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Fall 22: micro > Test 1: lecture 6: mycobacterium > Flashcards

Test 1: lecture 6: mycobacterium Flashcards

1
Q

what stain is used for mycobacteria

A

Ziehl-neelsen staining

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2
Q

the outer membrane of mycobacteria contain ___ and ___

A

mycolic acid

lipo-arabino-mannan

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3
Q

what shape is mycobacteria

A

gram + bacilli

(acid fast +)

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4
Q

what three bacteria are acid fast +

A

mycobacterium

nocardia

rhodococcus

(all gram + rods)

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5
Q

what type of bacteria are non acid fast

A

corynebacterium

actinomyces

dermatophilus

trueperella

(gram + rods of the actinomycetia family, no spores)

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6
Q

list the gram + rods

A
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7
Q

mycobacteria are important causes of human and animal ___

A

tuberculosis disease

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8
Q

what kind of animals are highly susceptible to TB?

A

elephants

can transfer from human to elephant to human

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9
Q

mycobacteria course of disease in most healthy individuals is ___ as long as immune function is maintained

A

asymptomatic

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10
Q

the function of what in the host is crucial for containment of mycobacteria

A

CD4+ T cells, IFNg, macrophage microbicidal mechanisms

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11
Q

TB lesions form ___ that have central caseating necrosis
surrounded by ____ and T cells

A

granulomas

‘epithelioid’ macrophages

(caused by mycobacteria gram + rod, acid fast +)

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12
Q

Johne’s disease is caused by ___

A

Mycobacterium avium subsp. Paratuberculosis

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13
Q

Mycobacterium avium subsp. Paratuberculosis causes ___

A

johne’s disease in cattle

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14
Q

mycobacteria cause debulitating ___ in cattle

A

Debilitating enteritis in cattle –

acquired during first 6 months of life, clinical disease appears 2-8 years later. Organisms shed before onset of clinical symptoms

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15
Q

3 important disease of mycobacteria

A

1) Leprosy
2) Tuberculosis
3) Paratuberculosis (Johne’s disease→ cattle)

(gram + rods, acid fast +)

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16
Q

sunlight promotes the production of ___ by macrophages

A

Vit D → IFN gamma in macrophages

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17
Q

4 important species of mycobacteria

A

1) M. leprae - - - - - - - leprosy in humans.
2) M. tuberculosis - - - TB in humans.
3) M. bovis - - TB in cattle, other animals & humans.

4) M. avium:
* *subspecies avium** - - -TB in chickens, other birds, some animals & in
(immunocompromised) humans.
* *subspecies paratuberculosis** – paratuberculosis (Johne’s Disease) of ruminants; infection of humans is controversial

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18
Q

___ cause leprosy in humans

A

1) M. leprae - - - - - - - leprosy in humans.

(gram + rod, acid fast +)

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19
Q

___ cause TB in humans

A

Mycobacteria tuberculosis

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20
Q

___ cause TB in cattle, other animals and humans

A

mycobacteria bovis

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21
Q

___ cause TB in chickens

A

Mycobacteria avium subspecies avium

(gram + rod, acid fast +)

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22
Q

___ cause paratuberculosis in ruminants

A

Mycobacteria avium subspecies paratuberculosis

(Johne’s Disease)

(might cause Crohn’s disease in humans??)

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23
Q

what are the two important subspecies of Mycobacteria avium

A
  • *subspecies avium -** - -TB in chickens, other birds, some animals & in
    (immunocompromised) humans.

subspecies paratuberculosis – paratuberculosis (Johne’s Disease) of ruminants; infection of humans is controversial

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24
Q

Ziel-Neelsen method is used for ___

A

mycobacteria are gram + but their cell wall do not react well with decolorization are appear weird gram - looking

bacteria is dyed with carbolfuchsin, then steamed, then decolorized with acidified alcohol (95% EtOH- 3 % HCl), then counterstained and produce Red rod shaped bacteria

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25
steps of acid fast stain
bacteria is dyed with **carbolfuchsin,** then **steamed**, then decolorized with **acidified alcohol** (95% EtOH- 3 % HCl), then counterstained and produce **Red** rod shaped bacteria
26
ziehl-nellsen acid fast staining (**mycobacteria, nocardia, rhodococcus** all acid fast +, gram + rods)
27
besides for acid fast stain what is another way to identify mycobacteria
**auramine fluorescent stain** auramine and rhodamine are flurochromes (non specific fluorescence can cause a problem in clinical specimens) (mycobacteria, nocardia and rhodococcus are gram + rods, + acid fast)
28
auramine fluorescent stain used to stain for mycobacterium (gram + rod, acid fast +)
29
\_\_\_ help stabilize mycobacteria cell wall
**lipoarabino mannan** also have fatty acid mycolic acid
30
\_\_\_ give mycobacteria cell wall its hydrophobic character
mycolic acid → fatty acid lipoarabino mannan
31
compare the make up of the cell wall of Gram +, gram - and mycobacteria
**gram +** → open faced sandwhich → thick peptidoglycan **gram -** → LPS outer layer and thin peptidoglycan in a periplasmic space **mycobacteria** → gram + rods, acid fast +→ thick outer membrane of mycolic acid and lipoarabino mannan, thin peptidoglycan
32
what are three tubercle bacilli
**Mycobacteria tuberculosis** **M. bovis** **M avium** (subspecies avium and subspecies paratuberculosis) (mycobacteria, nocardia and rhodococcus are all acid fast +, rod shaped gram +)
33
properties of tubercle bacilli
non motile aerobes no spores straight or slightly curved rods sometimes filamentous multiply slowly (14-24 hrs) takes \> 3-4 weeks to grow in culture
34
tubercle bacilli such as ___ multiply every \_\_\_
M. tuberculosis, M. bovis and M avium 12-14 hrs (slow growing)
35
tubercle bacilli such as ___ take ___ to grow in culture
M. tuberculosis, M. bovis and M avium \> 3-4 weeks
36
tubercle bacilli are aerobes or anaerobes?
non motile aerobes
37
how to grow mycobacteria in culture
**lowenstein- jensen agar** high lipids and contain egg products, glycerol, potato flour and salt **malachite green** in used to inhibit the growth of other bacteria → mycobacteria very slow growing, need to kill off other bacteria to allow them to grow
38
lowenstein-jensen agar is used to grow
mycobacterium very slow growing → **malachite green** added to kill off other bacteria high in lipids, glycerol, salt and potato flour
39
mycobacteria can survive moderate \_\_\_
**heat** but will be killed by pasteurization
40
mycobacteria is resistant to \_\_\_
desiccation (drying) most aqueous disinfectants→ acids and bases
41
\_\_\_ is used to kill mycobacteria
phenol and alcohol direct sunlight
42
2 common resistant TB strains
**MDR** - multi-drug resistant **XDR**- extensively drug resistant
43
\_\_\_\_is defined as resistance to isoniazid and rifampin, plus resistance to any fluoroquinolone and at least one of three injectable second-line anti-TB drugs
XDR TB
44
Packy of Oregon Zoo had \_\_\_
TB got it from humans and could pass to other elephants and humans
45
3 routes of infection for TB
inhalation ingestion percutaneous (TB caused by mycobacteria→ gram + rod, acid fast +)
46
ingestion of mycobacteria leads to lesions in the \_\_\_
intestinal tract, lymph nodes, liver, and spleen | (would happen a lot before milk pasteurization)
47
what route of infection of TB is rare
percutaneous → infection after skin inoculation cause lesions in the skin, skin draining lymph nodes TB caused by mycobacteria (gram + rod, acid fast +)
48
miliary TB rare granulomas form in the lungs of immuncompromised cattle caused by mycobacteria (gram + rods, acid fast +)
49
BCG
**Bacillus Calmette Guerin (BCG) vaccine for TB** not used in animals because it can **cause false positive TB skin tests** most effective for childhood tuberculous meningitis and miliary disease
50
are there vaccines for TB
not really can use **Bacillus Calmette Guerin (BCG)** vaccine but causes false positive TB skin test and not very effective
51
immune response to M. Tb and M. bovis
bacteria infect macrophages and dendritic cells that activate CD4 Tcells to produce **IFN gamma and TNF alpha** which leads to increased macrophages and **granuloma formation**
52
how does skin test for TB work
delayed hypersensitivity response inoculated with a PPD (purified protein derivative) if previous exposure memory T cells will release IFN gamma and cause tissue swelling **will get response if had TB in past or if they had BCG vaccination**
53
what kind of diagnostic test for mycobacteria TB
chest xray acid fast staining and culture PPD skin test IFN gamma release assays → Elisa testing
54
QuantiFERON-TB Gold and T-SPOT.TB
IFN gamma release assays testing for memory cells for antigens of **M. bovis and M. avium that release INF gamma** will **not cause false positiv**e if previous BCG vaccination
55
how to control TB in food production
cull infected animals and monitor for lesions although most cattle show no lesions (caused by mycobacteria → gram + rods, acid fast +)
56
why is it not recommended to treat TB in pets
requires multiple antibiotics over a long course Isoniazid, rifampin, ethambutol, pyrazinamide. can lead to **resistance**
57
what drugs are used to treat TB
**Isoniazid, rifampin**, ethambutol, pyrazinamide. long treatment 6-12 months!
58
MAP
Mycobacterium avium subspecies paratuberculosis **Johne's disease** (gram +, short thick rods, acid fast +) bacteria produce **mycobactin** that allows bacteria to scavenge **iron** from their environment **parasitic pathogen** **takes 6-12 weeks to grow in culture**
59
how long does it take to grow Johne's disease in culture
Mycobacterium avium subspecies paratuberculosis (MAP) (gram +, short fat rods, acid fast +) ## Footnote **6-12 weeks**
60
what type of gram + rod are obligate parasitic pathogens?
Mycobacterium avium subspecies paratuberculosis (MAP) Johne's disease produce **mycobactin** that **steal iron** from the host
61
resistance of MAP
**same things as tubercle bacilli** → moderate resistance to heat, resistance to drying, fair resistance to disinfectants such as acids and bases, killed by alcohol, sensitive to direct sunlight but can survive for **250 days** in the environment, can't replicate but just sits there waiting for a host
62
wasting
cachexia
63
Johne's disease
caused by **Mycobacterium avium subspecies paratuberculosis (MAP)** gram + short rods, acid fast + chronic, debilitating enteritis in cattle, sheep, goats and other ruminants resulting in d**iarrhea, cachexia (wasting), and eventual death.** leads to **decreased milk production** symptoms start **2 years after infection** around 22% of dairy and 8% of beef infected transmitted by fecal/oral route, in utero and during milking
64
chronic, debilitating enteritis in cattle, sheep, goats and other ruminants resulting in diarrhea, cachexia (wasting), and eventual death.
Johne's disease caused by **Mycobacterium avium subspecies paratuberculosis (MAP)** gram + short rods, acid fast +
65
pathogenesis of johne's disease
caused by **Mycobacterium avium subspecies paratuberculosis (MAP)** gram + short rods, acid fast + eaten by macrophages in peyer's patches and intestinal mucosa → resistant to being killed and will slowly replicate which cause inflammation and **granuloma formation** in the wall of the intestine
66
caused by **Mycobacterium avium subspecies paratuberculosis (MAP)** **johne's disease** gram + short rods, acid fast +
67
3 ways to diagnose Johne's disease
**Fecal culture**, 12-16 wks – most sensitive & most reliable **Serum antibody tests** – less expensive, faster – becomes more reliable as disease progresses **PCR** – fast, as sensitive as fecal culture but expensive.
68
is there a vaccine for Johne's disease
yes but not really used does not stop infection or shedding, more prevents calves from getting it causes false positive tests
69
how to treat Johne's disease
drugs not very effective- expensive don't really work **cull infected** move babies away from adults very hard to remove caused by **Mycobacterium avium subspecies paratuberculosis (MAP)**
70
MAP infection common in humans with \_\_disease.
Crohn’s ## Footnote Mycobacterium avium subspecies paratuberculosis (MAP) (gram + short thick rod, acid fast +)

Fall 22: micro (25 decks)

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