Lecture 13 Flashcards

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1
Q

How do bacteria invade human body

A

-Through mucus membranes (respiratory and garstrointestinal tracts, urinary tract and genital openings)
-Non intact skin (bites, wounds, injections…)

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2
Q

How do bacterial pathogens damage host cells?

A
  1. Invasion
  2. Toxins
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3
Q

What is invasion

A

Ability to spread to other loc in host by invading cells or tissues. Atp that signs of illness and disease occur

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4
Q

what are Toxins

A

Very specific virulent factor produced by bacterial pathogens, poisonous substances to host

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5
Q

What is toxigenicity

A

Organism’s ability to make toxins

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6
Q

Two categories of toxins

A

Endotoxins and exotoxins

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7
Q

Exotoxins

A

Toxin secreted by microorganism into surrounding enviro

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8
Q

Endotoxin

A

Toxin release by microorganism into environment when it dies, it’s part of cell wall

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9
Q

Impacts to metabolic pathways in eukaryote host by bacterial toxins

A
  1. Damage cell membrane
  2. Disrupt prot synthesis
  3. Inhibiting function of nervous syst
  4. Inhibiting activation of host immune syst
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10
Q

Some pathogens

A

Gonorrhea, lyme disease, strep throat, tuberculosis, tetanus

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11
Q

What are antibiotics

A

Drugs to treat infections caused by bacteria

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12
Q

What is zone of inhibition (ZOI)

A

Clear zone surrounding antimicrobial agent, complete absence of bacteria

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13
Q

What is a bacterial lawn

A

Dense and uniform layer of bacteria on agar plate

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14
Q

What is selective toxicity

A

When agents affect pathogens and not host (by interacting with structures not present in/diff from host)

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15
Q

Antibiotic modes of action

A
  1. Cell wall synthesis
  2. Cell membrane function
  3. Metabolic reaction
  4. Prot synthesis
  5. Dna synthesis
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16
Q

Inhibitors of cell wall synthesis (ex penicillin)

A

Targets cell wall(critical for survival of bacteria)

17
Q

Inhibitors of cell membrane function:

A

Content of cell will leak out and cell dies. However, often poorly selective and can be toxic for systemic use in mammalian host -> only topical

18
Q

Inhibitors of metabolic processes:

A

Inhibits certain pathways necessary for bacteria survival

19
Q

Inhibitor of prot synthesis

A

Target ribosome components (diff from eukaryotic) and leads to death bc prot synthesis is necessary for multiplication/survival of bacteria

20
Q

Inhibitors of nucleic acid synthesis

A

Binding to components involved in process of dna or rna -> hinders multiplication

21
Q

Cell wall function

A

Very strong, resists bursting/maintains shape, structural support and protection

22
Q

What is composed of peptidoglycan

A

Cell wall in bacteria

23
Q

What is the gram stain

A

Determines gram positive (purple) and gram negative (red) bacteria and proper antibiotic to choose

24
Q

Which bacteria stain purple (gram positive)

A

Those with thick peptidoglycan walls

25
Q

Which bacteria stains red (gram negative?

A

Those with thin peptidoglycan wall with thick outer layer of lipids and carbohydrates

26
Q

Gran stain process steps

A
  1. Crystal violet added (primary stain)
  2. Iodine makes purple stick to peptidoglycan layer (if present)
  3. Alcohol is decolourizing agent (gram - lose colour)
  4. Safranin sticks to gram- cell walls
27
Q

Gran stain process steps

A
  1. Crystal violet added (primary stain)
  2. Iodine makes purple stick to peptidoglycan layer (if present)
  3. Alcohol is decolourizing agent (gram - lose colour)
  4. Safranin sticks to gram- cell walls
28
Q

Penicillin kills which gram bacteria

A

Gram positive

29
Q

Which bacteria-toxin

A

Endotoxin = gram negative
Exotoxin = gram positive

30
Q

Narrow Spectrum antibiotics

A

Affects small range of bacteria (each target specific one)

31
Q

Broad spectrum antibiotic

A

Affects large range of bacteria, also kills natural microbiota -> increases risk of opportunistic infections (ex yeast infections)

32
Q

Penicillin mechanism

A

Cell wall inhibitors (gram positive)

33
Q

Streptomycin (antibiotic) mechanism

A

Inhibits protein synthesis (broad spectrum, tuberculosis

34
Q

Where is the chromosome in prokaryotes

A

Nucleoid region

35
Q

Plasmids are and can

A

Smaller circular dna fragments (no genes essential for survival) and can be transferred between bacterial cells (conjugation)

36
Q

Why carry plasmid through evolution if not necessary?

A

Bc could be advantageous (ex antibiotic resistant gene -> gets passed on and more have it)

37
Q

Antibiotic resistant bacteria grow how

A

The more antibiotics used, the greater the “selective pressure”. Antibiotics create an enviro which favours growth of resistant bacteria by killing non resistant ones

38
Q

How fast can antibiotic resistant bacteria multiply

A

Once resistance established, rapidly evolves bc rapidly multiplies. Overnight, one can multiply to become a million