Infections of Cardiorespiratory system

Question 1

What are the characteristics of streptococci?

Answer 1

Gram positive 
mesophile 
facultative anaerobe 
growth at neutral-slightly acidic pH 
complex nutritional requirements

Question 2

What is the function of the mucociliary escalator?

Answer 2

primary defense of the lower respiratory tract and keeps the middle ear, sinuses, mastoids and lungs sterile

Question 3

How does a virus cause infection?

Answer 3

It can cause damage to the cilia which allows the establishment of infection due to the breakdown of the mucociliary escalator

Question 4

What is streptococci pneumoniae?

Answer 4

Gram positive diplococci which is part of the commensal microflora

Question 5

What are adhesions and how do they work?

Answer 5

cell surface components of bacteria that facilitate adhesion or adherence to other cells or to surfaces. They are a type of virulence factor. Adherence is an essential step in bacterial pathogenesis or infection

Question 6

What is the role of a capsule?

Answer 6

they are impedins and confer resistance to phagocytosis

Question 7

Clinical symptoms of Sp pneumoniae

Answer 7

Abrupt onset with high fever 
chest pain 
cough 
shortness of breath 
difficulty and pain on breathing 
most commonly associated with history of previous viral infection and/or chronic health problems

Question 8

What are the clinical symptoms of otitis media?

Answer 8

fever, earache, blocked eustachian tube

Question 9

What are the clinical symptoms of sinusitis

Answer 9

fever, facial pain, headache, blocked nose

Question 10

how does S. pneumoniae cayse infection?

Answer 10

When the mucociliary escalator is inhibited Sp colonises sterile areas of the upper/lower respiratory tract

Question 11

What are the sterile regions of the respiratory tract?

Answer 11

middle ear, mastoids, sinuses and lungs

Question 12

Name four significant respiratory tract pathogens

Answer 12

Streptococcus pneumoniea
Moraxella catarrhalis
Haemophilus influenzae
Neisseria meningitis

Question 13

What is the gram stain appearance of Streptococcus pneumoniea

Answer 13

Gram positive diplocicci

Question 14

What is the gram stain appearance of Moraxella catarrhalis

Answer 14

gram negative diplococci

Question 15

What is the gram stain appearance of Haemophilus influenzae

Answer 15

Gram negative coccobacilli

Question 16

What is the gram stain appearance of Neisseria meningitis

Answer 16

Gram negative dilococci

Question 17

Describe the pathophysiology of respiratory tract infections

Answer 17

Exogenous (and endogenous) pathogen colonises in the nose/throat which leads to the ciliated cell defense being impaired. This causes infection of normally sterile areas like the eustachian tube and lung which can lead to pneumonia, otitis media and sinusitis. This leads to inflammation and tissue damage which can cause progression to bacteremia

Question 18

What are the typical commensal flora of the URT?

Answer 18

neisseria spp
haemophilus spp
moraxella spp

Question 19

moraxella and neisseria are more common in which areas?

Answer 19

Moraxella: URT
Neisseria: LRT

Question 20

what are the sterile regions of the RT?

Answer 20

middle ear, sinuses, mastoids and lung

Question 21

what are 4 significant RT pathogens and what are their gram stain appearance?

Answer 21

s. pneumoniae - gram positive diplococci
moraxella catarrhalis - gram negative dipococci
Haemophilus influenzae - gram negative coccobacilli
Neisseria meningitidis - gram negative diplococci