dish to collect data off of, and check when the last time someone cleaned the door knob
...standing the nature of relationship between the residing microbes inside human cells and about their function is very important to put an end to this war and to live in peace with the natural organisms that are benefitting human body and their survival has become our primary importance.
Bacterial cells, like plant cells, are surrounded by a cell wall. However, bacterial cell walls are made up of polysaccharide chains linked to amino acids, while plant cell walls are made up of cellulose, which contains no amino acids. Many bacteria secrete a slimy capsule around the outside of the cell wall. The capsule provides additional protection for the cell. Many of the bacteria that cause diseases in animals are surrounded by a capsule. The capsule prevents the white blood cells and antibodies from destroying the invading bacterium. Inside the capsule and the cell wall is the cell membrane. In aerobic bacteria, the reactions of cellular respiration take place on fingerlike infoldings of the cell membrane. Ribosomes are scattered throughout the cytoplasm, and the DNA is generally found in the center of the cell. Many bacilli and spirilla have flagella, which are used for locomotion in water. A few types of bacteria that lack flagella move by gliding on a surface. However, the mechanism of this gliding motion is unknown. Most bacteria are aerobic, they require free oxygen to carry on cellular respiration. Some bacteria, called facultatibe anaerobes can live in either the presence or absence of free oxygen. They obtain energy either by aerobic respiration when oxygen is present or by fermentation when oxygen is absent. Still other bacteria cannot live in the presence of oxygen. These are called obligate anaerobes. Such bacteria obtain energy only fermentation. Through fermentation, different groups of bacteria produce a wide variety of organic compounds. Besides ethyl alcohol and lactic acid, bacterial fermentation can produce acetic acid, acetone, butyl alcohol, glycol, butyric acid, propionic acid, and methane, the main component of natural gas. Most bacteria are heterotrophic bacteria are either saprophytes or parasites. Saprophytes feed on the remains of dead plants and animals, and ordinarily do not cause disease. They release digestive enzymes onto the organic matter. The enzymes breakdown the large food molecules into smaller molecules, which are absorbed by the bacterial cells. Parasites live on or in living organisms, and may cause disease. A few types of bacteria are Autotrophic, they can synthesize the organic nutrients they require from inorganic substances. Autotrophic bacteria are either photosynthetic or Chemosynthetic. The photosynthetic bacteria contain chlorophyll that are different from the plant chlorophyll. In bacterial photosynthesis, hydrogen is obtained by the splitting of compounds other than water.
Microbes are microscopic life forms, usually too small to be seen by the naked eye. Although many microbes are single-celled, there are also numerous multi-cellular organisms. The human body has 10-100 trillion microbes living on it, making it one giant super-organism. Since the first link between microbes and diseases was made, people have been advised to wash their hands. Scientists, however, have recently started to investigate more closely how the microbes that call the human body home affect our health. While some microbes cause disease, others are more beneficial, working with our bodies in many subtle ways.
Knowledge is power when discussing the classes you have taken in college and how it affects your everyday life. Microbiology is one of those important classes where although for a majority of majors you do not have to take it and therefore will not learn the information discussed in it, other majors such as biology and nursing require you to take it. They will require you to take it because you will encounter some of the information being taught in it in the work field. As a nurse practitioner I have worked in the field with many patients who were diagnosed with Leprosy, Escherichia coli, Salmonella and other bacterial diseases. All of these diseases that I have encountered in patients were ones I was familiar with due to learning about them as a student in microbiology at CSUB. My children plan on