Microbiology

Question 1

corynebacterium diphtheriae

Answer 1

nonspore forming, non capsulated, gram positive bacteria

Question 2

medium that c. diphtheriae is grown on

Answer 2

Loeffler’s medium (coagulated serum). potassium tellurite (grayish black colonies)

Question 3

in the US, c. diphtheriae is a disease of

Answer 3

elderly, urban poor and immigrants from developing countries

Question 4

Diptheriae is caused by

Answer 4

the local and systemic effects of diphtheria toxin

Question 5

c. diptheriae toxin

Answer 5

A fragment inhibits protein synthesis, B fragment binds specifically to a cell surface receptor. systemic effects are seen mostly in the heart and peripheral nerves

Question 6

bull neck

Answer 6

grey-brown psuedomembrane from the pharynx to the larynx that causes severe respiratory distress. do not try to remove

Question 7

neuropathy can progress to

Answer 7

respiratory failure

Question 8

strep

Answer 8

gram positive, non spore forming, catalase negative, grows in pairs or chains of varying length

Question 9

strep are primarily

Answer 9

microaerophilic or facultative anaerobes

Question 10

β hemolysis

Answer 10

complete lysis, s. pyogenes

Question 11

α hemolysis

Answer 11

green, incomplete lysis, s. pneumoniae, viridians

Question 12

γ hemolysis

Answer 12

enterococcus

Question 13

GABHS

Answer 13

Group A β hemolytic strep, sensitive to bacitracin

Question 14

methods of transmission of GABHS

Answer 14

1. air (air not fomites); 2. food (open lesion); 3. hands

Question 15

hyaluronate capsule

Answer 15

virulence factor - binds to CD44 on host tissue

Question 16

extracellular matrix binding protein

Answer 16

surface proteins that bind fibronectin, fibrinogen, and collagen

Question 17

avoidance of immune response

Answer 17

m protein, hyaluronate capsule, Ig binding proteins, C5a peptidase

Question 18

C5a peptidase

Answer 18

cleaves the complement c5a chemotaxin to prevent recruitment of neutrophils to the site of infection

Question 19

invasion and spread to other tissues

Answer 19

spe B protease: secreted protease degrades host tissues, streptolysins: hemolysis, DNAses, streptokinase: degrades clots by activating host plasminogen, hyaluronidase

Question 20

superantigens

Answer 20

activates t cells in absence of MHC releasing large amounts of inflammatory cytokines

Question 21

primary method for clearance of GABHS

Answer 21

opsonophagocytosis by neutrophils or PMNs

Question 22

GABHS

Answer 22

aerobic sensitivity, rapid diagnostic test for strep throat, anti streptolysin O serology

Question 23

GABHS disease

Answer 23

asymptomatic carriage; purulent, self limiting infections of the oropharynx or skin,

Question 24

nonsupparative sequelae of GABHS

Answer 24

acute rheumatic fever, acute post streptococcal glomerulonephritis

Question 25

rapid onset strep throat

Answer 25

sore throat with malaise, feverishness, and headache

Question 26

acute otitis media

Answer 26

opaque, red/yellow/cloudy, bulging or full position, reduced mobility with pneumatic otoscopy, effusion present

Question 27

otitis media with effusion

Answer 27

neutral or retracted, reduced mobility, effusion present

Question 28

diagnosis of AOM requires

Answer 28

1. history of acute symptom onset; 2. MEE; 3. signs/symptoms of middle ear inflammation

Question 29

MEE

Answer 29

1. TM bulge, 2. limited TM mobility, 3. air fluid level behind TM; 4. otorrhea

Question 30

ME inflammation

Answer 30

TM erythema, distinct otalgia (discomfort referable to the ear that interferes with normal activity/sleep)

Question 31

bacterial pathogens from middle ear fluid (top 3)

Answer 31

s. pneumoniae, h. influenzae, m. catarrhalis

Question 32

h. influenzae

Answer 32

gram negative coccobacilli to filarmentous bacterium, type A encapsulated

Question 33

m. catarrhalis

Answer 33

gram negative diplococcus

Question 34

most important diagnosis for AOM

Answer 34

bulging, red TM

Question 35

why observe AOM?

Answer 35

often mild, self limited disease, with low incidence of complications, could reduce antibiotic use substantially

Question 36

spontaneous AOM resolution

Answer 36

a result of immune responses, eustachian tube drainage, bacteria dependent, age dependent

Question 37

h. influenzae cannot be treated with amoxicillin

Answer 37

has caluvanic acid (a β-lactamase inhibitor)