Corynebacterium

Question 1

Taxonomy of corynebacterium

Answer 1

Gram + pleomorphic rods, often club shaped “V” and “L” shaped characters, NOT acid fast

Question 2

Are corynebacterium normal flora?

Answer 2

Diphtheria species are not, but the others are. The normal flora bacteria are the ones causing disease now because the vaccine is preventive of diphtheria.

Question 3

Who is at risk for disease of all other species of corynebacterium?

Answer 3

Those that are immunocompromised

Question 4

What is the name of the “other” corynebacterium that do not cause diphtheria?

Answer 4

Diphtheroids

Question 5

What does arcanobacterium haemolyticum cause? and in what population?

Answer 5

Pharyngitis, esp in adolescents

Question 6

Taxonomy/reactions of arcanobacterium haemolyticum?

Answer 6

Beta-hemolytic

Question 7

What may arcanobacterium haemolyticum be confused with?

Answer 7

strep pyogenes

Question 8

Why is it ok to not tell the difference between s. pyogenes and a. haemolyticum?

Answer 8

They are both sensitive to PCN and macrolide.

Question 9

Virulence factors of corynebacterium diphtheria

Answer 9

• Cell wall antigens

- Diphtheria toxin

Question 10

What is the vaccine target for diphtheria?

Answer 10

Diphtheria toxin

Question 11

Where/What produces diphtheria toxin?

Answer 11

The to gene on the phage genome

Question 12

How does diphtheria toxin cause disease?

Answer 12

It binds to surface of susceptible cells (especially in the heart) and results in inhibition of the protein synthesis and cell death.

Question 13

Transmission of corynebacterium diphtheria

Answer 13

person to person via respiratory droplets, exchanging secretions, and direct skin to skin contact

Question 14

Classical Diphtheria

Answer 14

Respiratory infection-local infection with systemic toxemia

Question 15

What is the process of classical diphtheria disease?

Answer 15

2-6 days incubation with pharyngitis, slight fever, and malaise. The toxin causes necrosis of the mucosal tissue and it enters the bloodstream!

Question 16

Physical findings of diphtheria toxin:

Answer 16

• Grayish white exudate of pseudomembrane in throat and tonsils.
• Marked edema of neck “bull neck”
• Respiratory obstruction

Question 17

Systemic complications of classical diphtheria

Answer 17

Necrosis in heart muscle, kidneys, and nerves.

Question 18

What is cutaneous diphtheria

Answer 18

Skin infections, more common in the tropics.

Question 19

Diagnosis of classical diphtheria:

Answer 19

1. Clinical presentation with pharyngitis, pseudomembrane,
2. Swab from nose, throat, and skin-culture on blood agar
3. Test for toxin production

Question 20

Treatment of classical diphtheria

Answer 20

• Antitoxin Ab therapy

- Antibiotic therapy

Question 21

Specific antibiotics used in classical diphtheria treatment

Answer 21

Erythromycin or PCN G

Question 22

Antibiotics used in classical diphtheria treatment in immunocompromised pts

Answer 22

Vancomycin OR PCN G + aminoglycosides

Question 23

DTP vaccine:

Answer 23

DTap contains diphtheria, tetanus and pertussis

Question 24

What is the active portion of the vaccine?

Answer 24

Toxoid! It is inactivated diphtheria toxin. The toxoid is immunogenic but not toxin.

Question 25

Tdap Vaccine

Hint: d vs. D

Answer 25

booster given for teenagers and adults, contains lower dose of diphtheria toxoid.

Question 26

Td vaccine

Answer 26

traditional tetanus booster, also boosts immunity to diphtheria, lower dose of diphtheria toxoid than standard dose.