Diphtheria Flashcards Preview

Meharry Micro > Diphtheria > Flashcards

Flashcards in Diphtheria Deck (36):
1

What causes symptoms of diphtheria

Exotoxin

2

Why don’t we see a lot of diphtheria in the us

We have a vaccine

3

Diphtheria are gram positive or gram negative

Gram positive

4

Do diphtheria form spores

No

5

What is the selective medium for diphtheria

Potassium tellurite aka Tinsdale

6

How many virulence factors does diphtheria have and what does it do

Exotoxin, it inhibits protein synthesis

7

What is the structure of the exotoxin in diphtheria

A B toxin

A subunit - goes into cytoplasm and does ADP ribosylation , so protein synthesis can not occur .. which kills the cell
B subunit -binds to receptor in target cell

8

Toxin production is under what kind of control

Genetic

9

Where is the gene which encodes the toxin found

It is located on a bacteriophage called a beta phage

10

If the diphtheria do not carry a beta phage are they toxigenic ?

No, only if they have the phage will they be able to make toxin.

11

Describe lysogenic conversion

Non toxigenic diphtheria can be converted to toxic if they become infected with a beta phage. This process is lysogenic conversion

12

In addition to genetic control, what controls genetic toxin

Physiologic control

13

High concentrations of what suppress toxin repression

Iron

14

What is necessary for maximal toxin to be produced

Low iron

15

Where is the site of infection in diphtheria

Pharynx

16

Where is the repressor for the toxin found

On bacterial chromosome

17

Where is the gene for the toxin found

On the phage chromosome

18

In the presence of high iron what happens to the repressor

The complete repressor complex forms which binds to the operator which stops transcription of the toxin gene

19

When there are low iron levels can the repressor co repressor complex be made

No , so transcription can take place

20

The complete repressor complex is an example of what kind of regulation

Negative

21

What can cause obstruction of breathing

A pseudomembrane is formed

22

What kind of antibody is formed

Antitoxin

23

Getting immunity from having the disease is considered what kind of immunity

Natural active acquired

24

If maternal antibodies vaccinate you what is this called

Natural passive immunity

25

What kind of immunity is gained from getting diphtheria vaccine

Artificial active acquired

26

How would you prevent it

Active immunizations at 2,4,6 booster every 10 yrs

27

What are the treatments to diphtheria

Penicillin + antitoxin. ( erythromycin if allergic)

28

Why is anti toxin given as treatment in addition to penicillin

Some toxin has likely already been produced

29

Do all diphtheria carry toxin

No! Only if it has an bacteriophage

30

Describe Elek Immunodiffusion test

The strain making the toxin will make antigen antibody precipitin rings . The strain not making toxin will not make the rings

31

What is the name of the test used to see if the bacteria is carrying toxins

Elek Immunodeficiency test

32

What is a key give away for a child getting diphtheria

A yellowish thick membrane that bleeds easily and no immunizations

33

What does the morphology of this organism look like

Chinese letters

34

To cause disease does it invade the blood stream

It produces endotoxin

35

Is cell mediated or humoral immunity created

Humoral. (IgG) to exotoxin

36

How is the diesease prevented

Children given Diptheria vaccine at 2 months of age