Escherichia coli Psendomonas aeraginosa Proteus species Salmonella species
⇒Also M. tuberculosis Viruses:
Enteroviruses, especially echoviruses and coxsackieviruses. Rarely polioviruses may also be isolated from CSf.
Fungi: Cryptococcus neoformans Parasites: Trypanosoma species
Naegleria fowleri Acanthamoeba species
Angiostrongylus cantonensis and Dirofilaira immitis
Inflammation of the meninges (membranes that cover the brain and spinal cord) is called meningitis. Pathogens reach the meninges in the blood stream or occasionally by spreading from nearby sites such as the middle ear or nasal sinuses.
Pyogenic (purulent), when the C.S.f contains mainly poly morphonuclear neutrophils (pus cell), as in acute meningitis caused by N. meningitides, H. influenzae and S. pneumonae.
Pus cells are also found in the C.S.f in acute amoebic meningoencephalitis.