In meningococcal exposure, which of the following is an acceptable single-dose antibiotic prophylaxis option?

• A. vancomycin 250 mg PO qd for 2 days
• B. chloramphenicol 750 mg PO q12h for 2 days
• C. ceftazidime 250 mg PO times one dose
• D. ciprofloxacin 750 mg PO times one dose

Answer: (D)

Meningococcal exposure prophylaxis relies on rapidly eradicating nasopharyngeal carriage in close contacts to prevent subsequent disease, and a single-dose oral agent with reliable activity against Neisseria meningitidis is preferred for practicality and adherence. Ciprofloxacin given as a single 750 mg oral dose provides excellent adult bioavailability and quickly achieves bactericidal levels in the nasopharynx and bloodstream, effectively reducing carriage with a convenient one-time dose. This makes it an acceptable option for post-exposure prophylaxis in adults when rapid protection is needed and oral therapy is feasible. Other choices are less appropriate for a single-dose prophylaxis approach due to absorption, safety, or efficacy concerns, whereas regimens like rifampin or ceftriaxone are alternatives but typically require multiple doses or injections.