New Vitek MS Test System Identifies 193 Yeasts and Bacteria


August 21, 2013

Clinicians can automatically identify one of 193 yeasts and bacteria with a test system approved by the US Food and Drug Administration (FDA) today, and quickly get to the bottom of skin and bloodstream infections, pneumonia, meningitis, and other conditions associated with these microorganisms.

Among the culprits in the test's rogue's gallery are yeasts from the Candida, Cryptococcus, and Malassezia groups, and bacteria from the Staphylococcaceae, Streptococcaceae, Enterobacteriaceae, Pseudomonadaceae, and Bacteroidaceae families. The infections caused by these microorganisms pose a particular threat to patients with immune systems compromised or weakened by HIV/AIDS, cancer treatment, or antirejection therapy after an organ transplant.

"The ability for laboratories to use one device to identify almost 200 different microorganisms is a significant advance in the timely identification of pathogenic microorganisms," said Alberto Gutierrez, PhD, director of the Office of In Vitro Diagnostics and Radiological Health at the FDA's Center for Devices and Radiological Health, in a news release. "Rapid identification of harmful microorganisms can improve the care of critically ill patients."

The new technology, called Vitek MS (bioMerieux), is the first mass spectrometer system for automated identification of yeast and bacteria known to cause serious illnesses in humans. It incorporates a laser that breaks yeast and bacterial into particles that form a tell-tale pattern for each microorganism.

Clinicians can test patients with Vitek MS as soon as yeast or bacterial growth becomes visible, which usually happens in the first 18 to 24 hours of the infection. The test for each microorganism lasts about 1 minute, meaning that the entire series of tests will take less than 4 hours.

Older testing methods, said the FDA, are slower, taking up to 5 days to yield the same results. One reason for the longer time is that these other methods require more abundant organism growth to work with than Vitek MS does.

In a recent study of some 7100 microorganisms, Vitek MS got the scientific group or family right for 93.6% of them. It identified the species level for 87.5%. No identification" results came up for 3.2% of the microorganisms. "Of all test results, only 0.8% were incorrect and 2.4% were low discrimination with no correct result," the agency said.

More information on today's approval of Vitek MS is available on the FDA Web site.


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