Session 4- Introduction to Antibiotics and Resistance Flashcards

1
Q

bactericidal

A

kill the bacteria

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2
Q

bacteriostatic

A

stop the bacteria from reproducing

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3
Q

how to choose an antibiotic

A
is it active against target organism
does it reach site of infection
is it available in the right formulation
what is the half life 
does it interact with other drugs
are there toxicity issues 
does it require therapeutic drug monitoring 
does your patient have an allergy to any antibiotic class
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4
Q

what are the different ways to measure antibiotic resistance

A

Disc sensitivity/Diffusion testing- putting the organism on the agar plate and putting paper discs containing antobiotics and reading the zone of clearance

Minimum inhibitory clearance- the first concentration of antobiotic that inhibits the growth of bacteria,

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5
Q

what is intrinsic antibiotic resistance

A

a bacterial species is naturally resistant to a certain antibiotic or family of antibiotics, without the need for mutation or gain of further genes. The antibiotic does not that target the specific characteristics of the bacteria, therefore, unable to gain access to bacteria- this is usually a permanent ‘resistance’.

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6
Q

what is acquired antibiotic resistance

A

occurs when a particular microorganism obtains the ability to resist the activity of a particular antimicrobial agent to which it was previously susceptible

usually permanent and via chromosomal gene mutation/horizontal gene transfer

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7
Q

mechanisms for acquired antibiotic resistance

A
  • enzymatic modification or destruction of antibiotics
  • enzymatic alteration of antibiotic targets or mutation of bacterial target sites
  • overexpression of efflux pumps
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8
Q

adapted antibiotic resistance

A

This only causes a mild stress response to the bacteria- hence it will respond by becoming resistant to the antibiotic

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9
Q

antifungals

A

azoles

polyenes

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10
Q

antivirals

A

aciclovir

oseltamivir

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11
Q

metronidazone

A

anti bacterial and anti protozoal

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12
Q

beta-lactam antibiotics

A

prevent cell wall synthesis pennicilin, carbapenem, cephalosporin

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13
Q

what is antimocrobial stewardship

A

coordinated interventions designed to improve and measure the appropriate use of antimicrobials by promoting the selection of teh optimal antimicrobial drug regimen, dose, duration of therapy, and route of administration.

Antimicrobial stewards seek to achieve optimal clinical outcomes related to antimicrobial use, minimize toxicity and other adverse events, reduce the costs of health care infections, and limit the selection for antimicrobial resistant strains

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14
Q

MDR

A

multi drug resistant- non-susceptibility to at least one agent in three or more antimicrobial categories

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15
Q

XDR

A

extensively drug resistant- non-susceptibility to at least one agent in all but two or fewer antimicrobial categories

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16
Q

PDR

A

pan-drug resistant - non susceptibility to all agents in all antimicrobial categories

17
Q

name a penicllin

A

amoxicillin

18
Q

name a cephalosporin

A

cefadroxil

19
Q

name a tetracycline

A

tetracycline

20
Q

name a aminoglycoside

A

gentamicin

21
Q

name a macrolide

A

erythromycin

22
Q

name a sulfonamide

A

co-trmixazole

23
Q

name a quinolone

A

ciprofloxacin

24
Q

how does penicillin work

A

burst bacterial cell walls by acting directly on peptidoglycand which play an essential role in cell walls of bacter

25
Q

how do cephalosporins work

A

bactericidal (kill bacteria) and work in a similar way to penicillins. They bind to and block the activity of enzymes responsible for making peptidoglycan, an important component of the bacterial cell wall.

26
Q

how do tetracyclines work

A

Tetracycline is a short-acting antibiotic that inhibits protein synthesis

27
Q

how do aminoglycosides work

A

Aminoglycosides inhibit protein synthesis by binding, with high affinity, to the A-site on the 16S ribosomal RNA of the 30S ribosome

28
Q

how do macrolides work

A

inhibit protein synthesis

29
Q

how do sulfonamides work

A

binding and inhibiting a specific enzyme called dihydropteroate synthase (DHPS). This enzyme is critical for the synthesis of folate, an essential nutrient

30
Q

how do quinolones work

A

inhibit replication of bacterial DNA by blocking the ligase domain of bacterial DNA gyrase (topoisomerase II); some also inhibit topoisomerase IV.

Bactericidal

31
Q

which antibacterials affect cell wall synthesis

A

beta-lactams- penicillins, cephalosporinsn

glycopeptides

32
Q

which antibacterials affect protein synthesis

A

tetracycline
aminoglycosides
macrolides

33
Q

what antibacterials affect cell membrane function

A

polymixins- colistin

34
Q

what antibacterials affect nucleic acid synthesis

A

quinolones
trimethoprim
rifampicin

35
Q

what is disc sensitivity testing

A

putting the organism on a agar plate and putting paper discs containing antibiotics and reading the zone of clearance

36
Q

what is MIC

A

minimum inhibitory concentration- the first concentration of antibiotic that inhibits the growth of bacteria