antibiotic actions *

Question 1

penicillins

Answer 1

inhibit cell wall synthesis by preventing cross linking of peptidoglycan subunits
- bactericidal
- betalactam antibiotic

excreted rapidly via kidney
type 1 hypersensitivity reaction

Question 2

cephalosporins examples

Answer 2

ceftriaxone, cefuroxime

caution in penicillin allergy

Question 3

cephalosporins

Answer 3

inhibit cell wall synthesis
- bactericidal
- betalactam antibiotic
- excreted by kidney

Question 4

which antibiotics act by inhibiting the synthesis of the peptidoglycan layer of bacterial cell walls

Answer 4

β-Lactam antibiotics, including
- penicillins
- cephalosporins
- monobactams
- carbapenems

Question 5

glycopeptides MoA

Answer 5

inhibit synthesis of cell well peptidoglycan and inhibit bacterial cell membrane permeability
- bactericidal
- only active against gram pos cell walls
- excreted in urine
—> vancomycin can damage kidneys

Question 6

example of a glycopeptide antibiotic

Answer 6

vancomycin

Question 7

macrolide examples

Answer 7

erythromycin, clarithromycin, azithromycin

(NOT vancomycin -> glycopeptide)

Question 8

antibiotics which inhibit protein synthesis

Answer 8

macrolides - erythromycin
tetracyclines - doxy
aminoglycosides - gentamicin

attach to bacterial ribosomes
macro + tetra = bacteriostatic (protein synthesis can resume when antibiotic is removed)
aminoglycosides = bactericidal

Question 9

drug class of gentamicin

Answer 9

aminoglycoside
- inhibits protein synthesis

Question 10

antibiotics that act of bacterial DNA

Answer 10

metronidazole
trimethoprim
fluoroquinolones - ciprofloxacin, levofloxacin

Question 11

metronidazole

Answer 11

causes strand breakage of bacterial DNA
treat true anaerobic infections
interacts with alcohol

Question 12

trimethoprim

Answer 12

inhibits bacterial folic acid synthesis
some activity against gram + some pos

Question 13

fluoroquinolones

Answer 13

ciprofloxacin, levofloxacin
prevent supercoiling of bacterial DNA
bactericidal

restricted use due to Cdiff

Question 14

antiobiotvs + pregnancy

Answer 14

trimethoprim + metronidazole avoid in first 3 months

gentamicin, tetracycline + fluoroquinolones are to be avoided!

Question 15

mechanisms of antibiotic resistance

Answer 15

change in bacterial DNA can cause change in gene product which is target of the antibiotic (MRSA)

destruction of antibiotic, bacteria can code for enzymes that chemically degrade or inactivate antibiotic

increased efflux

Question 16

mangement of impetigo

Answer 16

fusidic acid

v infectious, may be off school, dont share towels

Question 17

which antibiotic can give you a rash in glandular fever

Answer 17

amoxicillin

Question 18

allergic conjunctivitis Mx

Answer 18

1st = oral/topical antihistamines
2nd = sodium cromoglicate