Microbiology I Practical Guide
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Questions and Answers

What type of hemolysis is associated with the organism that caused the recurrent surgical wound infection?

  • Gamma-hemolysis
  • Beta-hemolysis (correct)
  • Alpha-hemolysis
  • Delta-hemolysis

    • Which of the following characteristics is used to identify Staphylococcus aureus?

  • Coagulase positive (correct)
  • Catalase negative
  • Alpha-hemolytic on blood agar
  • Gram-negative cocci in clusters

    • What is the result of the catalase test for Staphylococcus aureus?

  • Inconclusive
  • Positive (correct)
  • Determined by coagulase test
  • Negative

    • Which medium would be selectively used to isolate Staphylococcus aureus?

    <p>Mannitol salt agar</p> Signup and view all the answers

    What organism is indicated by Gram-positive cocci arranged in chains?

    <p>Streptococcus pyogenes</p> Signup and view all the answers

    What specific test would be utilized to differentiate between Streptococcus pyogenes and Streptococcus agalactiae?

    <p>Bacitracin sensitivity test</p> Signup and view all the answers

    What is a common clinical manifestation of skin scalded syndrome caused by Staphylococcus aureus?

    <p>Rash with vesicles</p> Signup and view all the answers

    Which characteristic would you expect in a Gram stain of Streptococcus faecalis?

    <p>Cocci in chains</p> Signup and view all the answers

    What is the purpose of the catalase test?

    <p>To differentiate between streptococci and staphylococci</p> Signup and view all the answers

    Which of the following statements about Staphylococcus aureus is true?

    <p>It produces yellow colonies on mannitol salt agar</p> Signup and view all the answers

    What is the expected outcome when performing a catalase test on Staphylococcus aureus?

    <p>Bubbles are produced</p> Signup and view all the answers

    What is the role of the enzyme coagulase in Staphylococcus aureus?

    <p>To convert fibrinogen to fibrin</p> Signup and view all the answers

    In the tube coagulase test, what is added to the positive control tube?

    <p>Staphylococcus aureus</p> Signup and view all the answers

    Which type of coagulase can be detected by the clumping factor during the slide coagulase test?

    <p>Bound coagulase</p> Signup and view all the answers

    What could lead to a false positive result in a catalase test?

    <p>Using a metal loop to transfer the sample</p> Signup and view all the answers

    How is rabbit or human plasma used in the testing process?

    <p>As a reagent in the coagulase test</p> Signup and view all the answers

    Which test is used for the identification and typing of pneumococci?

    <p>Quellung test</p> Signup and view all the answers

    What is the result of S. pyogenes in the CAMP factor test?

    <p>Negative</p> Signup and view all the answers

    Which of the following statements about pneumococci is true?

    <p>They appear as unstained halos in a gram-stained film.</p> Signup and view all the answers

    On blood agar, pneumococci show which type of hemolysis?

    <p>Alpha hemolysis</p> Signup and view all the answers

    What result indicates a positive Quellung test?

    <p>Swollen capsule around the organism</p> Signup and view all the answers

    What type of bacteria is S. agalactiae regarding its CAMP factor production?

    <p>Produces CAMP factor</p> Signup and view all the answers

    Which culture condition is optimal for pneumococci?

    <p>Incubation in 5-10% CO2 at 35˚C</p> Signup and view all the answers

    Which characteristic helps differentiate pneumococci from Strept. viridans?

    <p>Quellung positivity</p> Signup and view all the answers

    Which test is used for the direct detection of meningococcal antigen?

    <p>Latex agglutination test</p> Signup and view all the answers

    What is a positive oxidase test indicated by?

    <p>Color change to purple within 10 seconds</p> Signup and view all the answers

    Which microorganism is NOT identified by using the oxidase test?

    <p>Escherichia coli</p> Signup and view all the answers

    What type of environment is required for the incubation of Neisseria meningitidis?

    <p>CO2 incubator or candle jar</p> Signup and view all the answers

    What is the primary biochemical characteristic of Moraxella catarrhalis?

    <p>It shows no acid production from glucose</p> Signup and view all the answers

    What is a common clinical manifestation caused by Moraxella catarrhalis?

    <p>Pneumonia</p> Signup and view all the answers

    In laboratory identification, what is observed in the Gram stain of Neisseria species?

    <p>Gram-negative kidney-shaped diplococci</p> Signup and view all the answers

    Which specimen type is commonly associated with diagnosing Moraxella catarrhalis?

    <p>Ear discharge</p> Signup and view all the answers

    What characteristic appearance do Bacillus anthracis colonies exhibit on blood agar?

    <p>Non-haemolytic reaction with Medusa head colonies</p> Signup and view all the answers

    Which staining technique is used to demonstrate the polypeptide capsule of Bacillus anthracis?

    <p>Polychrome methylene blue stain</p> Signup and view all the answers

    What type of morphology do Bacillus cereus bacilli typically have?

    <p>Gram positive bacilli with square ends</p> Signup and view all the answers

    Which of the following statements about Bacillus anthracis and Anthracoids is false?

    <p>Both produce a β-haemolytic reaction on blood agar.</p> Signup and view all the answers

    What is a key feature when identifying Anthracoids on nutrient agar?

    <p>The formation of large white colonies with a rough surface</p> Signup and view all the answers

    What distinctive feature is observed in the gelatin liquefaction test for Bacillus anthracis?

    <p>Inverted fire tree appearance</p> Signup and view all the answers

    Which of the following is NOT a specimen type for the isolation of anthracoids?

    <p>Sputum sample</p> Signup and view all the answers

    What is the Gram stain characteristic of Bacillus anthracis?

    <p>Gram positive bacilli with square ends and central spores</p> Signup and view all the answers

    What culture medium is used for isolating Clostridium perfringens?

    <p>Robertson cooked meat medium</p> Signup and view all the answers

    What type of hemolysis is produced by Clostridium perfringens?

    <p>Double zone of beta hemolysis</p> Signup and view all the answers

    Which of the following is a characteristic of Clostridium perfringens identified through biochemical tests?

    <p>Gelatin liquefier</p> Signup and view all the answers

    What is the result of the Nagler’s reaction for Clostridium perfringens?

    <p>Opacity around the control streak</p> Signup and view all the answers

    What microscopy method is used to identify Clostridium perfringens from a culture?

    <p>Gram stain</p> Signup and view all the answers

    In what setting is Clostridium perfringens typically cultured for laboratory diagnosis?

    <p>Anaerobic conditions</p> Signup and view all the answers

    What indicates a stormy clot formation in litmus milk medium?

    <p>Coagulation of milk protein</p> Signup and view all the answers

    Which organism is responsible for tetanus with identified Gram positive bacilli containing terminal spores?

    <p>Clostridium tetani</p> Signup and view all the answers

    Staphylococcus aureus is identified by Gram-positive bacilli arranged in clusters.

    <p>False</p> Signup and view all the answers

    The blood agar test for Staphylococcus aureus helps in testing hemolytic reactions.

    <p>True</p> Signup and view all the answers

    Corynebacterium diphtheriae is classified as a Gram-negative bacterium.

    <p>False</p> Signup and view all the answers

    The catalase test for Staphylococcus aureus typically yields a positive result.

    <p>True</p> Signup and view all the answers

    Mycobacterium tuberculosis is classified as a Gram-positive cocci.

    <p>False</p> Signup and view all the answers

    Bacillus anthracis colonies typically exhibit a rough appearance on blood agar.

    <p>True</p> Signup and view all the answers

    The total magnification of a microscope is calculated by multiplying the objective lens power by the ocular lens power.

    <p>True</p> Signup and view all the answers

    Haemophilus influenzae is typically included in the identification of anaerobic bacteria.

    <p>False</p> Signup and view all the answers

    Streptococcus pyogenes produces the CAMP factor.

    <p>False</p> Signup and view all the answers

    Pneumococci exhibit beta hemolysis on blood agar.

    <p>False</p> Signup and view all the answers

    The Quellung test is used for the typing of pneumococci.

    <p>True</p> Signup and view all the answers

    Capsules of Streptococcus pneumoniae appear as stained halos under the microscope.

    <p>False</p> Signup and view all the answers

    Streptococcus pneumoniae is catalase positive.

    <p>False</p> Signup and view all the answers

    Sputum specimens mixed with specific antiserum can demonstrate the Quellung reaction.

    <p>True</p> Signup and view all the answers

    The optimal incubation for pneumococci is at 20°C.

    <p>False</p> Signup and view all the answers

    Alpha hemolysis indicates complete lysis of red blood cells.

    <p>False</p> Signup and view all the answers

    Streptococcus faecalis is catalase positive.

    <p>False</p> Signup and view all the answers

    Enterococcus faecalis can produce black colonies on bile esculin agar.

    <p>True</p> Signup and view all the answers

    The PYR test shows a positive result with a dark pink or cherry-red color appearance.

    <p>True</p> Signup and view all the answers

    Gram positive cocci arranged in chains characterize Enterococcus faecalis.

    <p>False</p> Signup and view all the answers

    The culture of Streptococcus faecalis on blood agar shows complete hemolysis.

    <p>False</p> Signup and view all the answers

    The bile solubility test is used to identify streptococci species.

    <p>True</p> Signup and view all the answers

    Streptococcus faecalis is frequently associated with pneumonia.

    <p>False</p> Signup and view all the answers

    Gram positive cocci can be found in water samples as an indicator of fecal pollution.

    <p>True</p> Signup and view all the answers

    Mycobacterium tuberculosis is classified as Gram-positive.

    <p>False</p> Signup and view all the answers

    Lowenstein-Jensen medium is a selective medium for isolating Mycobacterium tuberculosis.

    <p>True</p> Signup and view all the answers

    Acid-fast bacilli appear as red-pink rods against a blue background when stained.

    <p>True</p> Signup and view all the answers

    Sputum is the appropriate specimen for isolating Mycobacterium tuberculosis.

    <p>True</p> Signup and view all the answers

    The growth rate of Mycobacterium tuberculosis is fast, typically taking 1-2 weeks.

    <p>False</p> Signup and view all the answers

    Tuberculin skin tests are considered indirect methods for detecting Mycobacterium tuberculosis infection.

    <p>True</p> Signup and view all the answers

    Mycobacterium tuberculosis can grow in anaerobic conditions.

    <p>False</p> Signup and view all the answers

    PCR testing is a rapid diagnostic method that detects protein in patient specimens.

    <p>False</p> Signup and view all the answers

    Clostridium perfringens is a Gram-negative bacilli with terminal spores.

    <p>False</p> Signup and view all the answers

    The Nagler’s reaction for Clostridium perfringens shows a clear zone around the streak where antibodies against α-toxin inhibit activity.

    <p>True</p> Signup and view all the answers

    Stormy clot formation occurs in litmus milk when Clostridium perfringens is present.

    <p>True</p> Signup and view all the answers

    Clostridium perfringens produces strictly aerobic cultures.

    <p>False</p> Signup and view all the answers

    Clostridium perfringens has a characteristic double zone of β-hemolysis on blood agar.

    <p>True</p> Signup and view all the answers

    Motility is a positive characteristic for identifying Clostridium perfringens.

    <p>False</p> Signup and view all the answers

    Clostridium perfringens is identified as a rapidly gelatin liquefying organism.

    <p>False</p> Signup and view all the answers

    Subterminal spores are a distinguishing feature of Clostridium tetani.

    <p>False</p> Signup and view all the answers

    Haemophilus influenzae is classified as a Gram-positive coccus.

    <p>False</p> Signup and view all the answers

    The result of the catalase test for Listeria monocytogenes is typically positive.

    <p>True</p> Signup and view all the answers

    Diphtheroids are characterized by a unique stormy clot reaction in litmus milk.

    <p>False</p> Signup and view all the answers

    Neisseria meningitidis is commonly associated with cases of meningitis.

    <p>True</p> Signup and view all the answers

    Staphylococcus aureus is a key pathogen associated with pneumonia.

    <p>False</p> Signup and view all the answers

    The primary biochemical characteristic of Moraxella catarrhalis is its ability to ferment lactose.

    <p>False</p> Signup and view all the answers

    Actinomyces israelii is identified by its unique appearance during Gram staining.

    <p>True</p> Signup and view all the answers

    The biochemical tests for identification of H.influenzae include evaluation on blood agar.

    <p>True</p> Signup and view all the answers

    Study Notes

    Microbiology I Practical Guide

    • Course code: MIB2117
    • Level: 2/S1
    • Academic year: 2023/2024
    • Instructor: Prof. Dr. Haneya Anani
    • Faculty: Faculty of Medicine
    • School: School of Applied Health Science

    Lab. No. 1: Laboratory Identification of Staphylococci

    • Learning Outcomes:
      • Understand the morphology and culture characteristics of Staphylococcus aureus.
      • Learn the laboratory identification of staphylococcal infections.

    Lab. No. 2: Laboratory Identification of Streptococcus pyogenes, Streptococcus agalactiae and Streptococcus faecalis

    • Learning Outcomes:
      • Understand the morphology and culture characteristics of Streptococcus pyogenes.
      • Understand the morphology and culture characteristics of Streptococcus faecalis.
      • Know the laboratory identification of Streptococcus pyogenes and Streptococcus faecalis.

    Lab. No. 3: Laboratory Identification of Neisseria Infection

    • Learning Outcomes:
      • Understand the characteristics of Neisseria species (commensals and pathogenic).
      • Understand the laboratory diagnosis of Neisseria infections.
      • Understand flashcard information for each test.

    Lab. No. 4: Laboratory Identification of Corynebacterium diphtheriae and Diphtheroids

    • Learning Outcomes:
      • Understand morphology and culture characteristics of Corynebacterium diphtheriae.
      • Understand laboratory identification of Corynebacterium diphtheriae and Diphtheroids.

    Lab. No. 5: Laboratory Identification of Mycobacterium tuberculosis Infection

    • Learning Outcomes:
      • Understand the morphology and growth characteristics of M. tuberculosis.
      • Understand the laboratory identification of Mycobacterium tuberculosis.

    Lab. No. 6: Laboratory Identification of Bacillus anthracis

    • Learning Outcomes:
      • Understand the laboratory identification of Bacillus anthracis.
      • Understand the differences between Bacillus anthracis and Anthracoids.

    Lab. No. 7: Laboratory Identification of Anaerobic Bacteria

    • Learning Outcomes:
      • Understand what anaerobic bacteria are.
      • Understand the medically important anaerobic bacteria and their laboratory identification.

    Lab. No. 8: Laboratory Identification of Listeria & Haemophilus

    • Learning Outcomes:
      • Understand diseases caused by Listeria and Haemophilus.
      • Understand laboratory identification for Listeria and Haemophilus.
      • Understand the results of case studies regarding Listeria and Haemophilus.

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    This practical guide focuses on the identification of various bacteria, including Staphylococcus aureus, Streptococcus pyogenes, and Neisseria infections. Students will gain an understanding of the morphology and culture characteristics necessary for laboratory identification. Ideal for level 2 students in the Faculty of Medicine.

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