Mycobacterium

Question 1

why do we report out M. Avium-intracellulare or M.avium complex (MAC)?

Answer 1

M. avium and M. intracellulare are actually two seperate organisms but so far routine clinical testing can not tell them apart

Question 2

T or F

Maldi-ToF has been shown to distinguish M. avium and M. intracellulare

Answer 2

T

Question 3

Mycobacterium are typically gram___
There cell wall contains ___
and because of there high lipid content they are___,
which means they resist decoloration with acid alcohols

Answer 3

• gram positive
• mycolic acid
• acid fast

Question 4

Mycobacterium are obligate____ and are slow growing which can take from___ days to__ days

Answer 4

anaerobes

-2-60 days

Question 5

Mycobacterium should be staied using what 2 methods?

Answer 5

-Ziehl-neelsen and Kinyoun methods

Question 6

2 major Groups of Mycobacterium are

Answer 6

Mycobacterium Tuberculosis complex and

and NMT

Question 7

3 characteristics of the group Mycobacterium Tuberculosis complex.

Answer 7

1) slow growers
2) non-pigmented
3) not-normal flora

Question 8

NTM is broken up into ___ groups (classification) they are 1)___2)___3)___4)___

Answer 8

• Runyons groups
  1) Phtochromogens
  2) scotochromogens
  3) nonphotochromogens
  4) rapid growers

Question 9

Photochromgens are___ and include: 1)__2)__3)__

Answer 9

NTM’s that require light to form pigment following incubation in the dark

1) M. kansasii
2) M. marinum
3) M. asiaticum

Question 10

Scotochromogens are __ and include: 1)__2)__3)__ which species causes cervical adenitis?

Answer 10

NTM’s that produces pigment in dark or light conditions

1) M. scrofulaceum (cause of cervical adenitis in children).
2) M. szulgai
3) M. gordonae

Question 11

Nonphotochromogens are__ and include: 1)__2)__3)__4)__

Which specie(s) is found in hot water taps in hospitals and causes pulmonary infections?

Answer 11

non-pigmented regardless of incubation in dark or light conditions

1) M.avium/intracellulare complex (MAC)
2) M.shimoidae
3) M. xenopi – found in hot water taps in hospitals, causes pulmonary infections and disseminated disease\
4) M. genavense

Question 12

which mycobacterium spp. causes lymphadentitis and Pulmonary infections but is not consided TB because patients rarely presents with granulomas or tissue death?

Answer 12

Mycobacterium avium Complex

MAC

Question 13

Important pathogen in AIDS patients.

Not spread from person to person, (which is different than TB).

Answer 13

Mycobacterium avium Complex (MAC)

Question 14

Pateints infected by MAC often aquire bronchitis, why?

Answer 14

-increased mucous production puts miechanical stress on the bronchioles that results in inflamation.

Question 15

Rapid growers are__ and include 1)__2)__

They will grow on 3)___ and appear 4)___ on that media
How many days are the plates innoculated 5)__ and when will you see growth?(6)

Answer 15

1) M. fortuitum
2) M. chelonae
3) MacConkey’s
4) It has crystal violet omitted
5) 7 days
6) 5 days

Question 16

• Has not been grown in vitro
• it is an obligate intracellular bacteria
  2) what are the natural reservour of this?
  3) what disease does this orginism cause?

Answer 16

M. leprae

2) armadillos and mice
3) leprosy

Question 17

what is the most common sample for Mycobacterium? when should it be collected?

Answer 17

• sputum

- early morning for 3 cons. days

Question 18

for the processing of sputum specimens for acid fast bacteria what special steps are required?
2) is this necissary with specimens from sterile sites?

Answer 18

• digestion (lyse mucin to release agents)
• decontamination (elimination of mixed bacterial flora using NaOH)
• neutralization (with buffer or water)
• centrifugation
  2) no

Question 19

what is the preferred method for digestion/ decontamination?

2)what agent is the mucolytic agent?

Answer 19

N-acetyl-L-cysteine (NALC) NaOH method – NaOH reduced to 2% when mixed with NALC
2) NALC

Question 20

ATS level I____1)
ATS level II____2)
ATS level III____3)
which levels can only be performed in a BSL3 Lab?

Answer 20

1)grow mycobacterium and stain but do not ID
2)Identify TB only.
3)Identify all mycobacteria spp. and perform susceptibility testing.
II and III

Question 21

• BSC & centrifuge room should have nonpermeable walls and work surfaces.
• Directional air flow.
• BSL space air vented through HEPA filters directly to outside.

what BSL level is this?

Answer 21

3

Question 22

Mycobacerium staining methods:

1) (cold) method- uses a higher concentration of __ in the primary stain to accelerate the staining process and thus does not require heat.
3) Hot method

Answer 22

1) Kinyoun method
2) phenol
3) Ziehl-neelsen

Question 23

‘fast’ in Acid-‘fast’ here means___1)

due to high lipid cell content mycobacterium binds___2)dye and resist____3)

Answer 23

1) firmly fixed, or securely attached
2) fuchsin dye
3) destaining of acid alcohols

Question 24

the ____ stain saves time in examination and is equivalent to ___ fields of view vs. 300 for acid fast

Answer 24

• fluorochrome

- 30

Question 25

- For optimal recovery of Mycobacteria spp. should use at ____ - Two solid media (tubed or plates) should be used: 1) ____ 2)___

Answer 25

- least one solid media and a liquid medium 1) one with agar base 2) one with egg- potato base

Question 26

2 examples of egg potato base solid medium is? 1) coagulated whole eggs, glycerol__(does what)__1.5), potato flour, Malachite green 2) coagulated whole eggs, egg yolks, whole milk, potato, potato flour, Malachite green.

Answer 26

1) Löwenstein-Jensen 1. 5) enhances growth 2) Petragnani

Question 27

skin specimens should be incubated at___ C what species of mycobacterium is this typically for?? Mycobacterium tuberculosis takes on average__3)weeks to grow and susceptibility testing takes and additional __4)weeks for a total of 4-8 weeks on average

Answer 27

1) 25-30 2) M. marinum M.ulcerans 3) 2-4 4) 2-4

Question 28

1) scotochromogens tend to be a ___ pigment | 2) non pigmented tend to be __ pigment

Answer 28

1) deep yellow to orange | 2) buff tan to pale yellow

Question 29

All mycobacterium produce___1) but some species lack the enzyme to cover___ 1) to __1) ribonucleotide resulting in an accumulation in ___1) in the culture medium

Answer 29

1) niacin

Question 30

Spp. that lack the enzyme to convert niacin into niacin ribonucleotide and there for would be considered ___ for niacin accumulation is this test enough for ID of mycobacterium?

Answer 30

- M. tuberculosis, M. simile and occasionally (M. bovis, M. africanum, M. marinum) - positive - no

Question 31

M. tuberculosis and M. Kansasii are nitrate reduction__1) and __ 2) are quick positive 3-6hrs for Tween 8 hydrolysis test 3) those in Mycobacterium Tuberculosis complex tend to be Tween Hydrolysis___ and do not produce___

Answer 31

positive - M. kansasii - negative - heat stable catalase

Question 32

T or F GenoType Mycobacteria direct test (Germany)- is possibly more sensitive than other molecular methods in smear negative samples.

Answer 32

T

Question 33

Enhanced Amplified Mycobacterium Tuberculosis Direct Test is possibly more sensitive than other molecular methods in smear negative samples

Answer 33

F

Question 34

M. Tuberculosis ID - Culture growth w/in 4 – 8 weeks - Rough, dry, buff, non-pigmented on ___1) - Strong Acid-fast +, ___2) appearance. - niacin & nitrate reduction___3). - 68 degree Catalase ___4).

Answer 34

1) Lowenstein-Jensen media. 2) slightly curved rods, beaded 3) positive 4) negative

Question 35

TB is ___ resistant

Answer 35

rifampin

Question 36

inoculate organism to media with varying known concentrations of antibiotic and looks for inhibition providing MIC.

Answer 36

absolute concentration

Question 37

T or F Everyone that is exposed to TB will progress to active TB disease

Answer 37

F

Question 38

T or F | not everyone that is exposed to TB will progress to active TB disease

Answer 38

T

Question 39

person with latent TB that manifests as disease at later time (immune system becomes compromised for some reason)

Answer 39

secondary (reactivation) TB

Question 40

form of TB: | spread to other organs hematogenously.

Answer 40

Military TB

Question 41

form of TB: the initial infection in a previously unexposed individual, 2 potential outcomes: Latent TB infection(have antibodies but no disease) and Active infection/disease

Answer 41

Primary TB

Question 42

Why are Macrophages unable to kill mycobacteria?

Answer 42

Mycobacteria block the proteins that mediate the fusion of the phagosome with the lysosome.

Question 43

TH1 cells also recruit monocytes to the infection site and they differentiate into ___1) like cells which are the hallmark of___2) formation effectively walling off the bacteria. This formation allows for ___(type TB infection)__

Answer 43

1) “epithelioid” 2) granuloma 3) secondary TB

Question 44

``` Mimics others – asymptomatic to symptomatic Low grade fevers Anorexia and weight loss Fatigue & night sweats Productive cough Fever/chills ```

Answer 44

Clinical Presentation for Pulmonary TB

Question 45

Clinical screening for TB: Blood test utilizing 3 proteins derived from Mycobacteria tuberculosis complex and tests for interferon-gamma released by the patients T cells in response to the 3 proteins (memory) using ELISA technology.

Answer 45

QuantiFERON-TB Gold In-Tube test

Question 46

Clinical screening for TB: - Delayed appearance of indurated (raised, hard) reaction with/wo erythema. - Positive test does not distinguish between present & past infection. - Recent conversion of a negative to a positive reaction demands clinical attention. - Results Interpretation

Answer 46

Purified Protein Derivative (PPD) – intradermally

Question 47

TB resistance to isoniazid and rifampin.

Answer 47

Multidrug Resistant TB-

Question 48

TB resistant to isoniazid and rifampin, plus any fluoroquinolone and at least one of three injectable second-line aminoglycosides (i.e., amikacin, kanamycin, or capreomycin).

Answer 48

Extensively Drug Resistant TB-

Question 49

association between Johne’s disease in cattle (inflammatory bowel disease) and Crohn’s disease in humans

Answer 49

M. avium subsp. paratuberculosis

Question 50

Leprosy aka ___

Answer 50

Hansen’s Disease