Otitis, Diphtheria, Pertussis Flashcards
What is the causative agent of Pertussis
Bordetella pertussis
Most common bacterial causes of otitis externa:
- Pseudomonas aeruginosa
2. Staphylococcus aureus
What does dermonecrotic toxin do?
Bordetella pertussis
vasoconstriction and ischemic necrosis
immune cells can’t get to where they need to go
What does Adenylate Cyclase toxin do?
Bordetella pertussis
decreased chemotaxis
Unique testing for Moraxella catarrhalis
oxidase positive
B-lactamase producer
Pseudomonas aeruginosa
Gram: ____
Shape: ______
Pseudomonas aeruginosa
Gram: negative
Shape: bacilli
Moraxella catarrhalis
Gram: ____
Shape: ______
Gram: negative
shape: diplococci***
Streptococcus pneumoniae effect on RBCs
a-hemolytic
partially lyse RBCs
What is Pyoverdin
pigment produced by Pseudomonas aeruginosa
not a virulence factor
Used to identify
Green
How long does the Catarrhal stage of Pertussis last
1-2 weeks
What type of toxin is diphtheria toxin
A-B exotoxin
What is Pyocyanin
pigment produced by Pseudomonas aeruginosa
virulence factor
Blue
What is the special test associated with testing for the toxin production of diphtheria
Elek test
immunodiffusion assay to secretion of exotoxin
Transmission of diphtheria
person-to-person
Respiratory droplets or skin contact
What are the weird dots at the end of Corynebacterium called
metachromatic (volutin) granules
Virulent strains of Streptococcus pneumoniae have what?
encapulated
What are the pigments produced by Pseudomonas aeruginosa
pyocyanin
pyoverdin
Which stage of Pertussis are patients most contagious
Catarrhal stage
Bordetella pertussis
Gram: ____
Shape: ______
gram: negative
shape: coccobacilli
*very small
Your tiny baby patient has pertussis and has fewer paroxysms than before. What stage of Pertussis does this baby have?
What are you most worried about?
Convalescent stage
pneumonia** but also encephalopathy, seizures, death
P. Aeruginosa and S. Aureus are the two major bacterial causes of otitis externa because:
they grow best in moisture
Swimmer’s Ear
(Bordetella pertussis)
______ mediate attachment to ________ and subsequent colonization of the ciliated respiratory epithelium
(Bordetella pertussis)
ADHESINS mediate attachment to INTEGRINS and subsequent colonization of the ciliated respiratory epithelium
What is the causative agent of Diphtheria
Corynebacterium
You’ve determined the species to be Staphylococcus from a gram stain, but we need to see if it is Staphylococcus aureus. How can we do this
Coagulase test
Staphylococcus aureus is coagulase positive (can cause blood clotting)
How long does the Paroxysmal stage of Pertussis last
” weeks “
What stimulates diphtheria toxin
low iron concentration
Describe the process of the diphtheria toxin
- B subunit binds to heparin-binding EGF receptor
- Exotoxin endocytosed
- A subunit inactivates EF-2 via ADP ribosylation
- halts protein synthesis - kills cell
What does Pyoverdin do
Sequesters Iron (a siderophore)
Your tiny baby patient has pertussis and has paroxysmal coughing, often followed by vomiting. The cough sounds like a whoops. What stage of Pertussis does this baby have?
Paroxysmal stage
Staphylococcus aureus effect on RBCs
B-hemolytic
can completely lyse RBCs
Your tiny baby patient has pertussis and has nonsepcific upper respiratory tract symptoms. I don’t know how you know they have Pertussis from these nonspecific symptoms but whatever. What stage of Pertussis does this baby have?
Catarrhal stage
What are the four extotoxins associated with Bordetella pertussis
- Dermonecrotic toxin
- Tracheal cytotoxin
- Pertussis toxin (A-B exotoxin)
- Adenylate cyclase toxin
What does Pertussis (A-B exotoxin) do?
Bordetella pertussis
large-scale destruction
causes lymphocytosis
What does Pyocyanin do
generates ROSs
reactive oxygen species
What does Tracheal cytotoxin do?
Bordetella pertussis
kills ciliated respiratory epithelial cells
stimulated IL-1 release
Haemophilus influenzae
Gram: ____
Shape: ______
Gram: negative
Shape: coccobacilli
Staphylococcus aureus
Gram: ____
Shape: ______
Gram: positive
shape: Cocci in CLUSTERS
Two clinical manifestations of diphtheria toxin that are very important
- formation of pseudomembrane
2. bull neck
Which bacteria is fluorescent even without a UV light
Pseudomonas aeruginosa
What two cultures are associated with diphtheria diagnosis
- Loeffler’s medium (volutin granules)
2. Cysteine-tellurite agar (black to tellurite reduction)
Most common bacterial causes of otitis media and sinusitis:
- Streptococcus pneumoniae (50%)
- Haemophilus influenzae (20%)
- Moraxella catarrhalis (10%)
Streptococcus pneumoniae is sensitive to what antibiotic on an agar
optochin
Corynebacterium
Gram: ____
Shape: ______
Gram: positive
Shape: pleomorphic bacilli, “palisades” or “V” shape
What two cultures are associated with a definitive diagnosis of Bordetella pertussis
- Bordet-Gengou agar
2. Regan-Lowe Agar
How long is the incubation phase of Pertussis
7-10 days
After localized damage of the exotoxin of diphtheria (causing pseudomembrane, bull neck, and gross stuff) what other crazy thing can happen
systemic toxicity
myocarditis
demyelination
Streptococcus pneumoniae
Gram: ____
Shape: ______
Gram: positive
shape: diplococci**
