Corynebacteriu m diphtheriae

Question 1

type

Answer 1

Gram+ rod
-non spore
forming
- Aerobic
- club shaped;
Pleomorphic:
“Chinese Letters
arrangement”
4 biotypes:gravis,
mitis, belfanti,
intermedium
B prophage
carrying genes for
the
toxin(lysogeny, B
corynephage) -
can infect
nontoxigenic
diphteroid

Question 2

Transmission
& season

Answer 2

DTaP: full dose
Td: lower dose
Endemic in
tropical &
subtropical
countries

Question 3

presentation

Answer 3

Respiratory diphtheriae:
sudden onset exudative
pharyngitis, sore throat, fever,
malaise, dysphagia, stridor
- thick pseudomembrane
develops over pharynx →
respiratory obstruction
- severely ill → carditis,
recurrent laryngeal nerve
palsy
** before pseudomembrane
you see volutin granules &
chinese letter

Question 4

pathogenesis

Answer 4

NON-invasive
- severe can block airways →
suffocation. “Stridor”
-Main virulence
factor=diphtheria exotoxin
- genes for toxin acquired via
lysogenic
conversion(bacteriophage)
- Inhibits EF2 by ADP
ribosylation. No protein
synthesis
- Toxin is responsible for local &
systemic sx
- inflammation &
pseudomembrane
- damage to organs
- bull neck : cervical
lymphadenopathy