Which antibiotic class is preferred for treatment of anthrax due to CNS penetration?

Which antibiotic class is preferred for treatment of anthrax due to CNS penetration?

• A. Macrolides
• B. Fluoroquinolones
• C. Tetracyclines
• D. Aminoglycosides

Answer: (B)

Fluoroquinolones are favored when anthrax may involve the CNS because they achieve high concentrations in the cerebrospinal fluid, especially with meningeal inflammation, and they’re bactericidal against Bacillus anthracis. This combination—strong CNS penetration plus reliable killing of the organism—makes them the most effective choice for treating anthrax with potential CNS involvement. Macrolides have limited activity and poorer CNS penetration against this bug; tetracyclines like doxycycline can reach the CSF but are typically bacteriostatic and considered secondary when CNS penetration is a concern; aminoglycosides penetrate poorly into the CSF and are not preferred for CNS infections.

Fluoroquinolones are favored when anthrax may involve the CNS because they achieve high concentrations in the cerebrospinal fluid, especially with meningeal inflammation, and they’re bactericidal against Bacillus anthracis. This combination—strong CNS penetration plus reliable killing of the organism—makes them the most effective choice for treating anthrax with potential CNS involvement. Macrolides have limited activity and poorer CNS penetration against this bug; tetracyclines like doxycycline can reach the CSF but are typically bacteriostatic and considered secondary when CNS penetration is a concern; aminoglycosides penetrate poorly into the CSF and are not preferred for CNS infections.