chemistry of antimicrobial agents

Question 1

antibiotics that inhibit cell wall synthesis

Answer 1

• beta-lactams
• glycopeptides
• bacitracin

Question 2

antibiotics that inhibit protein synthesis

Answer 2

• macrolides
• aminoglycosides
• tetracyclines

Question 3

antibiotics that inhibit folic acid metabolism

Answer 3

• trimethoprim
• sulphonamides

Question 4

Penicillins

Answer 4

• phenoxymethylpenicillin
• flucloxacillin
• amoxicillin

Question 5

cephalosporins

Answer 5

• cefaclor
• cefadroxil
• cefalexin

Question 6

tetracyclines

Answer 6

• tetracycline
• doxycycline
• lymecycline

Question 7

aminoglycosides

Answer 7

• gentamicin
• tobramycin

Question 8

macrolides

Answer 8

• erythromycin
• azithromycin
• clarithromycin
• clindamycin

Question 9

sulphonamides

Answer 9

• metronidazole
• tinidazole
• co-trimoxazole (sulphonamide + trimethoprim)

Question 10

quinolones

Answer 10

• ciprofloxacin
• levofloxacin
• norfloxacin

Question 11

glycopeptides

Answer 11

• vancomycin
• teicoplanin
• ramoplanin

Question 12

Beta-lactam antibiotics

Answer 12

• penicillin
• cephalosporins
• carbapenem
• monobactam

Question 13

Beta-lactam mode of action

Answer 13

penicillin binding proteins that lead to irreversible inhibition of cross-linking and bacterial cell lysis

Question 14

narrow spectrum penicillins

Answer 14

• benzylpenicillin
• phenoxymethyl penicillin

Question 15

phenoxymethylpenicillin

Answer 15

• braid spectrum antibiotic
• gastric acid stable so can be taken orally
• respiratory tract infections in children
• streptococcal tonsillitis
• used for prophylaxis against streptococcal infections following rheumatic fever or in sickle-cell disease

Question 16

flucloxacillin

Answer 16

• gastric acid stable and well absorbed in the gut can be taken orally
• effective in penicillin-resistant staphylococci
• narrow spectrum (gram + bacteria)

Question 17

temocillin

Answer 17

• active against gram - bacteria
• stable against beta-lactamases (OMe group)
• not active against pseudomonas aeruginosa

Question 18

amoxicillin

Answer 18

• derivative of ampicillin
• broad spectrum (gram +/- bacteria)
• when taken orally it produces a higher plasma and tissue concentrations
• treatment of Lyme disease

Question 19

Beta-lactamase inhibitors

Answer 19

• they bind covalently to Beta-lactamases
• clavulanic acid, tazobactam
• are not given alone always with another antibiotic

Question 20

co-amoxiclav

Answer 20

amoxicillin + clavulanic acid
against resistant strains of :
- staph aureus
- E. coli
- H. influenzae
- Klebsiella

Question 21

antipseudomonal penicillins

Answer 21

piperacillin:
- only available with beta-lactamase inhibitor, tazobactam
- activity against gram - bacteria
- more active against pseudomonas aeruginosa
ticarcillin:
- only available with beta-lactamase inhibitor, clavulanic acid
for severe pseudomonas infections they can be given with an aminoglycoside (gentamicin) since they have a synergistic effect

Question 22

classification of cephalosporins

Answer 22

active on gram + :
- cefalexin, cefadroxil, cefaclor
Beta-lactamase resistant:
- cefuroxine
active on gram - and beta-lactamase resistant:
- cefotaxime, cefixime, cefpodoxime
active on gram - (ps. aeruginosa) and beta-lactamase resistant:
- ceftazidime

Question 23

oral (acid-stable) cephalosporins

Answer 23

• cefalexin
• cefaclor

Question 24

parenteral cephalosporins

Answer 24

ceftazidime
contains a zwitter ion

Question 25

antimicrobials with excellent tissue penetration

Answer 25

• chloramphenicol
• fluoroquinolones
• doxycycline
• metronidazole
• rifampicin