Mycobacterium

00:01 Mycobacterium, bacteria.

00:03 The mycobacteria are a large group of bacteria, in fact, so large as to represent their own genus of organism.

00:12 As a genus, the mycobacteria are obligate aerobes and they are facultatively intracellular, they grow best within a cellular target.

00:24 However, when appearing under a microscope, they are elongated with the shape of a rod or a bacillus.

00:31 Importantly the cell wall of the mycobacteria, all of them, is rich in mycolic acid, again another feature sometimes seen in fungus.

00:40 And it is the staining of that mycolic acid which makes them acid fast.

00:45 As you can see in the slides, the right, there are several versions of red appearing or acid fast rod-like organisms which represents mycobacteria in their tissue species.

00:58 We look at several different types of mycobacteria as causing typical or atypical disease.

01:05 When one thinks of typical mycobacterial illness, one immediately thinks of mycobacterium tuberculosis, the cause of tuberculosis.

01:14 However, there are several other subspecies of mycobacteria which also cause clinically important diseases which are typical.

01:22 Mycobacterium bovis, that which is associated with as you guessed it, a bovine or a cow-source, also can cause disease closely resembling that of straightforward tuberculosis.

01:34 Mycobacterium leprae, which causes leprosy, is completely different but again still exists in the typical pathway of disease with mycobacteria.

01:44 In the atypical forms, there are multiple organisms, three of which you see listed on the slide.

01:50 Mycobacterium avium -- intracellulare, sometimes abbreviated, MAI for short or even you heard the term, MAC, Mycobacterium avium complex, MAC.

02:01 Also in that group Mycobacterium kansasii and Mycobacterium scrofulaceum.

02:07 These will all be called atypical mycobacteria or many times to distinguish them from typical forms, they might be called, nontuberculous mycobacteria, NTM.