Gram negative bacteria

Question 1

What are virulence factors of gram negative bacteria?

Answer 1

• Colonisation factors: adhesins, invasins, nutrient acquisition, defence against the host
• Toxins (effectors): usually secreted proteins
  
  • Damage
  • Subversion

Question 2

What are the 4 main groups of gram negative bacteria?

Answer 2

1. Proteobacteria
2. Bacteroids
3. Chlamydia
4. Spirochaetes

Question 3

What shape are proteobacteria?

Answer 3

all are rod-shaped

Question 4

What shape are bacteroids?

Answer 4

rod-shaped

Question 5

What shape are chlamydia?

Answer 5

round pleimorphic

Question 6

What shape are spirochaetes?

Answer 6

spiral/ helical

Question 7

What are coliforms?

Answer 7

Rod-shaped aerobic gram negative bacteria

Question 8

What do coliforms colonise?

Answer 8

intestinal tract

Question 9

What is an example of a coliform?

Answer 9

salmonella

Question 10

What are the 2 species of salmonella?

Answer 10

• S. enterica - responsible for salmonellosis
• S. bongori - rare (contact with reptiles)

Question 11

What is helicobacter pylori?

Answer 11

Vibrio
aerobic gram negative rods

Question 12

What is n. meningitidis?

Answer 12

Neisseria
aerobic gram negative cocci

Question 13

What is n. gonorrhoeae?

Answer 13

Neisseria
aerobic gram negative cocci

Question 14

How does meningococcus show asymptomatic carriage?

Answer 14

Nasopharyngeal carriage in 5-10% population

Question 15

What are the main virulence factors in meningococcus?

Answer 15

Capsule
LPS (membrane ‘blebs’)
- Cytokine cascade
- Sepsis

Question 16

How is gonococcus spread?

Answer 16

Person-to-person only

Question 17

What is the difference between gonococcus and meningococcus?

Answer 17

gonococci are non-capsulated unlike pathogenic N. meningitidis