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Life Sciences 2 > Lecture 10 > Flashcards

Lecture 10 Flashcards

1
Q

Antimicrobials

A
  1. Naturally occurring substances produced by various species of microorganisms:
    - bacteria
    - fungi
  2. Synthetically produced
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2
Q

Bacterial clearance

A

Immunity to bacteria is mainly achieved by
Antibodies:
➢ Removing the bacteria
➢ Neutralisation and/or inactivation of
toxins
Bacteria that are introduced in low numbers or are weakly pathogenic can be cleared by
phagocytic cells alone:
➢ Removal can be due to binding of Ab
and/or complement leading to
phagocytosis and cell death

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3
Q

Antibiotics Actions:

A
  • Bactericidal
    ➢Kills bacteria, reduces bacterial load
  • Bacteriostatic
    ✓Inhibit growth and reproduction of bacteria
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4
Q

Bacteriocidal Mechanism of Action

A

Bacteriocidal agents inhibit synthesis of bacterial cell walls by affecting peptidoglycans
- Penicillins & cephalosporins
- Amoxicillin

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5
Q

Bacteriostatic Agents Affect

A
  • Protein production
  • DNA synthesis
  • Bacterial metabolic activities
  • Bacteriostatic drugs
    • Tetracyclines
    • Erythromycin
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6
Q

Spectrum of Activity

A

Narrow spectrum:
- Penicillin G
- Streptomycin

Broad spectrum:
- Tetracyclines
- Chloramphenicol

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7
Q

Broad vs Narrow Spectrum Antibiotics

A
  • Narrow-spectrum antibiotics work against a limited group of bacteria
    • Lower resistance potential
  • Broad-spectrum antibiotics work against a larger group of bacteria
  • Overuse of unnecessarily broad spectrum
    antibiotics can drive antimicrobial resistance
    Broad vs Narrow Spectrum Antibiotics
  • It is preferable to use narrow-spectrum antibiotics wherever possible
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8
Q

Where do we use antibiotics?

A

Humans:
* Community
* Hospital

Animals:
* Pets
* Livestock

Agriculture:
* Crops
* Aquaculture

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9
Q

Importance of antibiotics:

A
  • Vital life-saving medicines
  • Modern, especially surgery and cancer treatments to minimise the risk of infection.
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10
Q

What is antimicrobial resistance (AMR)?

A
  • Occurs when bacteria, parasites, viruses parasites, viruses or fungi change to protect themselves from the effects of antimicrobial drugs designed to destroy them.
  • Previously effective antimicrobial drugs used to treat or prevent infections may no longer work.
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11
Q

Types of antimicrobials

A

Antibiotics:
- Against bacteria

Antivirals:
- Against viruses

Antifungals:
- Against fungi

Antiparasitics:
- Against parasites

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12
Q

How has antimicrobial resistance developed?

A
  • Overprescription, overuse, misuse and inappropriate use.
  • Outdated medications
  • Prolonged hospitalisations
  • Antibiotics in food
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13
Q

Patient impact of antimicrobial
resistant infections

A
  • Treatment failures
  • Recurring infections
  • Longer hospital stays
  • Longer recovery times
  • A higher risk of mortality or long-term implications
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14
Q

Antimicrobial Stewardship

A

In the community:
* General Practice:
- Not prescribing antibiotics for colds and flu
- Delayed prescribing
- Shared decision making
- Public declarations in the practice about conserving antibiotics
* Pharmacies:
- Offering symptomatic support for cold and flu

In the home:
* Not taking antibiotics that haven’t been prescribed for you
* Discarding old antibiotic medicines appropriately

In the industry:
* Investing in research and development for antimicrobials

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15
Q

Vaccines:

A

A vaccine is any preparation intended for
immunological prevention of disease.

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16
Q

How Vaccines Work:

A
  • The body is exposed to a weakened or dead pathogen.
  • The body immune cells make antibodies to attack the pathogen.
  • If the body is exposed to the pathogen again the body will be prepared with antibodies
17
Q

Types of Immunisation

A

Active Immunisation:
- Induces protective immunity and immunological memory.

Passive Immunisation:
- Does not activate the immune system and does not generate memory.

18
Q

Passive immunisation

A
  • Pre-formed antibodies are transferred to a recipient
  • Passive immunisation can also involve the injection of antibodies into an individual
19
Q

Active immunisation:

A
  • Natural infection or vaccination
  • The immune system plays an active role with the proliferation of antigen-reactive T and B-lymphocytes resulting in memory cell
    formation
20
Q

Attenuation

A
  • Involves a loss of pathogenicity of a bacterium or virus yet retaining their capacity for transient growth within an inoculated host
  • Requires a single vaccination
21
Q

Purified macromolecules as vaccines

A

Vaccines for meningococcal meningitis
and pneumococcal pneumoniae use a
mixture of purified polysaccharides as
the immunogen.

22
Q

Types of Vaccines

A

Live Attenuated:
- Contain weakened pathogen, require 1-2 doses (rotavirus)

Inactivated:
- Contain killed pathogen, requires several doses (Rabies)

Subunit:
- Contain killed antigenic component of pathogen, requires several doses (pneumococcal)

Toxoid:
- Contain toxin made by pathogen, may require booster shots (pertussis)

23
Q

Adjuvants/preparation

A
  • Adjuvants are substance added to the vaccine to increase it effects.
  • Include aluminium salts which help localize the vaccine and allow its slow release.
24
Q

mRNA Vaccines

A
  • Carry genetic material that teaches our cells how to make a harmless piece of “spike protein,” which is found on the surface of the virus.
  • Cells display this piece on their surface, and an immune response is triggered. Produces antibodies to protect us from getting infected.
25
Q

Antibiotics are effective against:

A

Bacteria

26
Q

Describe the different mechanisms of bactericidal and bacteriostatic antibiotics. Give examples.

A

Bactericidal:
- Kills bacteria, reduces bacteria load, by affecting bacterial peptidoglycans’ cell wall ~ Penicillin, amoxicillin

Bacteriostatic:
- Inhibit growth and reproduction of bacteria by affecting bacteria protein production, DNA synthesis, bacterial metabolic activities ~ tetracyclines, erythromycin.

27
Q

What is antimicrobial resistance? List four factors contributing to antimicrobial resistance.

A

What is antimicrobial resistance?
- Occurs when bacteria, parasites, viruses or fungi change to protect themselves from the effects of antimicrobial drugs designed to destroy them.
- Previously effective antimicrobial drugs no longer work.

4 factors:
- Overprescription and overuse
- Prolonged hospilisation
- Overuse of antibiotics in livestock
- Use of outdated medications

28
Q

Discuss practices by which antibiotic resistance can be reduced, including practices in the community (general practice, pharmacies), practices at home, and in industry

A

In the community:
- General practice = not prescribing antibiotics for colds and flu, delayed prescribing, shared decision making.
- Pharmacies = offering symptomatic support for cold and flu.

In the home:
- Not taking antibiotics that haven’t been prescribed to you.
- Discarding old antibiotic medicines appropriately.

In the industry:
- Investing in research and development for antimicrobials.

29
Q

What are vaccines? How do vaccines work?

A

Any preparation intended for immunological prevention of disease

Work when:
- The body is exposed to a WEAKENED or dead pathogen.
- Body’s immune cells make antibodies to attack the pathogen.
- If the body is exposed to the pathogen again, the body will be prepared with antibodies to effectively fight the pathogen.

30
Q

What is active and passive immunisation? What advantages and disadvantages exist in their use?

A

Active:
- Induces protective immunity and immunological memory, so that subsequent exposure to the same pathogenic antigen will elicit a heightened immune response
Advantages and disadvantages:
- Can be achieved through natural infection or vaccination.
- Immunisation generally requires multiple boosters to achieve effective immunity.
- Not 100% effective.

Passive:
- Preformed Abs are transferred to a recipient
- Occurs during the placental transfer from the mother to the developing foetus or newborn.
- Maternal Abs in the colostrum also provides protection to the newborn
Advantages and disadvantages:
- Immediate protection
- Does not activate the immune system and does not generate memory

31
Q

Describe the mechanism of four types of vaccines: live attenuated, inactivated, subunit, and toxoid.

A

Live attenuated:
- Contain weakened pathogen, requires 1-2 doses. Examples: rotavirus, varicells

Inactivated:
- Contain killed pathogen, requires several doses. Examples: Hepatitis A, rabies, inactivated poliovirus vaccine

Subunit:
- Contain killed, an antigenic component of the pathogen, requires several doses. Examples: pneumococcal.

Toxoid:
- Contain toxin made by pathogen, may require booster shots. Examples: Diphtheria, pertussis

32
Q

What are mRNA vaccines?

A
  • mRNA vaccines carry genetic material that teaches our cells how to make a harmless piece of “spike protein”, which is found on the surface of a virus.
  • Cells display this piece of spike protein on their surface and an immune response is triggered inside our bodies. This produces antibodies to protect us from getting infected if the virus enters.
33
Q

What is attenuation and inactivation? What advantages and disadvantages exist in the use of vaccines generated by these two methods?

A

Attenuation:
- Involves a loss of pathogenicity of a bacterium or virus, yet retaining their capacity for transient growth within an inoculated host.
- Provide prolonged immune system exposure resulting in increased immunogenicity and memory cell production.
- Single vaccination.
- Disadvantage is the possibility of reversion to a virulent form.
- Presence of contaminating virus.

Inactivation:
- Inactivated viral or bacterial vaccines.
- Completely inactivates the pathogen and can be achieved by heat or chemical treatment.
- Prevents replication of the pathogen in the host.
- Allow a full immune response to be generated.
- Heat is not a good inactivator as it leads to denaturation of the proteins affecting their tertiary structure.
- Repeated boosters and induce primarily a humoral immune response

Life Sciences 2 (9 decks)

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