Perirectal swab specimen analysis
By Liz Hollis
The FDA has cleared expanded claims for the Xpert Carba-R, a molecular test for the detection of carbapenemase-producing gram-negative bacteria, from Sunnyvale, Calif.-based Cepheid Inc. The additional claims extend use to the analysis of perirectal swab specimens, allowing test results to guide therapeutic strategies for pure colonies.
"The addition of perirectal swab specimens to the product label should facilitate active surveillance testing programs, while the ability to use Xpert Carba-R results for therapeutic strategies should enhance antimicrobial stewardship efforts, especially in hospitals struggling with the spread of multidrug-resistant organisms," said Fred Tenover, Cepheid's vice president for scientific affairs and former director of CDC's Office of Antimicrobial Resistance.
Detection and differentiation of high-risk patients with Xpert Carba-R can highlight the presence of gene sequences associated with carbapenem non-susceptibility in gram-negative bacteria, including Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii.
The use of perirectal swabs also has a beneficial effect for patients.
"Perirectal swabs are considered less 'invasive,' so more comfortable for the patient, are easier to collect and also less of a risk of causing mucosal damage for oncology patients that have tender or friable mucosal surfaces," Tenover told BioWorld MedTech.
An ongoing problem
Each year in the U.S., about 2 million people become infected with bacteria that are resistant to antibiotics, according to the CDC. About 23,000 people die annually as a result of these infections. Carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CRE) potentially could be primarily responsible for the increasing spread of CRE in the U.S. and have caught the eye of the CDC for prevention measures. Hospitalized patients typically are at higher risk for infection, as they require care from ventilators, urinary catheters, or intravenous catheters. In addition, those on long courses of antibiotics face the risk of CRE infections.
Health care facilities have used carbapenem antibiotics to treat severe infections for many years, the FDA has noted, and CRE cases have been reported in almost all states within the U.S. Adding to the problem, as the CDC noted in an April 3 Vital Signs report, "unusual resistance germs" are on the rise. These germs are resistant to all or most antibiotics. The agency noted that unusual resistance was seen more than 200 times in 2017 with so-called nightmare bacteria alone. Early action, even if only a single case is detected, can prevent such germs from spreading. The agency has estimated that using such tactics could prevent 1,600 cases of CRE in one state over three years.
Cepheid, now a unit of Washington-based Danaher Corp., reported in March 2016 that it had received FDA clearance to market Xpert Carba-R to identify five distinct families of carbapenem-resistance genes that represented the most common carbapenemases. It was the first FDA-cleared test for detection and differentiation of carbapenemase genes in pure bacterial isolates, previously shown to be non-susceptible to carbapenem antibiotics. In June 2016, the FDA cleared expanded claims for Xpert Carba-R as an infection control aid to test patient specimens and detect specific genetic markers associated with bacteria that are resistant to Carbapenem antibiotics. (See BioWorld MedTech, July 1, 2016.) Cepheid received the CE mark in June 2014.
News of the expanded clearance comes about two weeks after Cepheid reported that it had received a green light from the FDA, as well as a waiver under the Clinical Laboratory Improvement Amendments (CLIA), for the Xpert Xpress Strep A test. The test can be performed by untrained users to provide molecular detection of Streptococcus pyogenes in as soon as 18 minutes.
During an April 19 earnings call, Danaher executives noted that Cepheid saw more than 40 percent core revenue growth. "Cepheid's fantastic results during the first quarter were driven by a combination of good commercial execution, test menu expansion, and what has been a particularly challenging flu season," said Thomas Joyce, president and CEO of Danaher. For example, Cepheid received clearance for its CLIA-waived Xpert Xpress flu test. Cepheid "continue[s] to exceed our initial expectations 18 months post acquisition," Joyce said. Danaher reported that it had closed its acquisition of Cepheid Nov. 4, 2016.
It has been noted that Danaher expects the acquisition of Cepheid, whose business is ready for expansion in China, will fuel its long-term growth. (See BioWorld MedTech, March 12, 2018.)
Published May 16, 2018