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Dx Focus May 25, 2011: Clinical and Regulatory PCR and Nucleic Acid Testing News


BioMérieux said this week that its automated molecular test for methicillin-resistant Staphylococcus aureus, the NucliSens EasyQ MRSA, has received 510(k) clearance from the US Food and Drug Administration.

NucliSens EasyQ MRSA is designed to screen patients colonized with MRSA, and uses BioMérieux’s nucleic acid sequence-based amplification, or NASBA, technology, combined with real-time detection of amplified targets by molecular beacon probes. The test uses specifically designed fluorophore-labeled probes to independently detect amplified gene sequences of the S. aureus mec A gene, the SCC mec junction, and an amplification inhibition control. This permits the detection of strains that have, in some cases, been found to lose their mec A region resulting in false positive results, BioMérieux said.

The test also detects seven MRSA types covering the most prevalent strains: MREJ genotypes 1, 2, 3, 4, 5, 7, and 12. The EasyQ instrument platform supports efficient batch processing of up to 46 MRSA screening tests with a turnaround time of three hours, the company said.

NucliSens EasyQ MRSA was cleared with a clinical sensitivity of 94.7 percent and a clinical specificity of 96.5 percent in nasal samples from adult patients; and clinical sensitivity of 100 percent and a clinical specificity of 97.3 percent in nasal samples from pediatric patients. The company said that the CE Marked test is already available in Europe, and that it complements BioMérieux's culture-based chromID MRSA screen.

Abbott said this week that it has received the CE Mark in the European Union to market the Abbott RealTime CMV assay, the company's real-time PCR molecular diagnostic test for cytomegalovirus DNA quantitation in human plasma or whole blood.

The test runs on the m2000, Abbott's fully automated platform for DNA and RNA testing, and is intended for use in conjunction with clinical presentation and other lab markers as an indicator to initiate therapy and as an aid in monitoring viral response to antiviral treatment. The test is not intended to be used as a screening test for CMV or as a diagnostic test to confirm the presence of CMV, the company said.

Roche said this week that its Cobas TaqScreen MPX Test, version 2.0, for use on the Cobas S 201 system, has received the CE Mark and is now commercially available in Europe.

Cobas TaqScreen MPX is a qualitative in vitro test to directly detect human immunodeficiency virus type 1 Group M RNA; HIV-1 Group O RNA; HIV-2 RNA; hepatitis C virus RNA; and hepatitis B virus DNA in human plasma. The test is intended to screen samples of donations of human whole blood and blood components, including source plasma, Roche said.

Version 2.0 of the test is more sensitive than its predecessor, and is the only commercially available test that provides simultaneous viral target resolution on an automated system, removing the need for further time-consuming testing of positive units, Roche said.

The fully automated Cobas S 201 system is designed to increase processing efficiency by using a modular design with ready-to-use reagents. The multi-dye technology allows signal detection in four separate channels, facilitating simultaneous monitoring of three viral targets — HIV, HCV and HBV — plus a full-process internal control.

Cobas TaqScreen MPX v2.0 is not yet approved or available in the US.

The US Food and Drug Administration late last week cleared the first nucleic acid amplification test for diagnosing Q fever infection in military personnel serving overseas.

The test was developed by Idaho Technology and funded by the Chemical Biological Medical System Joint Project Management Office within the US Department of Defense. It identifies and detects the bacteria that cause Q fever, or Coxiella burnetii, by determining whether DNA from the organism is present in a patient's blood sample.

The test is cleared for use on DOD's Joint Biological Agency Identification and Diagnostic System, or JBAIDS, also developed under contract by Idaho Tech, and as such is limited to designated DOD laboratories equipped with JBAIDS. Results can be achieved within four hours, FDA said.

Q fever is an emerging infectious disease among servicemen and servicewomen in Iraq and worldwide. It can cause acute or chronic illness and is acquired primarily from contact with infected animals or exposure to contaminated environments. Early treatment with antibiotics normally leads to full recovery.

Gen-Probe late last week said that it has filed for regulatory approval in the US for its Panther molecular diagnostics system.

The platform, which received CE marking in late 2010, is a fully automated and integrated molecular testing system that complements Gen-Probe's Tigris system. A single operator can process 275 samples in eight hours on Panther with hands-on time of less than an hour. For larger customers, Panther can continue running unattended, processing 500 samples in 12 hours.

The platform features primary tube sampling with random access loading for maximum flexibility and productivity. Multiple assays can be run from a single sample, and operators have continuous access to samples, reagents, and consumables.

The company filed for 510(k) clearance from the US Food and Drug Administration to run the Aptima Combo 2.0 assay, a dual test for chlamydia and gonorrhea, on Panther. Gen-Probe also said that it is developing several other qualitative and quantitative assays for the system.