CORNYNEBACYERIUM DIPHTHEREIAEA

• What is the scientific name for the Kleb-Loeffler Bacillus?

  Corynebacterium diphtheriae
• What is the morphology of Corynebacterium diphtheriae?

  Gram positive rods with club-shaped appearance
• How are Corynebacterium diphtheriae arranged?

  In L, V, or Y formation
• What are Babes-Ernst bodies?

  Polar bodies or metachromatic granules
• What staining method is used to demonstrate Babes-Ernst bodies?

  LAMB staining (Loeffler’s alkaline methylene blue)
• What type of aerobe is Corynebacterium diphtheriae?

  Facultative aerobe
• What media is used to culture Corynebacterium diphtheriae?

  Loeffler’s coagulated serum medium
• What is the major virulence factor of Corynebacterium diphtheriae?

  Diphtheria toxin
• How many fragments does diphtheria toxin have?

  Two fragments
• What does fragment B of diphtheria toxin do?

  Binds to receptors and mediates entry of fragment A
• What is the role of fragment A of diphtheria toxin?

  Inhibits elongation factor, blocking protein synthesis
• What is the clinical infection caused by Corynebacterium diphtheriae?

  Diphtheria
• Where can asymptomatic carriage of Corynebacterium diphtheriae occur?

  In the oropharynx or skin
• Who is the only known reservoir for Corynebacterium diphtheriae?

  Humans
• What is the mode of transmission for diphtheria?

  Respiratory droplets or contact
• What is the incubation period for diphtheria?

  2 to 6 days
• What are the common manifestations of diphtheria?

  Low-grade fever, malaise, mild sore throat
• What is the most common site of infection for diphtheria?

  Tonsils or pharynx
• What does the pseudomembrane in diphtheria look like?

  Gray to white in color
• What can happen if the pseudomembrane spreads?

  It can cause airway obstruction
• What is the appearance of massive cervical lymph node enlargement in diphtheria?

  “Bull neck” appearance
• What test is used to establish immunity to diphtheria?

  SCHICK test
• What does a negative SCHICK test indicate?

  Presence of immunity
• What does a positive SCHICK test indicate?

  Absence of circulating antitoxin
• What specimen is used for laboratory diagnosis of diphtheria?

  Throat swab
• How many throat swabs are taken for diagnosis?

  Two swabs
• What is the purpose of the first throat swab?

  For demonstration of metachromatic granules
• What is the purpose of the second throat swab?

  For culture
• What test is used for toxigenicity?

  Elek test
• What does the Elek test detect?

  Toxigenic strains of Corynebacterium diphtheriae
• What method is used to detect the tox positive gene?

  PCR-based nucleic acid amplification method
• What is the antibiotic of choice for treating diphtheria?

  Penicillin
• What is the role of diphtheria antitoxin in treatment?

  Inhibits production of toxin
• What supportive measures may be needed in severe cases of diphtheria?

  Tracheostomy and cardiovascular support
• When is the diphtheria toxoid vaccine given?

  As early as 2 months of age
• What does the DPT vaccine include?

  Diphtheria, pertussis, and tetanus
• When is the booster for diphtheria given?

  Prior to entering school and every 10 years
• How does the virulence factor of diphtheria toxin affect the body?

  It causes epithelial destruction and inflammation
• What is the significance of metachromatic granules in Corynebacterium diphtheriae?

  Indicates the presence of the bacterium in culture
• How does the incubation period of diphtheria influence its transmission?

  It allows asymptomatic carriers to spread the disease