
There are many organisms, viral, bacterial, and fungal, which can
cause meningitits, and the course of these infections varies
widely. The causes of bacterial meningitis vary with age: in adults
pneumococcus (the same organism which causes pneumococcal pneumonia)
is the most common cause, while in children Hemophilus influenzae
is the most common cause.

What you are describing is meningitis from Neisseria meningitidis,
which is the second most common cause of bacterial meningitis in
both groups, but with lower incidence in infants. This organism
is also called the "meningococcus", and is the source of the
common epidemics of meningitis that occur and are popularized in
the press. Without prompt treatment (and even WITH it in some cases),
the organism typically causes death within a day. 

This organism, feared as it is, is actually grown from the throats
of many normal adults. It can get to the meninges by different
ways, but blood borne spread is probably the usual case. 

Rifampin (an oral antibiotic) is often given to family and contacts
of a case of meningococcal meningitis, by the way.

Sorry, but I don't have time for a more detailed reply. Meningitis
is a huge topic, and sci.med can't do it justice.
