Microbiology SLP -2.4
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Questions and Answers

Which of the following statements about Porphyromonas catoniae is true?

  • It is present in healthy gingiva. (correct)
  • It commonly contributes to atypical pneumonia.
  • It is a member of the orange complex.
  • It is typically found in periodontal disease.
  • What is the primary disease associated with Legionella pneumophila?

  • Atypical pneumonia (correct)
  • Tuberculosis
  • Leprosy
  • Perio disease
  • Which Prevotella species is known to be associated with periodontal disease?

  • Prevotella nigrescens
  • Prevotella buccalis
  • Prevotella melaninogenica
  • Prevotella intermedia (correct)
  • Which Mycobacterium species is primarily linked to leprosy?

    <p>Mycobacterium leprae</p> Signup and view all the answers

    What is the only member of the genus Leptotrichia?

    <p>Leptotrichia buccalis</p> Signup and view all the answers

    What is the primary organism responsible for infections in neonates as indicated by its classification?

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

    Which species is known to cause enamel demineralization?

    <p>Actinomyces odontolyticus</p> Signup and view all the answers

    Which of the following organisms is part of the Neisseriaceae family associated with gonorrhea?

    <p>Neisseria gonorrhoeae</p> Signup and view all the answers

    Which group of bacteria is commonly associated with gas gangrene?

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

    Which organism is classified as a commensal species that can exhibit pathogenic behavior under certain conditions?

    <p>Bacteroides fragilis</p> Signup and view all the answers

    What is the significant pathogenic feature of Streptococcus pyogenes?

    <p>It can cause rheumatic fever</p> Signup and view all the answers

    What type of bacteria are typically recognized as obligate anaerobes?

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

    Which species of Neisseria is associated with meningitis?

    <p>Neisseria meningitidis</p> Signup and view all the answers

    Study Notes

    Streptococci

    • Streptococcus pyogenes - Group A
    • Streptococcus agalactiae - Group B
      • Found in the female genital tract and can cause infection in neonates
    • Group C strains cause disease in animals
    • Enterococci - Group D
    • Produces toxins: streptolysin O, streptolysin S, hyaluronidase, streptokinase, erythrogenic toxin
    • Pathogenicity: causes pharyngitis (Strep throat), scarlet fever, cellulitis, impetigo, necrotising fasciitis, toxic shock
    • Complications: rheumatic fever, acute glomerulonephritis
    • Treatment: penicillin
    • Streptococcus agalactiae (Group B) causes meningitis, septicaemia, pneumonia in neonates
    • Treatment: penicillin

    Oral Streptococci

    • Include: Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguinis, Streptococcus salivarius, Streptococcus mitis
    • Can cause infective endocarditis (viridans streptococci) if they enter the bloodstream

    Staphylococci

    • Staphylococcus aureus: commonly found on skin and mucous membranes
      • Produces: coagulase, hyaluronidase, lipase, protease, hemolysin, enterotoxins
    • Staphylococcus epidermidis: part of the normal skin flora
      • Can cause infections if the immune system is compromised
    • Pathogenicity: causes boils, abscesses, cellulitis, food poisoning, impetigo, toxic shock syndrome
    • Treatment: methicillin, vancomycin, linezolid

    Enterococci

    • Eg enterococcus faecalis
    • Pathogenicity: causes urinary tract infections, endocarditis, wound infections
    • Treatment: vancomycin, linezolid

    Actinomycetes

    • Types: Actinomyces israelii, Actinomyces odontolyticus
    • Actinomyces odontolyticus can cause enamel demineralisation
    • Actinomyces israelii: part of the normal oral flora
    • Pathogenicity: causes actinomycosis, a chronic infection that can affect various tissues
      • Characterized by abscesses and draining tracts
    • Types: Actinomyces israelii, A. naeslundii, A. viscosus
    • Treatment: penicillin, surgical drainage

    Clostridia

    • Types: Clostridium tetani, Clostridium botulinum, Clostridium perfringens
    • Clostridium tetani: causes tetanus
    • Clostridium botulinum: produces botulinum toxin, causing botulism
      • Pathogenicity: affects the nervous system, causing paralysis
    • Clostridium perfringens: causes gas gangrene
      • Pathogenicity: releases toxins that damage tissue
    • Treatment of gas gangrene: surgical debridement, hyperbaric oxygen therapy, antibiotics
    • Clostridium difficile: causes pseudomembranous colitis
      • Pathogenicity: produces toxins that disrupt the intestinal lining
    • Treatment: metronidazole, vancomycin

    Bacillus

    • Types: Bacillus anthracis, Bacillus cereus
    • Bacillus anthracis: causes anthrax
      • Pathogenicity: produces toxins that cause severe disease
    • Bacillus cereus: causes food poisoning
      • Pathogenicity: produces emetic toxin and diarrheal toxin

    Neisseriaceae

    • Types: Neisseria gonorrhoeae, Neisseria meningitidis
    • Neisseria gonorrhoeae (the gonococcus): causes gonorrhea
    • Pathogenicity of gonococci: causes urethritis, cervicitis, pelvic inflammatory disease
    • Treatment: ceftriaxone
    • Neisseria meningitidis (the meningococcus): causes meningococcal meningitis
    • Pathogenicity: causes fever, headache, stiff neck, rash, shock
    • Treatment: penicillin

    Commensal Species

    • Types: Staphylococcus epidermidis, Streptococcus salivarius, Lactobacillus spp., Corynebacterium spp.
    • Aerobic → facultative anaerobes → obligate anaerobes

    Enterobacteria

    • Types: Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Salmonella enterica, Shigella dysenteriae
    • Pathogenicity: causes urinary tract infections, pneumonia, septicaemia, gastroenteritis
    • Treatment: ciprofloxacin, ceftriaxone

    Bacteroides

    • Bacteroides fragilis: found in the gut
    • Pathogenicity: causes abscesses, peritonitis
    • Treatment: metronidazole

    Porphyromonas

    • Porphyromonas gingivalis: associated with periodontal disease
    • Pathogenicity: releases enzymes that degrade tissues and cause inflammation
      • Involved in the formation of periodontal pockets
    • Red complex = Porphyromonas gingivalis + Tannerella forsythia + Trepinema denticola
    • Porphyromonas catoniae: found in healthy gingiva

    Prevotella

    • Prevotella spp.: found in the oral cavity
    • Prevotella nigrescens: found in healthy gingiva
    • Prevotella intermedia: associated with periodontitis (orange complex)

    Fusobacterium

    • Types: Fusobacterium nucleatum, Fusobacterium necrophorum
    • Pathogenicity: associated with periodontitis, abscesses, and other infections
    • Treatment: metronidazole

    Spirochaetes

    • Types: Treponema pallidum, Trepinema denticola
    • Treponema pallidum: causes syphilis

    Leptotrichia

    • Leptotrichia buccalis: the only member of the genus
    • Found in the oral cavity

    Mycobacteria

    • Types: Mycobacterium tuberculosis, Mycobacterium bovis, Mycobacterium leprae
    • Mycobacterium tuberculosis: causes tuberculosis
    • Pathogenicity: infects the lungs leading to coughing, fever, weight loss
    • Treatment: isoniazid, rifampicin, pyrazinamide, ethambutol
    • Mycobacterium bovis: causes bovine tuberculosis
    • Mycobacterium leprae: causes leprosy
      • Pathogenicity: causes skin lesions, nerve damage, muscle weakness
      • Types: Lepromatous leprosy (multibacillary) and tuberculoid leprosy (paucibacillary)
    • Treatment: dapsone, rifampicin, clofazimine

    Mycobacteria Other Than TB

    • Types: Mycobacterium avium complex (MAC), Mycobacterium kansasii, Mycobacterium marinum
    • Pathogenicity: can cause infections in immunocompromised individuals

    Legionella

    • Most important is legionella pneumophila - causes atypical pneumonia (common in hospitals)
    • Legionella pneumophila: found in water sources
      • Pathogenicity: causes Legionnaire's disease
    • Treatment: azithromycin, levofloxacin

    Mycoplasmas

    • Mycoplasma pneumoniae: a common cause of pneumonia
    • Pathogenicity: causes mild pneumonia, bronchitis
    • Treatment: doxycycline, azithromycin

    Oral Mycoplasmas

    • Types: Mycoplasma salivarium, Mycoplasma orale, Mycoplasma hominis

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    Description

    Explore the fascinating world of Streptococci and Staphylococci in this microbiology quiz. Learn about various groups, their pathogenicity, treatments, and complications associated with infections. Test your knowledge on their role in human health and disease.

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