Antibacterial Resistance Flashcards

1
Q

Bacterial population can rapidly _____ themselves to gain resistance to antibiotics, _______ resistant traits, and ______ them to other bacteria

A

Bacterial population can rapidly modify themselves to gain resistance to antibiotics, propagate resistant traits, and transfer them to other bacteria

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2
Q

define antibacterial resistance

A

ability of bacterium to survive and multiply in presence of an antibiotic

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3
Q

define innate (intrinsic) resistance

A

innate ability of a bacterial species to resist the activity of an antibiotic through its inherent structural or functional characteristics

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4
Q

define acquired (extrinsic) resistance

A

organism obtains the ability to resist the activity of an antibiotic to which it was previously susceptible

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5
Q

why is antibacterial resistance a problem?

A

drug resistance is reversing the progress of antibiotic development

new antibiotic development has rapidly slowed down

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6
Q

How many deaths a year are from antibiotic-resistance infections?

A

23,000 deaths

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7
Q

Where are many of the bacteria that cause antibiotic resistant infections found?

A

in livestock

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8
Q

Are antibiotics used only for therapeutic reasons in animals?

A

used for therapeutic and non-therapeutic

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9
Q

How is antibacterial resistant spread?

A
  1. antibiotic use selects for drug-resistant organisms
  2. resistance not induced by antibiotic itself but by environment created by antibiotics
  3. resistant strains can spread far and wide
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10
Q

How do bacteria disrupt or prevent the action of the antibiotic?

A

-preventing antibiotic from reaching its target
-modifying or bypassing antibiotic target

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11
Q

What are the way bacteria prevent the antibiotic from reaching its target?

A

-reduce ability of antibiotic to enter the cell
-expel the antibiotic out of the cell via efflux pumps
-antibiotic inactivation by modification or degradation

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12
Q

how do bacteria reduce the ability of antibiotic to enter the cell?

A

altering porins in the cell wall

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13
Q

how do bacteria expel the antibiotic out of the cell via efflux pumps?

A

-membrane proteins export or pump out antibiotics
-decreases antibiotic concentration inside the cell

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14
Q

how do bacteria inactivate antibiotics through modification or degredation?

A

enzymes degrade or modify the antibiotic so it is no longer effective

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15
Q

What enzyme do most bacteria possess to degrade antibiotics? which antibiotics is degreaded?

A

B-lactamases
B-lactam antibiotics

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16
Q

what does B-lactamase inhibitors do?

A

-structural analog of B-lactams
-extend activity of B-lactam antibiotic
-inhibit activity of B-lactamase

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17
Q

which of the following will bind first to the B-lactamase - B-lactam antibiotic or B-lactamase inhibitors?

A

B-lactamase inhibitor - has a higher affinity

18
Q

How do bacteria modify the antimicrobial target?

A

bacteria have acquired mutations or modified structures that are no longer recognized by antibiotic

19
Q

How do bacteria bypass the antibiotic target?

A

bacteria acquired a “new” enzyme that allows bypass of a metabolic pathway that the bacteria could be blocking

20
Q

Can we prevent antibacterial resistance from developing?

A

no but we can slow it down by using antibiotics wisley

21
Q

Why can’t we stop antibiotic resistance from developing

A

bacteria naturally develop resistance - it is their constant survival mechanism since they are always competing with other bacteria

22
Q

what are some principles for using antibiotics wisley?

A

-prescribe antibiotics only for bacterial infections
-educate clients on the proper use of antibiotics
-determine the most appropriate antibiotic for the infection

23
Q

How can giving an antibiotic for a viral infection negatively affect the body?

A

affect/kill normal flora > decrease in normal flora > inc susceptibility to other pathogens

24
Q

Why is it important to give antibiotics to animals as directed and not only give 1/2 of the course?

A

stopping halfway through leaves a population that has been under antibiotic pressure and the fittest will the survive and they will proliferate > create antibiotic resistance population

25
How can you determine the most appropriate antibiotic for infection?
isolate the bacterial pathogen and performing antibiotic susceptibility testing (AST)
26
what are the 3 antibiotic susceptibility tests we are focusing on in this course?
disk diffusion broth dilution (MIC) E-tests
27
How are disk diffusions done?
1. make lawn bacterial culture (evenly inoculated) 2. place filter disks containing antibiotic 3. incubate 4. measure ZOI
28
where is the highest concentration of antibiotic with a disk diffusion test?
around the disk, decreases as drug diffuses away
29
what is zone of inhibition?
diameter around bacterial clearance from disk
30
Is a disk diffusion test quantitative or qualitative?
qualitative
31
Which antibiotic would you use?
Erythromycin
32
Is a broth dilution test quantitative or qualitative?
quantitative
33
How are broth dilution test read?
lowest concentration of antibiotic that inhibits bacteria growth is the MIC (minimum inhibitory concentration)
34
What is the tube that is circled in red in a broth dilution test?
minimum inhibitory concentration
35
what test is this?
broth dilution in a microtiter plate
36
what is MBC?
minimum bactericidal concentration
37
38
What is an E-test?
ease of Kirby-bauer test with ability to determine MIC value
39
what is the MIC?
0.25 ug/ml
40
How is the MIC value determined in a E-test?
where the elliptical zone of inhibition crosses the E-test
41
How are the plastic strips for E-test filled with antibiotic? (same conc. throughout, gradually inc, gradually dec?)
plastic test strips impregnated with gradually decreasing conc. of antibiotic