©THESTAR 2024/2025 ALL RIGHTS RESERVED.
Antibacterials Exam Questions And Answers
100% Guaranteed Pass.
Natural Penicillin:
Clinical indications?
Side effects? - Answer✔Gram + infections (anaerobic)
Generally safe drugs
- Allergic reactions
- Renal tubular necrosis
- Bleeding disorders
- Intestinal dysbiosis (Hind-gut fermenters)
- Procaine toxicity in horses
Natural Penicillin:
Example
MOA
Spectrum
Solubility - Answer✔Penicillin G, Benzylpenicillin
Cell wall disruption
Narrow, Gram +ve
Water soluble (poor oral availability), acid labile
Penicillins show cross-resistance with what other antibacterial drug? - Answer✔Cephalosporins
T/F: The bacterial effect of all cell wall disrupting antibiotics (β-lactams) is bacteriostatic. -
Answer✔False, all β-lactams are bactericidal (-lytic)
1|Page
, ©THESTAR 2024/2025 ALL RIGHTS RESERVED.
Pencillins and cephalosporins are most effective in __________ and least effective in
___________? - Answer✔Rapid dividing populations (early infection)
High osmolarity areas (i.e. pus / renal medulla)
Name the 4 mechanisms of action of antibacterial drugs. - Answer✔Cell wall disruption
Cell membrane function inhibition
Protein synthesis inhibition (30S, 50S)
Nucleic acid synthesis inhibition
Name 2 shared characteristics between penicillins and cephalosporins. - Answer✔1. Time-
dependent (short T/12, require frequent administration/CRI)
2. Bactericidal (-lytic) = most effective in rapidly dividing, early infection populations; NOT high
osmolarity areas (pus, renal medulla)
Procaine / benzathine benzylpenicillins - Answer✔Insoluble salts
Depot formulation (slow absorption due to relative insolubility)
Semi-synthetic Penicillin
Clinical indications?
Side effects? - Answer✔Gram + infections (anaerobic)
Side effects: Generally safe drugs
Allergic reactions
Renal tubular necrosis
Bleeding disorders
Intestinal dysbiosis (Hind-gut fermenters)
Procaine toxicity in horses
Compare natural penicillins and semi-synthetic penicillins in terms of reactions to acid,
solubility and response to β-lactamase. - Answer✔Natural penicillin: Acid-labile, water-soluble
(poor oral availability), β-lactamase sensitive
Semi-synthetic penicillin: Acid-stable, more lipid-soluble, β-lactamase stable
Semi-synthetic Penicillin
2|Page
Antibacterials Exam Questions And Answers
100% Guaranteed Pass.
Natural Penicillin:
Clinical indications?
Side effects? - Answer✔Gram + infections (anaerobic)
Generally safe drugs
- Allergic reactions
- Renal tubular necrosis
- Bleeding disorders
- Intestinal dysbiosis (Hind-gut fermenters)
- Procaine toxicity in horses
Natural Penicillin:
Example
MOA
Spectrum
Solubility - Answer✔Penicillin G, Benzylpenicillin
Cell wall disruption
Narrow, Gram +ve
Water soluble (poor oral availability), acid labile
Penicillins show cross-resistance with what other antibacterial drug? - Answer✔Cephalosporins
T/F: The bacterial effect of all cell wall disrupting antibiotics (β-lactams) is bacteriostatic. -
Answer✔False, all β-lactams are bactericidal (-lytic)
1|Page
, ©THESTAR 2024/2025 ALL RIGHTS RESERVED.
Pencillins and cephalosporins are most effective in __________ and least effective in
___________? - Answer✔Rapid dividing populations (early infection)
High osmolarity areas (i.e. pus / renal medulla)
Name the 4 mechanisms of action of antibacterial drugs. - Answer✔Cell wall disruption
Cell membrane function inhibition
Protein synthesis inhibition (30S, 50S)
Nucleic acid synthesis inhibition
Name 2 shared characteristics between penicillins and cephalosporins. - Answer✔1. Time-
dependent (short T/12, require frequent administration/CRI)
2. Bactericidal (-lytic) = most effective in rapidly dividing, early infection populations; NOT high
osmolarity areas (pus, renal medulla)
Procaine / benzathine benzylpenicillins - Answer✔Insoluble salts
Depot formulation (slow absorption due to relative insolubility)
Semi-synthetic Penicillin
Clinical indications?
Side effects? - Answer✔Gram + infections (anaerobic)
Side effects: Generally safe drugs
Allergic reactions
Renal tubular necrosis
Bleeding disorders
Intestinal dysbiosis (Hind-gut fermenters)
Procaine toxicity in horses
Compare natural penicillins and semi-synthetic penicillins in terms of reactions to acid,
solubility and response to β-lactamase. - Answer✔Natural penicillin: Acid-labile, water-soluble
(poor oral availability), β-lactamase sensitive
Semi-synthetic penicillin: Acid-stable, more lipid-soluble, β-lactamase stable
Semi-synthetic Penicillin
2|Page
