Bacterial meningitis remains a serious threat to global health, accounting for an estimated 170,000 deaths annually worldwide. Even with antimicrobial therapy and the availability of sophisticated intensive care, case fatality rates remain at 5–10% in industrialized countries and even higher in the developing world. Between 10–20% of survivors develop permanent sequelae such as epilepsy, mental retardation or sensorineural deafness(http://www.who.int/immunization/topics/meningitis/en/index.html).