I had meningitis once. they found it after taking a blood culture that was positive for strep pneumoniae. do you always have some type of germ that shows in your bloodstream when you have meningitis?

Somewhat complicated topic. Some meningitis is chronic, caused by TB, various fungi, and many more. Others are acute, with rapid onset and often the most severe symptoms. Among acute cases, there are two broad categories, bacterial and viral. In acute bacterial meningitis, he causative germ (such as Streptococcus pneumoniae, i.e. pneumococcus) can be cultured from blood in some but not all cases.

Bacterial meningitis often is secondary to an infection elsewhere in the body, and if sepsis is present, a blood culture may be definitive. But usually, especially with meningococcal meningitis, and listeria, cultures of spinal fluid origin are confirmatory. There are many exceptions, and no specific consistencies in general in this area.