FDA Supports Expanded Claims for Carbapenem Resistance Test

An infection control aid that tests patient specimens to detect specific genetic markers associated with bacteria that are resistant to Carbapenem antibiotics has been cleared for marketing.

Carbapenem antibiotics are widely used in hospitals to treat severe infections and these resistant organisms are commonly referred to as Carbapenem-resistant Enterobacteriaceae, or CRE, and have been reported in almost all states within the USA.


The US Food and Drug Administration (FDA, Silver Springs, MD, USA), decided to provide clearance based on data from two clinical studies. A prospective study used rectal swabs from 755 patients in hospitals for long-term care facilities to compare results from the Xpert Carba-R assay (Cepheid, Sunnyvale, CA, USA) with results from reference cultures and automated real-time polymerase chain reaction (PCR) sequencing. A second study designed to test the clinical performance of the Xpert Carba-R assay used 432 rectal swabs that were artificially prepared with specific concentrations of bacteria containing the genes detected by the test. The results of these studies demonstrated similar performance between the Xpert Carba-R assay and culture method.

The Xpert Carba-R assay tests specimens directly taken from patients, which are usually obtained by rectal swabs, for the presence of five different genetic markers that are associated with carbapenemase, the enzyme produced by CRE. The Xpert Carba-R assay also does not detect all types of carbapenemase genes, and it is important to recover bacteria for accurately tracking the spread of carbapenem resistance. Laboratories should continue to perform standard bacterial culture in conjunction with the Xpert Carba-R assay. In addition, concomitant cultures are necessary to recover organisms for epidemiological typing, antimicrobial susceptibility testing, and for confirmatory bacterial identification.

The Xpert Carba-R assay is intended as an aid in infection control and can be used in conjunction with other clinical and laboratory findings. Although the Xpert Carba-R assay tests for the most prevalent carbapenemase genes associated with resistance to carbapenem antibiotics, it does not detect the bacteria, carbapenemase activity or other possible non-enzymatic causes of carbapenem resistance. The Xpert Carba-R assay tests only for genetic material.

Related Links:
US Food and Drug Administration
Cepheid