infective organisms in meningitis classified by patient age

Last reviewed 01/2018

The likely meningitic causative-organism varies with age. Listed in order of likelihood in the UK:

  • neonates - ie less than one month:
    • E.coli (K1)
    • group B beta-haemolytic
    • streptococci
    • Listeria monocytogenes
    • Staphylococcus aureus
    • Pneumococcus

  • children from one month to 15 years:
    • Haemophilus influenzae B
    • Meningococcus
    • Pneumococcus

  • adults over 15 years:
    • Pneumococcus
    • Meningococcus

  • elderly adults:
    • Staphylococcus aureus
    • Gram negative organisms