Antimicrobial Resistance Flashcards

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1
Q

What are the 3 ways of physical sterilization?

A

Heat

Radiation

Filter

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2
Q

What “metric” quantitfies antimicrobial effectiveness?

A
  • Decimal Reduction time - time it takes to reduce microbial population by 90%
  • D = -t / log Nf - log No
  • T = Tfinal - Tinitial
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3
Q
  • What is the most widely used method of controlling microbial growth?
  • How does this method work against microbes?
A
  • Heat sterilization
  • High temperatures denature macromolecules
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4
Q

What are some things you can’t kill/sterilize in an autoclave?

A
  • spores
  • Anything you want to keep living
  • Scrubs, electronics, etc.
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5
Q

How does an autoclave work?

A
  • Sealed device that use steam under pressure
    • allows temps of water to get above 100 C
    • Pressure doesnt kill, but high temperature does.
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6
Q

What is pasteurization?

Is pasteurization a form of sterilization?

A
  1. process of using precisely controlled heat to reduce the microbial load in heat-sensitive liquids
  2. Does not kill all organisms - so technically it is not sterilization.
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7
Q

What types of surfaces can/can’t be affected by UV radiation?

A
  • Can
    • tops of surfaces
  • Can’t
    • solid, opaque, or light-absorbing surfaces
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8
Q

Is radiation sterilization approved by the WHO for the decontamination of foods susceptible to microbial contamination?

A

Yes

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9
Q

What is filter sterilization good for?

A
  1. Allow liquid and gas to fit through but catches very small microbes
  2. Good for heat sensitive things that need to be sterilized.
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10
Q

Most bacteria are [] - [] microns long, but HEPA filters catch anything greater than [] um….

A
  • 3-5 microns
  • >.3 um
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11
Q

What is the MAIN target for most antimicrobials?

A

essential proteins and cell membrane

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12
Q

What species of bacteria make 2/3 of the useful antibiotics?

A

Streptomyces species

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13
Q

What are the 3 main compounds produced to stop the growth of microbes?

A

Antibacterials

Antivirals

Antifungus

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14
Q

What is the minimum inhibitory concentration?

A
  • Smallest amount of an agent needed to inhibit growth of a microorganism
  • Varies between organism, not real precies
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15
Q

How are viable cell counts used to quantify chemical growth control of microbes?

What is the draw back to viable cell count?

A
  • Gives information about bacteriostatic / cidal /lytic
    • since you actually look at the plates and shit
  • Can be used to calculate decimal reduction times
  • However, can be very laborious
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16
Q
  1. Stopping growth of cell and disrupting viability =
  2. Stopping growth and destroying cells =
  3. Stopping growth/reproduction without distupting the viability of cells =
A
  1. bacteriocidal
  2. Bacteriolytic
  3. Bacteriostatic
17
Q

What are the 2 categories of chemical agents?

A
  1. Products use to control microbes for external use
    1. Industrial settings, chemicals in food, sterilants, disinfectants antiseptics, etc….
  2. Chemical sdesigned for internal use
    1. antibiotics - antibacterials, antivirals, antifungals, antiparasitics
18
Q

What chemical antimicrobial agent is ok to use on human and living tissues?

A

Antiseptics

Ex: Ethanol, soap, iodine

19
Q

What antimicrobial agent destorys all microbial life, including spores?

A
  • Sterilants
  • Hydrogen peroxide, ethylene oxide gas, bleach
  • 6-7 log reduction
20
Q

What chemical antimicrobial agent kills most microbes, except for spores, on surfaces?

A
  • Disinfectants
  • Ex: Ethanol, ozone, chlorine gas, Pine-Sol
  • 4-5 log reduction
21
Q

What chemical antimicrobial agent reduces the total number of microbes?

A
  • Sanitizers
  • Ex: Alcohol gels
  • 2-3 log reduction
22
Q

How do synthetic antibiotics generally attack microbes?

A
  • Analogs similar to vitamins, amino acids, and other compounds
  • Adding a bromine or fluorine to nucleic acid base and amino acid analogs
23
Q

How do sulfa - synthetic drugs work?

A
  • They are a competitive inhibitor to the enzyme dihydropteroate synthase (DHPS)
  • Enzyme involve din foalte synthesis
24
Q

How do Isoniazid antibiotics work?

A
  • It is a growth analog effective against mycobacterium
    • interferes with synthesis of mycolic acid
25
Q

What are the major naturally occuring antimicrobial drugs created by…Streptomyces?

A
  • tetracyclines
  • aminoglycosides
  • macrolides
  • chloramphenicol
  • 60-80% of naturally occuring antibiotics
26
Q

What are the major naturally occuring antimicrobial drugs created by…Fungi?

A
  • Penicillium
  • Cephalosporium
  • B-lactams
27
Q

What are the major naturally occuring antimicrobial drugs created by…Bacillus?

A
  • Polymixins
  • Bacitracin
28
Q

What do B-lactams inhibit?

What specific protein do they inhibit and which type of bacterial cell are they most effective against?

A
  1. transpeptidation - final step of inserting NAG-NAM into peptid
  2. PBPs that crosslink peptidoglycan
  3. Most effective against against G+ since they have a large peptidoglycan layer
29
Q

What does Daptomycin inhibit?

What is it produced by?

Use to treat [] bacterial infections

How does it effect the membrane?

A
  1. Membrane function
  2. Streptomyces
  3. Treats G+ infection
  4. Forms pores in cytoplasmic membrane
30
Q

What are polymixins made by?

What do they distrupt and how?

A
  • Paneibacillus polymyxa
  • Bind to LPS of G- and disrupt inner membrane and outer membrane
31
Q

What new class of broad-sprectrum antibiotics inhibit fatty acid biosynthesis?

A

Platensimycin