Staphylococcus aureus Quiz
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Questions and Answers

What is a common infection caused by Staphylococcus aureus in surgical wounds?

  • Bacteremia
  • Furuncles (correct)
  • Pneumonia
  • Skin ulcers

    • Staphylococcus aureus can only be found in hospitals.

    False

    What are the characteristic colors and sizes of Staphylococcus aureus colonies on blood agar?

    Medium to large colonies, cream to golden color

    Staphylococcus aureus can cause ______ which is characterized by a toxic shock.

    <p>staphylococcal toxic shock</p> Signup and view all the answers

    Match the following infections with their corresponding characteristics:

    <p>Furuncles = Skin/hair follicle infections Pneumonia = Respiratory infection Bacteremia = Presence of bacteria in the bloodstream Scalded skin syndrome = Toxin-producing skin condition</p> Signup and view all the answers

    Which of the following is NOT a notable characteristic of Staphylococcus aureus on blood agar?

    <p>Small colonies</p> Signup and view all the answers

    Staphylococcus aureus infections can lead to sepsis.

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

    What percentage of people are likely to carry Staphylococcus aureus in their nose or on their skin?

    <p>10 - 40%</p> Signup and view all the answers

    Which of the following is associated with catalase-negative bacteria?

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

    All strains of Staphylococcus are catalase-positive.

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

    What is the primary identifying feature of Enterococcus species?

    <p>They are catalase-negative and often found in chains.</p> Signup and view all the answers

    The ______ are known for their role in causing pneumonia.

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

    Which group is associated with enterococcus species?

    <p>Gamma-hemolytic</p> Signup and view all the answers

    Match the following bacteria with their characteristics:

    <p>Streptococcus pyogenes = Beta-hemolytic Staphylococcus aureus = Catalase positive Streptococcus viridans = Alpha-hemolytic Enterococcus = Gamma-hemolytic</p> Signup and view all the answers

    Staphylococcus saprophyticus is commonly found in urine infections.

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

    What characterizes the group D streptococci?

    <p>They are often associated with enterococcus species.</p> Signup and view all the answers

    What type of stain is used to differentiate between Gram-positive and Gram-negative bacteria?

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

    Gram-positive bacteria will appear pink after the Gram staining process.

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

    What is the purpose of a wet mount in microscopic examination?

    <p>To observe motility.</p> Signup and view all the answers

    The ___ stain is used to detect Mycobacterium species.

    <p>Acid fast</p> Signup and view all the answers

    Match the following types of bacteria with their characteristics:

    <p>Cocci = Spherical shape Bacillus = Rod shape Coccobacillus = Short, rounded rod Pleomorphic = Variable shape</p> Signup and view all the answers

    What is the role of the iodine in the Gram staining process?

    <p>Crystal violet fixative</p> Signup and view all the answers

    Colony morphology is usually definitive for bacterial identification.

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

    What are the two main groups of bacteria determined by Gram staining?

    <p>Gram-positive and Gram-negative</p> Signup and view all the answers

    What is the dilution ratio used in the serial dilutions starting from the tube labeled '8 μg/ml'?

    <p>2-fold</p> Signup and view all the answers

    The Minimum Bactericidal Concentration (MBC) is defined as the lowest concentration of antimicrobial that inhibits 99.9% of bacteria.

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

    What is the optimal inoculum concentration needed for testing bacterial susceptibility?

    <p>10^5 to 10^6 cells/ml</p> Signup and view all the answers

    The breakpoint is the cutoff MIC that determines if bacteria are ____, ____, or ____.

    <p>susceptible, intermediate, resistant</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>S = Susceptible I = Intermediate R = Resistant MIC = Minimum Inhibitory Concentration</p> Signup and view all the answers

    Which of the following concentrations represents the highest dilution in the prepared series?

    <p>0.06 μg/ml</p> Signup and view all the answers

    Adding 1 ml of bacterial suspension to each tube prepared is necessary for determining the Minimum Inhibitory Concentration (MIC).

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

    What concentration is defined as 5 x 10^9 cells/ml in the dilution process?

    <p>5 x 10^7 cells/ml and then 5 x 10^5 cells/ml</p> Signup and view all the answers

    Which of the following statements accurately describes Listeria monocytogenes?

    <p>Hippurate positive and bile-esculin positive</p> Signup and view all the answers

    Haemophilus influenzae is a motile organism.

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

    What are the two main types of Listeria monocytogenes strains based on encapsulation?

    <p>Typeable strains and non-typeable strains</p> Signup and view all the answers

    Listeria monocytogenes exhibits _____ motility.

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

    Match the following Haemophilus species with their characteristics:

    <p>H. influenzae = Causes respiratory infections in children H. parainfluenzae = Normal resident of the upper respiratory tract Haemophilus = Blood-loving organism H. ducreyi = Causes chancroid</p> Signup and view all the answers

    Which of the following is a major virulence factor for strains of H. influenzae causing invasive disease?

    <p>Polysaccharide capsule</p> Signup and view all the answers

    Bacitracin is a reliable test to distinguish Listeria from Streptococcus.

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

    What is the primary mode of transmission for H. influenzae infections?

    <p>Inhalation of aerosolized respiratory droplets</p> Signup and view all the answers

    Which bacterium is associated with causing diphtheria?

    <p>Corynebacterium diphtheriae</p> Signup and view all the answers

    Moraxella catarrhalis can grow on Nutrient agar.

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

    What is the primary virulence factor of Corynebacterium diphtheriae?

    <p>AB exotoxin</p> Signup and view all the answers

    Neisseria lactamica can grow on CA and BA but not on _____ agar.

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

    Match the following bacterial species with their characteristics:

    <p>Neisseria lactamica = Tends to be non-pathogenic, can ferment glucose and lactose Corynebacterium diphtheriae = Causes diphtheria, produces exotoxin Moraxella catarrhalis = Grows on various agars, distinct 'hockey puck' appearance Listeria = Facultative anaerobic, can cause foodborne illness</p> Signup and view all the answers

    Which statement is true regarding the characteristics of Corynebacterium species?

    <p>They form club-shaped structures and can show palisade arrangements.</p> Signup and view all the answers

    Neisseria lactamica and Corynebacterium diphtheriae are both motile bacteria.

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

    What kind of oxygen requirement do Corynebacterium and Listeria species have?

    <p>Facultative anaerobes</p> Signup and view all the answers

    Corynebacterium diphtheriae can result in the formation of a _____ in the throat.

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

    Which of the following may be used to differentiate between Corynebacterium species?

    <p>Sugar fermentation patterns</p> Signup and view all the answers

    Study Notes

    Course Information

    • Course name: Microm 443
    • Instructors: Kendall M. Gray, Ph.D., Rebecca Rashid Achterman, Ph.D., and Mira Beins, Ph.D.
    • Department: Microbiology
    • Course components: Lectures and Lab
    • Schedule available in lab manual; required
    • Course website: schedule, lecture outlines, announcements, grading system, videos (required), and optional resources.
    • Required textbook: Sherris' Medical Microbiology (online, Canvas link)
    • Additional resources: Photographic Atlas for the Microbiology Lab, and Gram Stain Tutor (Canvas)

    Course Purpose

    • Learn to identify causative agents of bacterial infections
    • Understand treatment approaches and surveillance methods for bacteria
    • Understand importance of microbial identification

    Lab Information

    • Lab sessions are held.
    • If no lecture, lab is still mandatory.
    • Lab safety procedures are essential and outlined in lab manual

    General Course Information

    • Course meets at 11:30 am.
    • Lab work occurs on specific days
    • Lab schedule includes specific procedures for different weeks and specific pages in manual
    • Quizzes occur every week, with best 6/7 used for grade (20-25% of final grade)
    • Quizzes are cumulative
    • Unknowns (7 + differentiation scheme, 2-3 pts each; ~10-15% of final grade)
    • Lots of help for early unknowns.
    • Midterm (~20-25% of final grade)
    • Final (~40-50% of final grade).

    Safety

    • Working with pathogens (BSL-2)
    • Standard lab safety procedures required and included in the lab manual
    • Proper aseptic techniques are essential.
    • Infectious dose (ID50) of Shigella species: 10-100 cells
    • Avoid aerosols
    • Safety quiz due week 2 (Monday) on-line with questions on last page of the lab manual.
    • Alcohol swabs.

    Microbiology Information Overview

    • Identifying Bacteria, What is a clinical specimen?, and Basic Microscopy
    • Microscopic exam of clinical specimens involves identifying host cells (WBC, epithelial) and bacterial cells (size, shape, grouping).
    • Identification follows with culture methods..
    • Culture → identification: cultivating bacteria, microscopic exam of pure culture, and identification.
    • Colony morphology for a clue.
    • Microscopic examinations: wet mount - simple, for motility, dark field - enhances light field, and Gram stain - differential stain
    • Gram-positive cells stain purple.
    • Gram-negative cells become colorless.
    • Cyto. membrane, Peptidoglycan, Over-decolonized, Outer Membrane..
    • Gram- positive cocci (GPC), Gram-negative cocci (GNDC). shape diagrams are provided
    • Gram-positive and gram-negative rods
    • Types of rods include pleomophic, curved rods, and coccobacilli.

    Microbial Techniques

    • Dark field (earlier described)
    • Methylene blue staining for observation of metachromatic granules
    • Capsule staining using negative staining
    • Acid fast staining detects Mycobacterium spp. (pathogens like M. tuberculosis)
    • Fluorescence tagging: antibody and/or nucleic acid probes

    Media Identification

    • Routine media (TSY, Nutrient agar, and Mueller-Hinton): support many bacterial types
    • Blood agar: 5% sheep blood for increased growth.
    • Chocolate agar: lysed blood cells to support growth
    • MacConkey (selective): inhibits all except intestinal GNR
    • Differential media: ex. blood agar
    • hemolysis
    • MacConkey: lactose fermentation
    • Other Media for specific organisms

    Bacterial Identification

    • Genus and species identification from phenotypic (observable) characteristics
    • Examples: Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, MRSA ,E. coli.
    • Various characteristic of each listed above, including testing methods.

    Antimicrobial drugs

    • Determining the susceptibility of an organism to different drugs
    • Minimum inhibitory concentration (MIC) method: broth dilution
    • Kirby-Bauer disk diffusion

    Additional Notes

    • Student evaluations support the excellent structure of the course, emphasizing the repeated use of the skills learned in the first half of the quarter.
    • Various aspects of procedures, specimens, and testing methods

    Additional Microbial Procedures

    • Cultivating bacteria, including proper technique -Different environments for incubation -Incubation time (35°C, increased CO2) and materials, such as candle jars, and anaerobic pouches or boxes for specific oxygen requirements. -various media options such as blood agar and MacConkey media.
    • Methods of culturing bacteria such as the streak plate technique
    • Various testing methods - Gram strains, methods on plates for various organisms.

    Additional Bacterial Specifics and Identification

    • Different bacterial species and identification methods
    • examples included: Corynebacterium diphtheriae, Listeria monocytogenes, Haemophilus influenzae, Neisseria gonorrhoeae, Neisseria meningitidis, and various others
    • Specific tests and characteristics for each bacterium are given

    Other Notes

    • Various aspects of procedures, specimens, and testing methods are presented in the provided notes to aid students with study and lab endeavors

    Lab Information to include

    • Using pipettes (1ml and 5ml varieties)
    • Using lab racks, as needed.

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    Micro 443 Combined PDF

    Description

    Test your knowledge on Staphylococcus aureus and its role in infections. This quiz covers various aspects such as characteristics, infections, and identification of this bacterium. Ideal for students studying microbiology or healthcare professionals.

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