Atypical Mycobacteria

Question 1

M. Kansaii

Answer 1

1. Cattle, swine, Southwest/Midwest
2. Pneumoconiosis (dust inhalation), COPD, immunodeficient
3. Erythema nodosum

Question 2

M. marinum

Answer 2

Fish, skin trauma, crustaceans

Question 3

M. avium

Answer 3

1. Survives water chlorination, spread by aerosol.

2. MC non-TB mycobacterium infection

Question 4

Tx for M. avium

Answer 4

Macrolide + EMB + RIF + Aminoglycoside

Question 5

M. leprae

Answer 5

1. Usually w/ travel; Curved bacillus
2. Metachromatic granule, oxidizes DOPA
3. Infects peripheral nerves
4. Transmission via nasal discharge, NOT SKIN

Question 6

Differentiate the 2 types of Leprosy

Answer 6

Lepromatous: Seen in Asia; Langerhans cells
Tuberculoid: Seen in Africa
Sarcoid granulomas (non-caseating), nerve bundles grossly swollen & infiltrated w/ macrophages

Question 7

Clinical presentation of Leprosy

Answer 7

Full Tuberculoid: large erythematous plaques w/ sharply demarcated & raised edges; Area is anesthetic

Full Lepromatous: bilateral symmetrical erythematous macules/papules/nodules, skin thickening of face/nose/ears

Question 8

How is a Leprosy infection confirmed via culture?

Answer 8

+ culture from 2 sputum samples OR
+ culture from 1 bronchial lavage OR
Biopsy w/ mycobacterial histopathologic features