Lecture 16 - Respiratory bacteriology 1

Question 1

what are the components of the upper respiratory tract

Answer 1

1. nasal cavity
2. sinuses
3. nasopharynx
4. larynx
5. trachea

Question 2

what is the epithelium of the upper respiratory tract

Answer 2

ciliated, pseudostratified columnar epithelium

Question 3

what are the primary functions of the upper respiratory tract

Answer 3

1. warm and humidify air
2. cleanse air
3. initial defense against pathogens
4. conduct air to lower respiratory tract

Question 4

what are the 2 functions of alveoli

Answer 4

1. gas exchange
2. acid-base balance

Question 5

what is the main defense mechanism in the nasal cavity, trachea, and bronchi

Answer 5

mucociliary apparatus

Question 6

what is the 1st line of innate defense in the respiratory tract

Answer 6

pulmonary macrophages

Question 7

describe the humoral immunity in the respiratory tract

Answer 7

IgA > IgG > IgM

Question 8

what is the disease triad

Answer 8

1. host
2. agent
3. environment

Question 9

colonization

Answer 9

presence of microorganisms WITHOUT clinical disease or immune response

Question 10

infection

Answer 10

colonization by a pathogen

Question 11

endogenous infection

Answer 11

commensal organism that invades when body defense is impaired

ex: yeast infection

Question 12

exogenous infection

Answer 12

direct or indirect transmission to an infected animal

Question 13

disease

Answer 13

change from a state of health

Question 14

infectious disease

Answer 14

caused by microorganism or its toxic product

Question 15

contagious disease

Answer 15

spread by contact

Question 16

subclinical infection

Answer 16

presence of microorganisms and interaction with the host but no clinical illnesses

Question 17

latent infection

Answer 17

pathogen remains inactive until the conditions become favorable to cause infection

Question 18

nosocomial infection

Answer 18

acquired in hospital

Question 19

carrier

Answer 19

host that harbors an infectious agent without showing clinical signs and can transmit the agent to others

Question 20

what are the 3 routes of bacterial infection

Answer 20

1. aerosol
2. bloodborne
3. direct penetration

Question 21

how do extreme temperatures impair the defense mechanisms of URT

Answer 21

cold = cilia are sluggish or stop, mucus thickens

hot = dries out mucus and decreases clearance

Question 22

how does airway epithelial damage impair the defense mechanisms of URT

Answer 22

reduced mucociliary clearance

Question 23

why would it be beneficial to decrease the innate defenses present in the URT

Answer 23

decrease production of harmful [to the pathogen] antimicrobial substance

Question 24

what factors would create a decreased immune response

Answer 24

1. stress
2. young age
3. immunodeficiency
4. viral infection

Question 25

what are the 3 types of pathogens

Answer 25

1. opportunistic
2. primary
3. secondary

Question 26

define pathogenicity

Answer 26

qualitative (yes or no); the ability of a microbe to damage a host

Question 27

define virulence

Answer 27

quantitative; the degree of damage caused

Question 28

primary pathogen

Answer 28

can cause disease on its own; strain or host-dependent

Question 29

blood agar shows

Answer 29

types of hemolysis

Question 30

chocolate agar shows

Answer 30

heat lysed RBC and released factors V and X

Question 31

MacConkey agar shows

Answer 31

gram-negative selectivity
lactose fermentation

Question 32

group of calves from Virginia are weaned, castrated, and moved to the feedlot in Kansas where they are vaccinated and mixed.

a steer dies and its lungs appear to have fibrin and exudate on necropsy. what is the microorganism responsible? what is the colloquial disease term?

Answer 32

mannheimia haemolytica; shipping fever

Question 33

an increase Ct on a PCR equals

Answer 33

decreased amount of bacteria