Antimicrobial chemotherapy

Question 1

what do anti-fungal drugs target

Answer 1

class 2 reactions

Question 2

what do fungal cell membranes contain

Answer 2

ergosterol
instead of cholesterol

Question 3

what do drugs that inhibit ergosterol synthesis do

Answer 3

impair fungal membrane function without affecting the host cell membrane

e.g. fluconazole

Question 4

drugs targeting endoplasmic reticulum

Answer 4

allylamines
benzylamines
imidazoles
triazoles

Question 5

drugs targeting cell wall

Answer 5

echinocandins

Question 6

drugs targeting plasma membrane

Answer 6

polyenes (amphotericin B)

Question 7

drugs targeting DNA synthesis

Answer 7

flucytosine

Question 8

drugs targeting the mitotic spindle

Answer 8

griseofulvin

Question 9

what is fungal synthesis of nucleic acid dependent on

Answer 9

folate mechanism
some anti-fungals are converted to anti-metabolites (false substrates) in fungi but not in host cells

Question 10

what is flucytosine metabolised to in fungi

Answer 10

5-FU

Question 11

which stages of the cell cycle to anti-viral drugs target

Answer 11

entry to host cells
nucleic acid replication
viral protein synthesis
exit from host cells

Question 12

how do anti-viral drugs target the entry to host cells

Answer 12

drugs may inhibit fusion of virus with host cell membrane following binding to surface receptor

Question 13

how do anti-viral drugs target nucleic acid replication

Answer 13

drugs may inhibit DNA/RNA polymerases e.g. aciclovir or retroviral reverse transcriptase (zidovudine)

Question 14

how do anti-viral drugs target viral protein synthesis

Answer 14

may inhibit girl proteases involved in processing large poly proteins

Question 15

how do anti-viral drugs target exit from host cells

Answer 15

may inhibit neuraminidase-catalysed cleavage (oseltamivir)

Question 16

attachment and entry inhibitor anti-virals

Answer 16

maraviroc
enfuvirtide

Question 17

ion channel blockers anti-virals

Answer 17

amantadine
rimantadine

Question 18

polymerase inhibitors anti-virals

Answer 18

acyclovir
zidovudine
efavirenz

Question 19

integrase inhibitors anti-virals

Answer 19

raltegravir

Question 20

protease inhibitors anti-virals

Answer 20

saquinavir
ritonavir

Question 21

neuraminidase inhibitors anti-virals

Answer 21

zanamivir
oseltamivir

Question 22

remdesivir mechanism of action

Answer 22

RNA- dependent RNA polymerase inhibitor

Question 23

ribavirin mechanism of action

Answer 23

RNA dependent RNA polymerase inhibitor

Question 24

Lopinavir-ritonavir mechanism of action

Answer 24

3CL protease inhibitor

Question 25

favipiravir mechanism of action

Answer 25

RNA dependent RNa polymerase inhibitor

Question 26

chloroquine mechanism of action

Answer 26

viral entry inhibitor

Question 27

hydroxychloroquine mechanism of action

Answer 27

viral entry inhibitor

Question 28

oseltamivir mechanism of action

Answer 28

neuraminidase inhibitor

Question 29

umifenovir mechanism of action

Answer 29

spike protein/ ACe2 membrane fusion inhibitor

Question 30

examples of immunomodulatory agents

Answer 30

tocilizumab
interferons

Question 31

examples of adjunctive agents

Answer 31

arithromycin
corticosteroids

Question 32

tocilizumab mechanism of action

Answer 32

IL-6 inhibitor

Question 33

interferon mechanism of action

Answer 33

activate interferon-stimulated genes
-interfere with viral replication
-immunomodulatory effects

Question 34

azithromycin mechanism of action

Answer 34

antibacterial, used in combination with hydroxychloroquine for synergistic antiviral effect

Question 35

corticosteroid mechanism of action

Answer 35

cytokine gene expression inhibitor

Question 36

camostat mesylate mechanism of action

Answer 36

serine protease inhibitor

Question 37

ACE inhibitor mechanism of action

Answer 37

Ace inhibitor; inhibitor the formation of angiotensin 11
ARB; angiotensin 11 receptor antagonist

Question 38

how do bacteria transmit resistant

Answer 38

spontaneous mutation
gene transfer or transferred resistance

Question 39

spontaneous mutations

Answer 39

happens when cells replicate
within a population there will be some bacteria with acquired resistance
drug eliminates the sensitive organisms and the resistant ones proliferate

Question 40

gene transfer or transferred resistance

Answer 40

usually spread through conjugative transfer of R plasmid (may be virally mediated)

Question 41

4 mechanisms responsible for resistance to antimicrobial drugs

Answer 41

1. inactivating enzymes that destroy the drug (beta lactamases)
2. decreased drug accumulation (tetracyclins, beta lactams)
3. altering the binding sites ( aminoglycosides and erythromycin)
4. development of alternative metabolic pathways (sulphonamides e.g. dihydropteroate synthease and trimethoprim e.g. dihydrofolate reductase)

Question 42

increased elimination

Answer 42

drug enters cell but efflux pump ejects it

Question 43

drug-inactivating enzyme

Answer 43

enzyme modifies drug
inactivates it

Question 44

alteration in target

Answer 44

drug can’t bind to the target

Question 45

decreased uptake

Answer 45

prone proteins prevent entry into the cell

Question 46

4 ways to slow the emergence and spread of antimicrobial resistance

Answer 46

1. understand the mechanisms
2. use of combination therapies
3. responsibilities of physicians: work to identify the microbe and prescribe suitable antimicrobials, educate patients
4. responsibilities of patients: carefully follow instructions

Question 47

in the absence of drug will a sensitive or resistant cell grow faster

Answer 47

the sensitive cell
resistant cells use more energy