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27 Cards in this Set
- Front
- Back
Staining characteristics and growth profile of Bordetella pertussis |
tiny, Gram-negative coccobacilli
SLOW growing and requires NAD for growth; high maintenance |
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Order of disease phases in Bordetella pertussis (4)? How long is incubation? |
1. Incubation = 1-3 weeks |
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Catarrhal phase: a. How does it present? b. What happens at the end of this phase? c. Is the pt contagious? |
begins as symptoms appear
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Paroxysmal phase: 1. When does it occur? 2. Characteristic symptom? 3. Sign seen on serology?
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1. follows after 1-2 weeks |
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When severe, the paroxysmal coughing causes ____ and is followed by ______ |
When severe, the paroxysmal coughing causes cyanosis and is followed by vomiting |
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Convalescent phase: 1. When does it occur? 2. characterized by? 3. What type of pt STARTS with this phase? |
1. appears 2-4 weeks later |
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How is Bordetella pertussis transmitted?
What pt population is at risk? |
aerosolized droplets
Pts under 1 y/o and immunocompromised |
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Notable virulence factors of Bordetella pertussis? |
filamentous hemagglutinin, tracheal cytotoxin, pertussis toxin |
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Filamentous hemagglutinin is a ________ that Mediates attachment to _____ and ______ |
Filamentous hemagglutinin is a Surface protein that Mediates attachment to ciliated respiratory epithelial cells and macrophages |
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Tracheal cytotoxin is a fragment of _______ and causes _____ at low concentrations and ______ at higher concentrations |
Tracheal cytotoxin is a fragment of Peptidoglycan and causes ciliostasis at low concentrations and cell death/extrusion at higher concentrations; disrupts the normal clearance mechanisms |
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Pertussis toxin: 1. What type of toxin? 2. Mechanism and effect? |
1. Typical A-B toxin 2. ADP-ribosylates GPCR. This cause adenylate cyclase to continuously increase cAMP, which increases mucus/secretions |
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describe the critical factors that must be considered when collecting and culturing H. influenza and B. pertussis for lab diagnostic tests. |
Culture is hard and labs can't do it:
Because of diagnostic limitations, pertussis is almost always a clinical diagnosis. |
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basic treatment options for diseases caused by B. pertussis. |
Erythromycin, azithromycin, or clarithromycin
Supportive therapy includes close monitoring vital signs, nasotracheal suctioning, provision of oxygen, parenteral nutrition and hydration |
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describe the vaccines available for B.pertussis, including the components.
Who should get a booster? |
Acellular vaccines composed of several antigens, including pertussis toxoid and filamentous hemagglutinin and are combined with diptheria and tetanus toxoids
individuals aged 11-12; one dose of Tdap to replace Td for ages 19-64; all health care workers.
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Explain the implications of B.pertussis carriage and disease for vaccination strategies |
Vaccine uptake in the U.S. is around 98%, but some parents are still refusing to immunize children on either religious grounds or concerns about vaccine safety. Failure to vaccinate against pertussis represents a public health concern |
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Staining characteristics and growth profile of Haemophilus influenzae |
small, Gram-negative coccobacilli, often
Fastidious nature and growth requirements: |
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Is H. influenzae capsulated? |
Both encapsulated (serotypeable) and non-encapsulated strains (non- typeable) exist; this characteristic corresponds to the organism’s propensity for invasion in non-immune hosts |
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Diseases caused by H. influenzae? (6) |
1. Bacteremia 2. Meningitis 3. Septic Arthritis 4. Epiglotitis 5. Pneumonia 6. cellulitis |
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What is the most serious acute manifestation of H. influenzae?
What else is notably a medical emergency? |
most serious = meningitis
other = epiglotits |
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Transmission of H. influenzae? |
Transmission is via aerosolized droplets |
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Who is at risk for H. influenzae infection? |
1. children up to 5 2. people without spleens or other immunodeficiencies 3. genetic predisposition 4. having another resp. infection/disease 5. day care or siblings of similar age |
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Major virulence factors of H. influenzae |
capsule (in encapsulated strains), IgA protease, pili/fimbrae. |
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How does the capsule of H. influenzae contribute to virulence?
What is special about the type b capsule? |
Anti-phagocytic
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Lab methods of diagnosis of H. influenzae |
-Gram stain -Culture -Direct detection |
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Treatment of H. influenzae |
Very resistant:
Life threatening illness: Third generation cephalosporins
Non-Life Threatening: Macrolides and Quinolone |
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Vaccine for H. influenzae |
All licensed vaccines are conjugate vaccines containing PRP capsule |
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explain the implications of H.influenzae and carriage and disease for vaccination strategies. |
-Vaccine has significantly reduced disease
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