Lecture 16 - Respiratory bacteriology 1 Flashcards
what are the components of the upper respiratory tract
- nasal cavity
- sinuses
- nasopharynx
- larynx
- trachea
what is the epithelium of the upper respiratory tract
ciliated, pseudostratified columnar epithelium
what are the primary functions of the upper respiratory tract
- warm and humidify air
- cleanse air
- initial defense against pathogens
- conduct air to lower respiratory tract
what are the 2 functions of alveoli
- gas exchange
- acid-base balance
what is the main defense mechanism in the nasal cavity, trachea, and bronchi
mucociliary apparatus
what is the 1st line of innate defense in the respiratory tract
pulmonary macrophages
describe the humoral immunity in the respiratory tract
IgA > IgG > IgM
what is the disease triad
- host
- agent
- environment
colonization
presence of microorganisms WITHOUT clinical disease or immune response
infection
colonization by a pathogen
endogenous infection
commensal organism that invades when body defense is impaired
ex: yeast infection
exogenous infection
direct or indirect transmission to an infected animal
disease
change from a state of health
infectious disease
caused by microorganism or its toxic product
contagious disease
spread by contact
subclinical infection
presence of microorganisms and interaction with the host but no clinical illnesses
latent infection
pathogen remains inactive until the conditions become favorable to cause infection
nosocomial infection
acquired in hospital
carrier
host that harbors an infectious agent without showing clinical signs and can transmit the agent to others
what are the 3 routes of bacterial infection
- aerosol
- bloodborne
- direct penetration
how do extreme temperatures impair the defense mechanisms of URT
cold = cilia are sluggish or stop, mucus thickens
hot = dries out mucus and decreases clearance
how does airway epithelial damage impair the defense mechanisms of URT
reduced mucociliary clearance
why would it be beneficial to decrease the innate defenses present in the URT
decrease production of harmful [to the pathogen] antimicrobial substance
what factors would create a decreased immune response
- stress
- young age
- immunodeficiency
- viral infection
what are the 3 types of pathogens
- opportunistic
- primary
- secondary
define pathogenicity
qualitative (yes or no); the ability of a microbe to damage a host
define virulence
quantitative; the degree of damage caused
primary pathogen
can cause disease on its own; strain or host-dependent
blood agar shows
types of hemolysis
chocolate agar shows
heat lysed RBC and released factors V and X
MacConkey agar shows
gram-negative selectivity
lactose fermentation
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?
mannheimia haemolytica; shipping fever
an increase Ct on a PCR equals
decreased amount of bacteria
