Mycobacterium Flashcards
(20 cards)
What are the two groups of mycobacterium?
Fast growers (24h)
Slow growers (8-18 weeks)
Characteristics of mycobacterium
Gram +
Aerobes or facultative anaerobes
Cell wall thicker than any other bacteria, survive harsh conditions
Cannot tolerate long exposure to heat/dry conditions
Why are mycobacterium resistant to antibiotics?
Cell walls are hydrophobic, waxy and high in mycolic acids
What are the 4 slow growers?
M. tuberculosis (human)
M. bovis (bovine and human)
M. leprae (leprosy)
MAP (cattle)
What does MAP stand for?
M. avium paratuberculosis
Characteristics of MAP cells
Non-spore forming
Non-motile
Fastidious organism (special agar)
12 weeks to grow
What is required for MAP to grow?
Mycobactin J (iron)
What does MAP cause?
Johne’s disease
Johne’s disease characteristics
Effects ruminants
Thickens intestines reducing absorption of nutrients
Causes weight loss
What are the impacts of Johne’s disease?
Milk yield decrease therefore less money
Route of infection of Johne’s disease
Faeces on grass
Contaminated milk
When does MAP multiply?
When the immune system is weak
How can MAP live in dormancy for long periods?
Go into stasis by forming granulomas
What are the 2 phases of infection of MAP?
Response activation of macrophages
Antibodies are produced later
MAP are facultative intracellular pathogens, what does this mean?
Can replicate inside macrophages
Cell wall protects from harsh environment
Produces protein factors that prevent phagosome maturation
Replication inside macrophage hides bacteria from immune system
How much MAP can be found in unpasteurised milk?
10^6 cfu/g
What could consumption of unpasteurised milk cause?
Crohn’s disease
Symptoms of Crohn’s disease
Thickened intestine wall
Ulcers
Diarrhoea
Immune dysfunction
Who does Crohn’s disease affect?
15-24 year olds
How does Crohn’s disease cause infection?
NOD2 gene activates nuclear factor KB from cell walls
