Test Bank for Antibacterials- Questions and Correct Answers Latest Update (2025-2026)
Natural Penicillin:
Clinical indications?
Side effects? - Answers 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 - Answers 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? - Answers Cephalosporins
T/F: The bacterial effect of all cell wall disrupting antibiotics (β-lactams) is bacteriostatic. - Answers
False, all β-lactams are bactericidal (-lytic)
Pencillins and cephalosporins are most effective in __________ and least effective in ___________? -
Answers Rapid dividing populations (early infection)
High osmolarity areas (i.e. pus / renal medulla)
Name the 4 mechanisms of action of antibacterial drugs. - Answers Cell wall disruption
, Cell membrane function inhibition
Protein synthesis inhibition (30S, 50S)
Nucleic acid synthesis inhibition
Name 2 shared characteristics between penicillins and cephalosporins. - Answers 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 - Answers Insoluble salts
Depot formulation (slow absorption due to relative insolubility)
Semi-synthetic Penicillin
Clinical indications?
Side effects? - Answers 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. - Answers 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
MOA
Spectrum
Solubility - Answers Cell wall disruption
Natural Penicillin:
Clinical indications?
Side effects? - Answers 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 - Answers 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? - Answers Cephalosporins
T/F: The bacterial effect of all cell wall disrupting antibiotics (β-lactams) is bacteriostatic. - Answers
False, all β-lactams are bactericidal (-lytic)
Pencillins and cephalosporins are most effective in __________ and least effective in ___________? -
Answers Rapid dividing populations (early infection)
High osmolarity areas (i.e. pus / renal medulla)
Name the 4 mechanisms of action of antibacterial drugs. - Answers Cell wall disruption
, Cell membrane function inhibition
Protein synthesis inhibition (30S, 50S)
Nucleic acid synthesis inhibition
Name 2 shared characteristics between penicillins and cephalosporins. - Answers 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 - Answers Insoluble salts
Depot formulation (slow absorption due to relative insolubility)
Semi-synthetic Penicillin
Clinical indications?
Side effects? - Answers 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. - Answers 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
MOA
Spectrum
Solubility - Answers Cell wall disruption
