A new test that speeds up the identification of carbapenem-resistant Enterobacteriaceae (CRE) by detecting the genetic fingerprint of the bacteria within an hour won approval today from the US Food and Drug Administration (FDA).
The test, called the Xpert Carba-R Assay (Cepheid), checks patient specimens, usually obtained by rectal swabs, for the presence of five different genetic markers associated with carbapenemase. This is the enzyme produced by CRE that disables carbapenem-class antibiotics, widely used in hospitals to treat severe infections.
Few treatment options remain when bacteria become resistant to carbapenems, the FDA noted in a press release. "Some CRE bacteria have become resistant to almost all available antibiotics and present a significant public health threat."
While not intended to replace standard bacterial culture, the new genetic-marker test hastens the process for identifying CRE. Growing bacteria from fecal material in cultures and then subjecting them to antimicrobial susceptibility tests may take up to 4 days, and additional testing often is needed to confirm the presence of carbapenemase.
The Xpert Carba-R Assay comes with several limitations and caveats that underline the need to use it in conjunction with other clinical and laboratory findings, according to the agency. The test does not detect CRE itself, carbapenemase activity, or other possible nonenzymatic causes of carbapenem resistance.
Furthermore, it is not designed to detect all types of carbapenamase genes, the agency said. Hospitals should continue to recover bacteria to accurately track the spread of carbapenem resistance, and grow concomitant cultures to recover organisms for epidemiological typing, antimicrobial susceptibility testing, and confirmatory bacterial identification.
The FDA based its decision to approve Xpert Carba-R Assay on two clinical trials. One study involving rectal swabs from 755 patients in hospitals and long-term care facilities compared results from the new test with those from reference cultures and automated real-time polymerase chain reaction sequencing. In the other study, the Xpert Carba-R Assay processed rectal swabs that contained specific concentrations of bacteria bearing the genes the test was designed for. "The results of these studies demonstrated similar performance between the Xpert Carba-R Assay and culture method," the FDA said.
More information on today's announcement is available on the FDA website.
Follow Robert Lowes on Twitter @LowesRobert.
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Cite this: FDA OKs Test for Gene Markers of Carbapenem-Resistant Bugs - Medscape - Jun 29, 2016.
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