Lecture 1/27/14: Bordetella, Haemophilus, and Legionella Flashcards
What are the 3 stages of Bordetella pertussis infection?
Catarrhal - low fever, runny nose, cough (This is where Abx will work b/c the most bact., and most contagious)
Paroxysmal - Sever cough; Whoop on inspiration; post tussive vomiting
Convalescent - less sever cough, ~45 days
Why is B. pertussis hard to detect before spread?
Catarrhal stage is most contagious, but paroxysmal stage is when symptoms are the most severe
4 reasons for the rise in whooping cough?
- Increased Surveillance
- Inc. in Ptx by bact.
- Acellular vax targets few antigens
- Most ppl don’t get booster vax
What is Fha
Filamentous hemagglutinin which allows B. pertussis to bind to glycoprot. receptor on ciliated epithelial cells causing ciliary stasis
Describe Pertussis toxin and its effects
AB5 toxin. 5 B parts bind ganglioside specific ciliated cells and phagocytes
A part ADP-ribosylates Gi protein and prevents inactivation of adenyl cyclase. This results in H2O secretion into lungs
How is the best way to test for B. pertussis?
PCR b/c no bact. when have the worst symptoms
What is special about Bordetella parapertussis?
Similar to whooping cough, but not as severe. Has the cryptic pyx operon
How can children present w/ HIB
Meningitis
What is the main virulence factor for Haemophilus Influenzae
Polyribosylribitol phosphate capsule that allows invasion of caps. And allows it to cross the BBB
How do you treat H. Influenzae?
Amoxycillin or 3rd gen. cephalosporins
Rifampin for BBB crossing as prophylaxis
What are the 2 presentations of Legionella pneumophilia?
Pontiac Fever - high infectious, mild flu-like malaise, done in day
Legionnaires’ Disease - acute pneum. w/ high fever, fibrin deposition in lower lungs
Who are at risk for Legionnaires’ Disease?
Elderly, males, smokers, emphysema, lung cancer, bronchitis
Epidemiology of Legionella pneumophilia?
Invades and parasitizes amoeba and protozoa; forms films in standing H2O; Droplets need to be aerosolized and inhaled; no person-person transmission b/c infection is deep in lungs
Pathogenesis of L. pneumophilia?
Coiling phagocytosis uptake by macrophages so can live inside; release LPS blebs; has macrophage-specific adhesion pili
How is the best way to detect legionella pneumophilia?
Urine antigen test
