Antimicrobials USMLE Step 1 Practice Question
A 37-year-old woman with pyelonephritis (BP 128/82, HR 98, Temp 38.2°C, WBC 14,200/μL, positive urine nitrites) is treated with ciprofloxacin. One week later, she presents with acute heel pain and swelling after jogging. Physical examination reveals Achilles tendon tenderness without rupture. The physician warns about fluoroquinolone-associated tendinopathy. Which of the following best describes the mechanism of action of this drug class?
Answer choices
- ABinding to the 30S ribosomal subunit causing misreading of mRNA
- BInhibition of peptidoglycan transpeptidation
- CInhibition of bacterial DNA gyrase and topoisomerase IVCorrect answer
- DBinding ergosterol to form membrane pores
- EInhibition of folate synthesis through dihydrofolate reductase only
- FIrreversible binding of the 50S ribosomal subunit preventing peptide elongation
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