Antibiotics

Question 1

What is the difference between bactericidal and bacteriostatic antibiotics?

Answer 1

Bactericidal abx mainly kill bacteria whilst bacteriostatic abx largely inhibit growth of bacteria (e.g. by affecting DNA or RNA)

[Nb. action can depend on dose]

Question 2

What is the difference between broad sprectrum and narrow spectrum antibiotics?

Answer 2

Broad spectrum abx are active against many bacterias (but can also kill normal flora) whilst narrow spectrum abx are active against few bacteria (but may not kill all pathogens)

Question 3

What antibiotic groups are classed as Beta-Lactams?

Answer 3

Penicillins
Cephalosporins
Carbapenems

Question 4

What antibiotics are in the penicillin group?

Answer 4

Penicillin
Amoxicillin
Flucloxacillin
Co-amoxiclav (a beta-lactamase inhibitor)

Question 5

What is penicillinase?

Answer 5

Enzyme that breaks down Penicillin

Question 6

Flucloxacillin

Answer 6

Beta-lactam (Penicillin Derivative)
Bactericidal - targets cell wall

Uses: Penicillinase-resistant (e.g. SSTIs)
Side effects: 0.05% anaphylaxis rate

Question 7

Benzylpenicillin

Answer 7

Beta-lactam (Penicillin Derivative)
Bactericidal - targets cell wall

Uses: Mild to moderate susceptible infections (e.g. tonsillitis)
Side effects: 0.05% anaphylaxis rate

Question 8

Amoxicillin

Answer 8

Beta-lactam (Penicillin Derivative)
Bactericidal - targets cell wall

Uses: LRTIs
Side effects: 0.05% anaphylaxis rate

Question 9

Co-amoxiclav

Answer 9

Beta-lactam (Penicillin Derivative)
Bactericidal - targets cell wall

Uses: Mixed infections
Side effects: 0.05% anaphylaxis rate

Question 10

Meropenem

Answer 10

Beta-lactam (Carbapenem)
Bactericidal - targets cell wall

Uses: Complex/ multi-drug resistant UTIs
Side effects: GI effects

Question 11

Ceftriaxone

Answer 11

Beta-lactam (4th gen Cephalosporin)
Bactericidal - targets cell wall

Uses: Broad spectrum - abdo sepsis; bacterial meningitis; orthopaedic infections
Side effects: CDAD risk; allergy risk (due to similarities to penicillin)

Question 12

Metronidazole

Answer 12

Nitromidazole
Bacteriostatic - targets DNA synthesis

Uses: Anaerobic infections (e.g. abscesses)

Question 13

Erythromycin

Answer 13

Macrolide
Bacteriostatic - targets DNA/RNA synthesis

Uses: URTI, LRTI, SSTI; allergic to penicillin

Question 14

Doxycycline

Answer 14

Tetracycline
Bacteriostatic - targets RNA/ protein synthesis

Uses: Atypical bacterias (e.g. chlamydia)
Side effects: GI effects; photosensitivity

Question 15

Ciprofloxacin

Answer 15

Quinolone
Bacteriostatic - Inhibits DNA coiling

Uses: Gram -ve bacterias (not anaerobic); MRSA
Side effects: CDAD risk

Question 16

Clindamycin

Answer 16

Lincosamide
Bacteriostatic - targets RNA and bacterial protein synthesis

Uses: SSTIs (when limited IV access or in case of penicillin allergy)

Question 17

Trimethoprim

Answer 17

Anti-folate
Bacteriostatic - targets folic acid synthesis (and therefore DNA synthesis)

Uses: uncomplicated UTIs
Nb. not for use in pregnant women