URIs Flashcards
What are the components of the upper respiratory system?
Conjunctiva Nasolacrima ducts Epiglottis Middle ear Sinuses and nasal cavity Pharynx Larynx The nose
What does surfactant contain that provides protection from pathogens?
IgA
Fibronectin
Surfactant
macrophages
What is the consequence of EtOH, smoke, and narcotis on the cilia of the upper respiratory tract?
Inhibits them
What parts of the UR system are not colonized by bacteria? (7)
mastoid air cells middle ear sinuses trachea bronchi bronchioles alveoli
True or false: Most healthy individuals have no bacteria in their conjunctiva
True
What keeps the conjunctiva usually sterile?
Lysozyme and eyelid blinking
What are the normal nose flora? (3)
Staphlococcus epidermidis
Staphylcococcus aureus
Corynebacterium spp (diptheroids)
What is the gram stain and morphology of staph?
Gram + cocci
What is the gram stain and morphology of strep?
Gram + cocci
What is the gram stain and morphology of corynebacterium?
Gram + rod
What are the four strep bacteria that are found in the nasopharynx (from the viridans group)? Are these usually pathogenic?
S. mutans
S. mitis
S. milleri
S. salivarius
These are not usually pathogenic
What are the three major groups of bacteria that are in the nasopharynx?
Strep
Moraxella catarrhalis
Bacteroides
Are strep bacteria aerotolerant?
Yes
What is the gram stain and morphology is moraella catarrhalis? Aerobic or anerobic?
Gram negative coccobacillus
Aerobic
What does staph aureus look like in tissue?
Bunches of grapes
What are the four common pathogens in the nasopharynx, especially in the winter months?
Strep penumoniae
Haemophilus influenze
Moraxella catarrhalis
Are strep bacteria catalase negative or positive?
Negative
Are staph bacteria catalase negative or positive?
Positive
What is group A strep?
S. pyogenes
What is group B strep?
S. agalactiae
What is group D strep?
S. bovis or Enterococcus faecalis
What is the one alpha hemolytic group of strep?
Strep Pneumoniae
What is the causative agent of strep throat?
Strep pyogenes (group A)
What is the hemolytic result of strep pyogenes?
beta
What is the target of a rapid strep test?
Cell wall antigen
What does alpha hemolytic mean?
Partial hemolysis of blood (green coloration)
What does beta hemolysis mean?
Complete hemolysis around colonies (clear zone around colonies)
What does gamma hemolysis mean?
No hemolysis
What is the M protein that is on Strep pyogenes?
Antiphagocytic essential for virulence (there are 80 serotypes). This degrades C3b
What is the importance of the capsule that some strep pyogenes have?
Inhibits phagocytosis and is a virulence factor
Why can someone get infected with strep mutiple times a year?
There are 80 serotypes of the virulence factor
What are the superantigens of strep pyogenes?
SPE A, B etc, that are the cause of toxic shock syndrome, fever, rash
What is the F protein that strep pyogenes has?
Mediates attachment to host cell
Only what disease that S pyogenes causes that is preceeded by a strep throat?
Scarlet fever
What is the function of streptolysin O that S. Pyogenes produces? What is this useful for?
cytotoxin responsible for beta hemolysis, lyse red and white cells.
Antibodies against streptolysin O useful for diagnosis
What is the function of streptokinase that S.Pyogenes produces?
lyses blood clots and facilitates dissemination of bacteria
What is the function of C5a peptidase that Strep Pyogenes produces?
enzyme that degrade C5a component of complement, inhibits attraction of phagocytes
Why do we treat strep throat with abx if it would resolve in 7 days anyway?
Scarlet fever and rheumatic fever
Why have vaccines been ineffective against Strep throat?
80 different serotypes
What is scarlet fever? What is caused by?
Redness of skin, and white coating on the tongue
Caused by erytherogenic toxin release
What is acute rheumatic fever? What is it caused by?
A cross reaction of our immune response to S. Pyogenes and our own tissues. This causes heart arrhythmias, arthralgias.
What is the treatment for rheumatic fever?
Immunosuppressants