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Microm442! > Lc 18 > Flashcards

Lc 18 Flashcards

1
Q

What distinguishes mycobacteria from mycoplasma?

A

Presence of waxy cell wall

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2
Q

Where are those mycobacterium found?

A

Water, soil, foodstuffs.
Many are opportunistic pathogens in humans

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3
Q

What are some important determinants of disease presence and severity for all of disease from mycobacteria?

A

Host susceptibility

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4
Q

Are mycobacterium gram negative or gram positive?

A

Neither, but slightly positive when stained

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5
Q

What are composed of in their cell wall?

A

60% mycolc acids. ( waxy coats), lipoarabinomannan

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6
Q

Mycobacteria are acid fastness. What does it mean?

A

Resists destaining( resistance to decolorization) by acid or ethanol

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7
Q

What does the waxy cell wall do?

A

It is very resistant to drying

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8
Q

Even if you stain the bug(mycobacteria), you won’t see any color but purple. True or false?

A

True.

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9
Q

How do you divide mycobacteria into two distinct types?

A

Slow growing and fast growing

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10
Q

Explain slow growing and fast growing.

A

Slow growing :
-M.tuberculosis, M.leprae are examples
- Generation times often 40x E.coli
- forms visible colonies > 7 days

Fast frowing:
- M. abscessus spp
- Forms visible colonies or growth < 7 ays

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11
Q

Explain mycobacteria’s characteristics

A

Aerobic
Nonmotile (except M.marinum)
Difficult to culture in vitro
Difficult to manipulate genetically
Susceptibility to infection is conferred by host characteristics

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12
Q

Mycobacyeria are hard to grow in in vitro and hard to manipulate genetically.
What does that result in?

A

Hard for lab study and diagnosis

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13
Q

What characteristics of slow mycobacteria growth makes them difficult to treat?

A

-less likely to respond to standard antibiotics
-often grows to high densities before immunity develops
- develop resistance to single agents easily

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14
Q

How do we treat mycobacterium?

A

Use multiple drugs

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15
Q

What are the cause of resurgence of mycobacterium?

A

Poverty
Crowding
Malnutrition
Africa-Asia hardest-hit
Multi drugs resistance
HIV/AIDS

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16
Q

HIV impacts TB. How do they do that?

A

They infect T cells

17
Q

AIDS increases susceptibility to to tuberculosis. True or false

A

False. AIDS increases susceptibility to to non tuberculosis disease, especially M. Avium complex

18
Q

Covid also impacts TB. Does poverty impact TB?

A

Yes. Sadly

19
Q

What are the clinical features of TB?

A

Primary : often quite
Immunocompromised - bugs go crazy and disseminated disease can occur

Secondary: reactivation disease .
Immune response(night sweats, fever, weight loss)

20
Q

How do TB get transmitted?

A

Via droplets
—> coughing, talking,sneezing
—> remain in the air for hrs
—> small droplet nuclei can penetrate lung airspaces
—> require prolonged recurrent exposure for infection

21
Q

Explain TB pathogenesis

A

-M. Tb replicate in macrophages, destroying them.
-Blood borne inflammatory cells migrate to infection —> granuloma
-infected macrophages disseminates via lymphatic to lymph nodes

22
Q

Define immunocompetent and immunocompromised

A

Immunocompetent : helathy individ. W good immune systems

Immunocompromised: unhealthy, susceptible individuals, —> often in infants and elderly

23
Q

When does TB get very infectious? Primary or secondary TB?

A

Secondary TB (deactivation)

24
Q

When does latency state happen?

A

Once they have developed immune response..
It splits into two categories :containment, reactivation

25
Q

How do we diagnose TB.

A

Microscopy, culture, PCR, skin yest(PPD), IFN-r release test

26
Q

What is the most important part of treating TB.

A

Use multiple drugs
Use more than 3 agents for disease
(High bacterial burden)
Single agent for known exposure, no disease (low bacterial burden)

27
Q

What is the first bacterium identified as causing disease in humans

A

Leprosy (Hansen’s disease)

28
Q

Can we cultivate leprosy in vitro?

A

No

29
Q

What are the hosts of leprosy?

A

Humans and primates
Armadillos
Eurasian red squirrel

30
Q

How does leprosy get transmitted?

A

Aerosol
Exposure to animals or soils

Epidemiology is very difficult

31
Q

We also need multidrug therapy for leprosy. True?

A

True.
Use multi drugs —> lose infection within 3 days

Microm442! (8 decks)

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