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Host And Defense - Exam 2 > Quiz 4 - Buxton - Anaerobes > Flashcards

Quiz 4 - Buxton - Anaerobes Flashcards

1
Q

What are anaerobes?

A

Don’t req O2 for life and reproduction

O2’s direct toxic effect may prohibit their growth

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2
Q

Why is O2 toxic?

A

Reacts with orgo matter. Grabs electrons and produces free radicals

It breaks down or renders useless the small metabolites that become components in cellular systems

O2 combines with the enzymes, proteins, nucleic acids, vitamins, and lipids that are vital to cell reproduction

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3
Q

What are toxic O2 products and free radicals?

A

O2-

H2O2

OH(dot)

*Lack of protective enzymes, such as superoxide dismutases and peroxidases help explain the toxic effects of O2

**Some anaerobes produce them in varying quantities

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4
Q

T/F - In vivo, bacteria tend to lower the redox potential at their site of growth

A

TRUE

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5
Q

Mixed colonies provide conditions __________ to the growth of anaerobes.

A

Favorable

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6
Q

T/F - Volatile and foul-smelling metabolic byproducts of other anaerobes contribute to a balanced environment.

A

TRUE

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7
Q

What does exogenous mean?

A

Environmental

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8
Q

What does endogenous mean?

A

Within

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9
Q

What is an important exogenous anaerobe?

A

Clostridium - Due to spores

*Though this can be endogenous as well

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10
Q

What sites are notorious for endogenous anaerobes?

A

Mouth, vagina, bowel, skin

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11
Q

What 5 organisms are found in the oral cavity?

A

Fusobacterium

Veilonella

Actinomyces

Porphyromonas

Prevotella

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12
Q

What species is found on the skin?

A

Propionibacterium

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13
Q

What is found in the vagina?

A

Lactobacillus

Prevotella bivia

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14
Q

What is found in the colon?

A

Bacteroides fragilis

Bacteroides

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15
Q

What are some factors that lead to anaerobic infections?

A

Trauma to mucous membranes or skin - trauma allows anaerobes of the indigenous microflora or soil to get access to deeper tissues

Vascular stasis - Stopping of circulation

Tissue necrosis

Decrease of redox potential of tissues

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16
Q

T/F - Anaerobes generally req longer incubation periods in the lab.

A

TRUE

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17
Q

Look at One Drive for the anaerobes you need to know.

A

There’s a lot. Look at it jacko

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18
Q

What is the treatment for anaerobic infections?

A

Create environment where anaerobes cannot proliferate
-Debridement, drainage

Arrest the spread of anaerobes into healthy tissue
-Antimicrobials play an important role here

Neutralize toxins

19
Q

What are biofilms?

A

Communities of microorganisms attached to a solid surface.

  • Can be a single species
  • Important survival mechanisms
  • Surface can be non-living or living
20
Q

What is the inter-species communication system called?

A

Quorum sensing

-Pheromones

21
Q

How does a biofilm form?

A

Attachment of cells to substrate

Growth and aggregation of cells into microcolonies

Maturation and maintenance of architecture

22
Q

What are the 5 stage of biofilm formation?

A

Attachment (seconds)

Irreversible binding (minutes)

Layering/Maturation-1

Ultimate thickness/Maturation-2 (days)

Dispersion (several days)

23
Q

Tell me about attachment.

A

REVERSIBLE binding

Log growth

Pili and adhesion molecules

Decrease flagella, increase adhesion molecules

24
Q

Tell me about irreversible binding?

A

Minutes

Exopolysaccharides trap nutrients and planktonic bacteria

Cells are sessile

25
Q

Tell me about layering/maturation-1.

A

Greater than 10 micrometers thick

26
Q

Tell me about ultimate thickness/maturation-2.

A

Days

Greater than 100 micrometers thick

Some cells released from substrate, but trapped in the EPS

27
Q

Tell me about dispersion.

A

Several days

Cells leaving

Nutrition become scarce, changes in gene expression

Cells again become planktonic

28
Q

How are biofilms constructed?

A

Stalks and mushroom-shaped microcolonies attached to the substratum

Matrix contains EPS, proteins, and DNA
-Viable, but not culturable

Fluid-filled channels

  • Exchange nutrients
  • Dispose of wastes
  • Some motile organisms
29
Q

What are the 3 layers of mature biofilm?

A

Outer

Intermediate

Innermost

30
Q

Tell me about the outer biofilm.

A

Most exposure to nutrients

Most ACTIVE organisms

Some become planktonic

31
Q

Tell me about the intermediate biofilm.

A

Metabolism is down-regged, but still using nutrients and exchanging genes

32
Q

Tell me about the innermost biofilm.

A

Attached

Earliest and least active

Includes the persister cells

33
Q

T/F - Biofilms are found in a lot of places. The interplay of biofilm and planktonic phenotypes are 3D architecture are universal.

  • Ships
  • Rocks
  • Sludge
  • Lungs of cystic fibrosis pts
  • DENTAL PLAQUE
A

TRUE

34
Q

What does planktonic mean?

What does sessile mean?

What does persister mean?

A

Free living

Attached/participating in the biofilm community

Metabolically inert
Present in ALL biofilms
Potential for maintenance of gene pool
Resist stresses, including antibiotics
Able to disable apoptosis
35
Q

What are some advantages to living in a biofilm?

A

Protection from host defenses

  • Protection from O2-reactive molecules
  • Physical barrier to PMNs

Potential to outcompete normal biota

Gene transfer

Protective enzymes

Orgo polymers
-Creeping like a lava flow on inanimate surface w/o detachment

36
Q

T/F - As biofilm forms, streamers of cells extend from the surface and break away to from new biofilms elsewhere.

A

TRUE

37
Q

T/F - Disaggregation can transmit already up-regged resistant aggregates of organisms to other body sites.

A

TRUE

38
Q

Dental biofilms are called?

A

Plaque

Bioflims of normal microbiota represent “baseline” organization

39
Q

How can biofilms reach the heart valves?

A

Poor hygiene

Blood stream

Heart valves

40
Q

After teeth cleaning, what happens?

A

Acquired pellicle
-Proteins and glycopeptides from host

Primary colonizers

  • S. Mutans and actinomyces
  • Pili and adhesion molecules
  • Glycocalyx (Glucan)

Bridge bacteria

  • Glucan-binding proteins
  • Fusobacterium
  • Can’t bind to pellicle, but CAN bind to primary colonizers

Late colonizers

  • Strep. Salivarius, propionibacterium/cutibacterium, prevotella, veillonella, selenomonas
  • Generally non-pathogenic
41
Q

With good oral hygiene, what happens to those organisms?

A

No disease

Balance b/t host and bacterial growth

Mostly gram positive organisms

42
Q

IF plaque remains, then what?

A

Microbiota changes
-Anaerobic and facultative G- bacilli and spirochetes

Pathogens
-Porphyromonas gingivalis
-Bacteroides forsythia
-Aggregatibacter actinomycetemcomitans
-Treponema denticola
*These require the late colonizers in order to attach
—Adhere to gingiva
—Invade tissue
—Initiate an inflammatory response

This causes gingivitis
-Reversible, mild

With really bad hygiene

  • Periodontitis
  • Loss of teeth
43
Q

What is sequelae to periodontitis?

A

Intimate relationship with ulcerated gums

Likely hematogenous spread of adherent bacteria

  • Heart valves
  • Prosthetic joints

Immune mimicry leading to arthrosclerosis

Host And Defense - Exam 2 (16 decks)

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