Which fluoroquinolone has greatest activity against Streptococcus pneumoniae and is considered 'respiratory fluoroquinolone' due to enhanced gram-positive coverage compared to ciprofloxacin?
- A Norfloxacin
- B Moxifloxacin ✓
- C Ofloxacin
- D Ciprofloxacin
Correct answer: B. Moxifloxacin
Explanation
Moxifloxacin and levofloxacin are classified as respiratory fluoroquinolones because they have significantly enhanced activity against gram-positive organisms, particularly Streptococcus pneumoniae (including penicillin-resistant strains) and atypical pathogens. Ciprofloxacin has poor pneumococcal coverage (MIC typically 1–4 mg/L) and should not be used for CAP. Moxifloxacin has the best gram-positive activity among the fluoroquinolones, inhibiting both topoisomerase IV (primary target in gram-positives) and DNA gyrase.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.