Antimicrobial Mechanisms Practice Test

A 52-year-old hospitalized man develops aspiration pneumonia after vomiting. CXR shows right lower-lobe consolidation. Sputum culture later grows mixed oral anaerobes. He is treated with metronidazole as part of his regimen. Which of the following mechanisms explains metronidazole’s antimicrobial action? (WBC 16,200/µL; creatinine 1.0 mg/dL.)

A 36-year-old man presents with severe community-acquired pneumonia after returning from a hotel conference. He has hyponatremia and diarrhea; urine antigen is positive for Legionella pneumophila. CXR shows patchy unilateral infiltrates. He is treated with levofloxacin. Which bacterial process is primarily inhibited by this antimicrobial class? (Na 128 mEq/L; WBC 11,500/µL; creatinine 1.0 mg/dL.)