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Flashcards in Bacterial Upper Respiratory Infections Deck (44):
0

Describe bordetella

Aerobic encapsulated gram negative coccobacilli
Single or in pairs

1

Bordetella pertussis causes what?

whooping cough, caused by local effect of toxins

2

There is waning immunity to bordetella pertussis. Who serves as a resevoir?

Adults

3

Bordetella pertussis isolation media?

Bordet-gengou media is selective
Contains blood and starch (absorbs and neutralizes inhibitors of growth)
Penicillin is added to inhibit other respiratory flora

4

How quickly does bordetella pertussis grow?

Takes 3-7 days for colonies to appear on Bordet-gengou media

5

Is there an animal reservoir for bordetella pertussis?

No

6

How is b. pertussis spread?

Person-person via airborne droplets

7

Pathogenesis of b. pertussis?

Organism adheres to and then kills ciliated epithelial cells of upper respiratory tract, this prevents clearance of pulmonary secretions
Does not invade the blood stream

8

Pertussis toxin action?

Binds to ciliated epithelial cells
Causes lymphocytosis and inhibits phagocyte function
2 subunit AB exotoxin: ADP ribosylating activity >> increases cAMP > increases secretions

9

What is filamentous hemagglutinin?

Adhesin that allows bacterium to bind to ciliated epithelial cells

10

What are the three clinical stages of pertussis?

Catarrhal stage ~1 week
Paroxysmal stage ~1-6 weeks
Convalescence weeks to months

11

Describe the catarrhal stage of pertussis

Presents like common cold, not very ill
Highly contagious - large number of organisms in respiratory organisms

12

Paroxysmal stage of pertussis

Burst of rapid coughs without inspiration due to difficulty clearing thick mucus, may end with vomiting, cyanosis, exhaustion, convulsions
Whoop sound from inhaling through narrowed glottis

13

What can happen to the eyes in pertussis?

Subconjunctival hemorrhages

14

How do you diagnose pertussis

Nasopharyngeal aspirate (preferred) culture

15

First line of defense against pertussis?

Antibody that prevents bacteria from binding to cilia of epithelium

16

Pertussis vaccine

Acellular or subunit vaccine

17

How much protection (%) does pertussis toxin monovaccine provide? Is it sufficient?

Not sufficient, only 70% protection

18

Which pertussis vaccine is used today, acellular or whole cell? Why?

Acellular
Reduced side effects

19

What is the DTaP vaccine? When is it given?

Diptheria, Tetanus, and acellular Pertussis toxoid
Three shots at 2, 4, 6 months

20

What is the Tdap vaccine?

It is a booster shot for adolescents and adults that contain less diptheria and acellular pertussis toxoid

22

Cyclic epidemic of pertussis spikes every how many years?

3-4 years

23

Describe corynebacterium?

Aerobic non-spore forming gram positive bacilli
Non-motile

24

Clinical manifestations of corynebacterium diphtheriae are due to what?

Toxin carried by a bacteriophage
Causes only localized disease

25

Gram stain of corynebacterium diphtheriae?

Gram positive
Clubbed or irregularly shaped
V or L shaped formations
Beaded staining

26

Corynebacterium diphtheriae culture media?

Blood agar: small granular gray colonies with irregular edges
Potassium tellurite agar (Tinsdale) black colonies - differential medium
Loeffler's medium: corynebacterium grow faster than other respiratory pathogens - selective medium

27

C. Diphtheriae, human or animal resevoir?

Just human
Normal flora of skin and mucous membranes
Infections of respiratory tract

28

How does C. diphtheriae spread and does it invade tissues/blood?

Airborne droplets
Does not invade tissues or blood

29

Diphtheria toxin is encoded by what? Can it still be pathogenic without the toxin?

Diphtheria toxin is encoded by a bacteriophage
If it is not infected by the bacteriophage then it is not pathogenic

30

Diphtheria toxin - 2 subunit AB toxin - describe

Highly potent toxin with necrotizing effect
Lethal at low dose
A subunit inhibits host protein synthesis (inactivates elongation factor EF-2 by ADP-ribosylation, which leads to cell death)

31

Diphtheria toxin absorbed by mucous membranes causes what?

Epithelial necrosis which causes a gray pseudomembrane to form over tonsils and throat

32

Can diphtheria toxin affect anything other than tonsils/throat?

Yes it can cause heart and nerve damage

33

What does diphtheria do to the neck?

Causes bull neck - marked edema of neck and cervical lymphadenopathy

34

Does diphtheria toxin cause wounds?

Yes, forms a membrane of a non-healing wound or ulcer

35

What is the population at risk for infection with diphtheria?

Adults with decreased antitoxin titers

36

Resistance to disease caused by diphtheria depends on what?

Specific neutralizing antitoxin in bloodstream and tissues

37

Is there a vaccine for diphtheria?

Yes, formalin-inactivated C. diphtheria

38

Diphtheria vaccine is often combined with what?

DTaP
Diphtheria, Tetanus, acellular Pertussis

39

Adults need a diphtheria booster shot how often and when?

Every 10 years
Also when they travel to developing countries
Given with tetanus toxoid

40

A derivative of the diphtheria toxoid (CRM 197) is used in which other vaccines? Why?

Haemophilus influenzae type B, pneumococcal, meningococcal conjugate vaccines
More immunogenic in children under 2

41

Which antibiotics for diphtheria toxin? How do they help?

Erythromycin or penicillin
Inhibit growth of toxin-producing bacteria
Stop toxin production
Reduce shedding of organism

42

Do diphtheria patients have to be isolated?

Yes

43

Describe propionibacterium acne?

Normal skin flora, anaerobic
Acne pathogenesis
Occasionally contaminates blood
Infections in patients with "hardware"

53

Which antibiotic is used for pertussis? What affect does it have during each stage?

Erythromycin
Catarrhal stage: eliminates organism
Paroxysmal stage: reduces severity and duration and lowers complication rate
Limited benefit if given more than 3 weeks after paroxysmal cough