FDA-Approved Test for Meningitis is a Home Run

DNAThe FDA approved a diagnostic test for use on cerebrospinal fluid (CSF) that can identity an infectious agent in about 60 minutes. If you are familiar with meningitis, than you know this is a big deal.

The test, made by BioMérieux's subsidiary BioFire, can detect the presence of DNA from 1 of 14 common causative agents of meningitis, including bacteria such as Neisseria meningitidis and Streptococcus pneumoniae as well as viruses such as Epstein-Barr Virus and Herpes simplex virus 1 and 2. It also detects the yeast Cryptococcus (which causes meningitis in immunocompromised patients).

As any physician will tell you, with meningitis, what matters is the kind you have: viral vs. bacterial. Viral meningitis is not generally lethal nor debilitating. Patients usually recover in time with rest, and no treatment is given.

However, bacterial meningitis is a severe, life-threatening infection that is also highly contagious. The infection also progresses quickly and can go from nondescript, with symptoms like fever and aches, to fatal in a few days. Patients with bacterial meningitis need to be put on antibiotics immediately.

Studies have shown that even delays of a couple hours in the administration of antibiotics can spell certain doom for the patient. It is imperative these patients be identified, treated with the appropriate antibiotics and quarantined quickly.

The first test the lab will do is a gram stain, basically put some CSF on a slide add a stain and look at it under the microscope. The test can rule-in bacterial meningitis (and get a passible identity of the bacteria based on morphology). But the test isn't perfect -- it's 60-90 percent sensitive -- so it can't rule it out either.

The test to rule it out is a culture, which can take days. For instance, N. meningitidis is the most aggressive causative agent of meningitis, which causes about 12 percent of bacterial cases, usually takes a minimum of 48 hours to show up on a culture.

The speed of the new test, called the FilmArray Meningitis/Encephalitis (ME) Panel, will not only revolutionize the speed at which doctors can make the call on the type on meningitis, but it also will revolutionize treatment.

Currently, if a physician suspects bacterial meningitis, the patient is immediately on broad spectrum antibiotics until it is ruled out. However, once the identity of the bacteria is known they can be put on narrow spectrum ones that target the bacteria. For example, vancomycin would not be appropriate for treating patients with meningitis cause by E. coli, but would be for Streptococcus pneumoniae.