Immunity And Antibiotics

Question 1

What are the four types of immunity?

Answer 1

Active natural, passive natural, passive artificial, active artificial

Question 2

Write a definition for active natural immunity

Answer 2

• An individual mounts a specific primary response after naturally contracting a pathogen and creates antibodies and memory cells.
• Long-term protection
  e.g. child exposed to chickenpox

Question 3

Write a definition for passive natural immunity

Answer 3

• Antibodies from one individual passed on to another by a natural process
  – short-term protection
  e.g. mother breastfeeding

Question 4

Write a definition of passive artificial immunity

Answer 4

Antibodies from one individual passed on to another via injection to provide immediate short-term protection
– e.g. someone injected with antibodies from someone else who has had a primary immune response for Ebola

Question 5

Write definition for active artificial immunity

Answer 5

A form of pathogen injected into an individual who then mounts a specific primary immune response to create antibodies and memory cells
– long-term protection
– e.g. measles vaccination

Question 6

What must a vaccine contain?

Answer 6

One or more antigens that can be found on the pathogen or toxin

Question 7

What are the four main types of vaccination?

Answer 7

Attenuated virus, killed bacteria, harmless toxin, antigen bearing fragment

Question 8

Give a description of attenuated virus vaccination?

Answer 8

– weakened virus that are harmless and less virulent
- Reproduce very slowly
– not result in symptoms in host

Question 9

Give a description of the killed bacteria vaccination

Answer 9

The bacteria have been killed by chemicals, heat or radiation

Question 10

Give a description of the harmless toxin vaccination

Answer 10

Inactivated toxic compound that causes the illness rather than the microorganism that produces it

Question 11

Give a description of the antigen bearing fragment vaccination

Answer 11

A new form of vaccine. Consists of surface protein of the microorganism i.e. glycoprotein.

Question 12

What is herd immunity?

Answer 12

– When more people are vaccinated, the disease is less likely to be transferred between people
– so there is less overall disease in the community
– group protection

Question 13

What does a vaccination not protect an individual against?

Answer 13

Contracting the pathogen

Question 14

What are disinfectant?

Answer 14

Kill bacteria from the area
– this reduces likelihood of bacteria being transferred from environment to the patient

Question 15

What is antiseptic?

Answer 15

Applied to skin and wounds
– reduce likelihood of wounds becoming infected

Question 16

What is an antibiotic?

Answer 16

• A chemical substance produced by microorganisms
  – has capacity to inhibit multiplication, replication or even to destroy bacteria within a patient
  – reduce likelihood of spreading infection

Question 17

Describe what is meant by the evolutionary race between bacteria and their host

Answer 17

– As the host evolves to combat pathogen, the pathogen evolves a new method of overcoming the immune system
– hosts antibodies and memory cells are now useless as the pathogen has evolved

Question 18

Name three reasons why bacteria evolved so quickly

Answer 18

– Bacteria reproduce very fast
– bacterial populations are very large, containing vast amount of mutations and large gene pool
– some random mutations in bacteria will be advantageous, may allow bacterial cell to reproduce more quickly
The bacteria with advantageous allele are more likely to survive, reproduce and spread

Question 19

What is the natural selection pressure acting on bacteria?

Answer 19

Immune system and antibiotics

Question 20

Name two types of antibiotics

Answer 20

Bactericidal antibiotics and bacteriostatic antibiotics

Question 21

What do bactericidal antibiotics do? What are they for?

Answer 21

Destroy almost all pathogens present, can cause cell lysis
For severe and dangerous infections, as well as in patients with suppressed immune system

Question 22

What do bacteriostatic antibiotics do?

Answer 22

• Antibiotic completely inhibits multiplication/replication of pathogen
  – host immune system can then destroy the pathogen

Question 23

Outline four ways how antibiotics can disrupt bacterial cell growth and division

Answer 23

– Inhibit bacterial cell synthesis
– disruption of cell membrane
– inhibition of new nucleic acid synthesis, replication and transcription, this can prevent cell division
– inhibition of protein synthesis
– inhibition of specific bacterial enzymes

Question 24

What do broad spectrum antibiotics do?

Answer 24

Destroy wide range of harmful bacteria pathogens, also destroy good bacteria

Question 25

What do narrow spectrum antibiotics do?

Answer 25

Target one or two specific pathogens

Question 26

The effectiveness of antibiotic depends on, 5 points

Answer 26

– Antibiotics concentration
– How quickly it reaches infected tissue
– The pH of local environment whether antibiotic is working
– Whether the host cell or pathogen destroys the antibiotic
– The susceptibility of pathogen to antibiotic

Question 27

Why don’t antibiotics destroy animal cells/viruses?

Answer 27

– Animal cells are eukaryotic cells (so have no cell walls, larger ribosomes, different enzymes)
- viruses don’t have subcellular components

Question 28

Why are bacteria becoming resistant to antibiotics?

Answer 28

– Antibiotic provides selection pressure, naturally occurring genetic variation in bacterial population
– a random mutation created new allele for resistance
– bacteria do not possess new allele so are more likely to be destroyed
- those which do have advantageous all are more likely to survive and reproduce e.g. new enzyme that can destroy antibiotic

Question 29

Give two examples of multi drug resistant bacteria

Answer 29

TB and MRSA

Question 30

Outline the measures hospitals use in controlling the development of multi drug resistant bacteria and their spread

Answer 30

They ensure that doctors and patients follow a code of conduct, can be insured by…
1. Doctors is only prescribing antibiotics when patients need it.
2. Patients should be educated by the doctor the importance of them completing their course of treatment even if they feel better.
3. Handwashing, entrance awards and hospitals and alcohol gel at the end of patients beds.
4. Clothing and personal items (which could be fomites) ensure rules regulated about these, doctors and nurses have rules preventing them wearing watches, ties and long sleeves
5. Antibiotic use, use of prophylactic antibiotic (used in case of infection) is strictly controlled
6. Different antibiotics used for repeat infections.