spirochetes (unit 18)

• What shape are spirochetes?

  Cylindrical
• What is a key feature of spirochetes?

  Helical
• What functions do spirochetes serve due to their thin and mobile structure?

  Locomotion, flexion, and rotation
• What type of bacteria stain as Gram-negative?

  Those with cell wall flexibility
• What are axial filaments also known as?

  Periplasmic endoflagella
• Why might spirochetes not be visible under an optical microscope?

  They are long but very narrow
• What microscopy techniques are required to visualize spirochetes?

  Darkfield or fluorescence microscopy
• What antibiotic are spirochetes resistant to?

  Rifampicin
• What is a characteristic of spirochetes regarding host specificity?

  Great host specificity
• What are the general features of spirochetes?

  • Outer membrane
  • Peptidoglycan
  • Cytoplasmic membrane
  • Periplasmic flagella
• What are the classifications within the Spirochaetales order?

  • Spirochaetaceae
  • Leptospiraceae
• What distinguishes the extremities of Spirochaetaceae from Leptospiraceae?

  Not incurved vs. incurved
• How do the respiration types differ between Spirochaetaceae and Leptospiraceae?

  Aerobe/anaerobe vs. aerobe
• What are the sources of carbon and energy for Spirochaetaceae?

  Carbohydrates and amino acids
• What are the sources of carbon and energy for Leptospiraceae?

  Fatty acids
• What are the genera of clinical interest in spirochetes?

  • Treponema
  • Borrelia
  • Leptospira
• What is a characteristic of Treponema bacteria?

  Long and thin bacteria
• Why can't Treponema be seen with Gram stain?

  They cannot be seen with Gram stain
• What type of bacteria are Treponema?

  Anaerobes
• Where are some Treponema species found as microbiota?

  Mouth, intestines, and genital tract
• What are the nutritional requirements of Treponema?

  • Strictly anaerobic
  • Many nutritional requirements
  • Usually difficult to culture
• How can Treponema be divided based on energy sources?

  By amino acids or carbohydrates
• Which Treponema species obtain energy from amino acids?

  1. denticola, T. orale, T. vincentii
• Which Treponema species obtain energy from carbohydrates?

  1. macrodentium, T. socranskii
• Where do oral Treponemes thrive?

  • Deep areas of supragingival plaque
  • Gingival sulcus (anaerobic conditions)
• What is required for oral Treponemes to thrive?

  • Synergy with other bacteria in plaque
  • Use compounds excreted by them
• What are the virulence factors of oral Treponemes?

  • Endotoxin
  • Mobility and ability to penetrate
• What effect does T. denticola have in vitro?

  Inhibition of PMN functionality
• What is a pathology associated with oral Treponemes?

  Related to periodontal disease
• What is Vincent's infection also known as?

  Trench mouth
• What is the nature of ANUG?

  Acute necrotizing ulcer gingivitis
• Who is most affected by ANUG?

  Young people and immunocompromised individuals
• What are the predisposing factors for ANUG?

  • Stress
  • Poor oral hygiene
  • Smoking
  • Immunosuppression
  • Malnutrition
• What is a pathognomic sign of ANUG?

  Crater-like ulcers between the teeth
• What are some symptoms of ANUG?

  Unpleasant taste, swollen gums, gum pain
• What is the treatment for ANUG?

  Chlorhexidine and antibiotics
• What is involved in the laboratory diagnosis of oral treponemes?

  • Subgingival plaque sample
  • Microscopy: darkfield, direct immunofluorescence
  • Positive BANA test for T. denticola
• What does the BANA test detect?

  Proteolytic activity of oral anaerobes
• What is required for the cultivation of oral treponemes?

  Liquid media with specific nutrients
• What is a characteristic of Treponema pallidum spp. pallidum?

  Spirochete with 6-12 deep spires