It is for this reason that Identification of bacteria is very important in the many areas of microbiology (Singh, 2009). There are many reasons for identifying an unknown bacterium. The reasons range from medical purposes, such as determining if the unknown could cause ailments in living things or knowing what microorganisms are needed to make antibiotics to other purposes such as knowing the exact microorganism has to be used to make certain foods (Burton, 2003). Throughout this report we will be addressing the differences in methods of identifying unknown microorganisms and differentiate between the results of these techniques by explaining how each outcome was achieved. The main aim of these experiments is to determine whether the unknown microorganisms are of Gram-Positive or Gram Negative nature and ultimately to determine exactly what kind on microorganism the unknowns are.
MacConkey agar was used to help determine this. The last test that helped determine this bacteria was the Methyl Red Voges-Proskauer broth. This test came back negative. In conclusion, I believe that the unknown bacteria number two to be Enterobacter aerogenes. In comparison of the descriptive chart and the comparative analysis sheet, 18 out 18 of the tests performed were alike.
Why are the specimens to be stained suspended in sterile saline or distilled water? Usage of sterile water to avoid false result by microorganisms having in the water and same reason for distilled also to avoid impurities like crystals of some metal ions to avoid other microorganism. 4. How does a stained preparation compare with a hanging drop for studying the morphology and motility of bacteria? The hanging drop is the classical method for viewing unstained microorganisms.
Selective Media Lab Report Introduction Biological media acts as food for the bacteria and allows the growth of bacteria. There are two types growth media, selective media and differential media. Selective media used is when trying to promote the growth of only one bacteria, while differential media is used when trying to distinguish one media from another growing on the same plate. This experiment uses one type of differential media, Blood agar, which is differential for detecting hemolytic activity. Three types of selective media are used: Phenyl Ethyl Alcohol (PEA) are both selective for gram positive agar and Deoxycholate Citrate Agar (DCA) is selective for enteric pathogens.
In Microbiology Lab 3 I chose the unknown culture #14 and ultimately identified it as Staphylococcus epidermidis bacteria. On a microscopic level I found the organism to be gram positive with a coccobacillus shape and both tetrad and cluster cell arrangement. I performed an isolation streak with S. epidermidis on Nutrient Agar which resulted in pinpoint, round, entire, and flat macroscopic morphology. I took a loopful of the organism from the Nutrient Agar and placed it on a slide to perform the catalase test. I added a few drops of 3% Hydrogen Peroxide and it resulted in bubble formation.
Differential Staining Brenda Blanchette, RN, CCTC Clinical Microbiology Laboratory Differential Staining There are several staining methods used with bacteria and are generally classified as simple, nonspecific, or differential (specific). Gram’s stain techniques are used to differentiate between types of bacteria as well as to differentiate between Gram-positive and Gram-negative bacteria. Gram’s stains are one of the most commonly used differential stains and are the focus of this experiment (Labpaq microbiology). Bacteria that stain purple are Gram-positive and bacteria that stain pink are Gram-negative. They stain differently due to differences in the structure of their cell walls.
However, when the dead skin from the epidermis occasionally blocks a sebaceous gland of a hair follicle, the bacteria may infect surrounding tissue resulting in inflammation and causing a pimple. 4. a) What is the pH of a substance? • In chemistry, pH (Potential Hydrogen) is a measure of the acidity of an aqueous solution. b) How does the pH describe the acidity of a substance? • It uses a scale to describe the acidity level and the pH scale ranges from 0 to 14.
August 29, 2012 Chapter 3 Study Guide 1. The chain of infection has six key components. The infectious agent which is also called the causative agent and it’s a pathogenic responsible for causing an infection like, a virus or bacteria. The reservoir is a place where a microbe can survive, grow or multiply in a human, animal, food, water, soil or contaminated articles or equipment. The Exit pathway is the way the reservoir gets rid of or exit a reservoir host in secretions from the eyes, nose, and mouth.
The purpose of these tests were to determine how the bacterium reacted to glucose with and without oxygen. My findings reported a gram stain negative along with positive tests for glucose oxidation and fermentation. Next I performed an Indole Production Test. This test determines whether the microbe produces indole from the amino acid tryptophan. The results from this test were negative.
Examine your living organism and determine if it is a bacteria, achaean or a eukaryote. At each step in classification, check the requirements for each category to determine where the species belongs. You then would begin to ask yourself a series of questions about the organism one question will lead to another. If the organism cannot be identified through the questions you will than need to do a gram staining process. You will look at the bacteria through a microscope exposing the bacteria's cell wall to two types of stains: a violet and a red one.