There are many types of meningitis but viral and bacterial meningitis are common.
Viral meningitis- It is milder form mostly affecting babies and children.
Bacterial meningitis- It can be life threatening. Those who recover from it may be left with some after-effects. The main bacteria that cause this type of meningitis are meningococcal, pneumococcal, TB and hib (hemophilus influenza-B). Neonatal meningitis occurs in new born babies and may be fatal.
Fungal meningitis- It is rare and is caused by cryptococcus. Immunocompromised patients like patients of AIDS and leukenmia are more susceptible.
Amoebic meningitis- It is rare but may be fatal. It is caused by amoebae living in geothermal pools and stagnating pools of fresh water.
Rare types of meningitis- Some cases are caused by rare bacteria which are many. Some common ones are streptococci group A C and G, pseudomonus sp, pseudomonus aeruginosa, clostridium sp, citrobactar sp, camylobactar sp, klebsiella sp, etc.