35 Bordetella Flashcards
1
Q
What is the structural morphology of Bordetella?
A
- Small, G (-) coccobacillus strictly aerobic, nonmotile oxidize amino acids and cannot ferment carbohydrates.
2
Q
What are the 4 species of Bordetella that can cause disease in humans?
A
- B. pertussis, B. parapertussi, B.bronchiseptica, B. holmesii
3
Q
Which strain of Bordetella causes Whooping cough?
A
- Bordetella pertussis
4
Q
What are the protein adhesions that mediate the B. pertussis to attach to ciliated epithelial cells?
A
- Pertactin and filamentous hemagglutinin
5
Q
Describe the Pertussis toxin.
A
- Classic A-B toxin consisting of a toxic subunit (S1) and five binding subunits (S2 to S5; two S4 subunits are present in each toxin molecule. The S2 subunit binds to lactosylceramide, a glycolipid present on ciliated respiratory cells.
6
Q
What does the S1 portion of the pertussis toxin have and what does it do?
A
- ADP-ribosylating activity for the membrane surface of G proteins (it regulates adenylate cyclase activity). The pertussis toxin inactivates G-i-alpha, the inhibitory protein that controls adenylate cyclase activity. The uncontrolled expression of the enzyme leads to an increase in cAMP and subsequent increase in respiratory secretion and mucus production characteristic of the paroxysmal stage of pertusis.
7
Q
What is the reservoir for B. pertussis?
A
Humans
8
Q
How is B. pertussis spread?
A
- Inhalation of infectious aerosols and the bacteria become attached to and proliferate on ciliated epithelial cells.
9
Q
What are the 3 stages of pertussis?
A
- 1) Catarrhal stage (resembling common cold, serous rhinorrhea, sneezing, malaise, low-grade fever) Peak number of bacteria is produced in this stage = Most contagious stage.
- 2) Paroxysmal stage (classic whooping cough paroxysms. 2-4 weeks.
- 3) Convalescent stage (paroxysms diminishes in number and severity but secondary complications can occur.
10
Q
What sucks about laboraty diagnosis of B. pertussis?
A
- Extremely sensitive to drying; specimen (best collected from nasopharyngeal aspirate) should be inoculated at patient’s bedside or Rogan-Lowe transport medium.
11
Q
What is the most sensitive tests available for pertussis?
A
- Polymerase chain reaction (PCR)
12
Q
What is the treatment for pertussis?
A
- Primarily supportive, with nursing supervision during the paroxysmal and convalescent stages of the illness. Macrolides are effective in eradicating the organism and can reduce the duration of infectivity.
