Mycobacterium
The mycobacteries constitute the Mycobacterium . They are rather long and fine, asporulés and acapsulés bacilli Aérobie S.
Their wall has a particular structure, rich in Cire S (acid mycolic) which enables them to retain to them dyes in spite of the combined action of Acide diluted and of alcohol. This wall confers a great resistance to disinfectants to them, with some Antibiotique S, the Macrophage S.
They are known as “acido-alcoolo-resistant bacilli” or BAAR.
This characteristic of the wall is used to highlight them during examination microscopic by the Coloration of Ziehl-Neelsen.
Their Time generation is extremely long (near to 20 hour S). Their %GC lies between 61 and 71%.
Taxonomy
The taxonomy of the kind Mycobacterium rests on the classification of Runyon (1954) based on the speed of growth and the pigmentation (4 groups presented in the following table).But in practice current, one distinguishes the mycobacteries tubercular patients from the complex Mycobacterium tuberculosis including/understanding the species determining the Tuberculose human ( Mr. tuberculosis ), bovine ( Mr. bovis ) or that generally observed in black Africa ( Mr. africanum ).
Pathogenic species for the man of the group tuberculosis
- Mycobacterium tuberculosis (BK = bacillus of Koch)
- Mycobacterium africanum
- Mycobacterium bovis
- BCG, the Bacillus of Calmette and Guerin, (stock of Mr. bovis modified by Calmette and Guerin to obtain a vaccine stock)
Pathogenic species for the man except group tuberculosis
- Mycobacterium leprae (agent of the Leprosy)
- Mycobacterium ulcerans (agent of the Ulcer of Buruli)
Mycobacteries known as “atypical”
They are sometimes Pathogène S for the man, in particular at the immunodéprimés (Cancer S, AIDS)
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