Causes

• Neisseria meningitidis
• Streptococcus pneumoniae
• Gram negative bacilli

• Listeria monocytogenes
• Haemophilus influenzae
• Group B Streptococcus (mainly neonates)
• tuberculosis
• Cryptococcus
• Viral infections (Coxsackie, Echovirus, Mumps, Polio) ^c

Meningococcus and pneumococcus are common causes of meningitis

cause of bacterial meningitis b c	%
Neisseria meningitidis	7.1% to 56%
Streptococcus pneumoniae	21% to 47%
Gram-negative bacilli	21%
Listeria monocytogenes	6% to 8%
Haemophilus influenzae	5% to 7%
Group B Streptococcus (mainly neonatal cases)	13%

• Most cases of meningococcal disease are serogroup B (56%: 95% CI: 52% to 60%). Serogroup C cases are less common (19%:95% CI: 16% to 22%). ^b