Atypical Mycobacteria & M. leprae (4)

Question 1

How are atypical mycobacteria aquired?

Answer 1

through the environment

Question 2

Are atypical mycobacteria PPD + or -?

Answer 2

PPD -

Question 3

Are atypical mucobacteria lethal in guinea pigs?

Answer 3

No, they are not

Question 4

What are the Group 1 Atypicals?

Answer 4

Photochromogens

M. kansasii and M. marinum

Question 5

What are the characteristics of group 1 atypicals?

Answer 5

Produces pigment in light and does not kill guinea pigs

Question 6

Where is M. kansasii found?

Answer 6

midwest, texas, england

Question 7

What disease does M. kansasii produce?

Answer 7

Some lung disease

Question 8

Where is M. marinum found?

Answer 8

Fresh and salt water

Question 9

Symptoms of M. marinum?

Answer 9

Forms “fish tank” granulomatous ulcerating lesions on abrasions exposed to swimming water or aquarium water

Question 10

How is M. marinum treated?

Answer 10

Tetracycline

Question 11

What are the group 2 atypicals?

Answer 11

Scotochromogens

M. scrofulaceum

Question 12

What are the characteristics of the group 2 atypicals?

Answer 12

Produces pigment in the dark and does not kill guinea pigs

Question 13

What illness does M. scrofulaceum produce?

Answer 13

Produces scrofula and is the most common PEDIATRIC cause of scrofula

Question 14

What is the reservoir for M. scrofulaceum?

Answer 14

water

Question 15

How is M. scrofulaceum treated?

Answer 15

Surgically removing the affected nodes

Question 16

What are the group 3 atypicals?

Answer 16

Nonchromogens

M. avium and M. intracellulare

Question 17

What are the characteristics of group 3 atypicals?

Answer 17

Do not produce pigment and does not kill guinea pigs

Question 18

What disease do M. avium and M. intraceullare produce?

Answer 18

Pulmonary disease indistinguishable from TB in severely immunocompromised patients

Question 19

What is the reservoir for M. avium and M. intracellulare?

Answer 19

Environmentally wide spread (soil and water)

Question 20

Treatment for M. avium and M. intracellulare?

Answer 20

Highly drug resistant!

Treat with a combo of clarithromycin and ethambutol, rifampin or cipro

Question 21

What are the group 4 atypicals?

Answer 21

Rapidly growing mycobacteria

M. fortuitum / M. chelonei

M. abscessus

M. smegmatis

Question 22

What are the characteristics of group 4 atypicals?

Answer 22

No pigment, does not kill guinea pigs

Culterable <1 week

Question 23

Who is generally susceptible to M. fortuitum / M. chelonei infections?

Answer 23

Immunosuppressed, people with prosthetic joints, indwelling catheters, puncture wounds

Question 24

How are M. fortuitum / M. chelonei infections treated?

Answer 24

Surgical excision, doxycycline, amikacin

Question 25

Illnesses caused by M. abscessus?

Answer 25

Chronic lung infection, skin and bone infections as well

Question 26

Where are M. fortuitum / M. chelonei, M. abscessus, M. smegmatis normally found?

Answer 26

M. fortuitum / M. chelonei- environment (soil and water)

M. abscessus- environment (soil and water)

M. smegmatis- normal flora under foreskin

Question 27

Which group 4 atypical is highly Ab resistant?

Answer 27

M. abscessus

Question 28

What disease does M. leprae cause?

Answer 28

Leprosy or Hansen’s Disease

Question 29

Reservoir for M. leprae?

Answer 29

Humans and armadillos

Question 30

What is the growth rate for M. leprae?

Answer 30

14 day doubling time–> increadibly slow growing

Question 31

What temperature does M. leprae prefer to grow at?

Answer 31

30C…so it sticks to the periphery of humans

Question 32

The symptoms of M. leprae are caused by both the ________ and the __________.

Answer 32

the infection and the immune response

Question 33

Mechanism of transmission for M. leprae?

Answer 33

Exact mechanism is unclear

Requires prolonged contact with infectious case and contact with nasal secretions and skin lesion contact

Rare zoonosis from animals is possible

Question 34

Where does M. leprae replicate?

Answer 34

Skin histiocytes, endothelial cells, and Schwann nerve cells

Question 35

Describe the tuberculoid form of Leprosy?

Answer 35

Big CMI response

Few bacilli

Asymmetric immunogenic peripheral nerve damage

Lepromatin PPDGranulomas containing giant cels form +

Question 36

Describe the Lepromatous form of leprosy?

Answer 36

Poort CMI response

Large numbers of bacilli

Symmetrical peripheral nerve damage from bacterial growth in schwann cells

PPD -

Foamy macrophages from

Question 37

What are some sensory and motor function loss systems seen in leprosy?

Answer 37

Claw hand, foot drop, plantar insensitivity and clawed toes

Question 38

Physical exam findings seen tubercloid leprosy?

Answer 38

Few sharply demarcated macules on butt, face or limbs

Superficial nerves lesions can enlarge

Asymmetric peripheral nerve damage–> neuropathic pain and muscle atrophy

Question 39

Symptoms seen in lepromatous leprosy?

Answer 39

Extensive bilateral symmetric cutaneous macules

Lesios have poorly defined borders and raised centers

Eye infection is possible

Question 40

T/F: Lepromin skin test is diagnostic of exposure to Leprosy

Answer 40

False…its used to determine patients ability to raise immune response

Question 41

What will appear in a skin smear of both forms of leprosy?

Answer 41

Lepromatous: “foam cells”

Tuberculoid: granulomatous cahnge with epithelial cells and lymphocytes

Question 42

What is the treatment for leprosy?

Answer 42

Tuberculoid: Dapsone and rifampin for 2 years

Lepromatous: Dapsone, rifampin and clofazimine for 2+ years

Peds: prophylaxis w/ dapsone after exposure