WEEK 2: Bordetella Flashcards
what bacteria causes bordetella?
Bordetella: pertussis, parapertussis, holmesii
is B.pertussis gram positive or negative?
gram negative coccobacillus
what is B.pertussis commonly known as?
whooping cough
how many children die due to whooping cough each year?
estimated 100,000. remains a leading cause of death in children
what happens during the catarrhal phase? include clinical features
- it lasts around 2 weeks
- highly contagious atp
- damage to the resp tract and inflammation of the mucous membrane of air passages
- nasal congestion
- cough
- low grade fever
what happens during the paroxysmal phase? include clinical features
- it lasts 1-6 weeks
- intensification of symptoms due to damage from bacteria
- paroxysms - rapid coughs due to difficulty expelling thick mucus
- long aspiratory effort accompanied by a high-pitched “whoop” at the end
- cyanosis (blue or purple colouration of the skin or mucous membranes due to low oxygen saturation)
- exhaustion
what are the stages of infection of B.pertussis?
stage 1 - catarrhal
stage 2 - paroxysmal
stage 3 - convalescent
what happens during the convalescent phase? include clinical features
- lasts 2-3 weeks
- gradual recovery
- less persistent, paroxysmal coughs
- airway heals
what are the stages of microbial pathogenesis?
EXPOSURE, ADHERENCE, INVASION, INFECTION
how is pertussis transmitted?
through a sneeze or cough, or from touching surfaces
what 3 virulence factors help anchor Bordetella pertussis to the epithelium?
filamentous hemagglutinin, pertactin, fimbriae
what 3 toxins help invasion of the virus?
tracheal cytotoxin, pertussis toxin, adenylate cyclase toxin
what does
what does tracheal cytotoxin do?
it paralyzes cilia so they can’t sweep the bacteria away
what triggers the violent cough reflux?
a build up of mucus due to the paralysation of the epithelial cilia
what is the DTAP vaccine?
A vaccine containing vaccinations for diphtheria, tetanus, acellular pertussis
how effective is the vaccine in defending against pertussis?
> 90% effective
how is Bordatella pertussis treated?
macrolide antibiotics - catarrhal or early paroxysm phase
What is the Bordetella virulence gene (BvgAS)?
The Bvg gene controls expression of all known protein virulence factor-encoding genes and is considered the “master virulence regulator”
What does FHA stand for?
filamentous hemagglutinin
What is the function of FHA?
It’s a protein that serves as a dominant attachment factor binding to sulphated carbohydrates and remains anchored to the cell surface and allows invasion into epithelial cells.
What cells does FHA bind?
Epithelial cells
What is fimbriae assembled of?
FimD - adhesin
Fim 2/3 - body of subunits
Fim C - OM pore
What is pertactin?
it is an outer membrane protein that promotes adhesion to epithelial cells
