diphtheria

Question 1

general characters of the causative agent

Answer 1

Corynebacterium diphtheriae
Gram-positive, non-capsulated, non-sporing, non-motile bacillus.
* Irregularly stained and frequently shows club-shaped swellings
-Chinese letter or cuneiform arrangement
-Metachromatic granules

Question 2

clinical manifestations

Answer 2

Respiratory Diphtheria- Faucial diphtheria
Extension of pseudomembrane
Bull-neck appearance

Question 3

laboratory diagnosis

Answer 3

1)Direct Smear Microscopy-Gram stain,Albert’s stain
2) Isolation of Diphtheria Bacilli
-Blood Agar: Colonies are small circular, white and sometimes hemolytic
-Loeffler’s serum slope: Colonies appear as small, circular, glistening, and white with a yellow tinge in 6–8 hours
2. Selective Medium-Potassium tellurite agar (PTA): black color colours

3. Identification
   -Biochemical tests such as: IMVIC,
   -Automated identification systems:MALDI-TOF or VITEK.
4. Toxin Demonstration (In Vitro Test)- Elek’s gel precipitation test

Question 4

prophylaxis

Answer 4

Vaccination
Post-exposure Prophylaxis
-booster dose of diphtheria vaccine+penicillinG (single dose)
or erythromycin (7–10 days)

Question 5

treatment

Answer 5

-antidiphtheric serum
-antibiotics: penicilin or erythromycin
-diphtheria antitoxin-must do skin test b4 administer

Question 6

Virulence Factors

Answer 6

Diphtheria toxin

Question 7

complications

Answer 7

Neurologic manifestations:
 Cranial nerve involvement  Peripheral neuropathy
 Ciliary paralysis.

Myocarditis