Immunity And Antibiotics Flashcards
What are the four types of immunity?
Active natural, passive natural, passive artificial, active artificial
Write a definition for active natural immunity
- 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
Write a definition for passive natural immunity
- Antibodies from one individual passed on to another by a natural process
– short-term protection
e.g. mother breastfeeding
Write a definition of passive artificial immunity
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
Write definition for active artificial immunity
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
What must a vaccine contain?
One or more antigens that can be found on the pathogen or toxin
What are the four main types of vaccination?
Attenuated virus, killed bacteria, harmless toxin, antigen bearing fragment
Give a description of attenuated virus vaccination?
– weakened virus that are harmless and less virulent
- Reproduce very slowly
– not result in symptoms in host
Give a description of the killed bacteria vaccination
The bacteria have been killed by chemicals, heat or radiation
Give a description of the harmless toxin vaccination
Inactivated toxic compound that causes the illness rather than the microorganism that produces it
Give a description of the antigen bearing fragment vaccination
A new form of vaccine. Consists of surface protein of the microorganism i.e. glycoprotein.
What is herd immunity?
– 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
What does a vaccination not protect an individual against?
Contracting the pathogen
What are disinfectant?
Kill bacteria from the area
– this reduces likelihood of bacteria being transferred from environment to the patient
What is antiseptic?
Applied to skin and wounds
– reduce likelihood of wounds becoming infected
What is an antibiotic?
- 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
Describe what is meant by the evolutionary race between bacteria and their host
– 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
Name three reasons why bacteria evolved so quickly
– 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
What is the natural selection pressure acting on bacteria?
Immune system and antibiotics
Name two types of antibiotics
Bactericidal antibiotics and bacteriostatic antibiotics
What do bactericidal antibiotics do? What are they for?
Destroy almost all pathogens present, can cause cell lysis
For severe and dangerous infections, as well as in patients with suppressed immune system
What do bacteriostatic antibiotics do?
- Antibiotic completely inhibits multiplication/replication of pathogen
– host immune system can then destroy the pathogen
Outline four ways how antibiotics can disrupt bacterial cell growth and division
– 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
What do broad spectrum antibiotics do?
Destroy wide range of harmful bacteria pathogens, also destroy good bacteria
What do narrow spectrum antibiotics do?
Target one or two specific pathogens
The effectiveness of antibiotic depends on, 5 points
– 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
Why don’t antibiotics destroy animal cells/viruses?
– Animal cells are eukaryotic cells (so have no cell walls, larger ribosomes, different enzymes)
- viruses don’t have subcellular components
Why are bacteria becoming resistant to antibiotics?
– 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
Give two examples of multi drug resistant bacteria
TB and MRSA
Outline the measures hospitals use in controlling the development of multi drug resistant bacteria and their spread
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.
