Lab 46 Bacteria of the Respiratory Tract

Question 1

upper respiratory tract

Answer 1

consists of nose and throat

Question 2

lower respiratory tract

Answer 2

consists of the larynx, trachea, bronchial tubes, and alveoli

Question 3

why is the lower respiratory tract normally sterile?

Answer 3

b/c of the efficient functioning of the ciliary escalator

Question 4

what kind of environment is the throat?

Answer 4

moist and warm environment hosting staphylococcus, streptococcus, Neisseria, Haemophilus

Question 5

how is the rate of infection in the upper respiratory tract minimized

Answer 5

by microbial antagonism

Question 6

microbial antagonism

Answer 6

certain microorganisms of the normal microbiota suppress the growth of other microorganisms through competition for nutrients and production of inhibitory substances

Question 7

Streptococci

Answer 7

gram positive, catalase negative

Question 8

what is blood agar made of?

Answer 8

defibrinated sheep blood, sodium chloride and nutrient agar

Question 9

What are the three patterns of hemolysis?

Answer 9

alpha-hemolysis
beta-hemolysis
gamma-hemolysis

Question 10

alpha hemolysis

Answer 10

green, cloudy zone around the colony; partial destruction of RBCs

Question 11

beta hemolysis

Answer 11

complete hemolysis, giving clear zone with a clean edge around the colony

Question 12

gamma hemolysis

Answer 12

no hemolysis, no change in the blood agar around colony

Question 13

which two patterns of hemolysis are normal microbiota

Answer 13

alpha and gamma hemolysis

Question 14

Optochin inhibition

Answer 14

optochin disk used to identify streptococcus pneumonia

Question 15

bile solubility

Answer 15

used to distinguish S. pneumoniae form the other alpha hemolytic streptococci

Question 16

Which bacteria is sensitive to the antibiotic bacitracin?

Answer 16

S. pyogenes

-other streptococci are resistant to bacitracin

Question 17

What do bile salts do?

Answer 17

activate an enzyme that destroys cell wall