Genus Corynebacterium. C. diphtheriae

• What is the genus of Corynebacterium Diphtheriae?

  Corynebacterium
• What type of bacteria is Corynebacterium Diphtheriae?

  Gram +ve Bacillus
• What is the shape of Corynebacterium Diphtheriae?

  Club-shaped
• Is Corynebacterium Diphtheriae sporulating or nonsporulating?

  Nonsporulating
• What is the oxygen requirement for Corynebacterium Diphtheriae?

  Facultative Anaerobe
• What is the primary reservoir for Corynebacterium Diphtheriae?

  Respiratory Tract
• Who are the only hosts for Corynebacterium Diphtheriae?

  Humans
• How is Corynebacterium Diphtheriae transmitted?

  Respiratory Droplets
• What is the main virulence factor of Corynebacterium Diphtheriae?

  Diphtheria Toxin
• What does the Diphtheria Toxin inactivate?

  Elongation factor (EF-2)
• What does the AB Toxin inhibit?

  RNA Translation
• How does Diphtheria Toxin impair protein synthesis?

  Via ADP ribosylation
• What encodes the Diphtheria Toxin?

  Beta-prophage
• What are the local features of Respiratory Diphtheria?

  Greyish-white pseudomembrane
• What causes the "Bull Neck" appearance in Diphtheria?

  Cervical lymphadenopathy
• What are systemic features of Diphtheria due to toxin dissemination?

  Fever, chills, malaise, cyanosis
• What is a common cardiac complication of Diphtheria?

  Myocarditis
• What neurological condition can occur due to Diphtheria?

  Reversible Polyneuropathy
• What type of specimens are used for microbiological diagnosis of Diphtheria?

  Secretions
• What staining methods are used in microscopy for Diphtheria diagnosis?

  Gram Staining and Neisser Staining
• What is observed in Neisser Staining for Diphtheria?

  Metachromatic granules
• What is the first step in Neisser Staining procedure?

  Prepare a smear
• What is the purpose of flooding the slide with Neisser 1?

  To stain with methylene blue and crystal violet
• What is the purpose of flooding the slide with Neisser 2?

  To stain with chrisoidin
• What culture media are used for Diphtheria diagnosis?

  Loeffler’s Medium and Tellurite Medium
• What does Loeffler’s Medium indicate in Diphtheria diagnosis?

  Metachromatic Granules
• What do black colonies on Tellurite Medium indicate?

  Presence of Diphtheria
• What is the Elek’s Test used for?

  To detect diphtheria antitoxin
• What happens in Elek’s Test after incubation?

  Examine plates for precipitin lines
• What is a positive result for C. diphtheria in Elek’s Test?

  Presence of precipitin lines
• What is the first-line treatment for Diphtheria?

  Macrolides (e.g., erythromycin)
• What is another antibiotic used to treat Diphtheria?

  Penicillin G
• What is administered alongside antibiotics for Diphtheria treatment?

  Diphtheria Antitoxin
• What is the primary prevention method for Diphtheria?

  Toxoid Vaccine
• What are the cultural features of Corynebacterium Diphtheriae?

  • Gram +ve Bacillus
  • Nonsporulating
  • Club-shaped
  • Indol Negative
  • Facultative Anaerobe
• What are the clinical manifestations of Respiratory Diphtheria?

  Local Features:

  • Greyish-white pseudomembrane
  • Bull Neck due to cervical lymphadenopathy

  
  

  Systemic Features:

  • Fever > 38C
  • Chills
  • Malaise
  • Cyanosis
  • Cough
  • Headache
  • Cardiac issues (Myocarditis, Arrhythmias)
  • Reversible Polyneuropathy
• What are the steps for microbiological diagnosis of Diphtheria?

  1. Collect secretions
  2. Perform Gram Staining
  3. Perform Neisser Staining
  4. Culture on Loeffler’s Medium and Tellurite Medium
  5. Conduct Elek’s Test
• What are the treatment options for Diphtheria?

  • Macrolides (e.g., erythromycin)
  • Penicillin G
  • Diphtheria Antitoxin
• What are the prevention methods for Diphtheria?

  • Toxoid Vaccine