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Nucleic acid-based test detects multiple pathogens from single sample of cerebrospinal fluid

Washington: The US Food and Drug Administration has allowed marketing of the first cerebrospinal fluid (CSF) nucleic acid-based test for simultaneous detection of multiple pathogens that can cause central nervous system infections.

The FilmArray Meningitis/Encephalitis (ME) Panel uses CSF specimens from patients who have signs and/or symptoms of meningitis or encephalitis. It is intended as an aid in the diagnosis of those diseases when used in conjunction with other clinical and laboratory findings.

Meningitis and encephalitis are inflammatory diseases of the membranes that surround the brain and spinal cord and can be caused by bacterial, viral or yeast infections. Such infections can cause brain damage and can be fatal if not treated rapidly.

The FilmArray ME Panel is designed to simultaneously test for 14 bacterial, viral and yeast pathogens using a small sample of CSF and can provide results in about an hour, which may enable clinicians to make informed treatment decisions earlier.

Currently, testing CSF for multiple organisms is not always possible because it can be difficult to obtain enough fluid from each patient to run multiple tests. Identification of the cause of bacterial central nervous system infections may sometimes take up to three days using current methods. Testing for viral infections may take even longer because many hospital laboratories do not perform such tests and specimens must then be shipped to specialized laboratories for testing.

“Testing one sample for many pathogens and potentially having test results sooner should allow physicians to use this information, along with other clinical findings and test results, to provide improved diagnosis and treatment for these very serious illnesses,” said Alberto Gutierrez, director of the Office of In Vitro Diagnostics and Radiological Health at the FDA’s Centre for Devices and Radiological Health.

Bacteria and yeast pathogens identified by the FilmArray ME Panel are Escherichia coli K1, Haemophilus influenzae, Listeria monocytogenes, Neisseria meningitidis, Streptococcus agalactiae, Streptococcus pneumoniae and Cryptococcus neoformans/gattii. Viruses identified by the FilmArray ME Panel are Cytomegalovirus, Enterovirus, Herpes simplex virus 1, Herpes simplex virus 2, Human herpesvirus 6, Human parechovirus, and Varicella zoster virus.

However, the FilmArray ME Panel does not detect all causes of central nervous system infections or provide information about which antimicrobial drugs may be most effective for treating bacterial infections.

Physicians should continue to perform standard CSF bacterial and fungal cultures in conjunction with the FilmArray ME Panel because false negative and false positive results are possible with the FilmArray ME Panel, and bacterial growth is needed for drug susceptibility testing when results are positive, according to the FDA.

False negative results could potentially occur when the concentration of organisms in the CSF specimen is below the limit of detection for the FilmArray ME Panel.

The FDA reviewed data for the FilmArray ME Panel through the de novo classification process, a regulatory pathway for some low- to moderate-risk devices that are novel and not substantially equivalent to any legally marketed device.

The clinical performance of the FilmArray ME Panel was evaluated by a prospective study of CSF samples taken from 1,560 patients with suspected meningitis/encephalitis where results for the FilmArray ME Panel were compared to results from other test methods, including culture.

Another study included 150 clinical CSF samples that were previously determined to contain microorganisms, while a third study included 425 CSF samples that were artificially prepared with specific concentrations of bacteria or viruses. Study results demonstrated high agreement between the FilmArray ME Panel, comparator methods and expected results.

The FilmArray ME Panel is manufactured by BioFire Diagnostics LLC, in Salt Lake City, Utah.

One Comment

  1. mk mk Tuesday, October 13, 2015

    Aforementioned (in the article) bacterial pathogens could be identified by Gram’s stain if one has good microscopic acumen and can be more accurate in giving diagnosis by identifying pathogens in culture and in consultation with treating physician.
    In fact specific molecular probes/assays are required to diagnose chronic meningitis caused by M. tuberculosis, C.cellulosae (neurocysticercosis), Cryptococcal meningitis and other pathogens of microbial origin (including non-cultivable) which cannot be possible to diagnose by culturing in the Microbiology Laboratory within 24-48h.
    The FilmArray ME Panel should be applied in all endemic areas across the globe in large patient size before it’s approved and marketed in countries like ours.

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