By Ben Butkus
Abbott and Dallas-based Genetics Laboratory are co-developing a molecular test designed to rapidly detect microorganisms that cause orthopedic infections, Abbott said this week.
The companies will develop and commercialize the assay for use on Abbott's Plex-ID automated microbial identification system. Plex-ID is currently intended only for non-diagnostic use, but Abbott and partners are developing additional assays for clinical diagnostic use on the system, particularly in the area of bacterial, viral, and fungal detection in immunocompromised patients, the company told PCR Insider this week.
Abbott launched the Plex-ID system in 2009 as the next-generation version of its Ibis T5000 Biosensor system. The system combines automated sample preparation, PCR amplification, electrospray ionization mass spectrometry, and information management to rapidly characterize known and unknown organisms.
According to Abbott, Plex-ID can identify a broad range of bacteria, viruses, fungi, and certain parasites, and provide information about drug resistance, virulence, and strain type. The platform can also provide test results in six to seven hours instead of three or more days as required with other laboratory methods.
Abbott already has a well-established clinical diagnostics system in the automated m2000 real-time PCR platform. The DNA and RNA testing system comprises the m2000sp module for automated sample extraction preparation and the m2000rt instrument for real-time PCR detection and analysis.
The platform received 510(k) approval from the US Food and Drug Administration in June 2010 along with a combined molecular diagnostic test for chlamydia and gonorrhea. In the US, Abbott also offers real-time tests for hepatitis B, hepatitis C, and HIV-1.
However, Abbott told PCR Insider in an e-mail that the m2000 and Plex-ID complement each other in that the former is ideal for specific, targeted molecular tests, particularly viral infections; while the latter is ideal for situations where the potential target is unknown, which is often the case in bacterial or fungal infections.
"Plex-ID has been designed to respond to the clinical challenge faced on a daily basis: a patient presents with the symptoms of an infection," the company said.
"Traditional approaches, including m2000 and culture, require the clinician to have a hypothesis about what the offending microbe is," the company added. The clinician would then order a specific molecular test such as those offered on the m2000 — tests that can only determine if one of a handful of viruses is present. "So, in fact, viral testing is like asking a series of closed-ended questions: Is X there? Is Y there?" the company said.
On the other hand, if a clinician suspects a bacterial or fungal infection, current gold standard protocols dictate that he or she then send the sample to be cultured or grown in a lab, which can take anywhere between 12 hours and five days.
"Plex-ID transforms infectious disease testing by allowing broad testing or asking open-ended questions," the company said. "Plex-ID responds with actionable information in less than eight hours, [and] … results can then be utilized to initiate, adjust, or alter a patient's therapy. By getting a patient on an effective antimicrobial sooner there is the potential of better patient outcomes and more cost-effective management of the patient."
To take advantage of the platform's abilities, Abbott is developing assays to address clinical scenarios in which the identity of the organism and the presence of a small set of antimicrobial resistance markers could allow treatment to be adjusted to more appropriate antimicrobial agents, the company said.
An example of a population that suffers from a broad spectrum of infectious diseases is the immunocompromised. "Therefore Plex-ID's ability to diagnose a very wide range of pathogens and even multiple pathogens from the same patient sample make it ideally suited" for this population, Abbott said.
"As a result we are creating a suite of assays — viral and fungal, in addition to the broad bacterial assay used for blood," the company added. "These assays will have use beyond this population in other patient groups suffering from serious or hard-to-diagnose infections."
In the case of orthopedic infections, bacteria — particularly antibiotic-resistant species such as methicillin-resistant Staphylococcus aureus — "are very dangerous in orthopedic patients because the bacterial colonies attach to the artificial surfaces of the implants," said Gerhard Maale, an orthopedic oncologic surgeon and expert in orthopedic infections in the Dallas-Ft. Worth area who will also serve as medical director for the Abbott-GenLab collaboration.
Abbott also said that another molecular diagnostic test for the Plex-ID is pending CE Marking in Europe, but it did not disclose the test's target.
Abbott is also marketing Plex-ID for use in applied markets, such as biodefense and forensics. In April 2010, it said that the system was being used for molecular identification and characterization of emerging infectious organisms as part of a biopreparedness evaluation program in collaboration with the Association of Public Health Laboratories and five state public health labs (PCR Insider, 4/5/10).
And last month Abbott said it had entered into an agreement with the University of North Texas Health Science Center to evaluate the platform for use in analyzing human remains to support missing persons and human trafficking investigations (PCR Insider, 2/23/12).
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