Antibiotics

Question 1

what are the different types of antimicrobial chemotherapy

Answer 1

antibacterial, antiviral, anti fungal, antiparasitic

Question 2

what are the majority of antibiotics based on

Answer 2

naturally occurring compounds or may be semi-synthetic or synthetic

Question 3

what does differential toxicity refer to

Answer 3

antimicrobial chemotherapy, based on the concept that the drug is more toxic to the infecting organism than to the host

Question 4

do we want a drug to be narrow or broad

Answer 4

as narrow/direct to the organism as possible

Question 5

what is the minimum inhibitory concentration (MIC)

Answer 5

the minimum concentration of antibiotic required to inhibit the growth of the test organism

Question 6

what is the minimum bactericidal concentration (MBC)

Answer 6

the minimum concentration of antibiotic required to kill the testosterone organism

Question 7

what is bacteriostatic

Answer 7

inhibit growth

antimicrobial keeps growth static when antimicrobial is removed the growth increases again

Question 8

what is bactericidal

Answer 8

kills growth

when antimicrobial is added it keeps killing the microbe until you remove the drug

Question 9

what is the goal of concentration dependent killing

Answer 9

maximize concentration so the drug can be dosed less frequently (1 or 2 times a day)

Question 10

what is the goal of time dependent killing

Answer 10

maximize exposure

keeping the drug above MIC as long as possible, have to dose my frequently though

Question 11

what is prophylaxis

Answer 11

antimicrobial agents are administered to prevent infection (ex. surgical prophyaxis so no bacteria gets into the body upon initial cut)

Question 12

what is the ideal antibiotic

Answer 12

no/low toxicity to the host

low propensity for development of resistance

does not induce hyper-sensitives in the host

Rapid and extensive tissue distribution

relatively long half life (dose less frequently)

free of interactions with other drugs (ex. old people take a lot of drugs that could interact)

Convenient for administration/relatively inexpensive

Question 13

what are the beta lactams

Answer 13

1. beta lactams
   - penicillins
   - cephalosporine
   - carbapenems
2. glycopeptides (vasomycin)
3. fosfomycin

Question 14

what is beta lactam resistant

Answer 14

1. from beta lactamase, it opens the beta lactam ring and makes it unable to bind to the pbp, so no cross linking enzyme (transpeptidase)and weaken cell wall
2. target site/pbp modification
3. altered permeability (gram-negs outer membrane so cant get in)

Question 15

how do you inhibit beta lactam

Answer 15

add an antibotic with a beta lactamase attached to it to prevent the ring from breaking

clavulanic acid
tazobactam

Question 16

what are cephalosporins

Answer 16

part of the beta lactams

they have 5 generations
gen 1 is for gram positive - get 5 is for gram neg

Question 17

what are cerbenenems

Answer 17

part of beta lactams
used to treat severe illness

Question 18

what are glycopeptides

Answer 18

the only drug is vasomycin

it binds to the peptidoglycan directly and makes it too big to fit into the pbp

only works with gram positives

1% of the time administered orally for C. difficile so goes directly to the gut

Question 19

what are glycopeptide reistsances

Answer 19

enterococcus makes d-lac instead of a-ala which is able to dind to the pbp so there is no cross linking (transpeptidase) and a weak cell wall

Question 20

what type of drugs require therapeutic drug monitoring

Answer 20

gycopeptides (vasomycin) and aminoglycosides

Question 21

what is fosfomycin

Answer 21

a type of beta lactam

old drug that has been brought back

used to treat UTIs

works in the cytoplasm to prevent the organism from synthesizing the building blocks requires to make peptidoglycan (cell wall)

Drug is only taken once

Question 22

fluoroquinolones

Answer 22

distrupt DNA synthesis

Bind to DNA gyrase and Toposisonmerase IV

DNA gyrase can unwind but cannot recoil together

Question 23

explain fluroroquinolone resistance

Answer 23

1. mutation: of parC and gyrA, changes AA and reduces affinity for the drug to bind
2. increase in efflux pumps
3. decrease in porins cant get in

Question 24

what are the antibiotics that disrupt the protein sythesis

Answer 24

1. macrolides
2. clindamycin
3. tetracyclines
4. aminoglycosides

all work by binding to ribosome and inhibiting protein synthesis

Question 25

what is macrolide resistance

Answer 25

efflux increase

target site modification by expression of the erm gene

Question 26

what are clindamycines

Answer 26

only work with gram positives

try not to take

most likely to develop C. difficult with this

Question 27

what are tetracyclines

Answer 27

not prescribed for kids because it can lead to teeth discolouration

Question 28

how do aminoglycosides work

Answer 28

entry through the inner membrane is from the ETC, do not in aerobic conditions or in abscesses

Question 29

what is aminoglycosides resistances

Answer 29

enzymatic modification, modify the drug so its inactive like B-lactamase

Question 30

what are ototoxic and nephrotoxic

Answer 30

adverse effects associated with aminoglycosides

effects hearing

effects kidneys

Question 31

what are TMP-SMX

Answer 31

inhibits focal metabolism

two drugs administered

used for UTIs and PJP pneumonia

Question 32

what is an Antabuse effect

Answer 32

with metronidazole (fagly) if you drink with drug in system you will puke