Session 4- Introduction to Antibiotics and Resistance

Question 1

bactericidal

Answer 1

kill the bacteria

Question 2

bacteriostatic

Answer 2

stop the bacteria from reproducing

Question 3

how to choose an antibiotic

Answer 3

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

Question 4

what are the different ways to measure antibiotic resistance

Answer 4

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,

Question 5

what is intrinsic antibiotic resistance

Answer 5

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’.

Question 6

what is acquired antibiotic resistance

Answer 6

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

Question 7

mechanisms for acquired antibiotic resistance

Answer 7

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

Question 8

adapted antibiotic resistance

Answer 8

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

Question 9

antifungals

Answer 9

azoles

polyenes

Question 10

antivirals

Answer 10

aciclovir

oseltamivir

Question 11

metronidazone

Answer 11

anti bacterial and anti protozoal

Question 12

beta-lactam antibiotics

Answer 12

prevent cell wall synthesis pennicilin, carbapenem, cephalosporin

Question 13

what is antimocrobial stewardship

Answer 13

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

Question 14

MDR

Answer 14

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

Question 15

XDR

Answer 15

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

Question 16

PDR

Answer 16

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

Question 17

name a penicllin

Answer 17

amoxicillin

Question 18

name a cephalosporin

Answer 18

cefadroxil

Question 19

name a tetracycline

Answer 19

tetracycline

Question 20

name a aminoglycoside

Answer 20

gentamicin

Question 21

name a macrolide

Answer 21

erythromycin

Question 22

name a sulfonamide

Answer 22

co-trmixazole

Question 23

name a quinolone

Answer 23

ciprofloxacin

Question 24

how does penicillin work

Answer 24

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

Question 25

how do cephalosporins work

Answer 25

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.

Question 26

how do tetracyclines work

Answer 26

Tetracycline is a short-acting antibiotic that inhibits protein synthesis

Question 27

how do aminoglycosides work

Answer 27

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

Question 28

how do macrolides work

Answer 28

inhibit protein synthesis

Question 29

how do sulfonamides work

Answer 29

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

Question 30

how do quinolones work

Answer 30

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

Question 31

which antibacterials affect cell wall synthesis

Answer 31

beta-lactams- penicillins, cephalosporinsn glycopeptides

Question 32

which antibacterials affect protein synthesis

Answer 32

tetracycline aminoglycosides macrolides

Question 33

what antibacterials affect cell membrane function

Answer 33

polymixins- colistin

Question 34

what antibacterials affect nucleic acid synthesis

Answer 34

quinolones trimethoprim rifampicin

Question 35

what is disc sensitivity testing

Answer 35

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

Question 36

what is MIC

Answer 36

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