Microbiology SLP - 24
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Questions and Answers

Which species is found in healthy gingiva?

  • Tannerella forsythia
  • Porphyromonas gingivalis
  • Trepinema denticola
  • Prevotella nigrescens (correct)

    • Which of the following is known to cause atypical pneumonia?

  • Porphyromonas catoniae
  • Mycobacterium bovis
  • Mycoplasma pneumoniae
  • Legionella pneumophila (correct)

    • What is the only member of the Leptotrichia genus?

  • Leptotrichia sanguinis
  • Leptotrichia anaerobica
  • Leptotrichia buccalis (correct)
  • Leptotrichia melatonia

    • Which Prevotella species is associated with periodontal disease?

    <p>Prevotella intermedia</p> Signup and view all the answers

    Which Mycobacterium species is classified as a causative agent of leprosy?

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

    Which group of streptococci is specifically associated with infections in the female genital tract leading to neonatal infections?

    <p>Group B - streptococcus agalactiae</p> Signup and view all the answers

    What is a characteristic pathogenic feature of viridans streptococci?

    <p>Leads to infective endocarditis when entering the bloodstream</p> Signup and view all the answers

    Identify the organism that causes enamel demineralisation.

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

    Which pathogenic feature is unique to Neisseria meningitidis?

    <p>Can lead to bacterial meningitis</p> Signup and view all the answers

    What type of pathogenicity is associated with Clostridia?

    <p>Produces enterotoxins leading to gastrointestinal diseases</p> Signup and view all the answers

    Which of the following treatments is applicable to Bacteroides fragilis?

    <p>Broad-spectrum antibiotics</p> Signup and view all the answers

    Which group of streptococci is responsible for causing diseases in animals?

    <p>Group C - streptococcus species</p> Signup and view all the answers

    Which of the following is a commensal species of the Neisseriaceae family?

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

    Which species is associated with the orange complex of periodontal pathogens?

    <p>Prevotella intermedia</p> Signup and view all the answers

    What is the primary pathogenicity of Mycobacterium tuberculosis?

    <p>Causes respiratory infections</p> Signup and view all the answers

    Which of the following statements accurately describes Legionella pneumophila?

    <p>It is the primary causative agent of atypical pneumonia in hospitals.</p> Signup and view all the answers

    Which of the following species is exclusively known for being the sole representative of its genus?

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

    Which transmission route is predominantly associated with Mycoplasma pneumoniae infections?

    <p>Airborne transmission</p> Signup and view all the answers

    Which group of streptococci is known for causing infections specifically in neonates?

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

    What is a consequence of the pathogenicity of viridans streptococci?

    <p>Bacteraemia leading to infective endocarditis</p> Signup and view all the answers

    Which organism is associated with enamel demineralisation?

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

    Which species is responsible for gas gangrene?

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

    What is the primary pathogenic feature of Neisseria gonorrhoeae?

    <p>Causes sexually transmitted infections</p> Signup and view all the answers

    What distinguishes enterococci from other groups of streptococci?

    <p>They can grow in high salt concentrations</p> Signup and view all the answers

    Which type of bacterium is Bacillus cereus primarily associated with?

    <p>Food poisoning</p> Signup and view all the answers

    Which group of bacteria is characterized by being facultative anaerobes?

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

    Study Notes

    Streptococci

    • Group A: Streptococcus pyogenes.
    • Group B: Streptococcus agalactiae, found in the female genital tract and can cause infections in neonates.
    • Group C: Causes diseases in animals.
    • Group D: Enterococci.

    Streptococcus pyogenes

    • Produces:
      • Streptolysins O and S (hemolysins).
      • Hyaluronic acid capsule.
      • M protein (anti-phagocytic).
      • Erythrogenic toxins (cause scarlet fever).
    • Pathogenicity:
      • Causes strep throat (pharyngitis).
      • Can cause scarlet fever, impetigo, cellulitis, erysipelas, and necrotizing fasciitis.
    • Complications:
      • Rheumatic fever.
      • Glomerulonephritis.
    • Treatment:
      • Penicillin.
      • Erythromycin.

    Streptococcus agalactiae

    • Can cause:
      • Neonatal sepsis.
      • Meningitis.
      • Pneumonia.
    • Treatment:
      • Intravenous penicillin.
      • Ampicillin.
      • Vancomycin.

    Oral Streptococci

    • Can include:
      • Viridans streptococci (e.g., Streptococcus mutans, Streptococcus sanguinis).
      • Streptococcus salivarius.
      • Streptococcus mitis.
    • Viridans streptococci can enter the bloodstream (bacteremia) and cause infective endocarditis.

    Staphylococci

    • Types:
      • Staphylococcus aureus.
      • Staphylococcus epidermidis.
    • Staphylococcus aureus:
      • Produces:
        • Coagulase enzyme.
        • Toxins:
          • Alpha-toxin (hemolysin).
          • Beta-toxin (hemolysin).
          • Enterotoxins (cause food poisoning).
          • Toxic shock syndrome toxin (TSST-1).
      • Pathogenicity:
        • Can cause skin infections (folliculitis, boils, carbuncles, impetigo, cellulitis).
        • Can cause pneumonia, endocarditis, osteomyelitis, toxic shock syndrome, and food poisoning.
    • Treatment:
      • Methicillin-sensitive strains:
        • Flucloxacillin.
        • Cefalexin.
      • Methicillin-resistant strains:
        • Vancomycin.
        • Linezolid.
    • Staphylococcus epidermidis:
      • Can cause:
        • Biofilm formation on indwelling catheters and implants.
        • Infections associated with the bloodstream, urinary tract, bones, and joints.
    • Treatment:
      • Vancomycin.

    Enterococci

    • Example: Enterococcus faecalis
    • Pathogenicity:
      • Often associated with nosocomial infections (hospital-acquired).
      • Can cause urinary tract infections, bacteremia, endocarditis, and wound infections.
    • Treatment:
      • Often resistant to multiple antibiotics.
      • Vancomycin is often used.

    Actinomycetes

    • Types:
      • Actinomyces israelii.
      • Actinomyces odontolyticus.
    • Actinomyces odontolyticus:
      • Can cause enamel demineralization.
    • Actinomyces israelii:
      • Can cause:
        • Lumpy jaw (actinomycosis) in cattle.
        • Actinomycosis in humans, often affecting the head and neck.
    • Treatment:
      • Penicillin.
      • Long-term treatment may be required.

    Clostridia

    • Types:
      • Clostridium perfringens.
      • Clostridium tetani.
      • Clostridium botulinum.
    • Clostridium perfringens:
      • Produces:
        • Alpha-toxin (lecithinase).
        • Other toxins including:
          • Theta-toxin.
          • Kappa-toxin.
        • Can cause:
          • Gas gangrene.
          • Food poisoning.
    • Treatment of gas gangrene:
      • Debridement (surgical removal of infected tissue).
      • Antitoxin.
      • Antibiotics (penicillin).
    • Clostridium tetani:
      • Produces tetanus toxin.
      • Can cause tetanus (lockjaw).
    • Clostridium botulinum:
      • Produces botulinum toxin.
      • Can cause botulism (food poisoning).
    • Treatment of botulism:
      • Antitoxin.
      • Supportive care.

    Bacillus

    • Types:
      • Bacillus anthracis.
      • Bacillus cereus.
    • Bacillus anthracis:
      • Produces lethal toxin, edema toxin, capsule.
      • Can cause anthrax, a serious infectious disease affecting animals and humans.
    • Bacillus cereus:
      • Can cause:
        • Food poisoning (diarrhea or vomiting type).

    Neisseriaceae

    • Types:
      • Neisseria gonorrhoeae.
      • Neisseria meningitidis.
      • Commensal species.
    • Neisseria gonorrhoeae (gonococcus):
      • Can cause:
        • Gonorrhea (sexually transmitted infection).
      • Pathogenicity:
        • Can cause:
          • Urethritis.
          • Cervicitis.
          • Pelvic inflammatory disease.
          • Meningitis.
          • Arthritis.
      • Treatment:
        • Ceftriaxone.
        • Azithromycin.
    • Neisseria meningitidis (meningococcus):
      • Can cause:
        • Meningitis.
        • Septicemia.
    • Pathogenicity:
      • Produces endotoxin.
      • Can cause:
        • Meningitis (inflammation of the meninges).
        • Septicemia (blood infection).
    • Treatment:
      • Penicillin.
      • Ceftriaxone.

    Commensal Species

    • Types:
      • Neisseria lactamica.
      • Moraxella catarrhalis.

    Enterobacteria

    • Types:
      • Escherichia coli.
      • Salmonella spp.
      • Shigella spp.
      • Klebsiella spp.
      • Proteus spp.
      • Serratia spp.
      • Yersinia spp.
    • Pathogenicity:
      • Can cause:
        • Urinary tract infections.
        • Gastroenteritis.
        • Pneumonia.
        • Sepsis.
        • Meningitis.
    • Treatment:
      • Fluoroquinolones.
      • Cephalosporins.
      • Aminoglycosides.

    Bacteroides

    • Bacteroides fragilis:
      • Can cause:
        • Abscesses.
        • Peritonitis.
      • Pathogenicity:
        • Produces capsular polysaccharide A (PSA), which helps evade the immune system.
      • Treatment:
        • Metronidazole.
        • Clindamycin.

    Porphyromonas

    • Porphyromonas gingivalis:
      • Can cause:
        • Periodontitis.
      • Pathogenicity:
        • Produces:
          • Gingipains (proteases that degrade host tissue).
          • Lipopolysaccharide (LPS) (endotoxin).
        • Involved in the Red complex, alongside Tannerella forsythia and Treponema denticola.
    • Porphyromonas catoniae:
      • Found in healthy gingiva.

    Prevotella

    • Prevotella spp.:
      • Can cause:
        • Periodontitis.
    • Prevotella intermedia:
      • Found in the orange complex, associated with periodontitis.
    • Prevotella nigrescens:
      • Found in healthy gingiva.

    Fusobacterium

    • Types:
      • Fusobacterium nucleatum.
      • Fusobacterium necrophorum.
    • Pathogenicity:
      • Can cause:
        • Periodontitis.
        • Abscesses.
      • Involved in the orange complex, alongside Prevotella intermedia and Tannerella forsythia.
    • Treatment:
      • Metronidazole.

    Spirochaetes

    • Types:
      • Treponema denticola (associated with the Red complex).
      • Borrelia burgdorferi (causes Lyme disease).

    Leptotrichia

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

    Mycobacteria

    • Types:
      • Mycobacterium tuberculosis.
      • Mycobacterium bovis.
      • Mycobacterium leprae.
      • Mycobacteria other than TB (MOTT).

    Mycobacterium tuberculosis

    • Can cause tuberculosis (TB):
      • A serious infectious disease that primarily affects the lungs.
    • Pathogenicity:
      • Produces:
        • Cord factor (allows bacteria to clump together, evading immune system).
        • Mycolic acids (make the cell wall resistant to harsh conditions).
    • Treatment:
      • Multidrug therapy is required:
        • Isoniazid, rifampin, pyrazinamide, ethambutol.
      • Long-term treatment for 6-24 months.
    • Resistance to antibiotics is a major concern.

    Mycobacterium bovis

    • Can cause TB in cattle.
    • Zoonotic, meaning it can be transmitted to humans.

    Mycobacterium leprae

    • Can cause leprosy (Hansen's disease).
    • A chronic disease that affects the skin, peripheral nerves, upper respiratory tract, eyes, and testes.
    • Pathogenicity:
      • Has a slow growth rate.
      • Intracellular parasite, residing in macrophages.
    • Treatment:
      • Multidrug therapy is required:
        • Dapsone, rifampin, clofazimine.
      • Long-term treatment for several years.

    Mycobacteria other than TB (MOTT)

    • Types:
      • Mycobacterium avium complex (MAC).
      • Mycobacterium kansasii.
      • Mycobacterium marinum.
      • Mycobacterium abscessus.
    • Pathogenicity:
      • Can cause a variety of infections, including:
        • Pulmonary disease.
        • Skin infections.
        • Lymphadenitis.
        • Osteomyelitis.

    Legionella

    • Legionella pneumophila:
      • Can cause Legionnaires' disease, a type of atypical pneumonia.
      • Common in hospitals.
    • Pathogenicity:
      • Can survive in water systems.
      • Found in:
        • Air conditioning systems.
        • Cooling towers.
        • Hot tubs.
    • Treatment:
      • Macrolides (e.g., azithromycin).
      • Quinolones (e.g., levofloxacin).

    Mycoplasmas

    • Types:
      • Mycoplasma pneumoniae.
      • Oral Mycoplasmas.

    Mycoplasma pneumoniae

    • Can cause:
      • Walking pneumonia (a mild type of pneumonia).
    • Pathogenicity:
      • Lacks a cell wall, making it resistant to antibiotics that target cell wall synthesis.
      • Attaches to respiratory epithelial cells, leading to inflammation.
    • Treatment:
      • Macrolides (e.g., azithromycin).
      • Tetracyclines (e.g., doxycycline).

    Oral Mycoplasmas

    • Examples:
      • Mycoplasma salivarium.
      • Mycoplasma hominis.
      • Mycoplasma orale.
      • Mycoplasma fermentans.
      • Mycoplasma genitalium.
    • Found in the mouth and throat.
    • May play a role in oral infections.

    Streptococci

    • Group A streptococci are known as Streptococcus pyogenes
    • Group B streptococci are known as Streptococcus agalactiae and commonly found in female genital tract, causing infections in neonates
    • Group C streptococci cause diseases in animals
    • Group D streptococci are known as enterococci

    Streptococcus pyogenes

    • Produces toxins such as streptolysin S, streptolysin O, erythrogenic toxins and hyaluronidase
    • Pathogenicity includes pharyngitis (sore throat), scarlet fever, impetigo, erysipelas, cellulitis, necrotizing fasciitis, and toxic shock syndrome
    • Complications include rheumatic fever, glomerulonephritis
    • Treatment involves penicillin

    Streptococcus agalactiae

    • Commonly found in the female genital tract and can be transmitted to the newborn
    • Causes neonatal sepsis, pneumonia and meningitis
    • Treatment involves penicillin, ampicillin or vancomycin

    Oral Streptococci

    • Includes Streptococcus mutans, Streptococcus sobrinus and Streptococcus sanguinis
    • Viridans streptococci can cause Infective endocarditis if they enter the bloodstream (bacteraemia)

    Staphylococci

    • Staphylococcus aureus is the most important species
    • Other species include Staphylococcus epidermidis, Staphylococcus saprophyticus
    • Pathogenicity of Staphylococcus aureus includes skin infections, pneumonia, food poisoning, toxic shock syndrome, osteomyelitis
    • Treatment involves penicillinase-resistant penicillin, flucloxacillin, vancomycin
    • Staphylococcus epidermidis is a commensal organism
    • Pathogenicity includes infections especially in immunocompromised patients, biofilms
    • Treatment involves vancomycin

    Enterococci

    • Eg Enterococcus faecalis
    • Common commensals in the gut
    • Pathogenicity includes urinary tract infections, endocarditis, wound infections
    • Treatment involves vancomycin, penicillin and gentamicin

    Actinomycetes

    • Types include Actinomyces israelii, Actinomyces odontolyticus, Actinomyces naeslundii
    • Actinomyces odontolyticus causes enamel demineralisation
    • Actinomyces israelii causes actinomycosis, which is a chronic infection of the jaw, lungs or abdomen
    • Pathogenicity includes Actinomyces israelii causing cervicofacial actinomycosis, pulmonary actinomycosis, abdominal actinomycosis
    • Types include Actinomyces israelii, Actinomyces naeslundii
    • Treatment involves penicillin, amoxicillin or clindamycin
    • Nocardia asteroides is an example of a nocardia species with its own distinct properties

    Clostridia

    • Includes Clostridium tetani, Clostridium botulinum, Clostridium perfringens
    • Clostridium tetani causes tetanus
    •  Clostridium botulinum causes botulism
    • Clostridium perfringens causes gas gangrene
    • Pathogenicity includes Clostridium perfringens causing gas gangrene
    • Treatment of gas gangrene involves surgical debridement and penicillin
    • Clostridium difficile causes antibiotic-associated diarrhoea, colitis
    • Pathogenicity includes Clostridium difficile causing diarrhoea
    • Treatment involves metronidazole, vancomycin

    Bacillus

    • Includes Bacillus anthracis, Bacillus cereus
    • Bacillus anthracis causes anthrax
    • Bacillus cereus causes food poisoning

    Bacillus cereus

    • Causes emetic-type food poisoning and diarrhoeal-type food poisoning

    Neisseriaceae

    • Types include Neisseria gonorrhoeae, Neisseria meningitidis, Neisseria sicca
    • Neisseria gonorrhoeae is the gonococcus
    • Causes gonorrhoea
    • The gonococci can cause urethritis, cervicitis, prostatitis, epididymitis, pelvic inflammatory disease, conjunctivitis, arthritis
    • Treatment includes ceftriaxone or azithromycin

    Neisseria meningitidis

    • The meningococcus
    • Causes meningitis and septicaemia
    • Treatment involves penicillin, ceftriaxone or chloramphenicol

    Commensal Species

    • Includes Staphylococcus epidermidis, Streptococcus salivarius, Streptococcus mitis
    • Aerobic → facultative anaerobes → obligate anerobes
    • Some commensal species can become opportunistic pathogens in certain situations

    Enterobacteria

    • Includes Escherichia coli, Salmonella spp. , Shigella spp.
    • Pathogenicity includes urinary tract infections, gastroenteritis
    • Treatment involves fluoroquinolones, amoxicillin-clavulanate

    Bacteroides

    • Bacteroides fragilis is the most important species
    • Bacteroides fragilis can cause abscesses, peritonitis, bacteraemia
    • Treatment includes metronidazole

    Porphyromonas

    • Porphyromonas gingivalis is the key member
    • Pathogenicity includes Porphyromonas gingivalis causing chronic periodontitis, gingivitis
    • Porphyromonas gingivalis is part of the "red complex" responsible for periodontal disease
    • Porphyromonas catoniae is found in healthy gingiva

    Prevotella

    • Includes Prevotella intermedia, Prevotella nigrescens
    • Prevotella intermedia is associated with periodontal disease (orange complex)
    • Prevotella nigrescens is found in healthy gingiva

    Fusobacterium

    • Includes Fusobacterium nucleatum, Fusobacterium necrophorum
    • Fusobacterium nucleatum is associated with periodontal disease
    • Pathogenicity includes Fusobacterium nucleatum causing periodontitis
    • Treatment involves metronidazole

    Spirochaetes

    • Includes Treponema denticola, Borrelia burgdorferi
    • Treponema denticola causes periodontal disease
    • Treponema denticola is part of the "red complex" responsible for periodontal disease

    Leptorichia

    • Leptotrichia buccalis is the only member of the genus
    • Found in the mouth and implicated in periodontitis

    Mycobacteria

    • Includes Mycobacterium tuberculosis, Mycobacterium bovis, Mycobacterium leprae
    • Mycobacterium tuberculosis causes tuberculosis, which affects the lungs
    • Mycobacterium bovis is found in cattle and can cause tuberculosis in humans
    • Mycobacterium leprae causes leprosy
    • Pathogenicity of Mycobacterium leprae includes causing leprosy or Hansen’s disease
    • Types include tuberculoid leprosy and lepromatous leprosy
    • Treatment involves multidrug therapy including rifampicin, dapsone, clofazimine

    Mycobacteria other than TB

    • Includes Mycobacterium avium, Mycobacterium kansasii
    • Mycobacterium avium can cause lung infections in immunocompromised individuals

    Legionella

    • Most important is Legionella pneumophila causing atypical pneumonia (common in hospitals)
    • Pathogenicity includes Legionella pneumophila causing Legionnaires' disease, Pontiac fever
    • Treatment involves macrolides (azithromycin) or quinolones (ciprofloxacin)

    Mycoplasmas

    • Includes Mycoplasma pneumoniae
    • Mycoplasma pneumoniae causes atypical pneumonia
    • Pathogenicity of Mycoplasma pneumoniae includes causing walking pneumonia, bronchiolitis, tracheobronchitis
    • Treatment involves macrolides (erythromycin) or tetracyclines (doxycycline)

    Oral Mycoplasmas

    • Include Mycoplasma salivarium, Mycoplasma hominis, Mycoplasma orale

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    Description

    This quiz covers the various types of streptococci, including Group A and Group B, detailing their pathogenicity, complications, and treatment options. Explore the characteristics of Streptococcus pyogenes and Streptococcus agalactiae, along with the implications of oral streptococci. Test your knowledge on these bacteria and their impact on human health.

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