!!! General mycobacteria !!! Flashcards
What is mycobacteria?
A gram+ bacteria causing tuberculosis
Which type of pathogen is the mycobacterium?
It is:
- Obligate pathogenic
- Facultative pathogenic
- Saprhophytic pathogenic
Where can the obligate pathogenic myocobacterium replicate?
In the infected animal only
Where can the facultative pathogenic myocobacterium replicate?
Can replicate in:
- Infected animals
- Environment
- Plants
- Water
- Gut
Where can the saprophytic pathogenic myocobacterium replicate?
Can replicate in:
- Infected animals
- Environment
- Plants
- Water
- Gut
How the morphology of the mycobacterium?
They are rod shaped, but can also have different shapes: coccoid, filaments.
The contain a cell wall
All the componenets will make a specific factor, what is the name of it and what does it mean?
= Cord factor
The bacteria attach to each other, like a small rope
Name the components of the cell wall of mycobacterium:
- Lipoids ⭢ High amount
- Mycolic acid
- Wax
- Glycolipids
What is typical with the cell wall of the mycobacterium?
It contains components, which makes the mycobacterium extremely resistant, and these components also have a antiphagocytic effect where they inhibit the phagocytosis
How can we stain the mycobacterium?
Ziehl-Neelsen
Incubation time of the mycobacterium:
VERY slow replication
= Several weeks or months
Can there be a cross reaction between the mycobacterias? If yes, what makes this possible?
YES
The glycolipids and lipoproteins in the cell wall as well as the close antigen relationships
What is tuberculin?
A special antigen extract, used for diagnostics
How is the resistance of mycobacterium?
Very good !!
Despite the bacteria being non-spore forming, but due to the cell wall it is good.
How long can mycobacteria survive in different surroundings:
- Sunshine = 12 hours
- Dried discharge = 2-5 months
- Dung = 3 weeks
- Heat = They cannot stand boiling, but they will survive for 20 min in a temperature of 80°C
There are 3 groups of mycobacteria, regarding the pathogenesis, name them:
- Obligate pathogenic species
- Facultative pathogenic species
- Saprophytic species
Another name for the facultative pathogenetic species of mycobacteria?
Atypical mycobacteria
Because the generally do not cause tuberculosis
The mycobacteria are facultative intracellular bacteria, what does this mean?
They are able to replicate both intracellularly and extracellulary
What do we use for species identification of mycobacterium?
Its very difficult.
Today we use: 16S rRNA gene
Name the species complexes of mycobacterium:
- M.tuberculosis - complex
- M.avium - complex
- M.leprae and M.Lepraemurium
Name mycobacterium species in the M.tuberculosis - complex:
- M.tuberculosis
2. M.africanum - M.bovis
- M.caprae
5. M.microti
6. M.pinnipedii
Host range of M.tuberculosis:
Human
Monkeys
Swine
Rodents
Parrots
**Can colonise in cattle also, but not cause bovine tuberculosis, only local lesions can be seen !!! **
Host range of M.bovis:
Cattle
Ruminants
Swine
Dog
Cat
Badger ⭢ Maintaining role in some countries
Birds
Humans
BCG ⭢ A strain used for vaccination in humans
Bacterium species of M.avium - complex:
- M.avium subsp. avium
- M.avium subsp.paratuberculosis
3. M.avium subsp. silvaticum
4. M.avium subsp. hominissuis
Host range of M.avium subsp. avium:
Birds
= causative agent of avian tuberculosis
Host range og M.avium subsp. paratuberculosis:
Cattle
Ruminants
= Causative agent of paratuberculosis = chronic enteritis in ruminants
In which animals does the facultative pathogenic mycobacteria cause disease in?
- Cold-blooded animals ⭢ TB
- Cattle and swine ⭢ Local lesions
* ⭢ Might cause dianotis problems, giving a false positive reaction in the tuberculin test*
