Corynebacterium Diptheriae

Question 1

How to classify?

Answer 1

Gram positive bacilli

Question 2

What type of infection does it cause?

Answer 2

Pharyngeal (nasal, laryngeal, tracheal sites)
Skin

Question 3

Describe the toxin it has

Answer 3

Gene carried by phage
A and B fragments

Question 4

What are the clinical symptoms of pharyngeal diptheria?

Answer 4

• Sore throat, malaise, fever, pharyngitis
• Pseudomembrane formation obstructs airway (darkens later)
• Bull neck (gross swelling of neck)
• Palatal paralysis

Question 5

How is it transmitted?

Answer 5

Respiratory droplets with asymptomatic carriers

Question 6

What are the distant clinical symptoms?

Answer 6

1. Myocarditis (arrhythmias, heart failure)
2. Nerve damage/Neuropathy (visual disturbance, limb paralysis, difficulty swallowing)

Question 7

How does the toxin cause distant effects?

Answer 7

B toxin binds while A inhibits elongation factor 2 -> protein synthesis blocked -> cell death

Question 8

How to diagnose?

Answer 8

Must be clinical
PCR or culture (throat swab with Tinsdale’s selective medium)
Identify colonies and check for toxin production

Question 9

What does histology show?

Answer 9

Chinese characters

Question 10

Treatment

Answer 10

• Antiserum (antitoxin)
• Erythromycin/penicillin
• Isolate (infection control)
• Supportive/symptomatic treatment

Question 11

How to prevent?

Answer 11

• Vaccine (toxoid made from toxin) for patients and close contacts
• Antibiotics for patient and close contacts

Question 12

What is another Corynebacterium species? What does it cause?

Answer 12

C.ulcerans
Throat infections and sometimes full blown diptheria (same toxin)