Urinary tract infections: antimicrobial therapy MCQs With Answer

Urinary tract infections: antimicrobial therapy MCQs With Answer is a focused question bank designed for M.Pharm students studying Pharmacotherapeutics II (MPP 202T). This resource reinforces core concepts of antimicrobial selection, mechanism, pharmacokinetics, resistance, dose adjustments, safety in special populations, and clinical decision-making for various UTIs including uncomplicated cystitis, pyelonephritis, prostatitis, and catheter-associated infections. Questions emphasize evidence-based antibiotic choices, microbial spectrum (E. coli, Klebsiella, Enterococcus, Pseudomonas), resistance mechanisms such as ESBLs, and rational therapy considering renal function, pregnancy, and drug interactions. Each MCQ includes concise answer keys to aid exam preparation and clinical understanding.

Q1. Which antimicrobial is considered first-line oral therapy for uncomplicated cystitis in non-pregnant adult women when local E. coli resistance to TMP-SMX is <20%?

• Amoxicillin-clavulanate
• Nitrofurantoin (5-day regimen)
• Trimethoprim-sulfamethoxazole (3-day regimen)
• Fosfomycin (single dose)

Correct Answer: Trimethoprim-sulfamethoxazole (3-day regimen)

Q2. Which of the following antibiotics acts by inactivating pyruvyl transferase (MurA) and is commonly used as a single-dose oral treatment for uncomplicated cystitis?

• Nitrofurantoin
• Fosfomycin tromethamine
• Trimethoprim
• Levofloxacin

Correct Answer: Fosfomycin tromethamine

Q3. Nitrofurantoin’s efficacy in lower UTIs is primarily due to which of the following pharmacologic features?

• High serum concentrations with hepatic metabolism
• High renal excretion and urinary concentrations with multiple bacterial enzyme targets
• Concentrations above MIC in prostate tissue
• Significant activity against Pseudomonas aeruginosa

Correct Answer: High renal excretion and urinary concentrations with multiple bacterial enzyme targets

Q4. Which agent is contraindicated in the treatment of pyelonephritis due to poor renal tissue penetration and inadequate serum levels?

• Oral nitrofurantoin
• Oral ciprofloxacin
• Intravenous ceftriaxone
• Oral amoxicillin-clavulanate

Correct Answer: Oral nitrofurantoin

Q5. A patient with suspected acute pyelonephritis requires empiric parenteral therapy. Which antibiotic provides reliable Gram-negative coverage including many Enterobacterales and is often used empirically?

• Oral fosfomycin
• Intravenous ceftriaxone
• Oral nitrofurantoin
• Topical mupirocin

Correct Answer: Intravenous ceftriaxone

Q6. Extended-spectrum beta-lactamase (ESBL)-producing E. coli are typically resistant to which class, making which agent often necessary for severe infections?

• Resistant to fluoroquinolones; use nitrofurantoin
• Resistant to aminoglycosides; use TMP-SMX
• Resistant to third-generation cephalosporins; use carbapenems
• Resistant to tetracyclines; use fosfomycin

Correct Answer: Resistant to third-generation cephalosporins; use carbapenems

Q7. In male patients with acute bacterial prostatitis, which antimicrobial property is essential for effective therapy?

• High urinary concentration but no tissue penetration
• Good prostatic tissue penetration and bactericidal activity
• Only activity against Gram-positive cocci
• Minimal systemic absorption

Correct Answer: Good prostatic tissue penetration and bactericidal activity

Q8. Which antibiotic is associated with tendonitis and tendon rupture risk and should be used cautiously for complicated UTIs, especially in elderly patients?

• Fosfomycin
• Nitrofurantoin
• Fluoroquinolones (e.g., ciprofloxacin)
• Cephalexin

Correct Answer: Fluoroquinolones (e.g., ciprofloxacin)

Q9. For pregnant women with uncomplicated cystitis, which antibiotic is generally considered safe and effective (avoiding first trimester concerns and fetal risks)?

• Trimethoprim-sulfamethoxazole in the first trimester
• Nitrofurantoin (avoiding near term in G6PD deficiency concerns)
• Fluoroquinolones throughout pregnancy
• Fosfomycin is absolutely contraindicated

Correct Answer: Nitrofurantoin (avoiding near term in G6PD deficiency concerns)

Q10. In catheter-associated urinary tract infection (CAUTI) with Pseudomonas aeruginosa, which parenteral agent provides reliable activity and is concentration-dependent?

• Aminoglycosides (e.g., amikacin)
• Nitrofurantoin
• Fosfomycin oral
• Amoxicillin

Correct Answer: Aminoglycosides (e.g., amikacin)

Q11. Which dosing consideration is most important when prescribing renally-excreted antibiotics for elderly patients with UTI?

• No adjustment needed because urinary concentrations always suffice
• Adjust dose or interval based on estimated creatinine clearance to avoid toxicity
• Increase dose empirically to overcome resistance
• Switch to topical therapy to avoid systemic effects

Correct Answer: Adjust dose or interval based on estimated creatinine clearance to avoid toxicity

Q12. Trimethoprim acts by inhibiting which bacterial enzyme, leading to impaired folate synthesis?

• Dihydropteroate synthase
• Dihydrofolate reductase
• DNA gyrase
• Peptidoglycan transpeptidase

Correct Answer: Dihydrofolate reductase

Q13. Which oral agent is recommended for symptomatic uncomplicated cystitis in women when compliance is a concern and single-dose therapy is desired?

• Fosfomycin tromethamine (single dose)
• Nitrofurantoin 5-day course
• TMP-SMX 3-day course
• Oral cefuroxime for 10 days

Correct Answer: Fosfomycin tromethamine (single dose)

Q14. Which pathogen commonly causes UTIs and is intrinsically resistant to many cephalosporins, often requiring anti-pseudomonal agents when implicated?

• Escherichia coli
• Enterococcus faecalis
• Pseudomonas aeruginosa
• Streptococcus pyogenes

Correct Answer: Pseudomonas aeruginosa

Q15. Which adverse effect is most characteristically associated with prolonged nitrofurantoin use?

• Tendon rupture
• Interstitial lung disease and pulmonary fibrosis
• Ototoxicity
• Nephrolithiasis

Correct Answer: Interstitial lung disease and pulmonary fibrosis

Q16. Which statement about TMP-SMX (trimethoprim-sulfamethoxazole) is true in the context of UTI therapy?

• It is bactericidal for all urinary pathogens regardless of resistance
• It has synergistic inhibition of sequential steps in folate synthesis
• It is safe in late pregnancy without restrictions
• It concentrates poorly in urine

Correct Answer: It has synergistic inhibition of sequential steps in folate synthesis

Q17. Which strategy is recommended to prevent recurrent UTIs in selected patients with frequent symptomatic episodes?

• Continuous low-dose antimicrobial prophylaxis or postcoital single-dose prophylaxis guided by susceptibility
• Daily broad-spectrum fluoroquinolone without follow-up cultures
• Indefinite high-dose intravenous antibiotics
• Use of topical antibiotics in the urethra

Correct Answer: Continuous low-dose antimicrobial prophylaxis or postcoital single-dose prophylaxis guided by susceptibility

Q18. A patient on warfarin is prescribed TMP-SMX for UTI. What interaction concern should the M.Pharm student recognize?

• TMP-SMX induces CYP enzymes reducing warfarin effect
• TMP-SMX increases warfarin anticoagulant effect leading to elevated INR and bleeding risk
• No interaction; both drugs act independently
• TMP-SMX causes warfarin inactivation via renal excretion

Correct Answer: TMP-SMX increases warfarin anticoagulant effect leading to elevated INR and bleeding risk

Q19. In severe urosepsis due to multidrug-resistant Enterobacterales sensitive only to fosfomycin and an aminoglycoside, which pharmacologic principle supports combination therapy?

• Combination decreases the risk of renal toxicity
• Combination provides synergistic or additive bactericidal activity and reduces resistance emergence
• Combination lengthens half-life of both drugs
• Combination reduces urinary excretion of both agents

Correct Answer: Combination provides synergistic or additive bactericidal activity and reduces resistance emergence

Q20. For acute uncomplicated cystitis, which pharmacodynamic classification best describes beta-lactam antibiotics and their dosing strategy?

• Concentration-dependent killing; maximize peak concentrations
• Time-dependent killing; maintain plasma levels above MIC for a defined percentage of dosing interval
• Post-antibiotic effect dominant; single large dose sufficient
• Dependent on urinary pH only; no relation to time or concentration

Correct Answer: Time-dependent killing; maintain plasma levels above MIC for a defined percentage of dosing interval

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