Bacterial evolution

Question 1

What is bacterial carriage?

Answer 1

Carrying bacteria without showing symptoms of disease.

Question 2

What is the difference between bacterial carriage and infection?

Answer 2

Carriage is asymptomatic presence; infection causes disease symptoms.

Question 3

Why is bacterial composition important for vaccine design?

Answer 3

Vaccines target bacterial components that are accessible to immune cells.

Question 4

What is a bacterial capsule and its significance?

Answer 4

A polysaccharide layer helping bacteria evade immune detection and phagocytosis.

Question 5

Which bacteria have prominent capsules?

Answer 5

Streptococcus pneumoniae, Neisseria meningitidis, Klebsiella.

Question 6

What does the adaptive immune system include?

Answer 6

B cells, T cells, and memory formation.

Question 7

What does the innate immune system include?

Answer 7

Barriers, phagocytes, and inflammation at birth.

Question 8

What do vaccines aim to induce?

Answer 8

Strong and specific immune responses against pathogens.

Question 9

How do adjuvants function in vaccines?

Answer 9

Enhance immune response to the vaccine antigen.

Question 10

What is vaccine pressure on bacteria?

Answer 10

Selective pressure from vaccination leads bacteria to evolve.

Question 11

How do bacteria respond to vaccine pressure?

Answer 11

Mutate or modify surface proteins to avoid immune recognition.

Question 12

What is natural selection versus artificial selection in bacterial evolution?

Answer 12

Natural: environment-driven; Artificial: human-driven like vaccines.

Question 13

What happens to bacterial populations under vaccine pressure?

Answer 13

Bacteria less targeted by vaccines increase in frequency.

Question 14

Why are bacterial capsules good vaccine targets?

Answer 14

They are accessible to antibodies and important for virulence.

Question 15

What disease is caused by Neisseria meningitidis?

Answer 15

Meningitis and septicemia.

Question 16

How many serotypes of Neisseria meningitidis exist?

Answer 16

At least 13 known; 6 major human disease-causing types.

Question 17

What serogroups does the MenACWY vaccine cover?

Answer 17

A, C, W, and Y serogroups.

Question 18

Why was the MenACWY vaccine introduced in the UK?

Answer 18

Due to rise in MenW cases after MenC vaccination.

Question 19

What is serotype replacement in Streptococcus pneumoniae?

Answer 19

The rise of non-vaccine serotypes after vaccination.

Question 20

What problem was observed after introduction of PCV7 vaccine?

Answer 20

Non-vaccine serotypes increased in frequency.

Question 21

What is the consequence of expanding vaccines to PCV10 or PCV13?

Answer 21

Expanded vaccines may cause immune competition among antigens.

Question 22

What causes whooping cough?

Answer 22

Bordetella pertussis.

Question 23

What problem arose with the acellular pertussis vaccine?

Answer 23

Cases increased after switch to acellular vaccines.

Question 24

Why has whooping cough increased despite vaccination?

Answer 24

Acellular vaccine prevents disease but not carriage.

Question 25

What bacterial proteins are altered in whooping cough?

Answer 25

Loss of pertactin and changes in FIM proteins.

Question 26

Why is vaccine-driven resistance slower than antibiotic-driven resistance?

Answer 26

Vaccines exert weaker selection pressures than antibiotics.

Question 27

What is the key takeaway regarding vaccines and bacterial evolution?

Answer 27

Vaccines must be continuously adapted to pathogen evolution.

Question 28

What role does phase variation play in bacterial adaptation?

Answer 28

Generates variability to help bacteria escape immune attack.

Question 29

How can bacteria avoid immune detection after vaccination?

Answer 29

By altering or losing vaccine-targeted proteins.

Question 30

Why does vaccine coverage sometimes decline after introduction?

Answer 30

Broader vaccines may cause lower immune response to each serotype.

Question 31

Why is carriage important in bacterial evolution under vaccine pressure?

Answer 31

It determines transmission and selection under immune pressure.

Question 32

What is the goal of conjugate vaccines?

Answer 32

To improve immune response against poorly immunogenic polysaccharides.

Question 33

Why are whole-cell vaccines reactogenic?

Answer 33

They can cause strong inflammatory reactions.

Question 34

What is an acellular vaccine?

Answer 34

Contains specific bacterial proteins instead of whole bacteria.

Question 35

How does genetic diversity in bacteria impact vaccine effectiveness?

Answer 35

Increased diversity means higher chance of immune evasion.

Question 36

What does vaccine-driven evolution highlight about pathogen adaptation?

Answer 36

Bacteria constantly adapt under selective pressures like vaccines.

Question 37

Why is it important to monitor serotype distributions after vaccination?

Answer 37

To adapt vaccine strategies as pathogen populations evolve.

Question 38

What is the challenge with vaccines targeting multiple serotypes?

Answer 38

Because some serotypes may dominate or reemerge.

Question 39

How do changes in bacterial surface proteins affect vaccine success?

Answer 39

More serotypes can mean weaker immune responses to each.

Question 40

What is the relationship between bacterial genome modification and vaccine evasion?

Answer 40

By preventing immune recognition and neutralization.

Question 41

What are examples of bacteria that modify surface components to escape immunity?

Answer 41

Mutations and gene acquisition enable evasion.

Question 42

Why might adding more serotypes to a vaccine sometimes backfire?

Answer 42

Neisseria meningitidis, Streptococcus pneumoniae, Bordetella pertussis.

Question 43

What is immune competition in multi-valent vaccines?

Answer 43

May lower immune responses and reduce vaccine effectiveness.

Question 44

How does pathogen evolution under vaccination pressure inform public health policy?

Answer 44

Different antigens may compete for immune attention.

Question 45

What happens if a vaccine does not block carriage?

Answer 45

Guides updates to vaccine composition and deployment.

Question 46

What is meant by 'fitness' in bacterial evolution?

Answer 46

Pathogen can continue to transmit and evolve.

Question 47

How do vaccines select for bacterial populations over time?

Answer 47

Ability to survive and reproduce under given conditions.

Question 48

What is a serotype-specific vaccine?

Answer 48

Vaccines indirectly select for bacteria that evade immune detection.

Question 49

How can vaccines influence the dynamics of bacterial populations?

Answer 49

Protects against only specific serotypes included in the formulation.