Antimicrobials

Question 1

Name the 3 classes of antibiotics which inhibit the bacterial cell wall

Answer 1

penicillins
cephalosporins
carbepenems
vancomycin

Question 2

which of the bacterial cell wall inhibitors are beta lactam antibiotics?

Answer 2

penicillins
cephalosporins
carbepenems

Question 3

what is the mechanism of action of penicillin’s, cephalosporins and carbepenems?

Answer 3

inhibits CW biosynthesis
inhibit enzyme involved in transpepidase cross linking reaction, interferes with cell wall biosynthesis as individual chains can not link together

Question 4

name 5 penicillin’s

Answer 4

end: CILLIN
oxacillin
ampicillin
amoxicillin
cloxacillin
methicillin

Question 5

which bacteria are penicillin’s most effective against?

Answer 5

gram +

Question 6

what mechanism do beta lactam ring antibiotics use?

Answer 6

autolysis

Question 7

what is the beginning of all the cefhalosporins?

Answer 7

CEF
eg. cephalexin
cefazolin

Question 8

name 3 carbapenems

Answer 8

end: PENEM
meropenem
ertapenem
imipenem

Question 9

carbapenems can only be administered by which route?

Answer 9

IV

Question 10

what is the mechanism of action of vancomycin?

Answer 10

inhibits CW biosynthesis by encapsulating peptide bonds between PG layers to prevent joining

Question 11

name the 4 classes of antibiotics which inhibit protein synthesis

Answer 11

tetracycline (doxycyclin)
chloramphenicol
aminoglycosides (gentamycin, streptomycin)
macrolides (erythromycin)

Question 12

describe the mechanism of action of tetracycline (doxycyclin) and aminoglycosides (gentamycin, streptomycin)

Answer 12

bind to and inhibit protein of 30S subunit

Question 13

describe the mechanism of action of chloramphenicol and macrolides (erythromycin)

Answer 13

binds to and inhibits protein of 50S subunit

Question 14

which bacteria are antibiotics targeting protein synthesis effective against?

Answer 14

both gram + and - (broad spectrum)

Question 15

are antibiotics targeting protein synthesis bacteriostatic or bactericidal?

Answer 15

bacteriostatic

Question 16

are antibiotics targeting CW biosynthesis bacteriostatic or bactericidal?

Answer 16

bactericidal

Question 17

which class of antibiotics targets DNA systhesis?

Answer 17

fluoroquinolones

Question 18

name the fluoroquinolones?

Answer 18

end: FLOXIN
ciprofloxin
norfloxin
levofloxin
moxifloxin

Question 19

what are the mechanism of action of fluoroquinolones?

Answer 19

inhibit enzymes (DNA gyrase) which has essential role in DNA replication

Question 20

which class of antibiotics is effective against intracellular pathogens such as legionella and mycoplasma?

Answer 20

fluoroquinolones

Question 21

which bacteria are fluoroquinolones effective against?

Answer 21

broad spectrum

Question 22

what is the mechanism of action of Rifampicin?

Answer 22

inhibits RNA biosynthesis

inhibits bacterial DNA-dependant RNA polymerase

Question 23

which antibiotics is predominantly used to treat TB?

Answer 23

rafampicin

Question 24

name three antibiotics which directly inhibit nucleic acid by inhibiting folate biosynthesis?

Answer 24

sulphonamides
trimethoprim
co-trimetoxazole

Question 25

what is sulphonamides mechanism of action?

Answer 25

analogue of PABA; acts a substrate competion

Question 26

what is the mechanism of action of trimethoprim?

Answer 26

inhibits dihydrofolate reductase

Question 27

what is the mechanism of action of co-trimetoxazole?

Answer 27

mix of sulphonamides and trimethoprim

Question 28

why is folate a good target for antibiotics?

Answer 28

bacteria make folic acid and humans don't

Question 29

what antifungals are B1,3- glucan inhibitors?

Answer 29

echinocandins

Question 30

name 2 echinocandins

Answer 30

end: FUNGIN casofungin micafungin

Question 31

are echinocandins fungicidal or fungiostatic?

Answer 31

fungicidal

Question 32

what is B1,3- glucan?

Answer 32

allows synthesis of fungal cell wall - essential component and target for most antifungals

Question 33

what is the mechanism of action of echinocandins

Answer 33

inhibits enzyme B1,3 Glucan synthase thus blocking synthesis of fungal CW

Question 34

name the three classes of esgosterol inhibiting antifungals

Answer 34

polyenes azoles allylamines

Question 35

name 2 polyene antifungals

Answer 35

amphotericin B | nystatin

Question 36

what is the mechanism of action of polyenes?

Answer 36

bind to ergosterol in plasma membrane | forms pores in PM which disrupt integrity and cause leakage of cells constituents

Question 37

how can the severe side effects of polyenes be reduced?

Answer 37

use amphotericin B complex or liposomal | amphotericin B formulations

Question 38

are polyenes fungicidal or fungiostatic?

Answer 38

fungicidal

Question 39

name 2 types of azoles

Answer 39

imidazoles | triazoles

Question 40

name 3 imidazoles

Answer 40

end: AZOLE miconazole clotrimazole ketoconazole

Question 41

name 3 triazoles

Answer 41

end: AZOLE fluconazole voriconazole itraconazole

Question 42

what is the mechanism of action of azoles?

Answer 42

inhibit lanosterol C-14 demethylase - a key step in ergosterol synthesis

Question 43

name 2 allylamines

Answer 43

end: FINE terbinafine amorolfine

Question 44

what is the mechanism of action of allylamines?

Answer 44

inhibits earlier step in ergosterol biosynthesis

Question 45

which azole is more potent?

Answer 45

triazoles

Question 46

what is the mechanism of action of flucytosine?

Answer 46

metabolised by fungal cell to 5-fluorourcil which is toxic and inhibits RNA and DNA synthesis

Question 47

which other antifungal is flucytosine used in combination with?

Answer 47

azoles