Genus Mycobacterium. M. tuberculosis

• What family does the genus Mycobacteriaceae belong to?

  Mycobacteriaceae
• What type of organisms are some members of Mycobacteriaceae?

  Obligate parasites
• What characteristic defines Mycobacteriaceae as Acid-Fast Bacteria?

  Thick, hydrophobic cell wall
• What is the oxygen requirement for Mycobacteriaceae?

  Aerobic
• Are Mycobacteriaceae motile or nonmotile?

  Nonmotile
• What is the classification of Mycobacteriaceae based on growth rate?

  Slow, intermediate, and rapidly growing
• What are the slow-growing Mycobacterium species in the MTBC?

  • M. tuberculosis
  • M. bovis
  • M. bovis BCG
  • M. africanum
  • M. canetti
  • M. caprae
  • M. microti
  • M. pinnipedii
• What is the Mycobacterium Avium Complex (MAC) associated with?

  Disseminated infections, not lung infections
• Which Mycobacterium clade is known for causing significant death in AIDS patients?

  Mycobacterium Avium Complex (MAC)
• What are the rapidly growing Mycobacterium species?

  • Mycobacterium chelonae clade
  • Mycobacterium fortuitum clade
• What is the Gram stain characteristic of Mycobacterium tuberculosis?

  Considered Gram positive
• What staining method is used for Mycobacterium tuberculosis?

  Ziel-Neelsen Staining
• What is the generation time of Mycobacterium tuberculosis?

  Approximately 12 hours
• What is the appearance of Mycobacterium tuberculosis colonies?

  Rough 'cauliflower-like' colonies
• What type of activity does Mycobacterium tuberculosis exhibit?

  High fermentation rate
• What are the virulence factors of Mycobacterium tuberculosis?

  Cord factors and sulfatides
• How do cord factors affect Mycobacterium tuberculosis virulence?

  Increases TNF-alpha release and macrophage activation
• What is the role of sulfatides in Mycobacterium tuberculosis?

  Inhibit phagolysosomal fusion
• What mutation leads to multi-drug resistance in Mycobacterium tuberculosis?

  Mutation in KatG gene
• What is the pathophysiology of tuberculosis infection?

  Adherence and colonization of lung alveoli
• What are some risk factors for tuberculosis?


  Poverty, low BMI, and malnutrition
• What are the types of tuberculosis?

  • Primary/Relapsed
  • Acute/Latent
  • Symptomatic/Asymptomatic
  • Pulmonary/Extrapulmonary/Disseminated (Miliary)
• What are systemic symptoms of tuberculosis?

  Malaise, weight loss, and low-grade fever
• What are pulmonary symptoms of tuberculosis?

  Cough, shortness of breath, and pleuritic chest pain
• What specimens are used for microbiological diagnosis of tuberculosis?

  Pus, CSF, urine, and biopsied tissue
• What are the steps in Ziel-Neelsen Staining?

  1. Drop suspension onto slide
  2. Air dry at 60°C for 10 min
  3. Heat-fix at 90°C for 10 min
  4. Flood with Carbol Fuchsin
  5. Heat until steam appears
  6. Rinse with tap water
  7. Flood with 3% hydrochloric acid in isopropyl alcohol
  8. Rinse with water
  9. Flood with Methylene Blue
  10. Rinse with water and blot dry
• What is the purpose of preliminary treatment in culture for tuberculosis?

  To eliminate side flora
• What selective media are used for culturing Mycobacterium tuberculosis?

  • Kirchner Media
  • Middlebrook Media
  • Löwenstein-Jensen Media
• How long does it take to culture Mycobacterium tuberculosis?

  4 to 8 weeks
• What is the treatment regimen for tuberculosis?

  • RIPE: Rifampin, Isoniazid, Pyrazinamide, Ethambutol
• What is the intensive phase of tuberculosis treatment?

  2 months of RIPE therapy
• What is the continuation phase of tuberculosis treatment?

  4 months of Rifampin and Isoniazid
• What is the purpose of adjuvant treatment in tuberculosis?

  To prevent Vitamin B6 deficiency
• What vaccine is used for tuberculosis prevention?

  BCG Vaccine
• What type of vaccine is the BCG vaccine?

  Live attenuated strain of M. bovis