Atypical mycobacteria and M. leprae

Question 1

why is it called “atypical?”

Answer 1

1. caused neither by TB nor Leprosy
2. environmentally-acquired
3. PPD (purified protein derivative) and TST (tuberculin skin test) usually negative
4. less aggressive infection, not lethal in guinea pigs

Question 2

atypical pneumonia leading to systemic dz is very rare w/o predisposing condition such as

Answer 2

HIV, cancer, old age, infected surgical site, diabetes, and lung dz

Question 3

what are the 4 bugs that cause atypical pneumonia?

Answer 3

1. M. avium-intracellulare
2. M. kansasii
3. M. scrofulaceum
4. M. marinum

Question 4

what are the 2 mycobacterium strains that is considered as group 1, photochoromogens that produce pigment when grown in light?

Answer 4

1. M. kansaii

2. M. marinum

Question 5

what is the mycobacterium that belongs to group 2 which produce pigment when grown in dark or light?

Answer 5

M. scrofulaceum what produced scrofula (refers to a lymphadenitis of the cervical lymph nodes associated with tuberculosis as well as non tuberculous (atypical) mycobacteria.)

Question 6

what is the def of atypical mycobacteria?

Answer 6

environmentally-acquired infections that cause neither TB nor leprosy