Microbial Identification Techniques
43 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary purpose of microarrays in medical diagnostics?

  • To detect a wide range of infectious agents (correct)
  • To replace traditional laboratory tests
  • To isolate and purify nucleic acids
  • To provide treatment options for patients

    • Which step involves the matching of gene sequences to the chip?

  • Detection
  • Result Validation
  • Sample Preparation
  • Hybridization (correct)

    • How are patient samples processed before they interact with microarray chips?

  • They are filtered to remove impurities
  • They undergo a drying process
  • They are immediately analyzed by the computer program
  • They are incubated with labeled gene sequences (correct)

    • What impact do diagnostic tests have on health care decisions?

    <p>They influence 70% of health care decisions</p> Signup and view all the answers

    What percentage of US health care costs is spent on diagnostic tests?

    <p>2%</p> Signup and view all the answers

    What is the primary purpose of Polymerase Chain Reaction (PCR) in diagnosing microorganisms?

    <p>To produce numerous copies of DNA or RNA molecules</p> Signup and view all the answers

    Which method utilizes random primers to identify specific microbes from a mixed population?

    <p>Random Amplified Polymorphic DNA (RAPD)</p> Signup and view all the answers

    How does Hybridization identify specific microbes?

    <p>By analyzing genetic material using complementary probes</p> Signup and view all the answers

    What is the role of Fluorescent in situ Hybridization (FISH) in microbial identification?

    <p>To locate and identify specific microbes using fluorescent probes</p> Signup and view all the answers

    What does ribotyping analyze for microbial identification?

    <p>16s ribosomal RNA (rRNA)</p> Signup and view all the answers

    What is the significance of specificity in immunological tests?

    <p>The ability to focus on a specific antibody or antigen</p> Signup and view all the answers

    Which biological fluids can modern serological tests analyze?

    <p>Urine, cerebrospinal fluid, whole tissues, and saliva</p> Signup and view all the answers

    What is the main feature that allows modern serological tests to determine unknowns?

    <p>Using knowns to analyze unknowns</p> Signup and view all the answers

    What is the primary difference between agglutination and precipitation reactions?

    <p>Agglutination results in visible clumping, whereas precipitation forms cloudy zones.</p> Signup and view all the answers

    What type of antigens are primarily involved in agglutination reactions?

    <p>Whole cells like RBCs or bacteria.</p> Signup and view all the answers

    What is the purpose of the Western blot test in the context of HIV detection?

    <p>To detect the presence of HIV antibodies in serum.</p> Signup and view all the answers

    Which method is used to visualize the antigen-antibody reactions in a Western blot?

    <p>Applying a fluorescent or luminescent labeled antibody.</p> Signup and view all the answers

    How are titers determined in serological testing?

    <p>By serially diluting serum and observing agglutination.</p> Signup and view all the answers

    What indicates a positive result in the RPR test?

    <p>Visible black clumps from agglutination.</p> Signup and view all the answers

    In the context of immunodiffusion, what is the result of double diffusion (Ouchterlony)?

    <p>Formation of a line of identity when antigen and antibody are identical.</p> Signup and view all the answers

    What characteristic distinguishes precipitation reactions from agglutination reactions?

    <p>Precipitation involves soluble antigens forming insoluble complexes.</p> Signup and view all the answers

    What is a critical feature of the Western blot test that contributes to its high accuracy?

    <p>It separates proteins by charge before detection.</p> Signup and view all the answers

    Which of the following is NOT typically done during a precipitation reaction?

    <p>Measuring visible clumping in a test tube.</p> Signup and view all the answers

    What is the primary use of Western blotting in immunological testing?

    <p>To verify the presence of microbial-specific antigens</p> Signup and view all the answers

    In radioimmunoassay (RIA), what is primarily measured to determine the amount of antigen or antibody?

    <p>The level of radioactivity</p> Signup and view all the answers

    What does a direct ELISA determine?

    <p>The presence of an unknown antigen using known antibody</p> Signup and view all the answers

    How are antigen-antibody complexes visualized in immunofluorescence testing?

    <p>With the help of fluorescent microscopy</p> Signup and view all the answers

    What type of sample is used in the indirect ELISA method?

    <p>Patient serum</p> Signup and view all the answers

    What kind of reaction does the tuberculin test elicit in vivo?

    <p>Lesion formation at the injection site</p> Signup and view all the answers

    Which component is NOT part of the ELISA testing method?

    <p>Isotope counter</p> Signup and view all the answers

    What does the term 'immunofluorescence' refer to?

    <p>The use of fluorescent dyes for antibody detection</p> Signup and view all the answers

    What is the significance of using a verification test like Western blotting for HIV screening?

    <p>It verifies results from less specific tests</p> Signup and view all the answers

    What innovation drives the breakthrough methodologies in immunological testing?

    <p>Genetics, physics, and information science</p> Signup and view all the answers

    Which laboratory technique is primarily used for identifying predominant biochemical reactions in bacteria?

    <p>Biochemical testing</p> Signup and view all the answers

    What is the purpose of differential media in the isolation of pathogens?

    <p>To identify definitive characteristics and fermentation patterns</p> Signup and view all the answers

    Which of the following specimens requires a sterile transport swab for collection?

    <p>Blood culture</p> Signup and view all the answers

    Which of the following biochemical tests assesses the ability of bacteria to ferment carbohydrates?

    <p>Carbohydrate fermentation test</p> Signup and view all the answers

    In diagnosing infections like Haemophilus influenzae, what molecular technique is commonly employed?

    <p>Nucleic acid amplification (PCR)</p> Signup and view all the answers

    What is the initial step in the laboratory techniques used for pathogen identification?

    <p>Analyzing patient signs and symptoms</p> Signup and view all the answers

    Which characterization is NOT a part of evaluating a pure culture?

    <p>Serological reaction</p> Signup and view all the answers

    What is the main outcome of a phage typing test?

    <p>Identification of bacterial species</p> Signup and view all the answers

    Which of the following isolates is best tested using Salmonella/Shigella agar?

    <p>Salmonella enterica</p> Signup and view all the answers

    Which test would likely result in a color change to indicate a metabolic reaction?

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

    Study Notes

    Miscellaneous Tests

    • Makes it possible to identify a microbe by analyzing segments of its genetic material
    • Probes: small fragments of DNA or RNA known to be complementary to specific sequences in the nucleic acid from a microbe
    • Base pairing of the probe to the nucleic acid can provide evidence of the microbe's identity

    Hybridisation: Probing for Identity

    • Application of fluorescently labeled probes to intact cells within a patient specimen or environmental sample
    • Used to locate "glowing cells" and determine the identity of a specific microbe
    • Often used to confirm a diagnosis or identify the components of a biofilm

    Ribotyping: rRNA Analysis

    • One of the most viable indicators of evolutionary relatedness is comparison of 16S ribosomal RNA
    • Component of the 30S subunit of bacterial and archaeal ribosomes
    • Highly conserved across species and evolutionary time
    • Ribotyping is perfectly suited for bacterial identification and diagnosis of infection
    • rRNA is isolated, sequenced, and analyzed from cultured cells

    Immunological Methods

    • In vitro diagnostic testing of serum
    • Based on the concept that antibodies have extreme specificity for antigens
    • Visualizing this interaction provides a powerful tool for detecting, identifying, and quantifying antibodies or antigens
    • An unknown antibody can be detected using a known antigen or an unknown antigen can be detected using a known antibody
    • Modern serological methods can test:
      • Urine
      • Cerebrospinal fluid
      • Whole tissues
      • Saliva

    General Features of Immune Testing

      1. Specificity:
      • The property of a test to focus on only a certain antibody or antigen
      • Does not react with unrelated or distantly related antigens.
      1. Sensitivity:
      • The detection of even minute quantities of antibodies or antigens in a specimen
      • Reflects the degree to which a test will detect every positive person.

    Polymerase chain reaction (PCR)

    • Used in many nucleic acid tests
    • Results in the production of numerous copies of DNA or RNA molecules within hours
    • Can amplify minute quantities of nucleic acids in a sample, greatly improving the sensitivity of diagnostic tests
    • Can be performed on bacteria, viruses, protozoa, and fungi

    Random amplified polymorphic DNA (RAPD)

    • Used in cases where the microbial populations are relatively unknown
    • Employs primers of random sequences in an attempt to pick a microbial needle out of a haystack

    Pulse-Field Gel Electrophoresis

    • Since the DNA fragments are large, PFGE requires long changes ("pulses") in the direction of the electrical field to tease them apart

    Microarrays

    • Absorbent plates or "chips" that contain gene sequences from thousands of infectious agents
    • Selected based on the syndrome being investigated
    • Can be made to contain bacterial, viral, and fungal genes in a single test
    • Patient samples or nucleic acids isolated from them are incubated with labeled gene sequences
    • Matching sequences hybridize to the chip
    • The fluorescent label is detected by a computer program

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Explore various methods used to identify microbes through genetic analysis. This quiz covers the applications of hybridisation, ribotyping, and the use of fluorescent probes for diagnosing infections. Test your understanding of these essential microbiological techniques.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser