Micro - Diphtheria

Question 1

Corynebacterium = (G+, G-) (anaerobe, aerobe) (shape)

Answer 1

G+ aerobe, bacili

Question 2

Corynebacterium resembles:

Answer 2

Chinese letters (v-shaped arrangements)

Question 3

(T/F): Some corynebacteria are part of normal flora

Answer 3

T - almost any part of body, especially nares and skin (C. diphtheria is NOT normal)

Question 4

What is required for virulence of C. diphtheria?

Answer 4

Avirulent unless lysogenic beta-prophage produces diphtheria toxin

Question 5

Two subunits of diphtheria toxin and their function

Answer 5

A subunit (toxic enzyme) - diffuses through body and is endocytosed then it ADP-ribosylates elongation factor 2 to halt protein production
B subunit (adhesin) - binds heparin binding epidermal growth factors

Question 6

Where does C. diphtheria colonize?

Answer 6

Pharynx but toxin can spread in blood

Question 7

Characteristic lesion of C. diphtheria

Answer 7

Pseudomembrane of pharynx, tonsils, nose

Question 8

Organ particularly vulnerable to spread of diphtheria toxin

Answer 8

Heart

Question 9

What do you see in severe diphtheria infection?

Answer 9

Swollen neck

Question 10

Presenting symptoms: diphtheria

Answer 10

Very sore throat, low-grade fever, lymphadenitis

Question 11

How do you diagnose diphtheria?

Answer 11

Isolation of C. diphtheria required; presence of toxin confirmatory; imaging studies + EKG

Question 12

Two treatment options for diphtheria

Answer 12

Antitoxin

Abx

Question 13

MOA antitoxin

Answer 13

Neutralized circulating toxin (CANNOT reduce toxin already bound to tissue)

Question 14

Two Abx used for diphtheria

Answer 14

Erythromycin

PCN

Question 15

2 supportive measures that may be necessary for diphtheria pt

Answer 15

1. Breathing tube - airway obstruction can result from pseudomembranes
2. Cardiac monitoring