Bacterial disease examples

Question 1

Yersinia Pestis

Answer 1

Plague
Virulence factor: Yop effectors injected into macrophage
LPS induced inflammation causing haemorhagic inflammation

Question 2

Strep pneumoniae

Answer 2

Colonises nasopharynx using adhesions
Produces IgA protease and pneumolysin
Polysaccharide capsule avoids phagocytosis

Question 3

Bordetella Pertussis

Answer 3

Whooping cough
Uses adhesions to colonise ciliated epithelial cells
Makes pertussus toxin and adenylate cyclase
LPS inflammation
Toxin acts on neurones causing coughing

Question 4

Mycobacterium TB

Answer 4

use acid fast stain
Ingested by alveolar macrophages and modify these to inhibit phagosome and lysosome fusion

ESAT6 protein interferes with macrophage signalling

Question 5

Clostridium botulinum

Answer 5

Obligate anaerobe

Neurotoxin causes flaccid paralysis

Question 6

Staphylococcus aureus

Answer 6

Makes superantigen that causes vomiting

Question 7

Salmonella enterica

Answer 7

Lactose -ve on MacConkey
SPI-1 encoded needle and effectors
Stay in vacuole
May invade macrophages using SPI-2 encoded needle and effectors that inhibit maturation of phagolysosome

Question 8

ETEC

Answer 8

Travellers diarrhoea
Pili adhesins
Enterotoxin LT which causes diarrhoea (like cholera toxin)

Question 9

EPEC

Answer 9

Pedestal formation

Use injectosome to inject Tir to bind EPEC intimin

Question 10

EHEC

Answer 10

Pedestal formation
Makes shiva-like toxin to depurate 28rRNA to block translation and kill cells
-> Breaks down vascular endothelium to cause haemorrhage

Systemic infection damages glomeruli to cause haemolytic uraemia syndrome

Question 11

Shigella

Answer 11

Dysentry
Trigger mechanism
Actin comet tails 
Shiga toxin induced macrophage apoptosis
Mucosal ulcers and bloody diarrhoea

Question 12

Listeria

Answer 12

Zipper entry

can circulate in macrophages in immunocompromised

Question 13

Clostridium difficile

Answer 13

Spore forming obligate anaerobe that colonises gut after antibiotic removal of microflora

Forms pseudomembranes
Get perforation of colon and sepsis
Toxins: TcdA and TcdB are glycosylating of small GTPases

Question 14

Helicobacter pylori

Answer 14

Uses adhesins
Secretes ureases to neutralise stomach acid
VacA makes anion selective channel to disturb endoscope ion balance and release cytC from mitochondria triggering apoptosis