By Ben Butkus
Pall this week introduced the GeneDisc Rapid Microbiology System, a quantitative PCR-based system for monitoring microbial contamination in pharmaceutical manufacturing.
The system is intended to provide significant time savings over traditional culture-based microbial monitoring methods by allowing pharmaceutical manufacturers to release materials and final products more quickly, improve efficiency, and reduce inventories, Pall said.
In addition, a marketing executive for the company said that the GeneDisc system is the first qPCR-based platform on the market to simultaneously detect several indicator pathogens as required by the US Pharmacopeia.
Pall acquired the GeneDisc system in 2008 along with French biotech firm GeneSystems. At the time, Pall indicated that it targeted GeneSystems primarily to strengthen its presence in the biopharmaceutical process monitoring market, but also to provide it with new opportunities in the environmental, food and beverage, and water testing markets.
The system has three components: a membrane filtration-based sample prep component for extracting DNA; a consumable plate preloaded with PCR primers and probes for specific microorganisms; and a thermal cycler.
When Pall acquired GeneSystems, the French firm had already developed GeneDisc tests for food, beverage, water, and environmental testing, Maitry Ganatra, global product manager for Pall Biopharmaceuticals, told PCR Insider this week.
But Pall decided to develop a panel specifically for testing microbial contamination in pharmaceutical manufacturing, citing the time and cost savings it could provide for its customers in that area. Specifically, the new GeneDisc plate for Pharmacopeia-specific microorganisms includes primers and probes for testing for E. coli, Salmonella spp., P. aeruginosa, S. aureus, C. albicans, and A. brasiliensis.
"When focusing on pharma, time savings is definitely a big plus, because current testing typically takes anywhere from three to seven days" while the GeneDisc system can provide results in the same day, and even in as little as two hours, Ganatra said.
"What this means for pharmaceutical testing is that … if anything is wrong with the products or samples, you can take action much faster," Ganatra said. "There is always some risk, and there is nothing you can do after seven days. You can go back and resample the batch, which is money and time and labor; or you may have to discard the whole batch. And of course if there is a recall, it's a big damage to the company's reputation."
Another time-saving benefit can occur upon product release, Ganatra said. "When your product is ready, it is usually placed in quarantine until your microbiology results come back. But if you can get those a little faster, you can actually release those products a little faster to the market. So there are cost savings in terms of inventory, warehouse, and a huge benefit in the competing market."
Ganatra underscored GeneDisc's "simplicity," pointing out that all necessary primers and probes are already dried down on the GeneDisc plate, and that Pall provides master mix in a single tube "so you can control any contamination that might occur" during assay implementation.
"The sample prep is really highly simplified," Ganatra said. "You basically add your master mix and purified DNA. And then there is a vacuum step … that causes the sample to automatically flow to the valve, so you have uniform samples without the technician having to add small microliter volumes."
After that, a relatively unskilled technician then places the plate in the GeneDisc cycler and starts the test, Ganatra said. "Also, the cycler is unique because the thermal blocks all remain at a uniform temperature while the disc is rotating. That ensures that all the wells will achieve a uniform temperature, which helps with the reproducibility of the results."
Other companies such as Millipore, Life Technologies' Applied Biosystems business, and BioMérieux also offer various microbial contamination tests, some of which are molecular. Those products, however, are primarily for mycoplasma testing or may not offer the speed and reproducibility of qPCR (PCR Insider 1/28/2010 and 7/8/2010).
"In terms of qPCR, this would be the first test for pharmaceutical purposes," Ganatra said. "When it comes to this specific assay, I think this is a unique product, and there is nothing else out there that I can see."
Pall, too, already offered a product for rapid microbiology testing called the Pallchek. Based on ATP bioluminescence detection, Pallchek was the first system of its type to be used in an approved protocol for microbiological applications in US Food and Drug Administration- and European Medicines Agency-registered drug manufacturing processes, according to the company.
And even though Pallchek is faster than traditional microbial culture methods, the qPCR-based GeneDisc system may still offer even faster and more reproducible results.
Currently, Ganatra said, pharmaceutical manufacturing customers can choose either platform. "The applications are different," she said. "PallCheck is more for presence/absence-type testing, but using PCR, [GeneDisc] has the ability to quantify and, to some extent, identify species based on the primers and the probes used."
Ganatra said that although both platforms are still available, "eventually our focus will be on GeneDisc."
Unlike its competitors, Pall does not yet offer a qPCR-based mycoplasma test for GeneDisc, although Ganatra said "it is in our plans."
In general, Pall said that it plans to develop additional assays for GeneDisc that "will further expand the GeneDisc system to perform accelerated microbiological testing during various stages of pharmaceutical and biotech production."
Thus far, Pall has disclosed that Pfizer has been an early tester of the GeneDisc system, and that one of its scientists plans to present a white paper on its use at the Parenteral Drug Association's Global Conference on Pharmaceutical Microbiology next month in Washington, DC.