Corynebacterium and Listeria (non-spore forming rods)

Question 1

Corynebacterium diptheriae morphology?

Answer 1

1. G+ve rods (very pleomorphic and club shaped)
2. Non-spore forming
3. Non-motile

Question 2

Corynebacterium diptheriae transmission?

Answer 2

Respiratory droplets from a carrier

Question 3

Metabolism Corynebacterium diptheriae?

Answer 3

1. Facultative anaerobe

2. Catalase positive

Question 4

Corynebacterium diptheriae virulence?

Answer 4

Pseudomembrane forms in the pharynx.

-serves as a base from which it can secrete toxins

Question 5

Corynebacterium diptheriae toxins?

Answer 5

Exotoxin (coded by bacteriophage):

• A subunit: blocks protein synthesis
• B subunit: provides entry into cardiac and neural tissue

Question 6

Clinical presentation Corynebacterium diptheriae?

Answer 6

Diptheria:

1. Mild sore throat with fever
2. Pseudomembrane on pharynx
3. Myocarditis causing AV conduction block and dysrhythmia
4. Neural involvement

Question 7

Presentation of neural involvement in diptheria?

Answer 7

• Peripheral nerve palsies
• Guillain Barre-like syndrome
• Palatal paralysis and cranial neuropathies

Question 8

Treatment diptheria?

Answer 8

1. Antitoxin
2. Penicillin or erythromycin
3. Vaccine

Question 9

Diagnosis of diptheria?

Answer 9

1. G+ve pleomorphic rods

2. Culture: potassium, Loeflers medium

Question 10

Morphology of listeria?

Answer 10

1. G+ve rods
2. Non spore forming
3. Motile

Question 11

transmision of listeria?

Answer 11

1. Contaminated raw milk or cheese from infected cows
2. Vaginally (during birth)
3. Transplacental infection of fetus from bacteremic mother

Question 12

Clinical presentation of listeria monocytogenes?

Answer 12

1. Neonatal meningitis
2. Meningitis in immunosuppressed patients and the elderly
3. septicemia in pregnant women

Question 13

Treatment listeria monocytogenes?

Answer 13

1. ampicillin

2. trimethoprim / sulfamethoxazole