Microbiology Which one of the following organisms is the most frequent cause of acute pyogenic meningitis in adults: A Streptococcus pneumoniae B Neisseria meningitis C Haemophilus influenza D Listeria monocytogenes 💡 Explanation Which one of the following organisms is the most frequent cause of acute pyogenic meningitis in adults: ✓ Correct Answer: A. Streptococcus pneumoniae