URTI

Question 1

Moraxella catarrhalis

Answer 1

3rd for otitis media and sinusitis
G- cocci
oxidase +
does not ferment CHO
grows on blood agar
PCN resistant

Question 2

Haemophilus influenzae patho

Answer 2

#2 otits media and sinusitis
#1 epiglottitis (type b) --> barking cough
#1 meningitis --> unimmunized children
pneumonia --> pt with underlying dz

Question 3

H. influenzae virulence

Answer 3

polysacch capsule –> type b; most invasive; antiphago and blocks C’
IgA protease
outer membrane proteins
endotoxin

Question 4

H. influenzae Dx and Tx

Answer 4

culture on choc agar
serology via PRP capsular antigen
maternal Ab is protective for first few months
vaccine against PRP capsule conj to diphtheria

Question 5

Group A strep

Answer 5

S. pyogenes
G+ cocci
catalase -
beta hemolytic
bacitracin positive
CAMP -

Question 6

Group A Strep vir

Answer 6

M protein –>MAJOR –>Ab against cause rheumatic fever
adheres to epith containing keratin
Capsule –> hyaluronic acid; tolerated
Pyrogenic toxins A-C –> lysogenic conversion
Streptolysin O or S
DNase

Question 7

Group A Strep patho

Answer 7

1 pharyngitis or tonsilitis

scarlet fever –> tox+ / sandpaper rash and strawberry tongue
Comp: rheumatic fever and post-strep glomerulonephritis

Question 8

Bordetella pertussis

Answer 8

whooping cough
G- coccobacilli
strict aerobe
fastidous
charcoal blood agar or Bordet-Gengou agar

Question 9

B. pertussis vir

Answer 9

Filamentous hemagglutinin (Fha) –> med adhesino
Tracheal cytotoxin –> destroys cells
Pertussis toxin –> ADPR-xsferase; A unti inc cAMP
Invasive adenylate cyclase

Question 10

B. pertussis patho

Answer 10

1-2wk = catarrhal stage; infectious; tx with erythro
2-4wk = paroxysmal coughing
3-4wk = convalescent
recovery give some, but not life long immunity

Question 11

Corynebacterium diphtheriae

Answer 11

G+ rods
chinese lettering arrangements
metachromatic granules stain bluish purple
Tinsdale (tellurite) agar –> brown/black colonies

Question 12

C. diphtheriae vir

Answer 12

Diphtheria toxin –> inhib protein synth by blocking EF-2
AB subunits –> ADP ribosylation
encoded on a beta phasge –> lysogenic conversion

Question 13

C. diphtheriae patho

Answer 13

gray-white psuedomembrane
cervical lymphadenitis –> bull neck appearance
can disseminate to other organs
also a cutaneous form

Question 14

Haemophilus influenzae morpho

Answer 14

G- rods
pleomorphic
X and V factor media or chocolate agar
satellite phenom with S. aureus

Question 15

C. diphtheriae Dx and Tx

Answer 15

Dx via culture and toxin PCR and such

Tx with antitoxin, but watch out for serum sickness