Mycobacterium & Nocardia (Hull)

Front 1

Explain what is peptidoglycolipid (that MB Tuberculosis has)

Back 1

Peptidoglycolipid is peptidoglycan attached to Arabinogalactan (alternating arabinose & galactose), which is then attached to mycolic acid (highly branched fatty acids, can be 60 carbons long). Also, Wax D is a fragment of the peptidoglycolipid and is highly immunogenic (used in Freund's adjuvant)

Front 2

What is Wax D?

Back 2

Wax D is a fragment of the peptidoglycolipid and is highly immunogenic (used in Freund's adjuvant)

Front 3

Why did people used to this Mycobacterium TB was a fungi? (Myco = fungus)

Back 3

1) It's generation time was so long, ~40 hours which is more like a eukaryotic cell
2) It doesn't take up Gram stain due to its waxy cell wall

Front 4

All mycobacteria are ___________ aerobes, and because of this they have a strong predilection for the ______.

Back 4

obligate aerobes, and for this reason they have a strong predilection for the lung

Front 5

True or false, Mycobacterium TB does NOT make any exotoxins.

Back 5

True, MB TB makes no exotoxins

Front 6

What inhibits neutrophil migration?

Back 6

cord factor, a glycolipid that is lethal when injected into mice

Front 7

Mycobacterium TB are gram (+/-), niacin (+/-), and have pigmentation/don't have pigmentation

Back 7

*gram +
*niacin +
*don't have pigmentation

Front 8

Because they are so sticky, the MB TB show a rope or cording phenomenom that is very characteristic of MB TB. What causes this?

Back 8

cord factor

Front 9

What are the functions of the mycolic acid (the fatty acids)?

Back 9

*prevent dessication
*resistant to lytic enzymes (of the phagocytes), phagocytosis
*resistant to chemicals (ie disinfectants)
*resistance to taking up Gram stains, therefore DO NOT STAIN WITH GRAM STAIN

Front 10

Mycobacteria are visualized how?

Back 10

Acid fast stain (Ziehl-Nilsson or Kinyoun), using carbol fuchsin solution that penetrates mycobacteria, especially well if are also heated! Then washed with acidified alcohol, but the red stain remains in the mycobacteria because of the lipid layer keeps the stain in

Front 11

Laws were developed against spitting on the sidewalk to prevent spread of...

Back 11

Mycobacterium Tuberculosis

Front 12

Milk is still pasteurized to prevent the spread of Mycobacterium _______

Back 12

bovis

Front 13

Mycobacterium bovis is the basis of the ____ vaccine

Back 13

BCG, but is not used as vaccination in the US (more in other countries across the world)

Front 14

Why is Auromine-Rhodamine replacing the acid fast stain for diagnosis of MB TB?

Back 14

1) Normal acid fast stain could only tell you whether you had a Mycobacteria present or not (could not distinguish amongst different species of MB, whether pathogenic or not, in fact some nonpathogenic strands are in tap water and could affect the results of tests performed). the Fluorescent antibody test is specific for Mycobacterium Tuberculosis antigen!!! Will just light up for TB.
2) Easier to see with fluorescence
3) Much more sensitive, requires only 10^3 bacteria present to get a positive result, whereas took 10^5 with acid fast stains

Front 15

You can get a false - PPD skin test on _____ ?

Back 15

Immunocompromised patients, especially HIV patients, because their immunity is low, therefore cannot mount an appropriate immune response to the PPD being injected intradermally.

Front 16

Why is TB very common in HIV patients?

Back 16

Because, they cannot mount the normal T cell response that you normally see 2-6 weeks after infection where you send in macrophages to kill the mycobacterium. Because the uneducated macrophages cannot kill TB and allow it to persist.

Front 17

What can lead to a reactivation TB?

Back 17

alcohol especially suppresses your DTH response, age, underlying disease as well

Front 18

Treat aggressively with Direct Observed Therapy. Why?

Back 18

Because people who have it aren't really responsible for their own health care. And because this is such a major public health issue you want to ensure compliance, especially since they will be taking it for such a long time (at least 6 months). So, will even have a nurse go out everyday and give the patient the pills and watch him/her take them.

Front 19

TB is transmitted via _______

Back 19

person to person contact, inhalation

Front 20

Why is resistance common with TB?

Back 20

Because since the regimens were so long (6 months) people were quitting taking their antibiotics somewhere along the way.

Front 21

Mycobacterium Tuberculosis is a _____________ intracellular parasite

Back 21

facultative, therefore can still grow on culture media in the lab.

Front 22

The only other reservoir for Mycobacterium Leprae is ________

Back 22

knife bandit armadillo

Front 23

To get M. Leprae you need (short/prolonged) exposure to an infected person

Back 23

prolonged

Front 24

M. Leprae prefers what parts of the body?

Back 24

cooler parts (fingers, testicles, toes, eyes, ears, nose, lips)

Front 25

Why is M. Leprae called the perfect parasite?

Back 25

Because it doesn't kill the host.

Front 26

What is the leading cause of death for people with M. leprae infection?

Back 26

Heart disease, simply from dying of old age (mortality rate of leprosy infection is almost 0)

Front 27

*Are antibodies against M. TB or M. Leprae diagnostic? Protective?

Back 27

YES, NO

Front 28

Discuss the two forms of M. Leprae disease manifestation

Back 28

Depending on the body's response can have...
1) Tuberculoid leprosy - predominantly a macrophage response to T cells (cell mediated immunity), where granulomas are formed, a lot more damage done, but better for containment of the disease, no skin lesions
2) Lepromatous Leprosy - no granulomas formed, a B cell mediated antibody response, thick skin lesions form, less damage done, but more expansive disease

Front 29

Why would it not be uncommon to see a Leprosy patient with his hands wrapped entirely in bandages?

Back 29

Because the lesions may become anasthetic, don't have feelings in them anymore, it is easy to do much more damage to self as a result (ie touching a hot stove and not even realizing it)

Front 30

PPD test can only tell you how much?

Back 30

That you HAD a TB infection at some point in the past, or you may have one right now, but cannot definitely say you are dealing with a current infection

Front 31

What is the concern about Non-TB Mycobacterium being resistant to bleach?

Back 31

We use bleach to disinfect dialysis equipment (since we can't autoclave it), and because of this it is possible to infect patients with Non-TB MB on subsequent uses of equipment due to its bleach resistance

Front 32

What is considered the sentinal disease of HIV?

Back 32

Mycobacterium avium (gets grouped together with M. Intracellulare because they cannot be distinguished by normal laboratory means)

Front 33

What does M. kansasii produce?

Back 33

It produces a pulmonary infection very similar to TB, and is very common in the southwest, especially Texas

Front 34

What is the causative agent of scrofulus?

Back 34

M. scrofulaceum, which causes a lymph node infection in children

Front 35

How do kids get scrofulus?

Back 35

Eating dirt, sand in the sandbox

Front 36

If you are cleaning your fish tank and cut your finger, you may be at risk for contracting what type if Mycobacterium?

Back 36

M. marinum, because this lives in water and causes cutaneous infections and abscesses (M. fortuitum does the same, except its found in dirt)

Front 37

The Non-TB MB do not produce puss in their lesions of the skin. Why not?

Back 37

Because they also inhibit neutrophil migration according to Dr. Hull

Front 38

What has the appearance of rosary beads, and smells like dirt, and lives predominantly in dirt, and has a very low virulence for healthy people, but could be dangerous for immunocompromised individuals?

Back 38

Nocardia