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Flashcards in Respiratory Pathogens Deck (70)
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1

Name 6 pathogens that contribute to lower respiratory tract infections

- haemophilus influenza
- strep. Pneumoniae
- legionella pneumophila
- mycobacterium tuberculosis
- mycoplasma pneumonia
- chlamydia pneumonia

2

What are the two factors that affect the degree of pathogenicity of a disease causing organism?

- the proteins it expresses
- how effectively it can integrate environmental information

3

What does bacterial adhesion involve?

Surface interactions between specific receptors on the mammalian cell membrane (usually carbohydrates) and ligands (usually proteins) on the bacterial surface

4

What is bacterial invasion?

Bacteria invasion refers to the penetration of host cells and tissues, and is mediated by a complex array of molecules called invasins

5

What molecules mediate bacterial invasion?

Invasins

6

Mechanisms that result in the evasion of host defences (x5)

- immunity at mucosal surfaces
- destruction of immune cells
- interference with inflammatory response
- evasion of innate immunity
- overcome acquired immune responses

7

How does the bacteria overcome acquired immune responses?

Phase/Antigen variation - switching between on and off forms of a gene / allowing the bacterium to change the sequence of a gene

8

What are endotoxins?

Lipopolysaccharides complexed to proteins that occur in the outer membrane of the envelope of gram negative bacteria

9

Principal antibody type produced at mucosal surfaces? What molecules cleave these immunoglobulin?

IgA
Proteases

10

Incubation period of Diphtheria

2-6 days

11

What does corynebacterium diphtheria cause/what is it characterised by?

Infects mucous membranes (tonsils) - toxin produces acute inflammation and formation of pseudomembrane

12

Early symptoms of corynebacterium diphtheria

Sore throat
Low fever
Swollen neck glands

13

Late symptoms of corynebacterium diphtheria (x3)

Airway obstruction
Difficulty breathing
Shock -> hypotension, tachycardia, pale, cold skin, sweating, anxious

14

What are diphtheria outbreaks associated with? (X2)

Unsanitary/crowded conditions
Immunity gaps, vaccination failure

15

Is corynebacterium diphtheria
I) gram positive or gram negative
II) cocci or bacilli
III) aerobic or anaerobic
IV) motile or non-motile
V) growth medium

Gram positive
Bacilli
Aerobic
Non-motile
Grows in tellurite agar, which is toxic for other throat flora

16

How is corynebacterium diphtheria transmitted?

Direct contact droplets/skin
Indirect via contaminated object

17

Treatment of Diphteria (x2)

- immediate inoculation with diphtheria anti-toxin
- administer penicillin or erythromycin to eliminate the bacteria

18

Prevention of diphtheria

Active immunisation
Diphtheria Formal Toxoid (DFT Vaccine) - part of multiple vaccine - given at 2,3,4 months ; booster jab at 5 years

19

How does diphtheria enters the cell?

Endocytosis - proteolytic cleavage takes place in the cell, resulting in 2 fragments

20

Which bacteria causes whooping cough?

Bordetella Pertusis

21

Describe the appearance of B. Pertussis (x3)

Small,
Gram-negative
Cocci

22

Transmission of Bordetella Pertussis

Infection by exposure to infected individual

23

Clinical features of B. Pertussis infection (x4)

- insidious onset
- catarrhal stage with common cold symptoms
- paroxysmal coughing
- residual cough

24

What may adults suffering from bordetella pertussis experience? (X4)

- shortness of breath during coughing
- nocturnal coughing
- tingling sensation in back of throat
- post-tussive vomitting

25

Route of infection of B. Pertussis

The organism infects the ciliated epithelial layer of the respiratory tract without invading deeper, resulting in an acute tracheobronchitis

26

What mediates the action of B. Pertusis? (X2)

- filamentous hemagglutinin (FHA)
- cell bound pertussis toxin (PTx)

27

What is pertactin (PRN)?

The outer membrane protein that promotes the attachment of B. Pertussis to tracheal epithelial cells

28

What is the outer membrane protein that promotes the attachment of B. Pertussis to tracheal epithelial cells

Pertactin

29

Name 4 toxins involved with bordetella pertussis

1. Pertussis toxin
2. Adenylate cyclase/hemolysin
3. Tracheal cytotoxin (TCT)
4. Lipopolysaccharide (endotoxin)

30

Pathogenesis of B. Pertussis

- Growth on ciliate epithelial and toxin production, killing the ciliate epithelial cells and inducing mucous secretions
- Stimulates inflammatory response
- Kills leucocytes