Clinically Important NTM

Question 1

Photochromogens

Answer 1

(Only pigmented when exposed to light)
M. kansasii
M. marinum - low temp

Question 2

Scotochromogens

Answer 2

(always pigmented)
M. gordonae
M. xenopi
M. scrofulaceum

Question 3

Nonphotochromogens

Answer 3

(never pigmented)
M. avium complex (MAC
M. ulcerans - low temp

Question 4

Rapid growers

Answer 4

(5 days, no pigment)
M. abscessus
M. chelonae
M. fortuitum

Question 5

M. kansasii

Answer 5

Photochromagen

• chronic upper lobar pulm infection, clinically resembles Mtb
• tap water is a major reservoir
• dissemination rare except in AIDs
• ID by DNA probe

Question 6

M. marinum

Answer 6

Photochromogen
- cutaneous infection associated with exposure to salt/freshwater following trauma
"fish tank granuloma"
- southern states.
- grows at 30C not 37C
- ID biochem/molec

Question 7

M. gordonae

Answer 7

Scotochromogen

• non pathogenic, found in soil and water
• colonizes respiratory tract
• long, wide, branching, beaded AFB
• ID by DNA probe

Question 8

M. xenopi

Answer 8

Scotochromogen

• hot water systems
• chronic plum disease with COPD etc
• ID by biochem/molec

Question 9

MAC

Answer 9

M. avium, M intracellular, M. paratuberculosis

• nonchromogenic
• ID by DNA probe
• affects immunocompromised hosts (plum infections, disseminateddisease, lymphadentitis)
• disease v. contamination

Question 10

Rapid growing mycobacteria RGM

Answer 10

M. fortuitum, M. chelonae, M. abscessus

• > 7 days growth
• post traumatic, post-surgical, post-injection wound infections
• lower temps
• short, branching AFB in clusters, appear as GPR (gram+rod) on gram stain
• arysulfatase positive (turns pink), often drug resistant and difficult to treat

Question 11

M. leprae

Answer 11

• armadillo animal model (no in vitro)
• person-person via nasal secretions
• long incubation, requires prolonged exposure
• single, multiple or widespread anesthetic skin lesions

Question 12

Scombroid

Answer 12

Toxin in unrefridgerated fish that causes rapid onset flushing, allergic-type symptoms, often overlooked

Question 13

Ciguatera

Answer 13

Uncommin toxin from reef fish, dinoflagellates make it. Bluefish, dolphin, maui, maui, amberjacks and barracuda. Usually tourists.

Question 14

Fugu Tetrodotoxin

Answer 14

Pufferfish, block sodium channel, potent neurotoxin can be lethal. sushi.