Microbiology Staphylococcus Overview
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Questions and Answers

What percentage of healthy individuals typically carry staphylococci in the nose?

  • About 10–30% (correct)
  • About 1–5%
  • About 60–70%
  • About 40–50%

    • What is the percentage of vaginal carriage of staphylococci in healthy women under normal conditions?

  • 5–10% (correct)
  • 0–2%
  • 15–20%
  • 25–30%

    • During which condition does the vaginal carriage of staphylococci increase significantly?

  • After childbirth
  • Postmenopause
  • While on antibiotics
  • During menses (correct)

    • How is the vaginal carriage of staphylococci relevant to TSS (Toxic Shock Syndrome)?

    <p>It contributes to the pathogenesis of TSS during menstruation</p> Signup and view all the answers

    What is the implication of healthy individuals carrying staphylococci in their noses?

    <p>They are carriers without showing symptoms</p> Signup and view all the answers

    What characteristic do cloxacillin, oxacillin, flucloxacillin, and methicillin share?

    <p>They are penicillinase resistant penicillins.</p> Signup and view all the answers

    Which type of bacteria is specifically noted for being resistant to methicillin?

    <p>Methicillin-resistant Staphylococcus aureus (MRSA)</p> Signup and view all the answers

    Besides methicillin, which other antibiotics are MRSA known to be resistant to?

    <p>Other penicillins and cephalosporins</p> Signup and view all the answers

    What is the primary clinical significance of penicillinase resistant penicillins?

    <p>They are useful in treating infections caused by penicillinase-producing bacteria.</p> Signup and view all the answers

    Which of the following bacteria is associated with the genus Brucella?

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

    What type of organism is Legionella pneumophila?

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

    How are penicillinase resistant penicillins such as oxacillin and flucloxacillin used in clinical practice?

    <p>To treat infections where resistance to common penicillins is suspected.</p> Signup and view all the answers

    Which environmental code is associated with Pasteurella?

    <p>1-1-4</p> Signup and view all the answers

    Which of the following bacteria is NOT included in the list: Brucella, Pasteurella, Francisella?

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

    What disease is primarily caused by Legionella pneumophila?

    <p>Legionnaires' disease</p> Signup and view all the answers

    What type of disease is indicated by the information provided?

    <p>Autoimmune disease</p> Signup and view all the answers

    What is believed to cause the disease mentioned?

    <p>Cross-reactive components of bacteria and host tissues</p> Signup and view all the answers

    Which component of the immune system is involved in the pathogenesis of the disease?

    <p>T lymphocytes</p> Signup and view all the answers

    What role do antibodies play in this disease?

    <p>They are involved in the autoimmune response</p> Signup and view all the answers

    Which type of M types is associated with the disease?

    <p>Specific M types</p> Signup and view all the answers

    What is one way Acute Poststreptococcal Glomerulonephritis (AGN) differs from rheumatic fever?

    <p>AGN can develop after a skin infection.</p> Signup and view all the answers

    Which infection is primarily associated with the onset of rheumatic fever?

    <p>Pharyngeal infection</p> Signup and view all the answers

    Which scenario would likely NOT lead to Acute Poststreptococcal Glomerulonephritis?

    <p>A patient recovering from a viral infection.</p> Signup and view all the answers

    Which of the following statements about Acute Poststreptococcal Glomerulonephritis is accurate?

    <p>It can follow both pharyngeal and skin infections.</p> Signup and view all the answers

    What type of infection is NOT a known trigger for Acute Poststreptococcal Glomerulonephritis?

    <p>Bacterial eye infection</p> Signup and view all the answers

    Which DNA virus is primarily responsible for causing smallpox?

    <p>Smallpox virus</p> Signup and view all the answers

    What type of virus is the Herpes virus classified as?

    <p>DNA virus</p> Signup and view all the answers

    Which of the following viruses is NOT classified under DNA viruses?

    <p>Influenza virus</p> Signup and view all the answers

    Which virus is associated with cervical cancer due to its role in causing cellular changes?

    <p>Human Papillomavirus (HPV)</p> Signup and view all the answers

    Which DNA virus is commonly researched for genetic engineering applications due to its simple structure?

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

    Study Notes

    Gram Positive Cocci

    • Gram-positive cocci are spherical bacteria arranged in clusters.
    • They are non-spore forming, non-motile, and usually non-encapsulated.
    • Key species include:
      • Staphylococcus aureus: Coagulase-positive, significant pathogen.
      • Coagulase-negative staphylococci (CNS): S. epidermidis and S. saprophyticus.
    • Resistance:
      • S. aureus and other Micrococcaceae are highly resistant, often viable for 3-6 months.
      • Many strains can grow with 10% NaCl.

    Staphylococcal Toxins and Enzymes

    • Staphylococcus aureus virulence is due to various toxins and enzymes.
    • Toxins:
      • Cytolytic toxins (e.g., alpha, beta, gamma, delta hemolysins, leukocidin).
      • Enterotoxins (cause food poisoning).
      • Toxic Shock Syndrome Toxin-1 (TSST-1).
      • Epidermolytic toxins (cause scalded skin syndrome).
    • Enzymes:
      • Coagulase.
      • Catalase.
      • Hyaluronidase.
      • Fibrinolysin.
      • Lipases.
      • Nucleases.
      • Penicillinase.

    Staphylococcal Diseases

    • Cutaneous infections: Boils, furuncles, carbuncles, impetigo, wound infections.
    • Deep infections: Osteomyelitis, periostitis, tonsillitis, pharyngitis, sinusitis, other organ abscesses, septicemia.
    • Toxin-mediated diseases:
      • Food poisoning (faulty food with S. aureus containing toxin).
      • Toxic shock syndrome (TSS) (associated with tampon use).
      • Scalded skin syndrome

    Coagulase-Negative Staphylococci

    • S. epidermidis and S. saprophyticus are commonly found on human skin.
    • Opportunistic pathogens, causing infections in immunocompromised individuals, often associated with foreign bodies.
    • Urinary tract infections and other infections, such as endocarditis, are connected to these species.
    • Resistance to novobiocin distinguishes S. saprophyticus from S. epidermidis.
    • These organisms don't ferment glucose anaerobically.

    Methicillin-Resistant Staphylococcus aureus (MRSA)

    • MRSA isolates are resistant to methicillin and other beta-lactam antibiotics.
    • Frequent in hospitals and community settings due to overuse of antibiotics.
    • Important cause of infections in individuals with compromised immune systems.

    Treatment and Control

    • S. aureus: Benzylpenicillin (if sensitive), oxacillin, cloxacillin, Vancomycin, Glycopeptides (for severe infections).
    • Control:
      • Drain abscesses, prevent infection spread (e.g via hand washing).

    Streptococcus Species

    • Major bacterial species include:
      • Streptococcus pyogenes (Group A).
      • Streptococcus agalactiae (Group B).
      • Streptococcus Pneumoniae
      • Viridans streptococci.
      • Enterococcus faecalis (Group D).

    Streptococcal Diseases

    • Streptococcus pyogenes illnesses: Sore throat, scarlet fever, rheumatic fever, acute poststreptococcal glomerulonephritis (AGN), skin and soft tissue infections.
    • Streptococcus agalactiae (Group B Strep): Neonatal sepsis, pneumonia, meningitis.

    Pneumococcal Diseases

    • Streptococcus pneumoniae: Pneumonia (lobar, broncho), meningitis, bacteremia.

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    Related Documents

    Medical Microbiology Lecture 1 - Gram Positive Cocci PDF

    Description

    Explore the fascinating world of Gram-positive cocci, specifically focusing on Staphylococcus species. This quiz covers their characteristics, resistance mechanisms, and the various toxins and enzymes associated with Staphylococcus aureus. Test your knowledge and understanding of these important microbiological topics.

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