Infections of Cardiorespiratory system Flashcards
What are the characteristics of streptococci?
Gram positive mesophile facultative anaerobe growth at neutral-slightly acidic pH complex nutritional requirements
What is the function of the mucociliary escalator?
primary defense of the lower respiratory tract and keeps the middle ear, sinuses, mastoids and lungs sterile
How does a virus cause infection?
It can cause damage to the cilia which allows the establishment of infection due to the breakdown of the mucociliary escalator
What is streptococci pneumoniae?
Gram positive diplococci which is part of the commensal microflora
What are adhesions and how do they work?
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
What is the role of a capsule?
they are impedins and confer resistance to phagocytosis
Clinical symptoms of Sp pneumoniae
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
What are the clinical symptoms of otitis media?
fever, earache, blocked eustachian tube
What are the clinical symptoms of sinusitis
fever, facial pain, headache, blocked nose
how does S. pneumoniae cayse infection?
When the mucociliary escalator is inhibited Sp colonises sterile areas of the upper/lower respiratory tract
What are the sterile regions of the respiratory tract?
middle ear, mastoids, sinuses and lungs
Name four significant respiratory tract pathogens
Streptococcus pneumoniea
Moraxella catarrhalis
Haemophilus influenzae
Neisseria meningitis
What is the gram stain appearance of Streptococcus pneumoniea
Gram positive diplocicci
What is the gram stain appearance of Moraxella catarrhalis
gram negative diplococci
What is the gram stain appearance of Haemophilus influenzae
Gram negative coccobacilli
What is the gram stain appearance of Neisseria meningitis
Gram negative dilococci
Describe the pathophysiology of respiratory tract infections
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
What are the typical commensal flora of the URT?
neisseria spp
haemophilus spp
moraxella spp
moraxella and neisseria are more common in which areas?
Moraxella: URT
Neisseria: LRT
what are the sterile regions of the RT?
middle ear, sinuses, mastoids and lung
what are 4 significant RT pathogens and what are their gram stain appearance?
s. pneumoniae - gram positive diplococci
moraxella catarrhalis - gram negative dipococci
Haemophilus influenzae - gram negative coccobacilli
Neisseria meningitidis - gram negative diplococci
