Mycobacteria other than Tuberculosis-MOTTS/Atypical mycobacteria

The organisms which produce the pigment chiefly in the dark are called scotochromogens. M. scrofulaceum causes scrofula, a granulomatous cervical adenitis, usually in children.

(M. tuberculosis also causes scrofula.) The organism enters through the oropharynx and infects the draining lymph nodes.

Its natural habitat is environmental water sources, but it has also been isolated as a saprophyte from the human respiratory tract.

Scrofula can often be cured by surgical excision of the affected lymph nodes.

Ans. is ‘b’ i.e., M. Kansasii can cause a disease indistiguishable from tuberculosis

M. Kansasii can produce pulmonary and systemic disease indistinguishable from tuberculosis – Jawetz 

.   M tuberculosis and mycobacterium bovis are equally pathogenic for humans. 

Mycobacterium tuberculosis complex refers to a group of very closely related species, all of them cause tuberculosis in man and many other mammals. M. Africanum is one of the member of Mycobacterium tuberculosis complex, frequent sources of this are human or monkey. Environmental source is important for Atypical Mycobacteria (Non Tuberculosis mycobacteria)

.       Members of M. Tuberculosis complex

– M. tuberculosis

– M. bovis

– M. africanum

– M. microti

.    M. marinum causes swimming pool granuloma.

Ans. is ‘d’ i.e., M.kansasii 

Ans. is ‘a’ i.e., M. kansasii

Ans. is ‘d’ i.e., M.smegmatis 

Saprophytic mycobacteria not associated with human illness.

.     M. phlei                              . M. smegmatis

.     M. gordonae                      . M. paratuberculosis

Ans. is ‘c’ i.e., M. Marinum 

• ‘ Fish tank granuloma’, also called swimming pool granuloma’ , is caused by M. marinum.

Ans. is ‘c’ i.e., M. kansasii 

• M. kansasii is a non-tubercular (atypical) mycobacterium.
• Members of TB complex are M. tuberculosis, M. bovis, M. africanum, M. microti and M. conettii.

Ans. is ‘a’ i.e., M. Scrofulaceum 

Ans. is ‘c’ i.e., M.avium intracellulare 

Ans. is ‘a’ i.e., M. paratuberculosis 

Ans. is ‘d’ i.e., M.kansasii 

Ans. is ‘d’ i.e., M.Balanei 

M. marinum also called as M.balanei causes swiming pool granuloma

Ans. A: Non photochromogens

• Pigmentation studies

– Scotochromogens: Pigmentation in the dark (and light)

– Photochromogens: Pigmentation only after exposure to light

– Non-photochromogens: No pigment forms

Group I: photochromogens

–          Mycobacterium kansasii

–          Mycobacterium marinum Group II: scotochromogens

–          Mycobacterium scrofulaceium

–          Mycobacterium gordonae Group III: non-photochromogens

–          Mycobacterium avium complex Group IV: Rapid growers

–          Mycobacterium fortuitum

–           Mycobacterium chelonei

Ans. C: Mycobacterium marinum

The person usually has a history of exposure to swimming pools, salt water aquarium, or ocean fish.

The lesions appear as reddish bumps (papules) that slowly grow into purplish nodules.

The elbows, fingers, back of the hands, and knees are the most common sites affected. The nodules may break down and leave an open sore, or spread up the limb.

A skin biopsy and culture is usually needed to confirm the diagnosis. A PPD tuberculin skin test will usually be positive.