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National Veterinary Examination Veterinary Chemotherapy & Antimicrobial Stewardship: practice questions

National Veterinary Examination (獣医師国家試験) · Japan · Ministry of Agriculture, Forestry and Fisheries (MAFF), with the Veterinary Affairs Council

Original practice questions written to the published syllabus · not past papers
10worked here, free
56written to this exam in this subject
14syllabus units

What this subject covers

Antibacterial, antifungal, antiprotozoal, anthelmintic, ectoparasiticide and anticancer drugs, and the prudent use that slows antimicrobial resistance.

In the exams: ICAR AIEEA-PG 13 Unit IV (drug resistance); ICAR AICE-JRF core group 07; EAEVE Day One prescribing competences

Where the 56 questions fall

How our questions for National Veterinary Examination spread across the units of Veterinary Chemotherapy & Antimicrobial Stewardship. Difficulty: 13 easy, 37 medium, 6 hard.

Antifungal drugs6
Sulphonamides5
Aminoglycosides5
Anthelmintics5
Anticancer drugs5
Beta-lactam antibiotics4
Tetracyclines4
Macrolides4
Fluoroquinolones4
Antiprotozoal drugs4
Ectoparasiticides4
Prudent use of antimicrobials4
Mechanisms and problems of drug resistance1
Critically important antimicrobials1

10 practice questions, worked

Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.

1 · Sulphonamides · medium

A Doberman pinscher on trimethoprim-sulphonamide for ten days develops fever and shifting lameness with swollen joints. Which adverse reaction best fits?

  1. Hypothyroid myopathy from trimethoprim blocking iodine uptake
  2. Cartilage erosion of the kind caused by fluoroquinolones
  3. Idiosyncratic sulphonamide hypersensitivity with polyarthritis
  4. Crystalluria-induced renal failure presenting as lameness
Answer and working

C. Idiosyncratic sulphonamide hypersensitivity with polyarthritis

Dobermans are over-represented for immune-mediated sulphonamide reactions: fever, polyarthritis, skin eruptions, thrombocytopenia and hepatopathy. Cartilage erosion belongs to fluoroquinolones in growing animals.

Further reading: Riviere & Papich, Veterinary Pharmacology and Therapeutics, 10th ed.

2 · Beta-lactam antibiotics · easy

Why is a Mycoplasma pneumonia not treated with amoxicillin?

  1. Mycoplasma has no cell wall for beta-lactams to act on
  2. Mycoplasma lives only inside neutrophils, beyond the drug's reach
  3. Mycoplasma inactivates amoxicillin with a plasmid beta-lactamase
  4. Amoxicillin cannot cross the alveolar wall into the lung
Answer and working

A. Mycoplasma has no cell wall for beta-lactams to act on

Lacking peptidoglycan, Mycoplasma is intrinsically resistant to all beta-lactams. Macrolides, tetracyclines, pleuromutilins or fluoroquinolones are used instead.

Further reading: Giguère, Prescott & Dowling, Antimicrobial Therapy in Veterinary Medicine, 5th ed.

3 · Aminoglycosides · medium

Why is once-daily dosing of gentamicin preferred to the same daily dose divided three times?

  1. Gentamicin is time-dependent, so it must stay above the MIC for the whole day
  2. Once-daily dosing stops the drug reaching the inner ear at all
  3. Higher peak improves killing and the long trough reduces kidney uptake
  4. Divided doses saturate hepatic metabolism and cause liver damage
Answer and working

C. Higher peak improves killing and the long trough reduces kidney uptake

Aminoglycosides are concentration-dependent with a long post-antibiotic effect; a drug-free trough lets proximal tubular cells clear accumulated drug. They are excreted unchanged by the kidney, not metabolised by the liver.

Further reading: Riviere & Papich, Veterinary Pharmacology and Therapeutics, 10th ed.

4 · Aminoglycosides · hard

Why do many regulators discourage systemic gentamicin in cattle even where extra-label use is legal?

  1. Cattle convert gentamicin into a carcinogenic nitro metabolite
  2. It precipitates as crystals in the rumen and causes acidosis
  3. It inactivates ruminal cellulolytic bacteria for the rest of life
  4. Kidney residues persist for many months, making withdrawal impractical
Answer and working

D. Kidney residues persist for many months, making withdrawal impractical

Aminoglycosides bind kidney tissue and are eliminated very slowly, so residues persist far beyond the plasma half-life. Carcinogenic residues are the nitrofuran and chloramphenicol concern.

Further reading: Giguère, Prescott & Dowling, Antimicrobial Therapy in Veterinary Medicine, 5th ed.

5 · Fluoroquinolones · easy

Enrofloxacin is partly metabolised in most species to which active compound?

  1. Marbofloxacin
  2. Nalidixic acid
  3. Ciprofloxacin
  4. Norfloxacin
Answer and working

C. Ciprofloxacin

De-ethylation of enrofloxacin produces ciprofloxacin, which adds to antibacterial activity.

Further reading: Riviere & Papich, Veterinary Pharmacology and Therapeutics, 10th ed.

6 · Fluoroquinolones · medium

A cat becomes acutely blind with diffuse retinal degeneration after a high dose of an antimicrobial. Which drug is most likely?

  1. Clindamycin
  2. Enrofloxacin
  3. Doxycycline
  4. Amoxicillin
Answer and working

B. Enrofloxacin

Enrofloxacin at high doses causes dose-related retinal degeneration in cats, linked to a defect in a retinal drug transporter; label limits for cats must be respected.

Further reading: Riviere & Papich, Veterinary Pharmacology and Therapeutics, 10th ed.

7 · Fluoroquinolones · medium

In the United States, extra-label use of enrofloxacin in a beef calf is

  1. allowed if the withdrawal is doubled
  2. allowed if culture shows resistance
  3. prohibited under 21 CFR 530.41
  4. allowed with a written VFD order
Answer and working

C. prohibited under 21 CFR 530.41

Fluoroquinolones are on the list of drugs prohibited for extra-label use in food-producing animals. A VFD covers feed use of approved drugs and does not permit extra-label use.

Further reading: 21 CFR 530.41

8 · Antiprotozoal drugs · easy

Several horses die with myocardial necrosis after being fed a cattle ration. Which feed additive is the most likely cause?

  1. Decoquinate
  2. Amprolium
  3. Monensin
  4. Toltrazuril
Answer and working

C. Monensin

Ionophores such as monensin are extremely toxic to horses, causing cardiac and skeletal muscle necrosis.

Further reading: Riviere & Papich, Veterinary Pharmacology and Therapeutics, 10th ed.

9 · Anthelmintics · medium

A 400 kg steer is to receive injectable 1% ivermectin at 0.2 mg/kg subcutaneously (a regimen used here for the arithmetic — confirm against the product label and your national formulary). What volume is required?

  1. 0.8 mL
  2. 80 mL
  3. 8 mL
  4. 20 mL
Answer and working

C. 8 mL

Dose = 0.2 mg/kg x 400 kg = 80 mg. A 1% solution contains 10 mg/mL, so 80 / 10 = 8 mL. 80 mL confuses mg with mL; 20 mL treats the solution as 0.4%; 0.8 mL treats 1% as 100 mg/mL.

Further reading: Calculation

10 · Prudent use of antimicrobials · medium

In a dairy herd, selective dry-cow therapy means

  1. teat sealant only in cows with high cell counts and antibiotics for all others
  2. antibiotic tubes in every quarter at drying off but with a shorter withdrawal
  3. antimicrobial tubes only for infected cows or quarters, with teat sealant for the rest
  4. systemic antibiotics for heifers before first calving instead of dry tubes
Answer and working

C. antimicrobial tubes only for infected cows or quarters, with teat sealant for the rest

Selective dry-cow therapy uses somatic cell counts, culture or history to identify infected cows or quarters for antimicrobial treatment and uses an internal teat sealant in uninfected ones, cutting antimicrobial use without raising new infections.

Further reading: National dairy guidance

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Read the subject

Veterinary Chemotherapy & Antimicrobial StewardshipThe full study manual, free National Veterinary ExaminationFormat, sections and how it has changed

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Veterinary Chemotherapy & Antimicrobial Stewardship for other exams

ENADE · BrazilBCSE · USA / CanadaNAVLE · USA / CanadaRCVS Statutory Membership Examination · UKICAR AIEEA · IndiaNational Practising Veterinarian Qualification Examination · ChinaNational Licensure Examination for Veterinarians · NepalVeterinarian Licensure Examination · Philippines

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